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Sample records for biological hydrogen photoproduction

  1. Biological hydrogen photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Nemoto, Y. [Univ. of Miami, FL (United States)

    1995-09-01

    Following are the major accomplishments of the 6th year`s study of biological hydrogen photoproduction which were supported by DOE/NREL. (1) We have been characterizing a biological hydrogen production system using synchronously growing aerobically nitrogen-fixing unicellular cyanobacterium, Synechococcus sp. Miami BG 043511. So far it was necessary to irradiate the cells to produce hydrogen. Under darkness they did not produce hydrogen. However, we found that, if the cells are incubated with oxygen, they produce hydrogen under the dark. Under 80% argon + 20% oxygen condition, the hydrogen production activity under the dark was about one third of that under the light + argon condition. (2) Also it was necessary so far to incubate the cells under argon atmosphere to produce hydrogen in this system. Argon treatment is very expensive and should be avoided in an actual hydrogen production system. We found that, if the cells are incubated at a high cell density and in a container with minimum headspace, it is not necessary to use argon for the hydrogen production. (3) Calcium ion was found to play an important role in the mechanisms of protection of nitrogenase from external oxygen. This will be a clue to understand the reason why the hydrogen production is so resistant to oxygen in this strain. (4) In this strain, sulfide can be used as electron donor for the hydrogen production. This result shows that waste water can be used for the hydrogen production system using this strain.

  2. Biological Systems for Hydrogen Photoproduction (Presentation)

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    Ghirardi, M. L.

    2012-05-01

    This presentation summarizes NREL biological systems for hydrogen photoproduction work for the DOE Hydrogen and Fuel Cells Program Annual Merit Review and Peer Evaluation Meeting, May 14-18, 2012. General goal is develop photobiological systems for large-scale, low cost and efficient H{sub 2} production from water (barriers AH, AI and AJ). Specific tasks are: (1) Address the O{sub 2} sensitivity of hydrogenases that prevent continuity of H{sub 2} photoproduction under aerobic, high solar-to-hydrogen (STH) light conversion efficiency conditions; and (2) Utilize a limited STH H{sub 2}-producing method (sulfur deprivation) as a platform to address or test other factors limiting commercial algal H{sub 2} photoproduction, including low rates due to biochemical and engineering mechanisms.

  3. Biological hydrogen photoproduction

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    Brand, L.E.; Luo, Yao-Hua; Tsuzuki, T. [Univ. of Miami, FL (United States)

    1996-10-01

    The authors maintain a culture collection of over 2,500 cyanobacteria and photosynthetic bacteria and 2,000 eukaryotic algae for research on H{sub 2} biophotoproduction as well as other projects. A high H{sub 2}-producing strain Synechococcus sp. Miami BG 043511 from the collection has been used to examine H{sub 2} production in relation to water photolysis and substance degradation, high O{sub 2}-tolerance characterization of nitrogenase, and interactive effects of light intensity and cell density on H{sub 2} production and its stable isotope fractionation. When cellular carbohydrate is depleted, no H{sub 2} production occurs. However, when pyruvate or glucose is added, H{sub 2} production begins. On the other hand, when glucose and DCMU are added to cellular carbohydrate-depleted cells from synchronous cultures, H{sub 2} production is inhibited compared with that with glucose addition alone. These results indicate that water photolysis alone cannot directly induce H{sub 2} production, but it acts together with cellular glucose degradation to enhance H{sub 2} production. The cyanobacteria strain, unlike unicellular green algae, shows no significant difference in H{sub 2} evolution with or without O{sub 2} removal reagent (Fieser`s solution: sodium dithionite/sodium anthraquinon-{beta}-sulfonate/KOH water solution) treated. When 10-hr cells are incubated in the dark with injected O{sub 2}, H{sub 2} evolution is induced, accompanied by O{sub 2} consumption. When zero-hr cells of synchronous cultures are incubated with 5% CO{sub 2}, the carbon is assimilated under light and O{sub 2} accumulates. Even when cells are under aerobic conditions with 25 {mu}mol O{sub 2}/Mg dry wt., H{sub 2} production is still induced, comparable with that under anaerobic conditions. The H{sub 2}-light curve has a pattern similar to CO{sub 2}-light curves, the light saturation point increasing, and the magnitude of H{sub 2} accumulation decreasing, with increasing cell density.

  4. Photoproduction of molecular hydrogen by a plant-algal symbiotic system

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    Newton, J.W.

    1976-02-13

    The rapidly growing water fern Azolla, which contains a nitrogen-fixing blue-green algal symbiont, has been studied as a possible system for photoproduction of molecular hydrogen. When this plant is grown on a combined nitrogen supply, photochemically generated hydrogen can be diverted through the algal nitrogenase system, which serves as a source of molecular hydrogen generated from water. This symbiosis has several advantages as a possible biological energy conversion system. (auth)

  5. Enhanced hydrogen photoproduction by non-heterocystous cyanobacterium Plectonema boryanum

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    Kashyap, A.K.; Pandey, K.D.; Sarkar, S. [Banaras Hindu Univ., Varanasi (India). Centre of Advanced Study in Botany

    1996-02-01

    Nitrogenase activity was depressed in Plectonema boryanum following 18-24 h of microaerobic incubation. The cyanobacterium evolved hydrogen at a slow rate. Addition of reducing substances (sulfide, sulfite or dithionite) to the diazotrophic cultures resulted in an increase in nitrogenase activity or photoproduction of hydrogen. The reducing substances also restored phycocyanin degradation. (author)

  6. Significant Increase in Hydrogen Photoproduction Rates and Yields by Wild-Type Algae is Detected at High Photobioreactor Gas Phase Volume (Fact Sheet)

    Energy Technology Data Exchange (ETDEWEB)

    2012-07-01

    This NREL Hydrogen and Fuel Cell Technical Highlight describes how hydrogen photoproduction activity in algal cultures can be improved dramatically by increasing the gas-phase to liquid-phase volume ratio of the photobioreactor. NREL, in partnership with subcontractors from the Institute of Basic Biological Problems in Pushchino, Russia, demonstrated that the hydrogen photoproduction rate in algal cultures always decreases exponentially with increasing hydrogen partial pressure above the culture. The inhibitory effect of high hydrogen concentrations in the photobioreactor gas phase on hydrogen photoproduction by algae is significant and comparable to the effect observed with some anaerobic bacteria.

  7. Improved hydrogen photoproduction from photosynthetic bacteria and green algae

    Energy Technology Data Exchange (ETDEWEB)

    Weaver, P.F.; Lien, S.; Seibert, M.

    1979-01-01

    Photosynthetic bacteria evolve hydrogen at much higher rates than do other classes of photosynthetic microorganisms. In addition, they tolerate harsh environments, grow rapidly, and utilize both visible and near infrared light in photosynthesis. They do not split water, but this does not necessarily eliminate their potential use in future applied systems. They are easily manipulated genetically, and thus might be modified to metabolize common biomass waste materials in place of expensive defined organic substrates. Furthermore, the potential for increasing hydrogen photoproduction via genetic techniques is promising. Strains that partially degrade cellulose, have high photoproduction rates, or contain very large amounts of the enzymes associated with hydrogen metabolism have been isolated. Green algae also produce hydrogen but are capable of using water as a substrate. For example, C. reinhardi can evolve hydrogen and oxygen at a molar ratio approaching 2:1. Based upon effect of dichlorophenyl dimethylurea (a specific inhibitor of photosystem II, PSII) on hydrogen photoproduction in the wild type strain and upon results obtained with PSII mutants, one can demonstrate that water is the major source of electrons for hydrogen production. The potential efficiency of in vivo coupling between hydrogenase and the photosynthetic electron transport system is high. Up to 76% of the reductants generated by the electron transport system can be channeled directly to the enzyme for in vivo hydrogen production. Rates exceeding 170 ..mu..moles of H/sub 2/ mg Chl/sup -1/ hr/sup -1/ have been observed.

  8. Sustainable hydrogen photoproduction by phosphorus-deprived marine green microalgae Chlorella sp.

    Science.gov (United States)

    Batyrova, Khorcheska; Gavrisheva, Anastasia; Ivanova, Elena; Liu, Jianguo; Tsygankov, Anatoly

    2015-01-01

    Previously it has been shown that green microalga Chlamydomonas reinhardtii is capable of prolonged H2 photoproduction when deprived of sulfur. In addition to sulfur deprivation (-S), sustained H2 photoproduction in C. reinhardtii cultures can be achieved under phosphorus-deprived (-P) conditions. Similar to sulfur deprivation, phosphorus deprivation limits O2 evolving activity in algal cells and causes other metabolic changes that are favorable for H2 photoproduction. Although significant advances in H2 photoproduction have recently been realized in fresh water microalgae, relatively few studies have focused on H2 production in marine green microalgae. In the present study phosphorus deprivation was applied for hydrogen production in marine green microalgae Chlorella sp., where sulfur deprivation is impossible due to a high concentration of sulfates in the sea water. Since resources of fresh water on earth are limited, the possibility of hydrogen production in seawater is more attractive. In order to achieve H2 photoproduction in P-deprived marine green microalgae Chlorella sp., the dilution approach was applied. Cultures diluted to about 0.5-1.8 mg Chl·L-1 in the beginning of P-deprivation were able to establish anaerobiosis, after the initial growth period, where cells utilize intracellular phosphorus, with subsequent transition to H2 photoproduction stage. It appears that marine microalgae during P-deprivation passed the same stages of adaptation as fresh water microalgae. The presence of inorganic carbon was essential for starch accumulation and subsequent hydrogen production by microalgae. The H2 accumulation was up to 40 mL H2 gas per 1iter of the culture, which is comparable to that obtained in P-deprived C. reinhardtii culture. PMID:25629229

  9. Sustainable Hydrogen Photoproduction by Phosphorus-Deprived Marine Green Microalgae Chlorella sp.

    Directory of Open Access Journals (Sweden)

    Khorcheska Batyrova

    2015-01-01

    Full Text Available Previously it has been shown that green microalga Chlamydomonas reinhardtii is capable of prolonged H2 photoproduction when deprived of sulfur. In addition to sulfur deprivation (-S, sustained H2 photoproduction in C. reinhardtii cultures can be achieved under phosphorus-deprived (-P conditions. Similar to sulfur deprivation, phosphorus deprivation limits O2 evolving activity in algal cells and causes other metabolic changes that are favorable for H2 photoproduction. Although significant advances in H2 photoproduction have recently been realized in fresh water microalgae, relatively few studies have focused on H2 production in marine green microalgae. In the present study phosphorus deprivation was applied for hydrogen production in marine green microalgae Chlorella sp., where sulfur deprivation is impossible due to a high concentration of sulfates in the sea water. Since resources of fresh water on earth are limited, the possibility of hydrogen production in seawater is more attractive. In order to achieve H2 photoproduction in P-deprived marine green microalgae Chlorella sp., the dilution approach was applied. Cultures diluted to about 0.5–1.8 mg Chl·L−1 in the beginning of P-deprivation were able to establish anaerobiosis, after the initial growth period, where cells utilize intracellular phosphorus, with subsequent transition to H2 photoproduction stage. It appears that marine microalgae during P-deprivation passed the same stages of adaptation as fresh water microalgae. The presence of inorganic carbon was essential for starch accumulation and subsequent hydrogen production by microalgae. The H2 accumulation was up to 40 mL H2 gas per 1iter of the culture, which is comparable to that obtained in P-deprived C. reinhardtii culture.

  10. A comparison of hydrogen photoproduction by sulfur-deprived Chlamydomonas reinhardtii under different growth conditions.

    Science.gov (United States)

    Kosourov, Sergey; Patrusheva, Elena; Ghirardi, Maria L; Seibert, Michael; Tsygankov, Anatoly

    2007-03-10

    Continuous photoproduction of H(2) by the green alga, Chlamydomonas reinhardtii, is observed after incubating the cultures for about a day in the absence of sulfate and in the presence of acetate. Sulfur deprivation causes the partial and reversible inactivation of photosynthetic O(2) evolution in algae, resulting in the light-induced establishment of anaerobic conditions in sealed photobioreactors, expression of two [FeFe]-hydrogenases in the cells, and H(2) photoproduction for several days. We have previously demonstrated that sulfur-deprived algal cultures can produce H(2) gas in the absence of acetate, when appropriate experimental protocols were used (Tsygankov, A.A., Kosourov, S.N., Tolstygina, I.V., Ghirardi, M.L., Seibert, M., 2006. Hydrogen production by sulfur-deprived Chlamydomonas reinhardtii under photoautotrophic conditions. Int. J. Hydrogen Energy 31, 1574-1584). We now report the use of an automated photobioreactor system to compare the effects of photoautotrophic, photoheterotrophic and photomixotrophic growth conditions on the kinetic parameters associated with the adaptation of the algal cells to sulfur deprivation and H(2) photoproduction. This was done under the experimental conditions outlined in the above reference, including controlled pH. From this comparison we show that both acetate and CO(2) are required for the most rapid inactivation of photosystem II and the highest yield of H(2) gas production. Although, the presence of acetate in the system is not critical for the process, H(2) photoproduction under photoautotrophic conditions can be increased by optimizing the conditions for high starch accumulation. These results suggest ways of engineering algae to improve H(2) production, which in turn may have a positive impact on the economics of applied systems for H(2) production. PMID:17275940

  11. Biological hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Benemann, J.R. [Univ. of California, Berkeley, CA (United States)

    1995-11-01

    Biological hydrogen production can be accomplished by either thermochemical (gasification) conversion of woody biomass and agricultural residues or by microbiological processes that yield hydrogen gas from organic wastes or water. Biomass gasification is a well established technology; however, the synthesis gas produced, a mixture of CO and H{sub 2}, requires a shift reaction to convert the CO to H{sub 2}. Microbiological processes can carry out this reaction more efficiently than conventional catalysts, and may be more appropriate for the relatively small-scale of biomass gasification processes. Development of a microbial shift reaction may be a near-term practical application of microbial hydrogen production.

  12. Biological activity of photoproducts of merocyanine 540 generated by laser-light activation

    Science.gov (United States)

    Gulliya, Kirpal S.; Chanh, Tran C.; Pervaiz, Shazib; Harriman, Anthony; Matthews, James Lester

    1992-08-01

    Controlled exposure of photoactive compounds to light prior to their use in biological targets results in the formation of heretofore unknown photoproducts. This process of photoproduct generation, termed "preactivation," renders the photactive compound capable of systemic use without further dependence on light. Preactivation of mercyanin 540 (MC540) and several other photoactive compounds is achievable by exposure to CW and pulse laser radiation. The singlet oxygen generated at excited states attacks the dye molucule itself, resulting in the formation of biologically active photoproducts. For preactivated MC540 (photoproducts of MC540) generated by exposure to argon laser light (514 nm) and light from free-electron laser, we have demonstrated its effectiveness in selective killing of certain types of cultured tumor cells as well as human immunodeficiency virus type 1 (HIV-1) with very low, if any, damage to normal cells and tisues. For example, approximately 90% of the Burkitt's lymphoma Daudi cells and HL-60 leukemic cells are killed by preactivated MC540 at a concentration of 120 μg/ml. A two-hour treatment of cultured cells with buthionine sulfoxamine followed by the treatement with preactivated MC540 reults in 99.99% inhibition of clonogenic tumor stem cell growth. We also have demonstrated that preactivated MC540 is very effective in killing cell-free and cell-associated HIV-1. It also is very effective in killing HIV-1 and simian immunodeficiency virus (SIV) in virus-infected blood in vitro as determined by reverse transcriptase, P24, P17, core antigen expression and synctium formation. Treatment of HIV-1 with preactivated MC540 renders the treated HIV-1 incapable of binding to CD4 target molecules on T cells as determined by immunofluorescence and radioimmunoprecipitation assays. In vivo toxicology studies show that preactivated MC540 is very well tolerated and does not produce any signs of adverse reaction at the therapeutic doses, as determined by

  13. Plastidial Expression of Type II NAD(P)H Dehydrogenase Increases the Reducing State of Plastoquinones and Hydrogen Photoproduction Rate by the Indirect Pathway in Chlamydomonas reinhardtii1.

    Science.gov (United States)

    Baltz, Anthony; Dang, Kieu-Van; Beyly, Audrey; Auroy, Pascaline; Richaud, Pierre; Cournac, Laurent; Peltier, Gilles

    2014-05-12

    Biological conversion of solar energy into hydrogen is naturally realized by some microalgae species due to a coupling between the photosynthetic electron transport chain and a plastidial hydrogenase. While promising for the production of clean and sustainable hydrogen, this process requires improvement to be economically viable. Two pathways, called direct and indirect photoproduction, lead to sustained hydrogen production in sulfur-deprived Chlamydomonas reinhardtii cultures. The indirect pathway allows an efficient time-based separation of O2 and H2 production, thus overcoming the O2 sensitivity of the hydrogenase, but its activity is low. With the aim of identifying the limiting step of hydrogen production, we succeeded in overexpressing the plastidial type II NAD(P)H dehydrogenase (NDA2). We report that transplastomic strains overexpressing NDA2 show an increased activity of nonphotochemical reduction of plastoquinones (PQs). While hydrogen production by the direct pathway, involving the linear electron flow from photosystem II to photosystem I, was not affected by NDA2 overexpression, the rate of hydrogen production by the indirect pathway was increased in conditions, such as nutrient limitation, where soluble electron donors are not limiting. An increased intracellular starch was observed in response to nutrient deprivation in strains overexpressing NDA2. It is concluded that activity of the indirect pathway is limited by the nonphotochemical reduction of PQs, either by the pool size of soluble electron donors or by the PQ-reducing activity of NDA2 in nutrient-limited conditions. We discuss these data in relation to limitations and biotechnological improvement of hydrogen photoproduction in microalgae. PMID:24820024

  14. The involvement of carbohydrate reserves in hydrogen photoproduction by the green alga Chlamydomonas reinhardtii

    International Nuclear Information System (INIS)

    The unicellular green alga Chlamydomonas reinhardtii is able to produce hydrogen, using water as an electron donor, and sunlight as an energy source. Although this property offers interesting biotechnological perspectives, a major limitation is related to the sensitivity of hydrogenase to oxygen which is produced by photosynthesis. It had been previously shown that in conditions of sulfur deprivation, C. reinhardtii is able to produce hydrogen during several days (Melis et an. 2000). During this process, two pathways, one direct depending on photosystem II (PSII) activity and the other involving only the PSI, are involved, starch reserves being supposed to play a role in both of these pathways. The purpose of this phD thesis was to elucidate the mechanisms linking starch catabolism to the hydrogen photoproduction process. Firstly, the analysis of mutants affected in starch biosynthesis (sta6 and sta7) showed that if starch reserves are essential to the functioning of the indirect pathway, they are not involved in the direct one. Secondly, in order to identify metabolic steps and regulatory processes involved in starch breakdown, we developed a genetic approach based on the search of mutants affected in starch reserves mobilization. Eight mutant (std1 to std8) diversely affected in their ability to degrade starch after an accumulation phase have been isolated from an insertional mutant library of 15,000 clones. One of these mutants, std1, is affected in a kinase related to the DYRK family (dual-specificity tyrosine regulated serine threonine kinase). Although the targets of this putative kinase remain to be identified, the analysis of the granule bound proteome displayed profound alterations in the expression profile of starch phosphorylases, potentially involved in starch breakdown. STD1 represents the first starch catabolism regulator identified to date in plants. (author)

  15. Enhanced photoproduction of hydrogen peroxide by humic substances in the presence of phenol electron donors.

    Science.gov (United States)

    Zhang, Yi; Simon, Kelli A; Andrew, Andrea A; Del Vecchio, Rossana; Blough, Neil V

    2014-11-01

    Addition of a series of phenol electron donors to solutions of humic substances (HS) enhanced substantially the initial rates of hydrogen peroxide (H2O2) photoproduction (RH2O2), with enhancement factors (EF) ranging from a low of ∼3 for 2,4,6-trimethylphenol (TMP) to a high of ∼15 for 3,4-dimethoxyphenol (DMOP). The substantial inhibition of the enhanced RH2O2 following borohydride reduction of the HS, as well as the dependence of RH2O2 on phenol and dioxygen concentrations are consistent with a mechanism in which the phenols react with the triplet excited states of (aromatic) ketones within the HS to form initially a phenoxy and ketyl radical. The ketyl radical then reacts rapidly with dioxygen to regenerate the ketone and form superoxide (O2-), which subsequently dismutates to H2O2. However, as was previously noted for the photosensitized loss of TMP, the incomplete inhibition of the enhanced RH2O2 following borohydride reduction suggests that there may remain another pool of oxidizing triplets. The results demonstrate that H2O2 can be generated through an additional pathway in the presence of sufficiently high concentrations of appropriate electron donors through reaction with the excited triplet states of aromatic ketones and possibly of other species such as quinones. However, in some cases, the much lower ratio of H2O2 produced to phenol consumed suggests that secondary reactions could alter this ratio significantly.

  16. Control of Hydrogen Photoproduction by the Proton Gradient Generated by Cyclic Electron Flow in Chlamydomonas reinhardtii[W

    Science.gov (United States)

    Tolleter, Dimitri; Ghysels, Bart; Alric, Jean; Petroutsos, Dimitris; Tolstygina, Irina; Krawietz, Danuta; Happe, Thomas; Auroy, Pascaline; Adriano, Jean-Marc; Beyly, Audrey; Cuiné, Stéphan; Plet, Julie; Reiter, Ilja M.; Genty, Bernard; Cournac, Laurent; Hippler, Michael; Peltier, Gilles

    2011-01-01

    Hydrogen photoproduction by eukaryotic microalgae results from a connection between the photosynthetic electron transport chain and a plastidial hydrogenase. Algal H2 production is a transitory phenomenon under most natural conditions, often viewed as a safety valve protecting the photosynthetic electron transport chain from overreduction. From the colony screening of an insertion mutant library of the unicellular green alga Chlamydomonas reinhardtii based on the analysis of dark-light chlorophyll fluorescence transients, we isolated a mutant impaired in cyclic electron flow around photosystem I (CEF) due to a defect in the Proton Gradient Regulation Like1 (PGRL1) protein. Under aerobiosis, nonphotochemical quenching of fluorescence (NPQ) is strongly decreased in pgrl1. Under anaerobiosis, H2 photoproduction is strongly enhanced in the pgrl1 mutant, both during short-term and long-term measurements (in conditions of sulfur deprivation). Based on the light dependence of NPQ and hydrogen production, as well as on the enhanced hydrogen production observed in the wild-type strain in the presence of the uncoupling agent carbonyl cyanide p-trifluoromethoxyphenylhydrazone, we conclude that the proton gradient generated by CEF provokes a strong inhibition of electron supply to the hydrogenase in the wild-type strain, which is released in the pgrl1 mutant. Regulation of the trans-thylakoidal proton gradient by monitoring pgrl1 expression opens new perspectives toward reprogramming the cellular metabolism of microalgae for enhanced H2 production. PMID:21764992

  17. Biological hydrogen production from phytomass

    Energy Technology Data Exchange (ETDEWEB)

    Bartacek, J.; Zabranska, J. [Inst. of Chemical Technology, Prague (Czech Republic). Dept. of Water Technology and Environmental Engineering

    2004-07-01

    Renewable sources of energy have received wide attention lately. One candidate is hydrogen which has the added advantage of involving no greenhouse gases. Biological hydrogen production from wastewater or biowastes is a very attractive production technique. So far, most studies have concentrated on the use of photosynthetic bacteria. However, dark fermentation has recently become a popular topic of research as it has the advantage of not requiring light energy input, something that limits the performance of the photosynthetic method. While pure cultures have been used in most of the investigations to date, in industrial situations mixed cultures will probably be the norm because of unavoidable contamination. In this investigation the phytomass of amaranth (Amaranthus cruentus L) was used to produce hydrogen. Specific organic loading, organic loading, and pH were varied to study the effect on hydrogen production. 18 refs., 1 tab., 6 figs.

  18. Autotrophic hydrogen photoproduction by operation of carbon-concentrating mechanism in Chlamydomonas reinhardtii under sulfur deprivation condition.

    Science.gov (United States)

    Hong, Min Eui; Shin, Ye Sol; Kim, Byung Woo; Sim, Sang Jun

    2016-03-10

    Under autotrophic conditions, starch plays an important role in establishing anoxic conditions during PSII-dependent hydrogen (H2) photoproduction in microalgae. This is because starch is the sole organic substrate during respiratory consumption of internal oxygen (O2) from PSII-dependent direct pathway. Herein, we propose a novel approach to further facilitate the internal starch synthesis of Chlamydomonas reinhardtii through the operation of carbon-concentrating mechanism (CCM) along with a two-stage process based on sulfur (S) deprivation, thereby resulting in enhanced anaerobic capacity during PSII-dependent H2 photoproduction. When CCM-induced cells were exposed to high levels of carbon dioxide (CO2) (5%, v/v) with S deprivation, internal levels of starch were significantly elevated by retaining a functional CCM with the boosted photosynthetic activity during 24h of O2 evolution phase (I) of S deprivation. Consequently, during H2 production phase of S deprivation at irradiance of 50μEm(-2)s(-1), the concentrations of starch and H2 in CCM-induced cells were remarkably enhanced by 65.0% and 218.9% compared to that of CCM-uninduced cells, respectively. The treatment of low-CO2-driven CCM induction prior to S deprivation is a cost-effective and energy-efficient strategy that significantly improves the solar-driven H2 production by microalgae; this is particularly realizable in an industrial scale. PMID:26812657

  19. Biologically labile photoproducts from riverine non-labile dissolved organic carbon in the coastal waters

    Directory of Open Access Journals (Sweden)

    V. Kasurinen

    2015-06-01

    Full Text Available In order to assess the production of biologically labile photoproducts (BLPs from non-labile riverine dissolved organic carbon (DOC, we collected water samples from ten major rivers, removed labile DOC and mixed the residual non-labile DOC with artificial seawater for microbial and photochemical experiments. Bacteria grew on non-labile DOC with a growth efficiency of 11.5% (mean; range from 3.6 to 15.3%. Simulated solar radiation transformed a part of non-labile DOC into BLPs, which stimulated bacterial respiration and production, but did not change bacterial growth efficiency (BGE compared to the non-irradiated dark controls. In the irradiated water samples, the amount of BLPs stimulating bacterial production depended on the photochemical bleaching of chromophoric dissolved organic matter (CDOM. The apparent quantum yields for BLPs supporting bacterial production ranged from 9.5 to 76 (mean 39 (μmol C mol photons−1 at 330 nm. The corresponding values for BLPs supporting bacterial respiration ranged from 57 to 1204 (mean 320 (μmol C mol photons−1. According to the calculations based on spectral apparent quantum yields and local solar radiation, the annual production of BLPs ranged from 21 (St. Lawrence to 584 (Yangtze mmol C m−2 yr−1 in the plumes of the examined rivers. Complete photobleaching of riverine CDOM in the coastal ocean was estimated to produce 10.7 Mt C BLPs yr−1 from the rivers examined in this study and globally 38 Mt yr−1 (15% of riverine DOC flux from all rivers, which support 4.1 Mt yr−1 of bacterial production and 33.9 Mt yr−1 bacterial respiration.

  20. Plastidial Expression of Type II NAD(P)H Dehydrogenase Increases the Reducing State of Plastoquinones and Hydrogen Photoproduction Rate by the Indirect Pathway in Chlamydomonas reinhardtii1[W][OPEN

    Science.gov (United States)

    Baltz, Anthony; Dang, Kieu-Van; Beyly, Audrey; Auroy, Pascaline; Richaud, Pierre; Cournac, Laurent; Peltier, Gilles

    2014-01-01

    Biological conversion of solar energy into hydrogen is naturally realized by some microalgae species due to a coupling between the photosynthetic electron transport chain and a plastidial hydrogenase. While promising for the production of clean and sustainable hydrogen, this process requires improvement to be economically viable. Two pathways, called direct and indirect photoproduction, lead to sustained hydrogen production in sulfur-deprived Chlamydomonas reinhardtii cultures. The indirect pathway allows an efficient time-based separation of O2 and H2 production, thus overcoming the O2 sensitivity of the hydrogenase, but its activity is low. With the aim of identifying the limiting step of hydrogen production, we succeeded in overexpressing the plastidial type II NAD(P)H dehydrogenase (NDA2). We report that transplastomic strains overexpressing NDA2 show an increased activity of nonphotochemical reduction of plastoquinones (PQs). While hydrogen production by the direct pathway, involving the linear electron flow from photosystem II to photosystem I, was not affected by NDA2 overexpression, the rate of hydrogen production by the indirect pathway was increased in conditions, such as nutrient limitation, where soluble electron donors are not limiting. An increased intracellular starch was observed in response to nutrient deprivation in strains overexpressing NDA2. It is concluded that activity of the indirect pathway is limited by the nonphotochemical reduction of PQs, either by the pool size of soluble electron donors or by the PQ-reducing activity of NDA2 in nutrient-limited conditions. We discuss these data in relation to limitations and biotechnological improvement of hydrogen photoproduction in microalgae. PMID:24820024

  1. The involvement of carbohydrate reserves in hydrogen photoproduction by the green alga Chlamydomonas reinhardtii; L'implication des reserves carbonees dans la photoproduction d'hydrogene chez l'algue verte Chlamydomonas reinhardtii

    Energy Technology Data Exchange (ETDEWEB)

    Chochois, V.

    2009-09-15

    The unicellular green alga Chlamydomonas reinhardtii is able to produce hydrogen, using water as an electron donor, and sunlight as an energy source. Although this property offers interesting biotechnological perspectives, a major limitation is related to the sensitivity of hydrogenase to oxygen which is produced by photosynthesis. It had been previously shown that in conditions of sulfur deprivation, C. reinhardtii is able to produce hydrogen during several days (Melis et an. 2000). During this process, two pathways, one direct depending on photosystem II (PSII) activity and the other involving only the PSI, are involved, starch reserves being supposed to play a role in both of these pathways. The purpose of this phD thesis was to elucidate the mechanisms linking starch catabolism to the hydrogen photoproduction process. Firstly, the analysis of mutants affected in starch biosynthesis (sta6 and sta7) showed that if starch reserves are essential to the functioning of the indirect pathway, they are not involved in the direct one. Secondly, in order to identify metabolic steps and regulatory processes involved in starch breakdown, we developed a genetic approach based on the search of mutants affected in starch reserves mobilization. Eight mutant (std1 to std8) diversely affected in their ability to degrade starch after an accumulation phase have been isolated from an insertional mutant library of 15,000 clones. One of these mutants, std1, is affected in a kinase related to the DYRK family (dual-specificity tyrosine regulated serine threonine kinase). Although the targets of this putative kinase remain to be identified, the analysis of the granule bound proteome displayed profound alterations in the expression profile of starch phosphorylases, potentially involved in starch breakdown. STD1 represents the first starch catabolism regulator identified to date in plants. (author)

  2. Increased hydrogen photoproduction by means of a sulfur-deprived chlamydomonas reinhardtii D1 protein mutant

    Energy Technology Data Exchange (ETDEWEB)

    Torzillo, Giuseppe; Scoma, Alberto; Faraloni, Cecilia; Ena, Alba [Istituto per lo Studio degli Ecosistemi (ISE), CNR, via Madonna del Piano 10, 50019 Sesto Fiorentino (FI) (Italy); Johanningmeier, Udo [Martin-Luther-Universitaet Halle-Wittenberg, Institut fuer Pflanzenphysiologie, Halle-Saale (Germany)

    2009-05-15

    The photoproduction of H{sub 2} was studied in a sulfur-deprived Chlamydomonas reinhardtii D1 mutant that carried a double amino acid substitution. The leucine residue L159 was replaced by isoleucine, and the asparagine N230 was replaced by tyrosine (L159I-N230Y). Phenotypic characterization of the mutant showed some interesting features compared to its wild type, namely: (1) a lower chlorophyll content; (2) a higher photosynthetic capacity and higher relative quantum yield of photosynthesis; (3) a higher respiration rate; (4) a very high conversion of violaxanthin to zeaxanthin during H{sub 2} production; (5) a prolonged period of H{sub 2} production. In standard conditions, the mutant produced more than 500 ml of H{sub 2}, that is, more than one order of magnitude greater than its wild type, and about 5-times greater than the CC124 strain that was used for comparison. The better performance of the mutant was mainly the result of a longer production period. Biogas produced contained up to 99.5% H{sub 2}. (author)

  3. Hydrogen photoproduction by filamentous non-heterocystous cyanobacterium Plectonema boryanum and simultaneous release of ammonia

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, S.; Pandey, K.D.; Kashyap, A.K. (Banaras Hindu Univ., Varanasi (India))

    1992-09-01

    Plectonema boryanum (filamentous, non-heterocystous cyanobacterium) photoproduced H[sub 2] when cells grown aerobically in nitrate were transferred to microaerobic or anaerobic conditions without nitrate. It was observed that H[sub 2] photoproducing cells simultaneously excreted ammonium in the medium, which was possibly due to phycocyanin degradation. Although nitrogenase (measured as H[sub 2] evolution) was induced in Ar:CO[sub 2] (96:4 v/v), inclusion of N[sub 2] in the gas phase (Ar:CO[sub 2]:N[sub 2], 72:4:24 v/v) resulted in a 2-fold increase in H[sub 2] evolution. Addition of L-methionine DL-sulphoximine (MSX), besides stimulating ammonium excretion in the medium, resulted in a 4.5-fold increment of H[sub 2] photoproduction in comparison to cells in Ar:CO[sub 2] gas phase. Inhibition of photosystem II by 3(3,4-dichlorophenyl)1,1-dimethyl urea (DCMU) caused an increment of 1.6 and 3.2-fold in Ar:CO[sub 2] and Ar:CO[sub 2]:N[sub 2], respectively, in comparison to cells incubated in Ar:CO[sub 2] gas phase alone. Simultaneous production of H[sub 2] and NH[sub 4][sup +] was at a maximum when MSX and DCMU were added together in suboptical concentrations. Immobilization of cells in calcium alginate prolonged the duration (12 days) of H[sub 2] evolution and NH[sub 4][sup +] excretion. (author)

  4. Dephenolization of stored olive-mill wastewater, using four different adsorbing matrices to attain a low-cost feedstock for hydrogen photo-production.

    Science.gov (United States)

    Padovani, Giulia; Pintucci, Cristina; Carlozzi, Pietro

    2013-06-01

    This investigation deals with the conversion of olive-mill wastewater (OMW) into several feedstocks suitable for hydrogen photo-production. The goal was reached by means of two sequential steps: (i) a pre-treatment process of stored-OMW for the removal of polyphenols, which made it possible to obtain several effluents, and (ii) a photo-fermentative process for hydrogen production by means of Rhodopseudomonas palustris sp. Four different adsorbent matrices (Azolla, granular active carbon, resin, and zeolite) were used to dephenolize stored-OMW. The four liquid fractions attained by using the above process created the same number of effluents, and these were diluted with water and then used for hydrogen photo-production. The maximum hydrogen production rate (14.31 mL/L/h) was attained with the photo-fermenter containing 25% of the effluent, which came from the pre-treatment of stored-OMW using granular active carbon. Using the carbon effluent as feedstock, the greatest light conversion efficiency of 2.29% was achieved. PMID:23612177

  5. New biologically active hydrogen sulfide donors.

    Science.gov (United States)

    Roger, Thomas; Raynaud, Francoise; Bouillaud, Frédéric; Ransy, Céline; Simonet, Serge; Crespo, Christine; Bourguignon, Marie-Pierre; Villeneuve, Nicole; Vilaine, Jean-Paul; Artaud, Isabelle; Galardon, Erwan

    2013-11-25

    Generous donors: The dithioperoxyanhydrides (CH3 COS)2 , (PhCOS)2 , CH3 COSSCO2 Me and PhCOSSCO2 Me act as thiol-activated hydrogen sulfide donors in aqueous buffer solution. The most efficient donor (CH3 COS)2 can induce a biological response in cells, and advantageously replace hydrogen sulfide in ex vivo vascular studies. PMID:24115650

  6. Photoproduction of hydrogen peroxide in aqueous solution from model compounds for chromophoric dissolved organic matter (CDOM)

    International Nuclear Information System (INIS)

    Highlights: • CDOM produces hydrogen peroxide in sunlit surface waters. • Quinone moieties have been proposed as the photo-active chromophore in CDOM. • Hydrogen peroxide is produced in irradiated aqueous quinone solutions. • Concentrations and production rates are comparable to humic and fulvic acids. • Optical properties post-irradiation were similar to CDOM. - Abstract: To explore whether quinone moieties are important in chromophoric dissolved organic matter (CDOM) photochemistry in natural waters, hydrogen peroxide (H2O2) production and associated optical property changes were measured in aqueous solutions irradiated with a Xenon lamp for CDOM model compounds (dihydroquinone, benzoquinone, anthraquinone, napthoquinone, ubiquinone, humic acid HA, fulvic acid FA). All compounds produced H2O2 with concentrations ranging from 15 to 500 μM. Production rates were higher for HA vs. FA (1.32 vs. 0.176 mM h−1); values ranged from 6.99 to 0.137 mM h−1 for quinones. Apparent quantum yields (Θapp; measure of photochemical production efficiency) were higher for HA vs. FA (0.113 vs. 0.016) and ranged from 0.0018 to 0.083 for quinones. Dihydroquinone, the reduced form of benzoquinone, had a higher production rate and efficiency than its oxidized form. Post-irradiation, quinone compounds had absorption spectra similar to HA and FA and 3D-excitation–emission matrix fluorescence spectra (EEMs) with fluorescent peaks in regions associated with CDOM

  7. The microalga Chlamydomonas reinhardtii CW-15 as a solar cell for hydrogen peroxide photoproduction. Comparison between free and immobilized cells and thylakoids for energy conversion efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Scholz, W.; Galvan, F.; Rosa, F.F. de la [Instituto de Bioquimica Vegetal y Fotosintesis, Universidad de Sevilla y CSIC, Sevilla (Spain)

    1995-11-28

    Immobilized cells and thylakoid vesicles of the microalga Chlamydomonas reinhardtii CW-15 have been developed as a solar cell because of their capabilities of producing hydrogen peroxide. This compound is an efficient and clean fuel used for rocket propulsion, motors and for heating. Hydrogen peroxide is produced by the photosystem in a catalyst cycle in which a redox mediator (methyl viologen) is reduced by electrons obtained from water by the photosynthetic apparatus of the microalga and it is re-oxidized by the oxygen dissolved in the solution. The photoproduction has been investigated using a discontinuous system with whole cells, or thylakoid vesicles, free or immobilized on alginate. The stimulation by azide as an inhibitor of catalase has also been analyzed. Under determined optimum conditions, the photoproduction by Ca-alginate entrapped cells, with a rate of 33 {mu}mol H{sub 2}O{sub 2}/mg Chl.h, was maintained for several hours with an energy conversion efficiency of 0.25%

  8. Hydrogen peroxide and superoxide photoproduction in diverse marine waters: A simple proxy for estimating direct CO2 photochemical fluxes

    Science.gov (United States)

    Powers, Leanne C.; Miller, William L.

    2015-09-01

    The photoproduction of H2O2 and CO2 exhibits a well-defined relationship with an average CO2:H2O2 molar ratio of 6.6 ± 1.8 as determined in a variety of marine waters ranging from a dark tidal creek to clear offshore stations near the Gulf Stream. Even when corrected for photobleaching, accumulation of both H2O2 and CO2 was not linear beyond 12 h of constant irradiation, with interval rates indicating that production efficiency for both products decreased with increasing photon dose. Direct measurements of O2- photoproduction, together with its dark thermal decay to H2O2, indicate that O2- may be the better proxy for photochemical dissolved organic matter oxidation to CO2. Given the very short irradiation times needed to determine O2- production rates (~2-5 min), determination of O2- photoproduction may provide robust estimates for initial CO2 photoproduction rates even in blue water, allowing greatly improved estimates for the global significance of dissolved organic carbon photooxidation.

  9. Maximizing the Hydrogen Photoproduction Yields in Chlamydomonas Reinhardtii Cultures: The Effect of the H2 Partial Pressure

    Energy Technology Data Exchange (ETDEWEB)

    Kosourov, S. N.; Batyrova, K. A.; Petushkova, E. P.; Tsygankov, A. A.; Ghirardi, M. L.; Seibert, M.

    2012-05-01

    Photoproduction of H{sub 2} gas has been examined in sulfur/phosphorus-deprived Chalmydomonas reinhardtii cultures, placed in photobioreactors (PhBRs) with different gas phase to liquid phase ratios (V{sub g.p.}/V{sub l.p.}). The results demonstrate that an increase in the ratio stimulates H{sub 2} photoproduction activity in both algal suspension cultures and in algae entrapped in thin alginate films. In suspension cultures, a 4x increase (from {approx}0.5 to {approx}2) in V{sub g.p.}/V{sub l.p} results in a 2x increase (from 10.8 to 23.1 mmol l{sup -1} or 264-565 ml l{sup -1}) in the total yield of H{sub 2} gas. Remarkably, 565 ml of H{sub 2} gas per liter of the suspension culture is the highest yield ever reported for a wild-type strain in a time period of less than 190 h. In immobilized algae, where diffusion of H{sub 2} from the medium to the PhBR gas phase is not affected by mixing, the maximum rate and yield of H{sub 2} photoproduction occur in PhBRs with V{sub g.p.}/V{sub l.p} above 7 or in a PhBR with smaller headspace, if the H{sub 2} is effectively removed from the medium by continuous flushing of the headspace with argon. These experiments in combination with studies of the direct inhibitory effect of high H{sub 2} concentrations in the PhBR headspace on H{sub 2} photoproduction activity in algal cultures clearly show that H{sub 2} photoproduction in algae depends significantly on the partial pressure of H{sub 2} (not O{sub 2} as previously thought) in the PhBR gas phase.

  10. Biological hydrogen formation by thermophilic bacteria

    NARCIS (Netherlands)

    Bielen, A.A.M.

    2014-01-01

      Hydrogen gas (H2) is an important chemical commodity. It is used in many industrial processes and is applicable as a fuel. However, present production processes are predominantly based on non-renewable resources. In a biological H2 (bioH2) production process,

  11. Biological hydrogen formation by thermophilic bacteria

    OpenAIRE

    Bielen, A.A.M.

    2014-01-01

      Hydrogen gas (H2) is an important chemical commodity. It is used in many industrial processes and is applicable as a fuel. However, present production processes are predominantly based on non-renewable resources. In a biological H2 (bioH2) production process, known as dark-fermentation, fermentative microorganisms are able to generate H2 from renewable resources like carbohydrate-rich plant material or industrial waste streams. Because of their favourable biomass degrading capabilities...

  12. Assessment of biological Hydrogen production processes: A review

    Science.gov (United States)

    Najafpour, G. D.; Shahavi, M. H.; Neshat, S. A.

    2016-06-01

    Energy crisis created a special attention on renewable energy sources. Among these sources; hydrogen through biological processes is well-known as the most suitable and renewable energy sources. In terms of process yield, hydrogen production from various sources was evaluated. A summary of microorganisms as potential hydrogen producers discussed along with advantages and disadvantages of several bioprocesses. The pathway of photo-synthetic and dark fermentative organisms was discussed. In fact, the active enzymes involved in performance of biological processes for hydrogen generation were identified and their special functionalities were discussed. The influential factors affecting on hydrogen production were known as enzymes assisting liberation specific enzymes such as nitrogenase, hydrogenase and uptake hydrogenase. These enzymes were quite effective in reduction of proton and form active molecular hydrogen. Several types of photosynthetic systems were evaluated with intension of maximum hydrogen productivities. In addition dark fermentative and light intensities on hydrogen productions were evaluated. The hydrogen productivities of efficient hydrogen producing strains were evaluated.

  13. Photoproduction of hydrogen by a non-sulphur bacterium isolated from root zones of water fern Azolla pinnata

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S.P.; Srivastava, S.C.; Pandey, K.D. (Banaras Hindu Univ., Varanasi (IN). Centre of Advanced Study in Botany)

    1990-01-01

    A photosynthetic bacterium Rhodopseudomonas sp. BHU strain 1 was isolated from the root zone of water fern Azolla pinnata. The bacterium was found to produce hydrogen with potato starch under phototrophic conditions. The immobilized bacterial cells showed sustained hydrogen production with a more than 4-fold difference over free cell suspensions. The data have been discussed in the light of possible utilization of relatively cheaper raw materials by non-sulphur bacteria to evolve hydrogen. (author).

  14. Hydrogen photoproduction in green algae Chlamydomonas reinhardtii sustainable over 2 weeks with the original cell culture without supply of fresh cells nor exchange of the whole culture medium.

    Science.gov (United States)

    Yagi, Takafumi; Yamashita, Kyohei; Okada, Norihide; Isono, Takumi; Momose, Daisuke; Mineki, Shigeru; Tokunaga, Eiji

    2016-07-01

    Unicellular green algae Chlamydomonas reinhardtii are known to make hydrogen photoproduction under the anaerobic condition with water molecules as the hydrogen source. Since the hydrogen photoproduction occurs for a cell to circumvent crisis of its survival, it is only temporary. It is a challenge to realize persistent hydrogen production because the cells must withstand stressful conditions to survive with alternation of generations in the cell culture. In this paper, we have found a simple and cost-effective method to sustain the hydrogen production over 14 days in the original culture, without supply of fresh cells nor exchange of the culture medium. This is achieved for the cells under hydrogen production in a sulfur-deprived culture solution on the {anaerobic, intense light} condition in a desiccator, by periodically providing a short period of the recovery time (2 h) with a small amount of TAP(+S) supplied outside of the desiccator. As this operation is repeated, the response time of transition into hydrogen production (preparation time) is shortened and the rate of hydrogen production (build up time) is increased. The optimum states of these properties favorable to the hydrogen production are attained in a few days and stably sustained for more than 10 days. Since generations are alternated during this consecutive hydrogen production experiment, it is suggested that the improved hydrogen production properties are inherited to next generations without genetic mutation. The properties are reset only when the cells are placed on the {sulfur-sufficient, aerobic, moderate light} conditions for a long time (more than 1 day at least). PMID:27083446

  15. Biological hydrogen production using a membrane bioreactor.

    Science.gov (United States)

    Oh, Sang-Eun; Iyer, Prabha; Bruns, Mary Ann; Logan, Bruce E

    2004-07-01

    A cross-flow membrane was coupled to a chemostat to create an anaerobic membrane bioreactor (MBR) for biological hydrogen production. The reactor was fed glucose (10,000 mg/L) and inoculated with a soil inoculum heat-treated to kill non-spore-forming methanogens. Hydrogen gas was consistently produced at a concentration of 57-60% in the headspace under all conditions. When operated in chemostat mode (no flow through the membrane) at a hydraulic retention time (HRT) of 3.3 h, 90% of the glucose was removed, producing 2200 mg/L of cells and 500 mL/h of biogas. When operated in MBR mode, the solids retention time (SRT) was increased to SRT = 12 h producing a solids concentration in the reactor of 5800 mg/L. This SRT increased the overall glucose utilization (98%), the biogas production rate (640 mL/h), and the conversion efficiency of glucose-to-hydrogen from 22% (no MBR) to 25% (based on a maximum of 4 mol-H(2)/mol-glucose). When the SRT was increased from 5 h to 48 h, glucose utilization (99%) and biomass concentrations (8,800 +/- 600 mg/L) both increased. However, the biogas production decreased (310 +/- 40 mL/h) and the glucose-to-hydrogen conversion efficiency decreased from 37 +/- 4% to 18 +/- 3%. Sustained permeate flows through the membrane were in the range of 57 to 60 L/m(2) h for three different membrane pore sizes (0.3, 0.5, and 0.8 microm). Most (93.7% to 99.3%) of the membrane resistance was due to internal fouling and the reversible cake resistance, and not the membrane itself. Regular backpulsing was essential for maintaining permeate flux through the membrane. Analysis of DNA sequences using ribosomal intergenic spacer analysis indicated bacteria were most closely related to members of Clostridiaceae and Flexibacteraceae, including Clostridium acidisoli CAC237756 (97%), Linmingia china AF481148 (97%), and Cytophaga sp. MDA2507 AF238333 (99%). No PCR amplification of 16s rRNA genes was obtained when archaea-specific primers were used.

  16. Photoproduction of proton-antiproton Paris on hydrogen in the energy region 4.74 - 6.55 GeV

    International Nuclear Information System (INIS)

    The photoproduction of proton-antiproton pairs on hydrogen has been investigated in the elastic reaction γp → p anti p p. In an experiment at the Deutsches Elektronensynchrotron DESY this reaction has been identified. The distribution of the p anti p invariant mass has been measured and the basic features of the dynamics by which the reaction proceeds have been identified. The kinematic region for the experiment was: 4.74 2. The experiment used a tagged photon beam, a magnetic spectrometer with proportional- and spark-chambers, a time of flight system, and a Cerenkov counter. From a total number of 1.5 x 106 triggers about 65 events of the reaction γp → p anti p p have been identified by using the following criteria: The mass of at least the negative outgoing particle, computed from the time of flight information, was about the proton mass and the kinematic analysis of the event yielded the largest probability for the hypothesis γp → p anti p p in comparison with the competing reactions. The basic features of the dynamics by which the reaction proceeds have been identified through a comparison of the experimental momentum- and four momentum transfer distributions with the corresponding distributions of simulated events. The simulated events have been generated by Monte Carlo methods according of forward or backward p anti p photoproduction. The result of the comparison was that in the investigated reaction a proton-antiproton pair is produced in backward direction in the c.m. system and the angular distribution of the anti p in the p anti p rest system is nearly isotropic. The identification of the basic reaction dynamics, allowed us to determine which of the two outgoing protons has been produced together with the antiproton by the photon. Therefore it was possible to calculate the invariant mass of the proton-anti-proton pair unambiguously. The resulting p anti p mass distribution shows within our statistics no significant structures which would indicate

  17. Hydrogen Photoproduction by Nutrient-Deprived Chalamydomonas reinhardtii Cells Immobilized Within Thin Alginate Films Under Aerobic and Anaerobic Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kosourov, S. N.; Seibert, M.

    2009-01-01

    A new technique for immobilizing H{sub 2}-photoproducing green algae within a thin (<400 {micro}m) alginate film has been developed. Alginate films with entrapped sulfur/phosphorus-deprived Chlamydomonas reinhardtii, strain cc124, cells demonstrate (a) higher cell density (up to 2,000 {micro}g Chl mL{sup -1} of matrix), (b) kinetics of H{sub 2} photoproduction similar to sulfur-deprived suspension cultures, (c) higher specific rates (up to 12.5 {micro}mol mg{sup -1} Chl h{sup -1}) of H{sub 2} evolution, (d) light conversion efficiencies to H{sub 2} of over 1% and (e) unexpectedly high resistance of the H{sub 2}-photoproducing system to inactivation by atmospheric O{sub 2}. The algal cells, entrapped in alginate and then placed in vials containing 21% O{sub 2} in the headspace, evolved up to 67% of the H{sub 2} gas produced under anaerobic conditions. The results indicate that the lower susceptibility of the immobilized algal H{sub 2}-producing system to inactivation by O{sub 2} depends on two factors: (a) the presence of acetate in the medium, which supports higher rates of respiration and (b) the capability of the alginate polymer itself to effectively separate the entrapped cells from O{sub 2} in the liquid and headspace and restrict O{sub 2} diffusion into the matrix. The strategy presented for immobilizing algal cells within thin polymeric matrices shows the potential for scale-up and possible future applications.

  18. Hydrogen photoproduction from bio-derived alcohols in an optical fiber honeycomb reactor loaded with Au/TiO2

    OpenAIRE

    Taboada Cabellos, Elena; Angurell Purroy, Inmaculada; Llorca Piqué, Jordi

    2014-01-01

    Cordierite honeycombs loaded with 1 wt.% Au/TiO2 have been used in an optical fiber photoreactor illuminated with UV LEDs to produce hydrogen at 298 K from aqueous methanol, ethanol, glycerol, bio-ethanol, and bio-glycerol in liquid phase. The amount of alcohol has been varied between 1% and 100%. Under the same photoreaction conditions, the amount of hydrogen produced follows the trend: methanol similar to ethanol similar to glycerol > bio-ethanol >> bio-glycerol. Hydrogen photogeneration is...

  19. Electrochemical studies of a reconstituted photosynthetic electron-transfer chain or towards a biomimetic photoproduction of hydrogen; Etudes electrochimiques de chaines de transfert d'electrons photosynthetiques ou vers une photoproduction biomimetique d'hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    Fourmond, V

    2007-04-15

    The aim of this work is to find an efficient process to convert solar energy into hydrogen. The electrons transfers in reconstituted photosynthetic chains have been particularly studied with the aims 1)in one hand, to better understand the interactions of the different molecules of the photosynthetic chain in order to optimize the changes of the entire organisms for hydrogen production 2)in another hand, to insert the hydrogenases in a photosynthetic chain and then to photo reduce them in order to obtain kinetic data to better understand how it works. (O.M.)

  20. Electrochemical studies of a reconstituted photosynthetic electron-transfer chain or towards a biomimetic photoproduction of hydrogen

    International Nuclear Information System (INIS)

    The aim of this work is to find an efficient process to convert solar energy into hydrogen. The electrons transfers in reconstituted photosynthetic chains have been particularly studied with the aims 1)in one hand, to better understand the interactions of the different molecules of the photosynthetic chain in order to optimize the changes of the entire organisms for hydrogen production 2)in another hand, to insert the hydrogenases in a photosynthetic chain and then to photo reduce them in order to obtain kinetic data to better understand how it works. (O.M.)

  1. Hydrogen Sulfide and Polysulfides as Biological Mediators

    Directory of Open Access Journals (Sweden)

    Hideo Kimura

    2014-10-01

    Full Text Available Hydrogen sulfide (H2S is recognized as a biological mediator with various roles such as neuromodulation, regulation of the vascular tone, cytoprotection, anti-inflammation, oxygen sensing, angiogenesis, and generation of mitochondrial energy. It is produced by cystathionine β-synthase (CBS, cystathionine γ-lyase (CSE, and 3-mercaptopyruvate sulfurtransferase (3MST. The activity of CBS is enhanced by S-adenosyl methionine (SAM and glutathionylation, while it is inhibited by nitric oxide (NO and carbon monoxide (CO. The activity of CSE and cysteine aminotransferase (CAT, which produces the 3MST substrate 3-mercaptopyruvate (3MP, is regulated by Ca2+. H2S is oxidized to thiosulfate in mitochondria through the sequential action of sulfide quinone oxidoreductase (SQR, sulfur dioxygenase, and rhodanese. The rates of the production and clearance of H2S determine its cellular concentration. Polysulfides (H2Sn have been found to occur in the brain and activate transient receptor potential ankyrin 1 (TRPA1 channels, facilitate the translocation of nuclear factor erythroid 2-related factor 2 (Nrf2 to the nucleus, and suppress the activity of phosphatase and tensin homolog (PTEN by sulfurating (sulfhydrating the target cysteine residues. A cross talk between H2S and NO also plays an important role in cardioprotection as well as regulation of the vascular tone. H2S, polysulfides, and their cross talk with NO may mediate various physiological and pathophysiological responses.

  2. Technical suitability mapping of feedstocks for biological hydrogen production

    NARCIS (Netherlands)

    Panagiotopoulos, I.A.; Karaoglanoglou, L.S.; Koullas, D.P.; Bakker, R.R.; Claassen, P.A.M.; Koukios, E.G.

    2015-01-01

    The objective of this work was to map and compare the technical suitability of different raw materials for biological hydrogen production. Our model was based on hydrogen yield potential, sugar mobilization efficiency, fermentability and coproduct yield and value. The suitability of the studied r

  3. Recent Developments in Biological Hydrogen Production Processes

    Directory of Open Access Journals (Sweden)

    DEBABRATA DAS

    2008-07-01

    Full Text Available Biohydrogen production technology can utilize renewable energy sources like biomass for the generation of hydrogen, the cleanest form of energy for the use of mankind. However, major constraints to the commercialization of these processes include lower hydrogen yields and rates of hydrogen production. To overcome these bottlenecks intensive research work has already been carried out on the advancement of these processes such as the development of genetically modified microorganisms, the improvement of the bioreactor design, molecular engineering of the key enzyme hydrogenases, the development of two stage processes, etc. The present paper explores the recent advancements that have been made till date and also presents the state of the art in molecular strategies to improve the hydrogen production.

  4. Biological hydrogen production from industrial wastewaters

    Energy Technology Data Exchange (ETDEWEB)

    Peixoto, Guilherme; Pantoja Filho, Jorge Luis Rodrigues; Zaiat, Marcelo [Universidade de Sao Paulo (EESC/USP), Sao Carlos, SP (Brazil). School of Engineering. Dept. Hydraulics and Sanitation], Email: peixoto@sc.usp.br

    2010-07-01

    This research evaluates the potential for producing hydrogen in anaerobic reactors using industrial wastewaters (glycerol from bio diesel production, wastewater from the parboilization of rice, and vinasse from ethanol production). In a complementary experiment the soluble products formed during hydrogen production were evaluated for methane generation. The assays were performed in batch reactors with 2 liters volume, and sucrose was used as a control substrate. The acidogenic inoculum was taken from a packed-bed reactor used to produce hydrogen from a sucrose-based synthetic substrate. The methanogenic inoculum was taken from an upflow anaerobic sludge blanket reactor treating poultry slaughterhouse wastewater. Hydrogen was produced from rice parboilization wastewater (24.27 ml H{sub 2} g{sup -1} COD) vinasse (22.75 ml H{sub 2} g{sup -1} COD) and sucrose (25.60 ml H{sub 2} g{sup -1} COD), while glycerol only showed potential for methane generation. (author)

  5. Eta meson photoproduction on hydrogen from threshold up to 1100 MeV: Measurement of the {Sigma} beam asymmetry; Photoproduction du meson eta sur l`hydrogene du seuil jusqu`a 1100 MeV: Mesure de l`asymetrie faisceau {Sigma}

    Energy Technology Data Exchange (ETDEWEB)

    Ajaka, Jassem [Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France)

    1997-12-12

    The photoproduction of {eta} meson on hydrogen has been measured from threshold to 1100 MeV in GRAAL experiment performed in 1996 - 1997 at the ESRF in Grenoble by a collaboration of Italian, French and Russian groups. A tagged and linearly polarized photon beam has been produced by back-scattering a laser beam on the 6 GeV electron beam of the ESRF ring. The target was a liquid hydrogen target of 3 cm. A 4{pi} detection system was used. It is composed of three layers of detectors: wire chambers, scintillator counters and calorimeters. We had in charge to install and calibrate a double wall of scintillator bars (3 x 3 m) designed to detect at forward angles (1 deg. - 25 deg.) the charged particles and to measure their loss of energy and their time of flight. We analyzed the results of the reaction {gamma}p {yields} {eta}p by identifying the {eta} in the lateral calorimeter which is a BGO ball and by detecting the proton in the scintillation counters. The {Sigma} beam asymmetry was extracted from {phi} distribution of {eta} meson and was plotted against {theta}{sub CM} of {eta} for 6 intervals of energy between the threshold and 1100 MeV. The interpretation of {Sigma} beam asymmetry was performed in the frame of the isobaric model. The use of two resonances S11(1535) and D13(1520) to explain our results was not sufficient. We had to take into account in addition the excitation of the resonances P13(1720), D15(1675) and P13(1880). The last being missing in the table of resonances and recently revealed by quark models. (author) 94 refs., 56 figs., 20 tabs.

  6. Electricity-mediated biological hydrogen production

    NARCIS (Netherlands)

    Geelhoed, J.S.; Hamelers, H.V.M.; Stams, A.J.M.

    2010-01-01

    Anaerobic bacteria have the ability to produce electricity from the oxidation of organic substrates. They also may use electricity to support chemical reactions that are energetically unfavorable. In the fermentation of sugars, hydrogen can be formed as one of the main products. However, a yield of

  7. Biological hydrogen production from biomass by thermophilic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Claassen, P.A.M.; Mars, A.E.; Budde, M.A.W.; Lai, M.; de Vrije, T. [Wageningen UR, Agrotechnology and Food Sciences Group (AFSG), Business Unit Biobased Products, P.O. Box 17, 6700 AA Wageningen, (Netherlands); van Niel, E.W.J. [Lund University, Applied microbiology, P.O. Box 124, 221 000 Lund, (Sweden)

    2006-07-01

    To meet the reduction of the emission of CO{sub 2} imposed by the Kyoto protocol, hydrogen should be produced from renewable primary energy. Besides the indirect production of hydrogen by electrolysis using electricity from renewable resources, such as sunlight, wind and hydropower, hydrogen can be directly produced from biomass. At present, there are two strategies for the production of hydrogen from biomass: the thermochemical technology, such as gasification, and the biotechnological approach using micro-organisms. Biological hydrogen production delivers clean hydrogen with an environmental-friendly technology and is very suitable for the conversion of wet biomass in small-scale applications, thus having a high chance of becoming an economically feasible technology. Many micro-organisms are able to produce hydrogen from mono- and disaccharides, starch and (hemi)cellulose under anaerobic conditions. The anaerobic production of hydrogen is a common phenomenon, occurring during the process of anaerobic digestion. Here, hydrogen producing micro-organisms are in syn-trophy with methanogenic bacteria which consume the hydrogen as soon as it is produced. In this way, hydrogen production remains obscure and methane is the end-product. By uncoupling hydrogen production from methane production, hydrogen becomes available for recovery and exploitation. This study describes the use of extreme thermophilic bacteria, selected because of a higher hydrogen production efficiency as compared to mesophilic bacteria, for the production of hydrogen from renewable resources. As feedstock energy crops like Miscanthus and Sorghum bicolor and waste streams like domestic organic waste, paper sludge and potato steam peels were used. The feedstock was pretreated and/or enzymatically hydrolyzed prior to fermentation to make a fermentable substrate. Hydrogen production by Caldicellulosiruptor saccharolyticus, Thermotoga elfii and T. neapolitana on all substrates was observed. Nutrient

  8. Biological hydrogen production from biomass by thermophilic bacteria

    International Nuclear Information System (INIS)

    To meet the reduction of the emission of CO2 imposed by the Kyoto protocol, hydrogen should be produced from renewable primary energy. Besides the indirect production of hydrogen by electrolysis using electricity from renewable resources, such as sunlight, wind and hydropower, hydrogen can be directly produced from biomass. At present, there are two strategies for the production of hydrogen from biomass: the thermochemical technology, such as gasification, and the biotechnological approach using micro-organisms. Biological hydrogen production delivers clean hydrogen with an environmental-friendly technology and is very suitable for the conversion of wet biomass in small-scale applications, thus having a high chance of becoming an economically feasible technology. Many micro-organisms are able to produce hydrogen from mono- and disaccharides, starch and (hemi)cellulose under anaerobic conditions. The anaerobic production of hydrogen is a common phenomenon, occurring during the process of anaerobic digestion. Here, hydrogen producing micro-organisms are in syn-trophy with methanogenic bacteria which consume the hydrogen as soon as it is produced. In this way, hydrogen production remains obscure and methane is the end-product. By uncoupling hydrogen production from methane production, hydrogen becomes available for recovery and exploitation. This study describes the use of extreme thermophilic bacteria, selected because of a higher hydrogen production efficiency as compared to mesophilic bacteria, for the production of hydrogen from renewable resources. As feedstock energy crops like Miscanthus and Sorghum bicolor and waste streams like domestic organic waste, paper sludge and potato steam peels were used. The feedstock was pretreated and/or enzymatically hydrolyzed prior to fermentation to make a fermentable substrate. Hydrogen production by Caldicellulosiruptor saccharolyticus, Thermotoga elfii and T. neapolitana on all substrates was observed. Nutrient requirements

  9. Photoproduction of Heavy Quarks

    OpenAIRE

    Krämer, Michael

    1995-01-01

    Heavy quarks are copiously produced in two-photon collisions at $e^+e^-$ colliders. The theoretical predictions including QCD radiative corrections are compared to recent experimental data on $\\gamma\\gamma$ production of charm quarks at PETRA, PEP, TRISTAN and LEP. Photoproduction of heavy quarks at HERA is an important tool to measure the gluon distribution in the proton. New theoretical results on heavy quark photoproduction at large transverse momenta are discussed and NLO predictions for ...

  10. Biological hydrogen production measured in batch anaerobic respirometers.

    Science.gov (United States)

    Logan, Bruce E; Oh, Sang-Eun; Kim, In S; Van Ginkel, Steven

    2002-06-01

    The biological production of hydrogen from the fermentation of different substrates was examined in batch tests using heat-shocked mixed cultures with two techniques: an intermittent pressure release method (Owen method) and a continuous gas release method using a bubble measurement device (respirometric method). Under otherwise identical conditions, the respirometric method resulted in the production of 43% more hydrogen gas from glucose than the Owen method. The lower conversion of glucose to hydrogen using the Owen protocol may have been produced by repression of hydrogenase activity from high partial pressures in the gastight bottles, but this could not be proven using a thermodynamic/rate inhibition analysis. In the respirometric method, total pressure in the headspace never exceeded ambient pressure, and hydrogen typically composed as much as 62% of the headspace gas. High conversion efficiencies were consistently obtained with heat-shocked soils taken at different times and those stored for up to a month. Hydrogen gas composition was consistently in the range of 60-64% for glucose-grown cultures during logarithmic growth but declined in stationary cultures. Overall, hydrogen conversion efficiencies for glucose cultures were 23% based on the assumption of a maximum of 4 mol of hydrogen/ mol of glucose. Hydrogen conversion efficiencies were similar for sucrose (23%) and somewhat lower for molasses (15%) but were much lower for lactate (0.50%) and cellulose (0.075%).

  11. Pion photoproduction near threshold

    International Nuclear Information System (INIS)

    A review of the high accuracy π+ threshold photoproduction cross-section determinations on deuterium and helium-3 is presented. These must be considered on the same footing as the data on electromagnetic observables, with reference to the important question of the description of the non nucleonic degrees of freedom in the nucleus. The π0 threshold photoproduction on very light nuclei which conveys information on the elementary nucleonic amplitudes in an energy region where one is sensitive to the break down of isospin symmetry as revealed by the π+-, π0 and the n, p mass splittings is discussed

  12. Infrared Spectra and Hydrogen Bonds of Biologically Active Benzaldehydes

    Science.gov (United States)

    Tolstorozhev, G. B.; Skornyakov, I. V.; Belkov, M. V.; Shimko, A. N.; Shadyro, O. I.; Brinkevich, S. D.; Samovich, S. N.

    2013-09-01

    IR-Fourier spectra of solutions and crystals of biologically active benzaldehyde derivatives were studied. Specific features of the formation of intra- and intermolecular hydrogen bonds were analyzed. Spectral signatures that characterized participation of the hydroxyl OH group and also the OCH3 and C=O groups in the formation of intramolecular hydrogen bonds of the three different types O-H···O-H, O-H···O-CH3, and O-H···O=C were revealed. Intramolecular hydrogen bonds of the types O-H···O-H and O-H···O-CH3 were absent for benzaldehyde derivatives in the crystal phase. Only hydroxyl and carbonyl groups participated in intermolecular interactions. This resulted in the formation of linear intermolecular dimers. Seven various configurations of the linear dimers were identified in solutions and crystals.

  13. Literature on photoproduction experiments

    International Nuclear Information System (INIS)

    Literature on gamma-proton, gamma-neutron, gamma-deuteron, gamma-nucleus experiments, inclusive photoproduction, particle yields in gamma-proton and gamma-nucleus, inelastic compton scattering, search for new particles, Primakoff effect, photofission, and QED-tests are compiled. (BJ)

  14. Photoproduction of charmed hadrons

    Energy Technology Data Exchange (ETDEWEB)

    Gardner, R. [Univ. of Illinois, Urbana, IL (United States)

    1994-10-01

    Photoproduction data can be used to test QCD production mechanisms. In this paper the authors present results on the single-inclusive p{sub t}{sup 2} distributions of charm mesons and baryons, correlations between fully reconstructed charm pairs, and production asymmetries between charm and anticharm particles.

  15. Meson photoproduction (CLAS)

    Energy Technology Data Exchange (ETDEWEB)

    Steffen Strauch

    2009-10-01

    This is a brief and selective discussion of meson photoproduction measurements with the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. Meson photo- production is being used as a tool for various investigations, including the spectroscopy of baryons and mesons and the search for vector-meson medium modifications.

  16. Photoproduction of Pseudoscalar Mesons

    CERN Document Server

    Arndt, R A; O'Rielly, G V; Strakovsky, I I; Workman, R L

    2003-01-01

    Experiments that study the photoproduction of pseudoscalar mesons; pions, etas and kaons, have the potential to increase our knowledge of baryon and hyperon resonance properties. Recent experiments at JLab, Mainz, GRAAL, and Bonn are beginning to produce results in the form of polarization and asymmetry measurements and determinations of the differential and integrated cross sections. These new data are essential to the performance of Partial-Wave Analyses that are less model dependent and coupled-channels calculations that incorporate unitarity dynamically,combining hadronic reaction channels together with electromagnetic processes. This approach is necessary to extract resonance properties and may lead to the identification of missing, but predicted, resonances. Some recent experimental and phenomenological results for single and double pseudoscalar meson photoproduction are discussed.

  17. Hard photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, M. [Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier / CNRS-IN2P3, 53 Avenue des Martyrs, F-38026 Grenoble (France)

    2007-07-01

    In view of possible photoproduction studies in ultra-peripheral heavy-ion collisions at the LHC, we briefly review the present theoretical understanding of photons and hard photoproduction processes at HERA, discussing the production of jets, light and heavy hadrons, quarkonia, and prompt photons. We address in particular the extraction of the strong coupling constant from photon structure function and inclusive jet measurements, the infrared safety and computing time of jet definitions, the sensitivity of di-jet cross sections on the parton densities in the photon, factorization breaking in diffractive di-jet production, the treatment of the heavy-quark mass in charm production, the relevance of the color-octet mechanism for quarkonium production, and isolation criteria for prompt photons. (author)

  18. Transversity and Meson Photoproduction

    CERN Document Server

    Goldstein, G R; Goldstein, Gary R.; Gamberg, Leonard

    2002-01-01

    Both meson photoproduction and semi-inclusive deep inelastic scattering can potentially probe transversity in the nucleon. We explore how that potential can be realized dynamically. The role of rescattering in both exclusive and inclusive meson production as a source for transverse polarization asymmetry is examined. We use a dynamical model to calculate the asymmetry and relate that to the transversity distribution of the nucleon.

  19. Influence of phage proteins on formation of specific UV DNA photoproducts in phage T7

    NARCIS (Netherlands)

    Fekete, A.; Vink, A.A.; Gaspar, S.; Modos, K.; Berces, A.; Ronto, Gy.; Roza, L.

    1999-01-01

    Phage T7 can be used as a biological UV dosimeter. Its reading is proportional to the inactivation rate expressed in HT7 units. To understand the influence of phage proteins on the formation of DNA UV photoproducts, cyclobutane pyrimidine dimers (CPD) and (6-4)photoproducts ((6-4)PD) were determined

  20. Extracting amplitudes from photoproduction data

    Science.gov (United States)

    Workman, R. L.

    2011-09-01

    We consider the problems associated with amplitude extraction, from meson photoproduction data, over the first resonance regions. The notion of a complete experiment has motivated the FROST program at Jefferson Lab. Exercises applied to pion photoproduction data illustrate the problems to be confronted in any attempt to extract underlying resonance signals from these data (without introducing a model for the resonant process).

  1. Photoproduction of leptophobic bosons

    CERN Document Server

    Fanelli, Cristiano

    2016-01-01

    We propose a search for photoproduction of leptophobic bosons that couple to quarks at the GlueX experiment at Jefferson Lab. We study in detail a new gauge boson that couples to baryon number $B$, and estimate that $\\gamma p \\to p B$ will provide the best sensitivity for $B$ masses above 0.5 GeV. This search will also provide sensitivity to other proposed dark-sector states that couple to quarks. Finally, our results motivate a similar search for $B$ boson electroproduction at the CLAS experiment.

  2. Role of Light Intensity and Temperature in the Regulation of Hydrogen Photoproduction by the Marine Cyanobacterium Oscillatoria sp. Strain Miami BG7

    OpenAIRE

    Phlips, E. J.; Mitsui, A

    1983-01-01

    The effects of several key environmental factors on the development and control of hydrogen production in the marine blue-green alga (cyanobacterium) Oscillatoria sp. strain Miami BG7 were studied in relation to the potential application of this strain to a bio-solar energy technology. The production of cellular biomass capable of evolving hydrogen gas was strongly affected by light intensity, temperature, and the input of ammonia as a nutrient. Depletion of combined nitrogen from the growth ...

  3. The stable isotopic signature of biologically produced molecular hydrogen (H2)

    NARCIS (Netherlands)

    Walter, S.; Laukenmann, S.; Stams, A.J.M.; Vollmer, M.K.; Gleixner, G.; Roeckmann, T.

    2011-01-01

    Biologically produced molecular hydrogen (H2) is characterized by a very strong depletion in deuterium. Although the biological source to the atmosphere is small compared to photochemical or combustion sources, it makes an important contribution to the global isotope budget of molecular hydrogen (H2

  4. Photoproduction at TRISTAN energy

    International Nuclear Information System (INIS)

    Focussing our attention upon the structure of photon we discuss its complementary aspects represented by the vector meson dominance (VMD) and the perturbative quantum chromo-dynamics (QCD). Photoproduction of vector mesons and that of large transverse momentum jets are studied as testing ground for two aspects, in the energy range of TRISTAN (E sub(e-) x E sub(p) asymptotically equals 20 GeV x 300 GeV). It is found that Vector Mesons of mass up to -- 10 GeV will be produced more than once per day for tagged photons. Large- p sub(perpendicular) jet production is found rather copious and it can be a good probe to study the photon structure function predicted from QCD. (author)

  5. Photoproduction of charmed baryons

    International Nuclear Information System (INIS)

    The results of a search for the photoproduction of charmed baryons in the broad-band neutral beam at Fermi National Accelerator Laboratory are reported. The lowest lying charmed baryon (Λ/sub c/+) is observed through its decay to p-anti K0. The cross section times branching ratio of γ + C → Λ/sub c/+ + X, γ + C → p + anti K0 is measured to be sigma B = 3 nanobarns/nucleon. The total error on this measurement is estimated to be -20% to +40%. The mass of the Λ/sub c/+ is found to be 2.284 +- 0.001 GeV/c2, in good agreement with the Mark II result from SPEAR. Upper limits (90% confidence level) are set on sigma B for the modes Λ0π, Λ0πππ, pKπ

  6. Dijets in Photoproduction

    Science.gov (United States)

    Frising, Gilles

    2002-10-01

    Dijet cross sections as functions of several jet observables are measured in photoproduction using the H1 detector at HERA. The data sample comprises ep data with an integrated luminosity of 34.9 pb-1. Jets are selected using the inclusive kt algorithm with a minimum transverse energy of 25 GeV for the leading jet. The phase space covers longitudinal proton momentum fraction xp and photon longitudinal momentum fraction xγ in the ranges 0.05< xp<0.6 and 0.1

  7. Dijets in Photoproduction

    International Nuclear Information System (INIS)

    Dijet cross sections as functions of several jet observables are measured in photoproduction using the H1 detector at HERA. The data sample comprises ep data with an integrated luminosity of 34.9 pb-1. Jets are selected using the inclusive kt algorithm with a minimum transverse energy of 25 GeV for the leading jet. The phase space covers longitudinal proton momentum fraction xp and photon longitudinal momentum fraction xγ in the ranges 0.05 p γ< 1. The predictions of next-to-leading order perturbative QCD, including recent photon and proton parton densities, are found to be compatible with the data in a wide kinematical range. (author)

  8. Measurement and biological significance of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices

    NARCIS (Netherlands)

    Tangerman, Albert

    2009-01-01

    This review deals with the measurement of the volatile Sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices of rats and humans (blood, serum, tissues, urine, breath, feces and flatus). Hydrogen sulfide and methanethiol both contain the active thiol (-SH

  9. Measurement and biological significance of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices.

    NARCIS (Netherlands)

    Tangerman, A.

    2009-01-01

    This review deals with the measurement of the volatile sulfur compounds hydrogen sulfide, methanethiol and dimethyl sulfide in various biological matrices of rats and humans (blood, serum, tissues, urine, breath, feces and flatus). Hydrogen sulfide and methanethiol both contain the active thiol (-SH

  10. High-energy photoproduction of neutral mesons

    CERN Document Server

    Charity, Tim

    1987-01-01

    This thesis presents results from the first full period of data-taking of the experiment WA69 at the Omega^'^ectrometer, CERN, Geneva. The experiment used a tagged photon beam of energy 60-180 GeV incident on a liquid hydrogen target to study photoproduction of hadronic states. The various components of the experiment are described, with particular emphasis on the electromagnetic calorimeters, and the associated offline software for event reconstruction and acceptance calculation. The performance of the outer calorimeter is discussed, and the pi^0 detection and reconstruction efficiency is examined by comparison with pi^{+/- } production. Searches for photoproduction of neutral meson states reveal a clear signal for the pi^0, eta^0 , and omega^0 mesons. The cross-section for elastic omega^0 production is estimated, and found to be consistent with the established value of 1 mub. The cross-section for inclusive pi^0 and eta^0 production is studied using the variable Feynman-x (x_{F }), and pi^0 production as a ...

  11. Intramolecular Hydrogen Bond in Biologically Active o-Carbonyl Hydroquinones

    Directory of Open Access Journals (Sweden)

    Maximiliano Martínez-Cifuentes

    2014-07-01

    Full Text Available Intramolecular hydrogen bonds (IHBs play a central role in the molecular structure, chemical reactivity and interactions of biologically active molecules. Here, we study the IHBs of seven related o-carbonyl hydroquinones and one structurally-related aromatic lactone, some of which have shown anticancer and antioxidant activity. Experimental NMR data were correlated with theoretical calculations at the DFT and ab initio levels. Natural bond orbital (NBO and molecular electrostatic potential (MEP calculations were used to study the electronic characteristics of these IHB. As expected, our results show that NBO calculations are better than MEP to describe the strength of the IHBs. NBO energies (∆Eij(2 show that the main contributions to energy stabilization correspond to LPàσ* interactions for IHBs, O1…O2-H2 and the delocalization LPàπ* for O2-C2 = Cα(β. For the O1…O2-H2 interaction, the values of ∆Eij(2 can be attributed to the difference in the overlap ability between orbitals i and j (Fij, instead of the energy difference between them. The large energy for the LP O2àπ* C2 = Cα(β interaction in the compounds 9-Hydroxy-5-oxo-4,8, 8-trimethyl-l,9(8H-anthracenecarbolactone (VIII and 9,10-dihydroxy-4,4-dimethylanthracen-1(4H-one (VII (55.49 and 60.70 kcal/mol, respectively when compared with the remaining molecules (all less than 50 kcal/mol, suggests that the IHBs in VIII and VII are strongly resonance assisted.

  12. Improvements in Fermentative Biological Hydrogen Production Through Metabolic Engineering

    International Nuclear Information System (INIS)

    Dramatically rising oil prices and increasing awareness of the dire environmental consequences of fossil fuel use, including startling effects of climate change, are refocusing attention world-wide on the search for alternative fuels. Hydrogen is poised to become an important future energy carrier. Renewable hydrogen production is pivotal in making it a truly sustainable replacement for fossil fuels. (Author)

  13. Improvements in Fermentative Biological Hydrogen Production Through Metabolic Engineering

    Energy Technology Data Exchange (ETDEWEB)

    Hallenbeck, P. C.; Ghosh, D.; Sabourin-Provost, G.

    2009-07-01

    Dramatically rising oil prices and increasing awareness of the dire environmental consequences of fossil fuel use, including startling effects of climate change, are refocusing attention world-wide on the search for alternative fuels. Hydrogen is poised to become an important future energy carrier. Renewable hydrogen production is pivotal in making it a truly sustainable replacement for fossil fuels. (Author)

  14. Biological Hydrogen Production Using Chloroform-treated Methanogenic Granules

    Science.gov (United States)

    Hu, Bo; Chen, Shulin

    In fermentative hydrogen production, the low-hydrogen-producing bacteria retention rate limits the suspended growth reactor productivity because of the long hydraulic retention time (HRT) required to maintain adequate bacteria population. Traditional bacteria immobilization methods such as calcium alginate entrapment have many application limitations in hydrogen fermentation, including limited duration time, bacteria leakage, cost, and so on. The use of chloroform-treated anaerobic granular sludge as immobilized hydrogen-producing bacteria in an immobilized hydrogen culture may be able to overcome the limitations of traditional immobilization methods. This paper reports the findings on the performance of fed-batch cultures and continuous cultures inoculated with chloroform-treated granules. The chloroform-treated granules were able to be reused over four fed-batch cultures, with pH adjustment. The upflow reactor packed with chloroform-treated granules was studied, and the HRT of the upflow reactor was found to be as low as 4 h without any decrease in hydrogen production yield. Initial pH and glucose concentration of the culture medium significantly influenced the performance of the reactor. The optimum initial pH of the culture medium was neutral, and the optimum glucose concentration of the culture medium was below 20 g chemical oxygen demand/L at HRT 4 h. This study also investigated the possibility of integrating immobilized hydrogen fermentation using chloroform-treated granules with immobilized methane production using untreated granular sludge. The results showed that the integrated batch cultures produced 1.01 mol hydrogen and 2 mol methane per mol glucose. Treating the methanogenic granules with chloroform and then using the treated granules as immobilized hydrogen-producing sludge demonstrated advantages over other immobilization methods because the treated granules provide hydrogen-producing bacteria with a protective niche, a long duration of an active

  15. Hadron photoproduction at medium energy

    International Nuclear Information System (INIS)

    Results from measurements of multibody photoproduction at medium incident photon energy (2.8 to 4.8 GeV) are presented and discussed. Particular emphasis is placed on topics which are not well understood and which therefore motivate experiments with the upgraded electron accelerator and storage ring ELSA at the University of Bonn, FR Germany. (author)

  16. The stable isotopic signature of biologically produced molecular hydrogen (H-2)

    NARCIS (Netherlands)

    Walter, S.; Laukenmann, S.; Stams, A.J.M.; Vollmer, M.K.; Gleixner, G.; Rockmann, T.

    2012-01-01

    Biologically produced molecular hydrogen (H-2) is characterised by a very strong depletion in deuterium. Although the biological source to the atmosphere is small compared to photochemical or combustion sources, it makes an important contribution to the global isotope budget of H-2. Large uncertaint

  17. The stable isotopic signature of biologically produced molecular hydrogen (H2)

    NARCIS (Netherlands)

    Walter, S.; Laukenmann, S.; Stams, A.J.M.; Vollmer, M.K.; Gleixner, G.; Roeckmann, T.

    2012-01-01

    Biologically produced molecular hydrogen (H2) is characterised by a very strong depletion in deuterium. Although the biological source to the atmosphere is small compared to photochemical or combustion sources, it makes an important contribution to the global isotope budget of H2. Large uncertaintie

  18. Kinetic study of biological hydrogen production by anaerobic fermentation

    Energy Technology Data Exchange (ETDEWEB)

    Sangeetha, R. [Annamalai Univ., Chidambaram (India). Dept. of Chemical Engineering; Karunanithi, T. [Annamalai Univ., Tamilnadu (India). Dept. of Chemical Engineering

    2009-07-01

    This study examined the kinetics of batch biohydrogen production from glucose. Clostridium pasteurianum was used to produce biohydrogen by dark anaerobic fermentation. The initial substrate concentration, initial pH and temperature were optimized for biohydrogen production. The maximum production of hydrogen under optimum conditions was found to be 5.376 l/l. The kinetic parameters were determined for the optimized medium and conditions in the batch reactor. The by product was expressed as total acidic equivalent. This presentation discussed the logistic equation that was used to model the growth of the organism and described how the kinetic parameters were calculated. The Leudeking piret kinetic model was used to express the hydrogen production and substrate use because it combines both growth associated and non associated contributions. It was concluded the production of biohydrogen can be predicted well using the logistic model for cell growth kinetics and the logistic incorporated Leudeking Piret model for product and substrate utilization kinetics.

  19. A novel biological hydrogen production system. Impact of organic loading

    Energy Technology Data Exchange (ETDEWEB)

    Hafez, Hisham; Nakhla, George; El Naggar, Hesham [Western Ontario Univ. (Canada)

    2010-07-01

    The patent-pending system comprises a novel biohydrogen reactor with a gravity settler for decoupling of SRT from HRT. Two biohydrogenators were operated for 220 days at 37 C, hydraulic retention time 8 h and solids retention time ranged from 1.4 to 2 days under four different glucose concentrations of 2, 8, 16, 32, 48 and 64 g/L, corresponding to organic loading rates of 6.5-206 kg COD/m{sup 3}-d, and started up using anaerobically-digested sludge from the St. Marys wastewater treatment plant (St.Mary, Ontario, Canada) as the seed. The system steadily produced hydrogen with no methane. A maximum hydrogen yield of 3.1 mol H{sub 2} /mol glucose was achieved in the system for all the organic loading rates with an average of 2.8mol H{sub 2} /mol glucose. Acetate and butyrate were the main effluent liquid products at concentrations ranging from 640-7400 mg/L and 400-4600 mg/l, respectively, with no lactate detection. Microbial community analysis using denaturing gradient gel electrophoresis (DGGE) confirmed the absence of lactate producing bacteria Lactobacillus fermentum and other non-hydrogen producing species, and the predominance of various Clostridium species. Biomass concentrations in the biohydrogenators were steady, during the runs, varying form 1500 mg/L at the OLR of 6.5 kg COD/m{sup 3}-d to 14000 mg/L at the 104 kg COD/m{sup 3}-d, thus emphasizing the potential of this novel system for sustained stable hydrogen production and prevention of biomass washout. (orig.)

  20. Charmed hadron photoproduction at COMPASS

    CERN Document Server

    Wang, Xiao-Yun

    2016-01-01

    Photoproduction of the charmonium-like state $Z_{c}(4200)$ and the charmed baryon $\\Lambda_{c}^{\\ast }(2940)$ is investigated with an effective Lagrangian approach and the Regge trajectories applying to the COMPASS experiment. Combining the experimental data from COMPASS and our theoretical model we estimate the upper limit of $\\Gamma_{Z_{c}(4200)\\rightarrow J/\\psi \\pi }$ to be of about 37 MeV. Moreover, the possibility to produce $\\Lambda_{c}^{\\ast }(2940)$ at COMPASS is discussed. It seems one can try to search for this hadron in the missing mass spectrum since the $t$-channel is dominating for the $\\Lambda_{c}^{\\ast }(2940)$ photoproduction.

  1. Charmed hadron photoproduction at COMPASS

    Directory of Open Access Journals (Sweden)

    Wang Xiao-Yun

    2016-06-01

    Full Text Available Photoproduction of the charmonium-like state Zc(4200 and the charmed baryon Λc*$\\it\\Lambda _c^*$(2940 is investigated with an effective Lagrangian approach and the Regge trajectories applying to the COMPASS experiment. Combining the experimental data from COMPASS and our theoretical model we estimate the upper limit of ΓZc(4200→J/ψπ to be of about 37 MeV. Moreover, the possibility to produce Λc*$\\it\\Lambda _c^*$ (2940 at COMPASS is discussed. It seems one can try to search for this hadron in the missing mass spectrum since the t-channel is dominating for the Λc*$\\it\\Lambda _c^*$(2940 photoproduction.

  2. Quasifree kaon photoproduction on nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Frank Lee; T. MART; Cornelius Bennhold; Lester Wright

    2001-12-01

    Investigations of the quasifree reaction A({gamma}, K Y)B are presented in the distorted wave impulse approximation (DWIA). For this purpose, we present a revised tree-level model of elementary kaon photoproduction that incorporates hadronic form factors consistent with gauge invariance, uses SU(3) values for the Born couplings and uses resonances consistent with multi-channel analyses. The potential of exclusive quasifree kaon photoproduction on nuclei to reveal details of the hyperon-nucleus interaction is examined. Detailed predictions for the coincidence cross section, the photon asymmetry, and the hyperon polarization and their sensitivities to the ingredients of the model are obtained for all six production channels. Under selected kinematics these observables are found to be sensitive to the hyperon-nucleus final state interaction. Some polarization observables are found to be insensitive to distortion effects, making them ideal tools to search for possible medium modifications of the elementary amplitude.

  3. Diquark Substructure in $\\phi$ Photoproduction

    CERN Document Server

    Lebed, Richard F

    2015-01-01

    Observed enhancements in the forward and backward directions for $\\phi$ meson photoproduction off nucleons are shown to be explainable by the production of a nonresonant recoiling $(su)$ diquark, $(\\bar s ud)$ triquark pair. We show that the necessity of maintaining approximate collinearity of the quarks within these units constrains configurations with the minimum momentum transfer, and hence maximal amplitudes, to lie preferentially along the reaction axis.

  4. Biological conversion of hydrogen sulfide into elemental sulfur

    Energy Technology Data Exchange (ETDEWEB)

    Basu, R.; Clausen, E.C.; Gaddy, J.L. [Bioengineering Resources, Inc., Fayetteville, AR (United States)

    1996-12-31

    Currently, hydrogen sulfide is removed from process gas streams by a series of reactions at high temperature to produce elemental sulfur in Claus, Stretford or other processes. These physicochemical processes have high intrinsic capital and operating costs, often are restricted by contaminants, and do not effectively remove all the H{sub 2}S. As an alternative, the anaerobic, photosynthetic bacterium, Chlorobium thiosulfatophilum, has been demonstrated to convert hydrogen sulfide to elemental sulfur in a single step at atmospheric conditions. The autotrophic bacterium uses CO{sub 2} as the carbon source. Energy for cell metabolism is provided by incandescent light and the oxidation of H{sub 2}S. A bench scale study has been performed in a CSTR equipped with a sulfur separator. Optimum process conditions have been achieved to maximize cell growth and elemental sulfur production. Near total conversion of H{sub 2}S is achieved in a retention time of a few minutes. High concentrations of H{sub 2}S or organics do not affect the culture. Sulfur recovery by settling is very efficient and near theoretical yields of sulfur are achieved. Economic projections indicate that sour gas can be desulfurized for $0.08-0.12/MSCF. 13 refs.

  5. Molecular Imaging Approaches to Understanding the Roles of Hydrogen Peroxide Biology in Stress and Development

    OpenAIRE

    Dickinson, Bryan Craig

    2010-01-01

    The production of hydrogen peroxide (H2O2) in biological systems is associated with a variety of pathologies including neurodegenerative diseases, cancer, and the general process of aging. However, a growing body of evidence suggests that the reactivity of this particular reactive oxygen species (ROS) is also harnessed for physiological processes. Molecular imaging using fluorescence microscopy offers a valuable approach for deciphering the multifaceted roles of H2O2 in biological processes. ...

  6. Dilute-acid pretreatment of barley straw for biological hydrogen production using Caldicellulosiruptor saccharolyticus

    NARCIS (Netherlands)

    Panagiotopoulos, I.A.; Bakker, R.R.C.; Vrije, de G.J.; Claassen, P.A.M.; Koukios, E.G.

    2012-01-01

    The main objective of this study was to use the fermentability test to investigate the feasibility of applying various dilute acids in the pretreatment of barley straw for biological hydrogen production. At a fixed acid loading of 1% (w/w dry matter) 28-32% of barley straw was converted to soluble m

  7. Gamma irradiation induced disintegration of waste activated sludge for biological hydrogen production

    Science.gov (United States)

    Yin, Yanan; Wang, Jianlong

    2016-04-01

    In this paper, gamma irradiation was applied for the disintegration and dissolution of waste activated sludge produced during the biological wastewater treatment, and the solubilized sludge was used as substrate for bio-hydrogen production. The experimental results showed that the solubilization of waste activated sludge was 53.7% at 20 kGy and pH=12, and the SCOD, polysaccharides, protein, TN and TP contents in the irradiated sludge solutions was 3789.6 mg/L, 268.3 mg/L, 1881.5 mg/L, 132.3 mg/L and 80.4 mg/L, respectively. The irradiated sludge was used for fermentative hydrogen production, and the hydrogen yield was 10.5±0.7 mL/g SCODconsumed. It can be concluded that the irradiated waste activated sludge could be used as a low-cost substrate for fermentative hydrogen production.

  8. Phototransformation of amlodipine: degradation kinetics and identification of its photoproducts.

    Science.gov (United States)

    Jakimska, Anna; Śliwka-Kaszyńska, Magdalena; Nagórski, Piotr; Namieśnik, Jacek; Kot-Wasik, Agata

    2014-01-01

    Nowadays, monitoring focuses on the primary compounds and does not include degradation products formed during various biological and chemical processes. Transformation products may have the same effects to human health and the environment or sometimes they can be more toxic than the parent compound. Unfortunately, knowledge about the formation of degradation products is still limited, however, can be very important for the environmental risk assessment. Firstly, the photodegradation kinetic of amlodipine was investigated in two experimental conditions: during the exposure to solar radiation and during the exposure to the light emitted by the xenon lamp. In all cases degradation of amlodipine followed a pseudo-first-order kinetics. In the next step, identification of transformation products of amlodipine formed during the exposure to xenon lamp irradiation was performed using ultra high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS). As a result sixteen photoproducts were identified, their structures were elucidated and ultimately the transformation pathway was proposed. Fifteen compounds (out of 16 photoproducts) were newly identified and reported here for the first time; some of those compounds were formed from the first photoproduct, amlodipine pyridine derivative. Several analytes were formed only in acidic or basic conditions. Furthermore, the occurrence of amlodipine and its identified degradation products was investigated in environmental waters. Only one out of 16 compounds was found in wastewater effluent. The possibility of the sorption of examined analytes to sewage sludge particles was discussed based on QSAR. PMID:25279815

  9. Phototransformation of amlodipine: degradation kinetics and identification of its photoproducts.

    Directory of Open Access Journals (Sweden)

    Anna Jakimska

    Full Text Available Nowadays, monitoring focuses on the primary compounds and does not include degradation products formed during various biological and chemical processes. Transformation products may have the same effects to human health and the environment or sometimes they can be more toxic than the parent compound. Unfortunately, knowledge about the formation of degradation products is still limited, however, can be very important for the environmental risk assessment. Firstly, the photodegradation kinetic of amlodipine was investigated in two experimental conditions: during the exposure to solar radiation and during the exposure to the light emitted by the xenon lamp. In all cases degradation of amlodipine followed a pseudo-first-order kinetics. In the next step, identification of transformation products of amlodipine formed during the exposure to xenon lamp irradiation was performed using ultra high performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF-MS. As a result sixteen photoproducts were identified, their structures were elucidated and ultimately the transformation pathway was proposed. Fifteen compounds (out of 16 photoproducts were newly identified and reported here for the first time; some of those compounds were formed from the first photoproduct, amlodipine pyridine derivative. Several analytes were formed only in acidic or basic conditions. Furthermore, the occurrence of amlodipine and its identified degradation products was investigated in environmental waters. Only one out of 16 compounds was found in wastewater effluent. The possibility of the sorption of examined analytes to sewage sludge particles was discussed based on QSAR.

  10. Techno-economic evaluation of a two-step biological process for hydrogen production.

    Science.gov (United States)

    Ljunggren, Mattias; Zacchi, Guido

    2010-01-01

    An integrated biological process for the production of hydrogen based on thermophilic and photo-heterotrophic fermentation was evaluated from a technical and economic standpoint. Besides the two fermentation steps the process also includes pretreatment of the raw material (potato steam peels) and purification of hydrogen using amine absorption. The study aimed neither at determining the absolute cost of biohydrogen nor at an economic optimization of the production process, but rather at studying the effects of different parameters on the production costs of biohydrogen as a guideline for future improvements. The effect of the key parameters, hydrogen productivity and yield and substrate concentration in the two fermentations on the cost of the hydrogen produced was studied. The selection of the process conditions was based mainly on laboratory data. The process was simulated by use of the software Aspen Plus and the capital costs were estimated using the program Aspen Icarus Process Evaluator. The study shows that the photo-fermentation is the main contributor to the hydrogen production cost mainly because of the cost of plastic tubing, for the photo-fermentors, which represents 40.5% of the hydrogen production cost. The costs of the capital investment and chemicals were also notable contributors to the hydrogen production cost. Major economic improvements could be achieved by increasing the productivity of the two fermentation steps on a medium-term to long-term scale. PMID:20039381

  11. Photosynthetic hydrogen and oxygen production - Kinetic studies

    Science.gov (United States)

    Greenbaum, E.

    1982-01-01

    The simultaneous photoproduction of hydrogen and oxygen was measured in a study of the steady-state turnover times of two biological systems, by driving them into the steady state with repetitive, single-turnover flash illumination. The systems were: (1) in vitro, isolated chloroplasts, ferredoxin and hydrogenase; and (2) the anaerobically-adapted green alga Chlamydomonas reinhardtii. It is found that the turnover times for production of both oxygen and hydrogen in photosynthetic water splitting are in milliseconds, and either equal to, or less than, the turnover time for carbon dioxide reduction in intact algal cells. There is therefore mutual compatibility between hydrogen and oxygen turnover times, and partial compatibility with the excitation rate of the photosynthetic reaction centers under solar irradiation conditions.

  12. Biological production of hydrogen by dark fermentation of OFMSW and co-fermentation with slaughterhouse wastes

    Energy Technology Data Exchange (ETDEWEB)

    Moran, A.; Gomez, X.; Cuestos, M. J.

    2005-07-01

    Hydrogen is an ideal, clean and sustainable energy source for the future because of its high conversion and nonpolluting nature (Lin and Lay, 2003). There are different methods for the production of hydrogen, the traditional ones, are the production from fossil fuels. Aiming to reach a development based on sustainable principles the production of hydrogen from renewable sources is a desirable goal. Among the environmental friendly alternatives for the production of hydrogen are the biological means. Dark fermentation as it is known the process when light is not used; it is a preferable option thanks to the knowledge already collected from its homologous process, the anaerobic digestion for the production of methane. There are several studies intended to the evaluation of the production of hydrogen, many are dedicated to the use of pure cultures or the utilization of basic substrates as glucose or sucrose (Lin and Lay, 2003; Chang et al., 2002, Kim et al., 2005). This study is performed to evaluate the fermentation of a mixture of wastes for the production of hydrogen. It is used as substrate the organic fraction of municipal solid wastes (OFMSW) and a mixture of this residue with slaughterhouse waste. (Author)

  13. Innovation in biological production and upgrading of methane and hydrogen for use as gaseous transport biofuel.

    Science.gov (United States)

    Xia, Ao; Cheng, Jun; Murphy, Jerry D

    2016-01-01

    Biofuels derived from biomass will play a major role in future renewable energy supplies in transport. Gaseous biofuels have superior energy balances, offer greater greenhouse gas emission reductions and produce lower pollutant emissions than liquid biofuels. Biogas derived through fermentation of wet organic substrates will play a major role in future transport systems. Biogas (which is composed of approximately 60% methane/hydrogen and 40% carbon dioxide) requires an upgrading process to reduce the carbon dioxide content to less than 3% before it is used as compressed gas in transport. This paper reviews recent developments in fermentative biogas production and upgrading as a transport fuel. Third generation gaseous biofuels may be generated using marine-based algae via two-stage fermentation, cogenerating hydrogen and methane. Alternative biological upgrading techniques, such as biological methanation and microalgal biogas upgrading, have the potential to simultaneously upgrade biogas, increase gaseous biofuel yield and reduce carbon dioxide emission. PMID:26724182

  14. Photoproduction at RHIC and the LHC

    OpenAIRE

    Klein, Spencer

    2008-01-01

    The strong electromagnetic fields carried by relativistic highly charged ions make heavy-ion colliders attractive places to study photonuclear interactions and two-photon interactions. At RHIC, three experiments have studied coherent photoproduction of $\\rho^0$, 4$\\pi$, $J/\\psi$, $e^+e^-$ pairs, and $e^+e^-$ pairs where the electron is bound to one of the incident nuclei. These results show that photoproduction studies are possible, and demonstrate some of the unique possibilities due to the ...

  15. Neutral kaon photoproduction on the deuteron

    CERN Document Server

    Salam, A; Miyagawa, K

    2009-01-01

    Neutral kaon photoproduction on the deuteron has been investigated by including the final state effects and compared with the experimental data. Comparison shows that the models used in this calculation can reproduce the data in the $\\Sigma$ channel regions fairly well but still give over predictions in the $\\Lambda$ channel. It seems that the tensor target asymmetries are more suitable for studying the final state effects. The extractions of the elementary photoproduction amplitude are also demonstrated.

  16. Soft Contributions to Hard Pion Photoproduction

    OpenAIRE

    Afanasev, Andrei; Carlson, Carl E.; Wahlquist, Christian

    1999-01-01

    Hard, or high transverse momentum, pion photoproduction can be a tool for probing the parton structure of the beam and target. We estimate the soft contributions to this process, with an eye toward delineating the region where perturbatively calculable processes dominate. Our soft process estimate is based on vector meson dominance and data based parameterizations of semiexclusive hadronic cross sections. We find that soft processes dominate in single pion photoproduction somewhat past 2 GeV ...

  17. Model Selection for Pion Photoproduction

    CERN Document Server

    Landay, J; Fernández-Ramírez, C; Hu, B; Molina, R

    2016-01-01

    Partial-wave analysis of meson and photon-induced reactions is needed to enable the comparison of many theoretical approaches to data. In both energy-dependent and independent parametrizations of partial waves, the selection of the model amplitude is crucial. Principles of the $S$-matrix are implemented to different degree in different approaches, but a many times overlooked aspect concerns the selection of undetermined coefficients and functional forms for fitting, leading to a minimal yet sufficient parametrization. We present an analysis of low-energy neutral pion photoproduction using the Least Absolute Shrinkage and Selection Operator (LASSO) in combination with criteria from information theory and $K$-fold cross validation. These methods are not yet widely known in the analysis of excited hadrons but will become relevant in the era of precision spectroscopy. The principle is first illustrated with synthetic data, then, its feasibility for real data is demonstrated by analyzing the latest available measu...

  18. Hydrogen Production by Water Biophotolysis

    Energy Technology Data Exchange (ETDEWEB)

    Ghirardi, Maria L.; King, Paul W.; Mulder, David W.; Eckert, Carrie; Dubini, Alexandra; Maness, Pin-Ching; Yu, Jianping

    2014-01-22

    The use of microalgae for production of hydrogen gas from water photolysis has been studied for many years, but its commercialization is still limited by multiple challenges. Most of the barriers to commercialization are attributed to the existence of biological regulatory mechanisms that, under anaerobic conditions, quench the absorbed light energy, down-regulate linear electron transfer, inactivate the H2-producing enzyme, and compete for electrons with the hydrogenase. Consequently, the conversion efficiency of absorbed photons into H2 is significantly lower than its estimated potential of 12–13 %. However, extensive research continues towards addressing these barriers by either trying to understand and circumvent intracellular regulatory mechanisms at the enzyme and metabolic level or by developing biological systems that achieve prolonged H2 production albeit under lower than 12–13 % solar conversion efficiency. This chapter describes the metabolic pathways involved in biological H2 photoproduction from water photolysis, the attributes of the two hydrogenases, [FeFe] and [NiFe], that catalyze biological H2 production, and highlights research related to addressing the barriers described above. These highlights include: (a) recent advances in improving our understanding of the O2 inactivation mechanism in different classes of hydrogenases; (b) progress made in preventing competitive pathways from diverting electrons from H2 photoproduction; and (c) new developments in bypassing the non-dissipated proton gradient from down-regulating photosynthetic electron transfer. As an example of a major success story, we mention the generation of truncated-antenna mutants in Chlamydomonas and Synechocystis that address the inherent low-light saturation of photosynthesis. In addition, we highlight the rationale and progress towards coupling biological hydrogenases to non-biological, photochemical charge-separation as a means to bypass the barriers of photobiological

  19. Metabolic flux analysis of the hydrogen production potential in Synechocystis sp. PCC6803

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, E. [Departamento de Lenguajes y Ciencias de la Computacion, Campus de Teatrinos, Universidad de Malaga, 29071 Malaga (Spain); Montagud, A.; Fernandez de Cordoba, P.; Urchueguia, J.F. [Instituto Universitario de Matematica Pura y Aplicada, Universidad Politecnica de Valencia, Camino de Vera 14, 46022 Valencia (Spain)

    2009-11-15

    Hydrogen is a promising energy vector; however, finding methods to produce it from renewable sources is essential to allow its wide-scale use. In that line, biological hydrogen production, although it is considered as a possible alternative, requires substantial improvements to overcome its present low yields. In that direction, genetic manipulation probably will play a central role and from that point of view metabolic flux analysis (MFA) constitutes an important tool to guide a priori most suitable genetic modifications oriented to a hydrogen yield increase. In this work MFA has been applied to analyze hydrogen photoproduction of Synechocystis sp. PCC6803. Flux analysis was carried out based on literature data and several basic fluxes were estimated in different growing conditions of the system. From this analysis, an upper limit for hydrogen photoproduction has been determined indicating a wide margin for improvement. MFA was also used to find a feasible operating space for hydrogen production, which avoids oxygen inhibition, one of the most important limitations to make hydrogen production cost effective. In addition, a set of biotechnological strategies are proposed that would be consistent with the performed mathematical analysis. (author)

  20. Assessment of the Effects of Various UV Sources on Inactivation and Photoproduct Induction in Phage T7 Dosimeter

    NARCIS (Netherlands)

    Fekete, A.; Vink, A.A.; Gaspar, S.; Berces, A.; Modos, K.; Ronto, Gy.; Roza, L.

    1998-01-01

    The correlation between the biologically effective dose (BED) of a phage T7 biological dosimeter and the induction of cyclobutane pyrimidine dimers (CPD) and (6-4) photoproducts ((6-4)PD) in the phage DNA was determined using seven various UV sources. The BED is the inactivation rate of phage T7 exp

  1. Quasi-free $\\pi^0$ Photoproduction from the Bound Nucleon

    CERN Document Server

    Kossert, K; Wissmann, F; Ahrens, J; Annand, J R M; Arends, H J; Beck, R; Caselotti, G; Grabmayr, P; Jahn, O; Jennewein, P; Levchuk, M I; Lvov, A I; McGeorge, J C; Natter, A; Olmos de Léon, V; Petrunkin, V A; Rosner, G; Schumacher, M; Seitz, B; Smend, F; Thomas, A; Weihofen, W; Zapadtka, F

    2004-01-01

    Differential cross-sections for quasi-free $\\pi^0$ photoproduction from the proton and neutron bound in the deuteron have been measured for $E_\\gamma= 200 - 400$ MeV at $\\theta^{\\rm lab}_\\gamma = 136.2^\\circ$ usind the Glasgow photon tagger at MAMI, the Mainz 48 cm $\\varnothing$ $\\times$ 64 cm NaI(Tl) photon detector and the G\\"ottingen SENECA recoil detector. For the proton measurements made with both liquid deuterium and liquid hydrogen targets allow direct comparison of "free" $\\pi^0$ photoproduction cross-sections as extracted from the bound proton data with experimental free cross sections which are found to be in reasonable agreement below 320 MeV. At higher energies the "free" cross sections extracted from quasifree data are significantly smaller than the experimental free cross sections and theoretical predictions based on multipole analysis. For the first time, "free" neutron cross sections have been extracted in the $\\Delta$-region. They are also in agreement with the predictions from multipole anal...

  2. Eta(547) and Eta(958) Meson Photoproduction on the Proton

    Energy Technology Data Exchange (ETDEWEB)

    Michael Dugger

    2001-12-01

    Photoproduction of {eta} and {eta}{prime} mesons has been studied at the Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer (CLAS) using a tagged photon beam incident on a hydrogen target with photon energies from the respective production thresholds up to 2.4 GeV. The photoproduced mesons were identified via missing mass reconstruction using recoil proton momentum and time of flight information. Data were obtained in a range of {radical}s from threshold to 2.2 GeV for each meson. In this study, differential cross-section measurements for the {gamma}p {yields} p{eta} and {gamma}p {yields} p{eta}{prime} reactions are presented, and the results compared to recent data. An isobar analysis of the differential cross-sections is performed. The predicted differential cross-sections from the isobar analysis are used to predict behavior in unmeasured regions of phase space, and to infer total cross sections. For the {gamma}p {yields} p{eta} reaction, a value of the S{sub 11}(1535) proton helicity amplitude also was extracted and compared to recent analyses. The data presented greatly extends the energy and angle coverage for differential cross-sections of {eta} photoproduction, and significantly improves the accuracy with which {eta}{prime} cross sections are known.

  3. Transverse polarization of Λ hyperons from quasi-real photoproduction on nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Airapetian, A. [Justus-Liebig Univ., Giessen (Germany). II. Physikalisches Inst.; Univ. of Michigan, Ann Arbor, MI (United States). Randall Lab. of Physik; Akopov, N. [Yerevan Physics Inst. (Armenia); Akopov, Z. [DESY, Hamburg (Germany); Collaboration: The HERMES Collaboration; and others

    2014-06-15

    The transverse polarization of Λ hyperons was measured in inclusive quasi-real photoproduction for various target nuclei ranging from hydrogen to xenon. The data were obtained by the HERMES experiment at HERA using the 27.6 GeV lepton beam and nuclear gas targets internal to the lepton storage ring. The polarization observed is positive for light target nuclei and is compatible with zero for krypton and xenon.

  4. Transverse polarization of $\\Lambda$ hyperons from quasi-real photoproduction on nuclei

    CERN Document Server

    Airapetian, A; Akopov, Z; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetissian, A; Avetisyan, E; Belostotski, S; Bianchi, N; Blok, H P; Borissov, A; Bowles, J; Brodski, I; Bryzgalov, V; Burns, J; Capiluppi, M; Capitani, G P; Cisbani, E; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; Deconinck, W; De Leo, R; De Nardo, L; De Sanctis, E; Diefenthaler, M; Di Nezza, P; Düren, M; Ehrenfried, M; Elbakian, G; Ellinghaus, F; Fabbri, R; Fantoni, A; Felawka, L; Frullani, S; Gabbert, D; Gapienko, G; Gapienko, V; Garibaldi, F; Gavrilov, G; Gharibyan, V; Giordano, F; Gliske, S; Golembiovskaya, M; Hadjidakis, C; Hartig, M; Hasch, D; Hillenbrand, A; Hoek, M; Holler, Y; Hristova, I; Imazu, Y; Ivanilov, A; Jackson, H E; Jo, H S; Joosten, S; Kaiser, R; Karyan, G; Keri, T; Kinney, E; Kisselev, A; Kobayashi, N; Korotkov, V; Kozlov, V; Kravchenko, P; Krivokhijine, V G; Lagamba, L; Lapikás, L; Lehmann, I; Lenisa, P; Ruiz, A López; Lorenzon, W; Lu, X -G; Ma, B -Q; Mahon, D; Makins, N C R; Manaenkov, S I; Mao, Y; Marianski, B; de la Ossa, A Martinez; Marukyan, H; Miller, C A; Miyachi, Y; Movsisyan, A; Muccifora, V; Murray, M; Mussgiller, A; Nappi, E; Naryshkin, Y; Nass, A; Negodaev, M; Nowak, W -D; Pappalardo, L L; Perez-Benito, R; Reimer, P E; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubin, J; Ryckbosch, D; Salomatin, Y; Sanftl, F; Schäfer, A; Schnell, G; Schüler, K P; Seitz, B; Shibata, T -A; Shutov, V; Stancari, M; Statera, M; Steffens, E; Steijger, J J M; Stewart, J; Stinzing, F; Taroian, S; Terkulov, A; Truty, R; Trzcinski, A; Tytgat, M; Vandenbroucke, A; Van Haarlem, Y; Van Hulse, C; Veretennikov, D; Vikhrov, V; Vilardi, I; Wang, S; Yaschenko, S; Ye, Z; Yu, W; Zagrebelnyy, V; Zeiler, D; Zihlmann, B; Zupranski, P

    2014-01-01

    The transverse polarization of $\\Lambda$ hyperons was measured in inclusive quasi-real photoproduction for various target nuclei ranging from hydrogen to xenon. The data were obtained by the HERMES experiment at HERA using the 27.6 GeV lepton beam and nuclear gas targets internal to the lepton storage ring. The polarization observed is positive for light target nuclei and is compatible with zero for krypton and xenon.

  5. Multijets in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Krastev, Kaloyan

    2008-11-15

    In the analysis jets in photoproduction are studied with data collected by the H1 detector in 2006. Events with at least two jets with transverse energy greater than 9 GeV and pseudorapidity in the range of -0.5 to 1.5 in the laboratory frame are selected for the dijet sample. For the trijet and fourjet scenarios, one and two additional jets with transverse energy greater than 6 GeV and pseudorapidity in the range of -0.5 to 2.4 are required. The aim of the analysis is to study the dynamics of multijet events (events with more than two jets). In the perturbative picture the jet rate increases due to additional parton emissions. The jet rate can also be affected by multiple parton interactions when several pairs of partons within the incoming particles interact. Differential cross sections as a function of various variables for the dijet, trijet and fourjet scenario are measured. In addition, the applicability of two currently established multiple interaction models is tested. The results show that current models are not correctly describing the properties of multijet events in the analyzed phase space. (orig.)

  6. eta Photoproduction and N* resonances

    CERN Document Server

    Choi, Ki-Seok; Hosaka, Atsushi; Kim, Hyun-Chul

    2007-01-01

    We investigate the eta photoproduction from the nucleon using the effective Lagrangian approach at tree level. We focus on the nucleon resonance N*(1675) of possibly exotic nature, which was reported by the GRAAL, Tohoku LNS and CB-ELSA examining its spin and parity theoretically. In addition, we consider six nucleon resonances, D_{13}(1520), S_{11}(1535), S_{11}(1650), D_{15}(1675), P_{11}(1710), P_{13}(1720) as well as possible background contributions. We calculate the differential cross sections and beam asymmetries for the neutron and proton targets. They indicate that there is isospin asymmetry which can be interpreted as the large difference in the the transition photon couplings: mu_{gamma p p*} << mu_{gamma n n*}. Moreover, we find that the spin-1/2 state is preferred in order to reproduce the experimental data, although its parity remains undetermined. This observation implies that the new resonance may be identified as a non-strangeness member of the baryon antidecuplet.

  7. The stable isotopic signature of biologically produced molecular hydrogen (H2

    Directory of Open Access Journals (Sweden)

    T. Röckmann

    2011-12-01

    Full Text Available Biologically produced molecular hydrogen (H2 is characterized by a very strong depletion in deuterium. Although the biological source to the atmosphere is small compared to photochemical or combustion sources, it makes an important contribution to the global isotope budget of molecular hydrogen (H2. Large uncertainties exist in the quantification of the individual production and degradation processes that contribute to the atmospheric budget, and isotope measurements are a tool to distinguish the contributions from the different sources. Measurements of δD from the various H2 sources are scarce and for biologically produced H2 only very few measurements exist. Here the first systematic study of the isotopic composition of biologically produced H2 is presented. We investigated δD of H2 produced in a biogas plant, covering different treatments of biogas production, and from several H2 producing microorganisms such as bacteria or green algae. A Keeling plot analysis provides a robust overall source signature of δD = –712‰ (±13‰ for the samples from the biogas reactor (at 38 °C, δDH2O = 73.4‰, with a fractionation constant ϵH2−H2O of –689‰ (±20‰. The pure culture samples from different microorganisms give a mean source signature of δD = –728‰ (±39‰, and a fractionation constant ϵH2−H2O of –711‰ (±45‰ between H2 and the water, respectively. The results confirm the massive deuterium depletion of biologically produced H2 as was predicted by calculation of the thermodynamic fractionation factors for hydrogen exchange between H2 and water vapor. As expected for a thermodynamic equilibrium, the fractionation factor is largely independent of the substrates used and the H2 production conditions. The predicted equilibrium fractionation coefficient is positively correlated with temperature and we measured a change of 2.2‰/°C between 45 °C and 60 °C. This is in general agreement with the

  8. Soft Contributions to Hard Pion Photoproduction

    CERN Document Server

    Afanasiev, A V; Wahlquist, C; Afanasev, Andrei; Carlson, Carl E.; Wahlquist, Christian

    2000-01-01

    Hard, or high transverse momentum, pion photoproduction can be a tool for probing the parton structure of the beam and target. We estimate the soft contributions to this process, with an eye toward delineating the region where perturbatively calculable processes dominate. Our soft process estimate is based on vector meson dominance and data based parameterizations of semiexclusive hadronic cross sections. We find that soft processes dominate in single pion photoproduction somewhat past 2 GeV transverse momentum at a few times 10 GeV incoming energy. The recent polarization asymmetry data is consistent with the perturbative asymmetry being diluted by polarization insensitive soft processes. Determining the polarized gluon distribution using hard pion photoproduction appears feasible with a few hundred GeV incoming energy (in the target rest frame).

  9. Photoproduction of pi0-mesons from nuclei

    CERN Document Server

    Krusche, B; Ahrens, J; Annand, J R M; Beck, R; Bloch, Felix; Fog, L S; Hornidge, D; Janssen, S; Kotulla, M; McGeorge, J C; MacGregor, I J D; Messchendorp, J; Metag, V; Mosel, U; Novotny, R; Owens, R O; Pfeiffer, M; Sanderson, R; Schadmand, S; Watts, D P

    2004-01-01

    Photoproduction of neutral pions from nuclei (carbon, calcium, niobium, lead) has been studied for incident photon energies from 200 MeV to 800 MeV with the TAPS detector using the Glasgow photon tagging spectrometer at the Mainz MAMI accelerator. Data were obtained for the inclusive photoproduction of neutral pions and the partial channels of quasifree single pi0, double pi0, and pi0pi+/- photoproduction. They have been analyzed in terms of the in-medium behavior of nucleon resonances and the pion - nucleus interaction. They are compared to earlier measurements from the deuteron and to the predictions of a Boltzmann-Uehling-Uhlenbeck (BUU) transport model for photon induced pion production from nuclei.

  10. The FOREST detector for meson photoproduction experiments at ELPH

    Science.gov (United States)

    Ishikawa, T.; Fujimura, H.; Fukasawa, H.; Hashimoto, R.; Ishida, T.; Kaida, S.; Kasagi, J.; Kawano, A.; Kuwasaki, S.; Maeda, K.; Miyahara, F.; Mochizuki, K.; Nakabayashi, T.; Nakamura, A.; Nawa, K.; Ogushi, S.; Okada, Y.; Okamura, K.; Onodera, Y.; Saito, Y.; Sakamoto, Y.; Sato, M.; Shimizu, H.; Sugai, H.; Suzuki, K.; Takahashi, S.; Tsuchikawa, Y.; Yamazaki, H.; Yonemura, H.

    2016-10-01

    An electromagnetic calorimeter complex, FOREST, has been constructed for meson photoproduction experiments at the Research Center for Electron Photon Science, Tohoku University. It consists of three types of calorimeters, which are made of pure cesium-iodide crystals, lead scintillating-fiber modules, and lead glass Cherenkov counters. Each calorimeter is equipped with a plastic scintillator hodoscope to identify charged particles. The design and performance of FOREST are described. The energy responses of test calorimeters have been investigated by using 100-800 MeV positron beams. The energy resolutions of the three calorimeters are found to be approximately 3%, 7%, and 5% for 1-GeV photons, respectively. A cryogenic hydrogen/deuterium target system fitted to the FOREST experiments and a newly developed data acquisition system are also presented.

  11. Studies in deep inelastic scattering and vector meson photoproduction

    International Nuclear Information System (INIS)

    The first part of this thesis is devoted to a space-time analysis of deep inelastic scattering from protons at rest. Techniques are developed for identifying important space-time regions. These are then applied to obtain a space-time picture of deep inelastic scattering in the leading logarithmic approximation of QCD. Physical mechanisms responsible for the space-time picture are discussed. In the second part of this thesis we report on the observation of elastic ω photoproduction from hydrogen by Fermilab Experiment-401. The ω was detected via its decay into the π+π-π0 channel. Measurements of the energy, momentum transfer, and angular dependence of the cross section have been made for photon energies between 60 and 225 GeV

  12. Technical Key Figures for Photo-biological Hydrogen Production by Micro-algae

    International Nuclear Information System (INIS)

    One regenerative path to produce hydrogen is the photo-biological hydrogen production by the green micro-alga Chlamydomonas reinhardtii. This process can be divided into three phases: a growth phase, a phase in which the algae adapt from oxygen production and CO2-fixation to fermentative H2 production, and a phase in which H2 is produced. In a research project carried out at Ruhr-Universitat Bochum, a new developed flat panel bioreactor was investigated. A system analysis was conducted and energetic and environmental key figures were determined. The intention of this assessment on a very early technological stage was to collect first technical data in order to classify the current technological status of the photo-biological H2 production to identify future potentials and to uncover weaknesses. For this reason the key figures were evaluated for the status quo and for two scenarios which allow an outlook on the mid and the long term. The results were compared with other ways of regenerative H2 production. (authors)

  13. Pion photoproduction in nucleons at low energies

    International Nuclear Information System (INIS)

    A new semiphenomenological analysis of the multipoles for pion photoproduction from nucleons, in the region of the first π-N resonance is presented. Through an energy dependent model, multipoles with isospin 1/2 and 3/2 and total angular momentum J < = 3/2 are determined. (Author)

  14. Target asymmetry in inclusive photoproduction of pions

    International Nuclear Information System (INIS)

    We study the target asymmetry in inclusive pion photoproduction in the photon fragmentation region using a helicity dependent Mueller-Regge model, in which the Regge cut contributions are also included. We obtained predictions for the t-dependence and the magnitude of the target asymmetry. (orig.)

  15. Probing Polarized Parton Distributions with Meson Photoproduction

    CERN Document Server

    Afanasiev, A M; Wahlquist, C; Afanasev, Andrei; Carlson, Carl E.; Wahlquist, Christian

    1997-01-01

    Polarization asymmetries in photoproduction of high transverse momentum mesons are a flavor sensitive way to measure the polarized quark distributions. We calculate the expected asymmetries in several models, and find that the asymmetries are significant and also significantly different from model to model. Suitable data may come as a by-product of deep inelastic experiments to measure $g_1$ or from dedicated experiments.

  16. Biological hydrogen production by Anabaena sp. – Yield, energy and CO2 analysis including fermentative biomass recovery

    OpenAIRE

    Ferreira, Ana F.; Marques, Ana C.; Batista, Ana Paula; Marques, Paula Alexandra; de Gouveia, L.; Carla M. Silva

    2012-01-01

    This paper presents laboratory results of biological production of hydrogen by photoautrotophic cyanobacterium Anabaena sp. Additional hydrogen production from residual Cyanobacteria fermentation was achieved by Enterobacter aerogenes bacteria. The authors evaluated the yield of H2 production, the energy consumption and CO2 emissions and the technological bottlenecks and possible improvements of the whole energy and CO2 emission chain. The authors did not attempt to extrapolate the results to...

  17. Beam asymmetry Σ in π0 photoproduction off protons bound in carbon nuclei

    International Nuclear Information System (INIS)

    In order to study the dynamics of the inner components of the nucleon, its excitation spectrum is investigated through meson-photoproduction. Due to the strong overlap of the nucleon's excited states, it is insufficient to determine the cross section only. To identify all resonance contributions unambiguously, single and double polarization observables have to be measured. At the Crystal Barrel experiment at ELSA in Bonn, this is achieved utilizing linearly or circularly polarized photons and longitudinally or transversely polarized nucleons. Polarized protons are realized in a butanol target, which consists of hydrogen, oxygen and carbon. A pure carbon target was used to perform a background measurement. The results for the beam asymmetry Σ in π0 photoproduction, obtained with a carbon target and a linearly polarized photon beam, are presented. Furthermore, the influence of carbon background on the measured polarization observables is discussed.

  18. Redox biology of hydrogen sulfide: Implications for physiology, pathophysiology, and pharmacology

    Directory of Open Access Journals (Sweden)

    Asaf Stein

    2013-01-01

    Full Text Available Hydrogen sulfide (H2S has emerged as a critical mediator of multiple physiological processes in mammalian systems. The pathways involved in the production, consumption, and mechanism of action of H2S appear to be sensitive to alterations in the cellular redox state and O2 tension. Indeed, the catabolism of H2S through a putative oxidation pathway, the sulfide quinone oxido-reductase system, is highly dependent on O2 tension. Dysregulation of H2S homeostasis has also been implicated in numerous pathological conditions and diseases. In this review, the chemistry and the main physiological actions of H2S are presented. Some examples highlighting the cytoprotective actions of H2S within the context of cardiovascular disease are also reported. Elucidation of the redox biology of H2S will enable the development of new pharmacological agents based on this intriguing new redox cellular signal.

  19. Hydrogen sulfide releasing capacity of natural isothiocyanates: is it a reliable explanation for the multiple biological effects of Brassicaceae?

    Science.gov (United States)

    Citi, Valentina; Martelli, Alma; Testai, Lara; Marino, Alice; Breschi, Maria C; Calderone, Vincenzo

    2014-06-01

    Hydrogen sulfide is an endogenous pleiotropic gasotransmitter, which mediates important physiological effects in the human body. Accordingly, an impaired production of endogenous hydrogen sulfide contributes to the pathogenesis of important disorders. To date, exogenous compounds, acting as hydrogen sulfide-releasing agents, are viewed as promising pharmacotherapeutic agents. In a recent report, the hydrogen sulfide-releasing properties of some synthetic aryl isothiocyanate derivatives have been reported, indicating that the isothiocyanate function can be viewed as a suitable slow hydrogen sulfide-releasing moiety, endowed with the pharmacological potential typical of this gasotransmitter. Many isothiocyanate derivatives (deriving from a myrosinase-mediated transformation of glucosinolates) are well-known secondary metabolites of plants belonging to the family Brassicaceae, a large botanical family comprising many edible species. The phytotherapeutic and nutraceutic usefulness of Brassicaceae in the prevention of important human diseases, such as cancer, neurodegenerative processes and cardiovascular diseases has been widely discussed in the scientific literature. Although these effects have been largely attributed to isothiocyanates, the exact mechanism of action is still unknown. In this experimental work, we aimed to investigate the possible hydrogen sulfide-releasing capacity of some important natural isothiocyanates, studying it in vitro by amperometric detection. Some of the tested natural isothiocyanates exhibited significant hydrogen sulfide release, leading us to hypothesize that hydrogen sulfide may be, at least in part, a relevant player accounting for several biological effects of Brassicaceae.

  20. Development of a rechargeable optical hydrogen peroxide sensor - sensor design and biological application.

    Science.gov (United States)

    Koren, Klaus; Jensen, Peter Ø; Kühl, Michael

    2016-07-21

    Hydrogen peroxide (H2O2) is an important member of the reactive oxygen species (ROS) family. Among ROS, H2O2 is considered the most long-lived and can accumulate inside and outside of cells, where it is involved in both vital (signaling) and deadly (toxic) reactions depending on its concentration. Quantifying H2O2 within biological samples is challenging and often not possible. Here we present a quasi-reversible fiber-optic sensor capable of measuring H2O2 concentrations ranging from 1-100 μM within different biological samples. Based on a Prussian blue/white redox cycle and a simple sensor recharging and readout strategy, H2O2 can be measured with high spatial (∼500 μm) and temporal (∼30 s) resolution. The sensor has a broad applicability both in complex environmental and biomedical systems, as demonstrated by (i) H2O2 concentration profile measurements in natural photosynthetic biofilms under light stress reaching H2O2 concentrations as high as 15 μM, and (ii) the quantification of the transient increase of the extracellular concentration of H2O2 during stimulation of neutrophils. PMID:27183881

  1. The stable isotopic signature of biologically produced molecular hydrogen (H2)

    Science.gov (United States)

    Walter, S.; Laukenmann, S.; Stams, A. J. M.; Vollmer, M. K.; Gleixner, G.; Röckmann, T.

    2012-10-01

    Biologically produced molecular hydrogen (H2) is characterised by a very strong depletion in deuterium. Although the biological source to the atmosphere is small compared to photochemical or combustion sources, it makes an important contribution to the global isotope budget of H2. Large uncertainties exist in the quantification of the individual production and degradation processes that contribute to the atmospheric budget, and isotope measurements are a tool to distinguish the contributions from the different sources. Measurements of δ D from the various H2 sources are scarce and for biologically produced H2 only very few measurements exist. Here the first systematic study of the isotopic composition of biologically produced H2 is presented. In a first set of experiments, we investigated δ D of H2 produced in a biogas plant, covering different treatments of biogas production. In a second set of experiments, we investigated pure cultures of several H2 producing microorganisms such as bacteria or green algae. A Keeling plot analysis provides a robust overall source signature of δ D = -712‰ (±13‰) for the samples from the biogas reactor (at 38 °C, δ DH2O= +73.4‰), with a fractionation constant ϵH2-H2O of -689‰ (±20‰) between H2 and the water. The five experiments using pure culture samples from different microorganisms give a mean source signature of δ D = -728‰ (±28‰), and a fractionation constant ϵH2-H2O of -711‰ (±34‰) between H2 and the water. The results confirm the massive deuterium depletion of biologically produced H2 as was predicted by the calculation of the thermodynamic fractionation factors for hydrogen exchange between H2 and water vapour. Systematic errors in the isotope scale are difficult to assess in the absence of international standards for δ D of H2. As expected for a thermodynamic equilibrium, the fractionation factor is temperature dependent, but largely independent of the substrates used and

  2. The stable isotopic signature of biologically produced molecular hydrogen (H2

    Directory of Open Access Journals (Sweden)

    T. Röckmann

    2012-10-01

    Full Text Available Biologically produced molecular hydrogen (H2 is characterised by a very strong depletion in deuterium. Although the biological source to the atmosphere is small compared to photochemical or combustion sources, it makes an important contribution to the global isotope budget of H2. Large uncertainties exist in the quantification of the individual production and degradation processes that contribute to the atmospheric budget, and isotope measurements are a tool to distinguish the contributions from the different sources. Measurements of δ D from the various H2 sources are scarce and for biologically produced H2 only very few measurements exist. Here the first systematic study of the isotopic composition of biologically produced H2 is presented. In a first set of experiments, we investigated δ D of H2 produced in a biogas plant, covering different treatments of biogas production. In a second set of experiments, we investigated pure cultures of several H2 producing microorganisms such as bacteria or green algae. A Keeling plot analysis provides a robust overall source signature of δ D = −712‰ (±13‰ for the samples from the biogas reactor (at 38 °C, δ DH2O= +73.4‰, with a fractionation constant ϵH2-H2O of −689‰ (±20‰ between H2 and the water. The five experiments using pure culture samples from different microorganisms give a mean source signature of δ D = −728‰ (±28‰, and a fractionation constant ϵH2-H2O of −711‰ (±34‰ between H2 and the water. The results confirm the massive deuterium depletion of biologically produced H2 as was predicted by the calculation of the thermodynamic fractionation factors for hydrogen exchange between H2 and water vapour. Systematic errors in the isotope scale are difficult to assess in the absence of international standards for δ D of H2. As expected for a thermodynamic equilibrium, the fractionation factor is temperature dependent, but largely independent of the

  3. Rate-controlling steps in a three-phase (solid-liquid-gas) photoreactor: a phenomenological approach applied to hydrogen photoproduction using Pt-TiO/sub 2/ aqueous suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Escudero, J.C.; Simarro, R.; Cervera-March, S.; Gimenez, J.

    1989-01-01

    Water photolysis has been studied using a three-phase solid-liquid-gas photoreactor, continuous with respect to the gas phase. The Pt-TiO/sub 2/ catalytic powders were kept suspended in water by means of gas bubbling through the liquid. In this case the hydrogen production rate can be controlled by luminic and dark (chemical or mass-transfer) processes. The relative importance of each of these processes depends on the lamp-photoreactor system used, the nature and physical characteristics of the photocatalysts, and the operating (fluidodynamic) conditions. A description of the steps involved in the overall photocatalytic process is given. The importance of mass transfer in limiting the process yield is demonstrated, showing that this step has to be considered in the development of photocatalysts even at early stages.

  4. Biologically Induced Hydrogen Production Drives High Rate/High Efficiency Microbial Electrosynthesis of Acetate from Carbon Dioxide

    NARCIS (Netherlands)

    Jourdin, Ludovic; Lu, Yang; Flexer, Victoria; Keller, Jurg; Freguia, Stefano

    2016-01-01

    Electron-transfer pathways occurring in biocathodes are still unknown. We demonstrate here that high rates of acetate production by microbial electrosynthesis are mainly driven by an electron flux from the electrode to carbon dioxide, occurring via biologically induced hydrogen, with (99±1)% elec

  5. Exclusive Photoproduction of the Cascade (Xi) Hyperons

    CERN Document Server

    Price, J W; Berman, B L; Laget, J M; Strauch, S; Adams, G; Afanasiev, A V; Ambrozewicz, P; Anghinolfi, M; Annand, J R M; Armstrong, C; Asavapibhop, B; Avakian, H; Bagdasaryan, H; Ball, J P; Barrow, S; Battaglieri, M; Beard, K; Bektasoglu, M; Bellis, M; Benmouna, N; Bianchi, N; Biselli, A S; Boiarinov, S; Bonner, B E; Bouchigny, S; Bradford, R; Branford, D; Briscoe, W J; Brooks, W K; Burkert, V D; Butuceanu, C; Calarco, J R; Carman, D S; Carnahan, B; Chen, S; Cole, P L; Coleman, A; Cords, D; Corvisiero, P; Crabb, D; Crannell, H; Cummings, J P; De Sanctis, E; De Vita, R; Degtyarenko, P V; Denizli, H; Dennis, L; Dharmawardane, K V; Dhuga, K S; Djalali, C; Dodge, G E; Doughty, D; Dragovitsch, P; Dugger, M; Dytman, S; Dzyubak, O P; Egiyan, H; Egiyan, K S; Elouadrhiri, L; Empl, A; Ent, R; Eugenio, P; Fatemi, R; Fedotov, G; Feldman, G; Feuerbach, R J; Ficenec, J; Forest, T A; Funsten, H; Gavalian, G; Gilfoyle, G P; Giovanetti, K L; Golovatch, E; Gordon, C I O; Gothe, R W; Griffioen, K; Guidal, M; Guillo, M R; Guler, N; Guo, L; Gyurjyan, V; Hadjidakis, C; Hakobyan, R S; Hardie, J; Heddle, D; Heimberg, P; Hersman, F W; Hicks, K; Hleiqawi, K; Holtrop, M; Hu, J; Huertas, M; Hyde-Wright, C E; Ilieva, Y Y; Ireland, D; Ito, M M; Jenkins, D; Jo, H S; Joo, K; Jüngst, H G; Kellie, J; Khandaker, M; Kim, K Y; Kim, K; Kim, W; Klein, A; Klein, F J; Klimenko, A V; Klusman, M; Kossov, M; Kramer, L H; Kuang, Y; Kuhn, S E; Kühn, J; Lachniet, J; Langheinrich, J; Lawrence, D; Ji Li; Lima, A C S; Livingston, K; Lukashin, K; Manak, J J; Marchand, C; McAleer, S; McNabb, J W C; Mecking, B A; Melone, J J; Mestayer, M D; Meyer, C A; Mikhailov, K; Minehart, R C; Mirazita, M; Miskimen, R; Morand, L; Morrow, S A; Muccifora, V; Müller, J; Murphy, L Y; Mutchler, G S; Napolitano, J; Nasseripour, R; Niccolai, S; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niyazov, R A; Nozar, M; O'Brien, J T; O'Rielly, G V; Osipenko, M; Ostrovidov, A I; Park, K; Pasyuk, E A; Philips, S A; Pivnyuk, N; Pocanic, D; Pogorelko, O I; Polli, E; Popa, I; Pozdniakov, S; Preedom, B M; Prok, Y; Protopopescu, D; Qin, L M; Raue, B A; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Ronchetti, F; Rosner, G; Rossi, P; Rowntree, D; Rubin, P D; Sabatie, F; Salgado, C; Santoro, J P; Sapunenko, V; Schumacher, R A; Serov, V S; Shafi, A; Sharabyan, Yu G; Shaw, J; Skabelin, A V; Smith, E S; Smith, L C; Sober, D I; Stavinsky, A V; Stepanyan, S; Stoler, P; Strakovsky, I I; Suleiman, R; Taiuti, M; Taylor, S; Tedeschi, D J; Thoma, U; Thompson, R; Tkabladze, R; Todor, L; Tur, C; Ungaro, M; Vineyard, M F; Vlassov, A V; Wang, K; Weinstein, L B; Weygand, D P; Whisnant, C S; Williams, M; Wolin, E; Wood, M H; Yegneswaran, A; Yun, J; Zana, L

    2004-01-01

    We report on the first measurement of exclusive Xi-(1321) hyperon photoproduction in gamma p --> K+ K+ Xi- for 3.2 < E(gamma) < 3.9 GeV. The final state is identified by the missing mass in p(gamma,K+ K+)X measured with the CLAS detector at Jefferson Laboratory. We have detected a significant number of the ground-state Xi-(1321)1/2+, and have estimated the total cross section for its production. We have also observed the first excited state Xi-(1530)3/2+. Photoproduction provides a copious source of Xi's. We discuss the possibilities of a search for the recently proposed Xi5-- and Xi5+ pentaquarks.

  6. {eta} photoproduction off {sup 3}He

    Energy Technology Data Exchange (ETDEWEB)

    Witthauer, Lilian [Department of Physics, University Basel (Switzerland)

    2010-07-01

    Quark models predict many more states in the excitation spectrum of the nucleon than observed in experiments. Most previous experiments investigating the excitation spectrum of nucleons are based on elastic scattering of charged pions. This makes it probable that the data is biased against states that couple only weakly to N{pi}. Hence, one can study different excitation mechanisms and channels as the photoproduction of mesons via excitation of nucleon resonances. Measurements at ELSA in Bonn investigated the quasi-free {eta} photoproduction off the neutron (I. Jaegle et al., Phys. Rev. Lett 100 (2008) 252002). The resulting cross section shows a narrow structure at W=1.68 GeV with a width smaller than 60 MeV. This structure is only visible in the cross section on the neutron and not in that on the proton. Experiments of the GRAAL collaboration (V.Kuznetsov et al., arXiv:hep-ex/0606065v2) and LNS-Sendai (F. Miyahara et al., Prog. Theor. Phys. Suppl. 168 (2007) 90) showed the same effect in quasi-free photoproduction off the deuteron. In order to exclude any possibility that the structure could arise from nuclear effects (re-scattering of mesons, final state interaction) we have studied it for a nucleon system with different momentum distribution and different neutron/proton ratio, namely {sup 3}He. Preliminary results for the quasi-free {eta} cross section obtained in coincidence with recoil nucleons will be discussed.

  7. Measurement of Elastic Omega Photoproduction at HERA

    CERN Document Server

    Derrick, Malcolm; Magill, S; Mikunas, D; Musgrave, B; Okrasinski, J R; Repond, J; Stanek, R; Talaga, R L; Zhang, H; Mattingly, M C K; Anselmo, F; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Boscherini, D; Bruni, A; Bruni, G; Bruni, P; Cara Romeo, G; Castellini, G; Cifarelli, Luisa; Cindolo, F; Contin, A; Corradi, I; Gialas, I; Giusti, P; Iacobucci, G; Laurenti, G; Levi, G; Margotti, A; Massam, Thomas; Nania, R; Palmonari, F; Pesci, A; Polini, A; Sartorelli, G; Zamora-Garcia, Yu E; Zichichi, Antonino; Amelung, C; Bornheim, A; Crittenden, James Arthur; Deffner, R; Doeker, T; Eckert, M; Feld, L; Frey, A; Geerts, M; Grothe, M; Hartmann, H; Heinloth, K; Heinz, L; Hilger, E; Jakob, H P; Katz, U F; Mengel, S; Paul, E; Pfeiffer, M; Rembser, C; Schramm, D; Stamm, J; Wedemeyer, R; Campbell-Robson, S; Cassidy, A; Cottingham, W N; Dyce, N; Foster, B; George, S; Hayes, M E; Heath, G P; Heath, H F; Piccioni, D; Roff, D G; Tapper, R J; Yoshida, R; Arneodo, M; Ayad, R; Capua, M; Garfagnini, A; Iannotti, L; Schioppa, M; Susinno, G; Caldwell, A; Crtiglia, N; Jing, Z; Liu, W; Parsons, J A; Ritz, S; Sciulli, F; Straub, P B; Wai, L; Yang, S; Zhu, Q; Borzemski, P; Chwastowski, J; Eskreys, Andrzej; Jakubowski, Z; Przybycien, M B; Zachara, M; Zawiejski, L; Adamczyk, L; Bednarek, B; Jelen, K; Kisielewska, D; Kowalski, T; Rulikowska-Zarebska, E; Suszycki, L; Zajac, J; Dulinski, Z; Kotanski, Andrzej; Abbiendi, G; Bauerdick, L A T; Behrens, U; Beier, H; Bienlein, J K; Cases, G; Deppe, O; Desler, K; Drews, G; Flasinski, M; Gilkinson, D J; Glasman, C; Göttlicher, P; GroBe-Knitter, J; Haas, T; Hain, W; Hasell, D; Hessling, H; Iga, Y; Johnson, K F; Joos, P; Kasemann, M; Klanner, Robert; Koch, W; Kötz, U; Kowalski, H; Labs, J; Ladage, A; Löhr, B; Loewe, M; Lüke, D; Mainusch, J; Manczak, O; Milewski, J; Monteiro, T; Ng, J S T; Notz, D; Ohrenberg, K; Piotrzkowski, K; Roco, M T; Rohde, M; Roldán, J; Schneekloth, U; Schulz, W; Selonke, F; Surrow, B; Tassi, E; Voss, T; Westphal, D; Wolf, G; Wollmer, U; Youngman, C; Zeuner, W; Grabosch, H J; Mari, S M; Meyer, A; Schlenstedt, S; Barbagli, G; Gallo, E; Pelfer, P G; Maccarrone, G D; De Pasquale, S; Votano, L; Bamberger, Andreas; Eisenhardt, S; Trefzger, T M; Wölfle, S; Bromley, J T; Brook, N H; Bussey, Peter J; Doyle, A T; Saxon, D H; Sinclair, L E; Utley, M L; Wilson, A S; Dannemann, A; Holm, U; Horstmann, D; Sinkus, R; Wick, K; Burow, B D; Hagge, L; Lohrmann, E; Poelz, G; Schott, W; Zetsche, F; Bacon, Trevor C; Brümmer, N; Butterworth, Ian; Harris, V L; Howell, G; Hung, B Y H; Lamberti, L; Long, K R; Miller, D B; Pavel, N; Prinias, A; Sedgbeer, J K; Sideris, Daniel A; Whitfield, A F; Mallik, U; Wang, M Z; Wang, S M; Wu, J T; Cloth, P; Filges, E; An Shiz Hong; Cho, G H; Ko, B J; Lee, S B; Nam, S W; Park, H S; Park, S K; Kartik, S; Kim, H J; McNeil, R R; Metcalf, W; Nadendla, V K; Barreiro, F; Fernández, J P; Graciani, R; Hernández, J M; Hervás, L; Laberga, L; Martínez, M; Del Peso, J; Puga, J; Terrón, J; De Trocóniz, J F; Corriveau, F; Hanna, D S; Hartmann, J; Yung, L W; Lim, J N; Matthews, C G; Murray, W N; Ochs, A; Patel, P M; Riveline, M; Stairs, D G; Saint-Laurent, M G; Ullmann, R T; Zacek, G; Tsurugai, T; Bashkirov, V; Dolgoshein, B A; Stifutkin, A; Bashindzhagian, G L; Ermolov, P F; Gladilin, L K; Golubkov, Yu A; Kobrin, V D; Korzhavina, I A; Kuzmin, V A; Lukina, O Yu; Proskuryakov, A S; Savin, A A; Shcheglova, L M; Solomin, A N; Zotov, N P; Botje, M; Chlebana, F S; Engelen, J; De Kamps, M; Kooijman, P M; Kruse, A; Van Sighem, A; Tiecke, H G; Verkerke, W; Vossebeld, Joost Herman; Vreeswijk, M; Wiggers, L; De Wolf, E; Van Woudenberg, R; Acosta, D; Bylsma, B G; Durkin, L S; Gilmore, J; Ginsburg, C M; Kim, C L; Li Chuan; Ling, T Y; Nylander, P; Park, I H; Romanowsky, T A; Bailey, D S; Cashmore, Roger J; Cooper-Sarkar, A M; Devenish, R C E; Harmew, N; Lancaster, M; Lindemann, L; McFall, J D; Nath, C; Noyes, V A; Quadt, A; Tickner, J R; Uijterwaal, H; Walczak, R; Waters, D S; Wilson, F F; Yip, T; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; De Giorgi, M; Dosselli, U; Limentani, S; Morandin, M; Posocco, M; Stanco, L; Stroili, R; Voci, C; Zuin, F; Bulmahn, J; Feild, R G; Oh, B Y; Whitmore, J; D'Agostini, Giulio; Marini, G; Nigro, A; Hart, J C; McCubbin, N A; Shah, T P; Barberis, E; Dubbs, T; Heusch, C A; Van Hook, M; Lockman, W; Rahn, J T; Sadrozinski, H F W; Seiden, A; Williams, D C; Biltzinger, J; Seifert, R J; Schwarzer, O; Walenta, Albert H; Abramowicz, H; Briskin, G M; Dagan, S; Levy, A; Inuzuka, M; Ishii, T; Kuze, M; Mine, S; Nakao, M; Suzuki, I; Tokushuku, K; Umemori, K; Yamada, S; Yamazaki, Y; Chiba, M; Hamatsu, R; Hirose, T; Homma, K; Kitamura, S; Matsushita, T; Yamauchi, K; Cirio, R; Costa, M; Ferrero, M I; Maselli, S; Peroni, C; Sacchi, R; Solano, A; Staiano, A; Dardo, M; Bailey, D C; Bénard, F; Brkic, M; Fagerstroem, C P; Hartner, G F; Joo, K K; Levman, G M; Martin, J F; Orr, R S; Polenz, S; Sampson, C R; Simmons, D; Teuscher, R; Butterworth, J M; Catterall, C D; Jones, T W; Kaziewicz, P B; Lane, J B; Saunders, R L; Shulman, J; Sutton, M R; Lu, B; Mo, L W; Bogusz, W; Ciborowski, J; Gajewski, J; Grzelak, G; Kasprzak, M; Krzyzanowski, M; Muchorowski, K; Nowak, R J; Pawlak, J M; Tymieniecka, T; Wróblewski, A K; Zakrzewski, J A; Zarnecki, A F; Adamus, M; Coldewey, C; Eisenberg, Y; Hochman, D; Karshon, U; Revel, D; Zer-Zion, D; Badgett, W F; Breitweg, J; Chapin, D; Cross, R; Dasu, S; Foudas, C; Loveless, R J; Mattingly, S E K; Reeder, D D; Silverstein, S; Smith, W H; Vaiciulis, A W; Wodarczyk, M; Bhadra, S; Cardy, M L; Frisken, W R; Khakzad, M; Schmidke, W B

    1996-01-01

    The reaction $\\gamma p \\rightarrow \\omega p$ $(\\omega \\rightarrow interactions using the \\mbox{ZEUS} detector at photon-proton centre-of-mass energies between $70$ and $90\\uni{GeV}$ and $|t| < 0.6\\uni{GeV}^2$, where $t$ is the squared four momentum transferred at the proton vertex. The elastic \\ome photoproduction cross section has been measured to be $\\sigma_{\\gamma cross section $d\\sigma_{\\gamma p\\rightarrow \\omega p} /d|t|$ has an exponential shape $\\mbox{e}^{-b |t|}$ with a slope $b = 10.0\\pm 1.2\\pm 1.3\\uni{GeV}^{-2}$. The angular distributions of the decay pions are consistent with {\\it s}-channel helicity conservation. When compared to low energy data, the features of $\\omega$ photoproduction as measured at HERA energies are in agreement with those of a soft diffractive process. Previous measurements of the $\\rho^0$ and $\\phi$ photoproduction cross sections at HERA show a similar behaviour.

  8. Electronic structure of (6-4) DNA photoproduct repair involving a non-oxetane pathway.

    Science.gov (United States)

    Domratcheva, Tatiana; Schlichting, Ilme

    2009-12-16

    Mutagenic pyrimidine-pyrimidone (6-4) photoproducts are one of the main DNA lesions induced by solar UV radiation. These lesions can be photoreversed by (6-4) photolyases. The originally published repair mechanism involves rearrangement of the lesion into an oxetane intermediate upon binding to the (6-4) photolyase, followed by light-induced electron transfer from the reduced flavin cofactor. In a recent crystallographic study on a (6-4) photoproduct complexed with (6-4) photolyase from Drosophila melanogaster no oxetane was observed, raising the possibility of a non-oxetane repair mechanism. Using quantum-chemical calculations we find that in addition to repair via an oxetane, a direct transfer of the hydroxyl group results in reversal of the radical anion (6-4) photoproduct. In both mechanisms, the transition states have high energies and correspond to avoided crossings of the ground and excited electronic states. To study whether the repair can proceed via these state crossings, the excited-state potential energy curves were computed. The radical excitation energies and accessibility of the nonadiabatic repair path were found to depend on hydrogen bonds and the protonation state of the lesion. On the basis of the energy calculations, a nonadiabatic repair of the excited (6-4) lesion radical anion via hydroxyl transfer is probable. This repair mechanism is in line with the recent structural data on the (6-4) photolyase from D. melanogaster . PMID:19921821

  9. Cytosine photoproduct-DNA glycosylase in Escherichia coli and cultured human cells

    International Nuclear Information System (INIS)

    Ultraviolet irradiation of DNA produces a variety of pyrimidine base damages. The activities of Escherichia coli endonuclease III and a human lymphoblast endonuclease that incises ultraviolet-irradiated DNA at modified cytosine moieties were compared. Both the bacterial and human enzymes release this cytosine photoproduct as a free base. These glycosylase activities are linear with times of reaction, quantities of enzyme, and irradiation dosages of the substrates. Both enzyme activities are similarly inhibited by the addition of monovalent and divalent cations. Analysis by DNA sequencing identified loci of endonucleolytic incision as cytosines. These are neither cyclobutane pyrimidine dimers, 6-(1,2-dihydro-2-oxo-4-pyrimidinyl)-5-methyl-2,4(1H,3H)-pyrimidinediones, nor apyrimidinic sites. This cytosine photoproduct is separable from unmodified cytosine by high-performance liquid chromatography. This separation should facilitate identification of this modified cytosine and elucidation of its biological significance

  10. Hydrogen

    OpenAIRE

    John O’M. Bockris

    2011-01-01

    The idea of a “Hydrogen Economy” is that carbon containing fuels should be replaced by hydrogen, thus eliminating air pollution and growth of CO2 in the atmosphere. However, storage of a gas, its transport and reconversion to electricity doubles the cost of H2 from the electrolyzer. Methanol made with CO2 from the atmosphere is a zero carbon fuel created from inexhaustible components from the atmosphere. Extensive work on the splitting of water by bacteria shows that if wastes are used as the...

  11. Removal of hydrogen sulfide from gas streams using biological processes : a review

    Energy Technology Data Exchange (ETDEWEB)

    Syed, M.; Soreanu, G.; Falletta, P.; Beland, M. [Environment Canada, Burlington, ON (Canada). Wastewater Technology Centre

    2006-07-01

    Hydrogen sulfide (H{sub 2}S) is produced by the anaerobic digestion of biosolids and other organic materials, and can be corrosive to internal combustion engines. This study investigated biological H{sub 2}S removal processes with the aim of overcoming the chemical and disposal costs associated with existing chemically-based removal processes. Current biological H{sub 2}S removal processes were reviewed, and research needs for potential process improvements were identified. Processes included photoautotrophs; chemotrophs; bioreactors for H{sub 2}S removal involving phototrophic bacteria; continuous-flow reactors; phototube reactors; gas-fed batch reactors; bioscrubbers; biofilters; and biotrickling filters. Results of the review suggested that the preferred treatment method for H{sub 2}S gas containing streams depended on the source of the gas. In the case of H{sub 2}S in biogas, anaerobic methods involving phototrophic bacteria provided the inherent advantage of maintaining the anaerobic nature of the gas. Cholorobium limicola was recommended as a desirable bacterium due to its growth using inorganic substrates, its efficiency at converting sulfide to elemental sulfur, and its extracellular production of elemental sulfur. Fixed-film reactors had the greatest potential for cost-effective sulfide conversion. It was noted that light supply is one of the key cost components in the process and poses a major constraint. It was concluded that future research should focus on the development and use of energy efficient LEDs and the proper use of sunlight and reflectors to minimize the electrical energy use. 73 refs., 5 tabs., 5 figs.

  12. Large transverse momentum dilepton and photon production by photoproduction processes

    Institute of Scientific and Technical Information of China (English)

    FU Yong-Ping; LI Yun-De

    2012-01-01

    We calculate the production of large transverse momentum dileptons and photons by using direct and resolved photoproduction processes in relativistic heavy ion collisions.Considering the central collisions of heavy nuclei at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) energies,we find that the photoproduction processes modify the dilepton and photon production in the large transverse momentum region.

  13. Low-energy photoproduction of PHI-mesons

    CERN Document Server

    Barth, J; Glander, K H; Hannappel, J; Jöpen, N; Klein, F J; Klein, F; Lawall, R; Menze, D; Neuerburg, W; Ostrick, M; Paul, E; Schulday, I; Schwille, W J; Wiegers, B; Ernst, J; Kalinowsky, H; Klempt, E; Link, J; Pee, H V; Wieland, F W; Wisskirchen, J; Wu, C

    2003-01-01

    Photoproduction of PHI-vector-mesons has been studied from reaction threshold up to W=2.4 GeV with the SAPHIR spectrometer at the Bonn electron stretcher ring ELSA. Total cross-sections, differential cross-sections and decay angular distributions were measured. We find evidence for strong non-diffractive contributions to PHI photoproduction. (orig.)

  14. Hydrogen

    Directory of Open Access Journals (Sweden)

    John O’M. Bockris

    2011-11-01

    Full Text Available The idea of a “Hydrogen Economy” is that carbon containing fuels should be replaced by hydrogen, thus eliminating air pollution and growth of CO2 in the atmosphere. However, storage of a gas, its transport and reconversion to electricity doubles the cost of H2 from the electrolyzer. Methanol made with CO2 from the atmosphere is a zero carbon fuel created from inexhaustible components from the atmosphere. Extensive work on the splitting of water by bacteria shows that if wastes are used as the origin of feed for certain bacteria, the cost for hydrogen becomes lower than any yet known. The first creation of hydrogen and electricity from light was carried out in 1976 by Ohashi et al. at Flinders University in Australia. Improvements in knowledge of the structure of the semiconductor-solution system used in a solar breakdown of water has led to the discovery of surface states which take part in giving rise to hydrogen (Khan. Photoelectrocatalysis made a ten times increase in the efficiency of the photo production of hydrogen from water. The use of two electrode cells; p and n semiconductors respectively, was first introduced by Uosaki in 1978. Most photoanodes decompose during the photoelectrolysis. To avoid this, it has been necessary to create a transparent shield between the semiconductor and its electronic properties and the solution. In this way, 8.5% at 25 °C and 9.5% at 50 °C has been reached in the photo dissociation of water (GaP and InAs by Kainthla and Barbara Zeleney in 1989. A large consortium has been funded by the US government at the California Institute of Technology under the direction of Nathan Lewis. The decomposition of water by light is the main aim of this group. Whether light will be the origin of the post fossil fuel supply of energy may be questionable, but the maximum program in this direction is likely to come from Cal. Tech.

  15. Coherent Theta^+ and Lambda(1520) photoproduction off the deuteron

    CERN Document Server

    Titov, A I; Daté, S; Ohashi, Y

    2005-01-01

    We analyze an effect of the coherent $\\Theta^+\\Lambda(1520)$ photoproduction in $\\gamma D$ interaction near the threshold. We demonstrate that the coherence effect becomes manifest in a comparison of the $nK^+$ invariant mass distribution when the $pK^-$ invariant equals the $\\Lambda(1520)$ mass. Our model calculations indicate a sizeable contribution of resonant and non-resonant background processes in the $\\gamma D\\to np K^+K^-$ reaction which generally exceed the contribution of the coherent resonant channel. However, we find that the coherent $\\Theta^+\\Lambda(1520)$ photoproduction is enhanced relative to the background processes in the forward hemisphere of the $pK^-$ pair photoproduction. Moreover, the coherence effect does not depend on the $\\Theta^+$ photoproduction amplitude and is defined by the probabilities of the $\\Lambda(1520)$ photoproduction and the $\\Theta^+\\to NK$ transition. Therefore, this coherence effect may be used as an independent method for studying the mechanism of $\\Theta^+$ produc...

  16. Engineering Synechocystis PCC6803 for hydrogen production: influence on the tolerance to oxidative and sugar stresses.

    Directory of Open Access Journals (Sweden)

    Marcia Ortega-Ramos

    Full Text Available In the prospect of engineering cyanobacteria for the biological photoproduction of hydrogen, we have studied the hydrogen production machine in the model unicellular strain Synechocystis PCC6803 through gene deletion, and overexpression (constitutive or controlled by the growth temperature. We demonstrate that the hydrogenase-encoding hoxEFUYH operon is dispensable to standard photoautotrophic growth in absence of stress, and it operates in cell defense against oxidative (H₂O₂ and sugar (glucose and glycerol stresses. Furthermore, we showed that the simultaneous over-production of the proteins HoxEFUYH and HypABCDE (assembly of hydrogenase, combined to an increase in nickel availability, led to an approximately 20-fold increase in the level of active hydrogenase. These novel results and mutants have major implications for those interested in hydrogenase, hydrogen production and redox metabolism, and their connections with environmental conditions.

  17. Higgs boson photoproduction at the LHC

    CERN Document Server

    Ducati, M B Gay

    2011-01-01

    We present the current development of the photoproduction approach for the Higgs boson with its application to $pp$ and $pA$ collisions at the LHC. We perform a different analysis for the Gap Survival Probability, where we consider a probability of 3% and also a more optimistic value of 10% based on the HERA data for dijet production. As a result, the cross section for the exclusive Higgs boson production is about 2 fb and 6 fb in $pp$ collisions and 617 and 2056 fb for $p$Pb collisions, considering the gap survival factor of 3% and 10%, respectively.

  18. Charm and Beauty in Photoproduction at HERA

    Science.gov (United States)

    Dobre, Monica

    2014-04-01

    The photoproduction of beauty and charm quarks at the ep collider HERA are presented. The b-quarks production was investigated in the bb → eeX' channel and the differential production cross section was measured as a function of the average transverse momentum of the beauty quarks down to the threshold. The cross section of D* meson decaying in the golden channel was determined both inclusively and in D*-tagged dijet events. Exploiting the characteristics of the heavy-flavoured hadron decays, beauty and charm quark cross sections were also measured in dijet events using secondary vertices or semi-muonic decays.

  19. Status of Meson Photoproduction Experiments with CLAS

    Energy Technology Data Exchange (ETDEWEB)

    Pasyuk, Eugene A.

    2014-01-01

    A large part of the experimental program in Hall B of the Jefferson Lab is dedicated to baryon spectroscopy. Meson photoproduction experiments are essential part of this program. CEBAF Large Acceptance Spectrometer (CLAS) and availability of circularly and linearly polarized tagged photon beams in combination with longitudinally and transversely polarized frozen spin targets provide unique conditions for this type of experiments. For the first time, a complete or nearly complete measurement became possible and will allow model independent extraction of the reaction amplitude. The measurements were complete with both proton and deuteron targets. An overview of the collected experimental data will be presented.

  20. Exclusive photoproduction of {upsilon} mesons at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2009-03-15

    The exclusive photoproduction reaction {gamma} p {yields} {upsilon} p has been studied with the ZEUS experiment in ep collisions at HERA using an integrated luminosity of 468 pb{sup -1}. The measurement covers the kinematic range 60

  1. Threshold Neutral Pion Photoproduction on the Proton

    CERN Document Server

    Blin, Astrid Hiller; Ledwig, Tim

    2015-01-01

    The neutral pion photoproduction on the proton near threshold has a very small scattering cross section when compared to the charged channels, which in ChPT is explained by strong cancellations between the lowest order pieces. Therefore it is very sensitive to higher-order corrections of chiral perturbation theory. We perform a fully covariant calculation up to chiral order p^3 and we investigate the effect of the inclusion of the Delta(1232) resonance as an explicit degree of freedom. We show that the convergence improves, leading to a much better agreement with data at a wide range of energies.

  2. Photoproduction of neutral pions off protons

    Science.gov (United States)

    Crede, V.; Sparks, N.; Wilson, A.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, R.; Bartholomy, O.; Bayadilov, D.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Funke, Chr.; Gregor, R.; Gridnev, A.; Gutz, E.; Hillert, W.; Hoffmeister, P.; Jaegle, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Klein, Frank; Klein, Friedrich; Klempt, E.; Kotulla, M.; Krusche, B.; Löhner, H.; Lopatin, I. V.; Lugert, S.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Nanova, M.; Nikonov, V. A.; Novinski, D.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Roy, A.; Sarantsev, A. V.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S.; Sokhoyan, V.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Wendel, Ch.

    2011-11-01

    Photoproduction of neutral pions has been studied with the CBELSA/TAPS detector in the reaction γp→pπ0 for photon energies between 0.85 and 2.50 GeV. The π0 mesons are observed in their dominant neutral decay mode: π0→γγ. For the first time, the differential cross sections cover the very forward region, θc.m.<60∘. A partial-wave analysis of these data within the Bonn-Gatchina framework observes the high-mass resonances G17(2190), D13(2080), and D15(2070).

  3. Measurements of Heavy Flavour Photoproduction at HERA

    Science.gov (United States)

    Mergelmeyer, Sebastian

    2013-12-01

    Recent measurements of open charm and beauty photoproduction with the H1 and ZEUS detectors at the e±p-collider HERA are presented. These measurements reveal valuable details about the inner structure of the proton and the photon, the fragmentation of quarks into jets, and allow tests of perturbative QCD. Various experimental techniques were employed to identify and extract the heavy-quark signal. Their results are discussed, and compared to each other and to NLO QCD calculations. In addition the determination of charm fragmentation fractions is presented.

  4. Primakoff effect in {eta} -photoproduction off protons

    Energy Technology Data Exchange (ETDEWEB)

    Sibirtsev, A. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) und Bethe Center for Theoretical Physics, Bonn (Germany); Thomas Jefferson National Accelerator Facility, Excited Baryon Analysis Center (EBAC), Newport News, VA (United States); Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Center for Hadron Physics, Juelich (Germany); Haidenbauer, J.; Krewald, S. [Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Center for Hadron Physics, Juelich (Germany); Forschungszentrum Juelich, Institute for Advanced Simulation, Juelich (Germany); Meissner, U.G. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) und Bethe Center for Theoretical Physics, Bonn (Germany); Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Center for Hadron Physics, Juelich (Germany); Forschungszentrum Juelich, Institute for Advanced Simulation, Juelich (Germany)

    2010-05-15

    We analyse data on forward {eta} -meson photoproduction off a proton target and extract the {eta}{yields}{gamma}{gamma} decay width utilizing the Primakoff effect. The hadronic amplitude that enters into our analysis is strongly constrained because it is fixed from a global fit to available {gamma}p{yields}p{eta} data for differential cross-sections and polarizations. We compare our results with present information on the two-photon {eta} -decay from the literature. We provide predictions for future PrimEx experiments at Jefferson Laboratory in order to motivate further studies. (orig.)

  5. Primakoff effect in η -photoproduction off protons

    International Nuclear Information System (INIS)

    We analyse data on forward η -meson photoproduction off a proton target and extract the η→γγ decay width utilizing the Primakoff effect. The hadronic amplitude that enters into our analysis is strongly constrained because it is fixed from a global fit to available γp→pη data for differential cross-sections and polarizations. We compare our results with present information on the two-photon η -decay from the literature. We provide predictions for future PrimEx experiments at Jefferson Laboratory in order to motivate further studies. (orig.)

  6. Photoproduction of ω mesons off the proton

    Directory of Open Access Journals (Sweden)

    A. Wilson

    2015-10-01

    These data were included in the Bonn–Gatchina partial wave analysis (PWA. The dominant contribution to ω photoproduction near threshold was found to be the 3/2+ partial wave, which is primarily due to the sub-threshold N(17203/2+ resonance. At higher energies, pomeron-exchange was found to dominate whereas π-exchange remained small. These t-channel contributions as well as further contributions from nucleon resonances were necessary to describe the entire dataset: the 1/2−, 3/2−, and 5/2+ partial waves were also found to contribute significantly.

  7. Biological hydrogen production from probiotic wastewater as substrate by selectively enriched anaerobic mixed microflora

    Energy Technology Data Exchange (ETDEWEB)

    Sivaramakrishna, D.; Sreekanth, D.; Himabindu, V. [Centre for Environment, Institute of Science and Technology, Jawaharlal Nehru Technological University, Kukatpally, Hyderabad 500072, Andhra Pradesh (India); Anjaneyulu, Y. [TLGVRC, JSU Box 18739, JSU, Jackson, MS 32917-0939 (United States)

    2009-03-15

    Biohydrogen production from probiotic wastewater using mixed anaerobic consortia is reported in this paper. Batch tests are carried out in a 5.0 L batch reactor under constant mesophillic temperature (37 C). The maximum hydrogen yield 1.8 mol-hydrogen/mol-carbohydrate is obtained at an optimum pH of 5.5 and substrate concentration 5 g/L. The maximum hydrogen production rate is 168 ml/h. The hydrogen content in the biogas is more than 65% and no significant methane is observed throughout the study. In addition to hydrogen, acetate, propionate, butyrate and ethanol are found to be the main by-products in the metabolism of hydrogen fermentation. (author)

  8. Hydrogen Isotopes as a Sentinel of Biological Invasion by the Japanese Beetle, Popillia japonica (Newman.

    Directory of Open Access Journals (Sweden)

    Bruce A Hungate

    Full Text Available Invasive species alter ecosystems, threaten native and endangered species, and have negative economic impacts. Knowing where invading individuals are from and when they arrive to a new site can guide management. Here, we evaluated how well the stable hydrogen isotope composition (δ2H records the recent origin and time since arrival of specimens of the invasive Japanese beetle (Popillia japonica Newman captured near the Portland International Airport (Oregon, U.S.A.. The δ2H of Japanese beetle specimens collected from sites across the contiguous U.S.A. reflected the δ2H of local precipitation, a relationship similar to that documented for other organisms, and one confirming the utility of δ2H as a geographic fingerprint. Within weeks after experimental relocation to a new isotopic environment, the δ2H of beetles changed linearly with time, demonstrating the potential for δ2H to also mark the timing of arrival to a new location. We used a hierarchical Bayesian model to estimate the recent geographical origin and timing of arrival of each specimen based on its δ2H value. The geographic resolution was broad, with values consistent with multiple regions of origin in the eastern U.S.A., slightly favoring the southeastern U.S.A. as the more likely source. Beetles trapped from 2007-2010 had arrived 30 or more days prior to trapping, whereas the median time since arrival declined to 3-7 days for beetles trapped from 2012-2014. This reduction in the time between arrival and trapping at the Portland International Airport supports the efficacy of trapping and spraying to prevent establishment. More generally, our analysis shows how stable isotopes can serve as sentinels of biological invasions, verifying the efficacy of control measures, or, alternatively, indicating when those measures show signs of failure.

  9. Hydrogen Isotopes as a Sentinel of Biological Invasion by the Japanese Beetle, Popillia japonica (Newman).

    Science.gov (United States)

    Hungate, Bruce A; Kearns, Diana N; Ogle, Kiona; Caron, Melanie; Marks, Jane C; Rogg, Helmuth W

    2016-01-01

    Invasive species alter ecosystems, threaten native and endangered species, and have negative economic impacts. Knowing where invading individuals are from and when they arrive to a new site can guide management. Here, we evaluated how well the stable hydrogen isotope composition (δ2H) records the recent origin and time since arrival of specimens of the invasive Japanese beetle (Popillia japonica Newman) captured near the Portland International Airport (Oregon, U.S.A.). The δ2H of Japanese beetle specimens collected from sites across the contiguous U.S.A. reflected the δ2H of local precipitation, a relationship similar to that documented for other organisms, and one confirming the utility of δ2H as a geographic fingerprint. Within weeks after experimental relocation to a new isotopic environment, the δ2H of beetles changed linearly with time, demonstrating the potential for δ2H to also mark the timing of arrival to a new location. We used a hierarchical Bayesian model to estimate the recent geographical origin and timing of arrival of each specimen based on its δ2H value. The geographic resolution was broad, with values consistent with multiple regions of origin in the eastern U.S.A., slightly favoring the southeastern U.S.A. as the more likely source. Beetles trapped from 2007-2010 had arrived 30 or more days prior to trapping, whereas the median time since arrival declined to 3-7 days for beetles trapped from 2012-2014. This reduction in the time between arrival and trapping at the Portland International Airport supports the efficacy of trapping and spraying to prevent establishment. More generally, our analysis shows how stable isotopes can serve as sentinels of biological invasions, verifying the efficacy of control measures, or, alternatively, indicating when those measures show signs of failure. PMID:26959686

  10. Hydrogen Isotopes as a Sentinel of Biological Invasion by the Japanese Beetle, Popillia japonica (Newman)

    Science.gov (United States)

    Ogle, Kiona; Caron, Melanie; Marks, Jane C.; Rogg, Helmuth W.

    2016-01-01

    Invasive species alter ecosystems, threaten native and endangered species, and have negative economic impacts. Knowing where invading individuals are from and when they arrive to a new site can guide management. Here, we evaluated how well the stable hydrogen isotope composition (δ2H) records the recent origin and time since arrival of specimens of the invasive Japanese beetle (Popillia japonica Newman) captured near the Portland International Airport (Oregon, U.S.A.). The δ2H of Japanese beetle specimens collected from sites across the contiguous U.S.A. reflected the δ2H of local precipitation, a relationship similar to that documented for other organisms, and one confirming the utility of δ2H as a geographic fingerprint. Within weeks after experimental relocation to a new isotopic environment, the δ2H of beetles changed linearly with time, demonstrating the potential for δ2H to also mark the timing of arrival to a new location. We used a hierarchical Bayesian model to estimate the recent geographical origin and timing of arrival of each specimen based on its δ2H value. The geographic resolution was broad, with values consistent with multiple regions of origin in the eastern U.S.A., slightly favoring the southeastern U.S.A. as the more likely source. Beetles trapped from 2007–2010 had arrived 30 or more days prior to trapping, whereas the median time since arrival declined to 3–7 days for beetles trapped from 2012–2014. This reduction in the time between arrival and trapping at the Portland International Airport supports the efficacy of trapping and spraying to prevent establishment. More generally, our analysis shows how stable isotopes can serve as sentinels of biological invasions, verifying the efficacy of control measures, or, alternatively, indicating when those measures show signs of failure. PMID:26959686

  11. Biological deodorization of hydrogen sulfide using porous lava as a carrier of Thiobacillus thiooxidans.

    Science.gov (United States)

    Cho, K S; Ryu, H W; Lee, N Y

    2000-01-01

    Biological deodorization of hydrogen sulfide (H2S) was studied using porous lava as a carrier of Thiobacillus thiooxidans in a laboratory-scale biofilter. Three different samples of porous lava, A, B, and C, which were obtained from Cheju Island in Korea, were used. The water-holding capacities of samples A, B and C were 0.38, 0.25, and 0.47 g-H2O/g-lava, respectively. The pHs and densities of the lava samples ranged from 8.25-9.24 and 920-1190 kg/m3, respectively. The buffering capacities, expressed as the amount of sulfate added to lower the pH to 4, were 60 g-SO4(2-)/kg-lava for sample A, 50 g-SO4(2-)/kg-lava for B, and 90 g-SO4(2-)/kg-lava for C. To investigate the removal characteristics of H2S by the lava biofilters, T. thiooxidans was immobilized on the lava samples. Biofilters A and C showed a removal capacity of 428 g-S.m(-3).h(-1) when H2S was supplied with 428 g-S.m(-3).h(-1) of inlet load at a space velocity (SV) of 300 h(-1). At the same inlet load and SV, the removal capacity of biofilter B was 396 g-S.m(-3).h(-1). The H2S critical loads of biofilters A, B and C at a SV of 400 h(-1) were 396, 157 and 342 g-S.m(-3).h(-1), respectively. It is suggested that natural, porous lava is a promising candidate as a carrier of microorganisms in biofiltration.

  12. High-energy photoproduction of rho and phi vector mesons

    Energy Technology Data Exchange (ETDEWEB)

    Callahan, P.H.

    1983-01-01

    We have studied the photoproduction of rho and phi vector mesons from hydrogen in the Fermilab broad band neutral beam. Forward going two particle final states were detected in a multiparticle spectrometer consisting of two analyzing magnets, a multiwire-proportional-chamber tracking system and a particle identification system. Recoil protons and target fragments were observed in a recoil detector which surrounded the target. The total elastic cross-sections were measured to be independent of energy at the 10% level from 35 to 225 GeV at 10.6 ..mu..b for the rho and from 35 to 165 GeV at 0.64 ..mu..b for the phi. The elastic differential cross-sections were also measured. Approximately 20% of the diffractive rho and phi events were found to be inelastic from an analysis of the recoil detector. The t-dependence of the fraction of diffractive events which are inelastic for both the phi and the psi are consistent with a universal function determined from the rho data.

  13. Photoproduction of ω mesons off protons and neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, F.; Metag, V.; Gregor, R.; Kotulla, M.; Lugert, S.; Nanova, M.; Novotny, R.; Pant, L.M.; Pfeiffer, M.; Roy, A.; Trnka, D.; Varma, R. [Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Anisovich, A.V.; Bayadilov, D.E.; Nikonov, V.A.; Novinski, D.V. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- u. Kernphysik, Bonn (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Bacelar, J.C.S.; Castelijns, R.; Loehner, H.; Messchendorp, J.G.; Shende, S.V. [University of Groningen, Kernfysisch Versneller Institut, Groningen (Netherlands); Bantes, B.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Gothe, R.; Hillert, W.; Hoeffgren, S.; Kammer, S.; Kleber, V.; Klein, Frank; Klein, Friedrich; Konrad, M.; Menze, D.; Ostrick, M.; Schmieden, H.; Schoch, B.; Suele, A.; Walter, D. [Universitaet Bonn, Physikalisches Institut, Bonn (Germany); Bartholomy, O.; Beck, R.; Funke, C.; Gutz, E.; Hoffmeister, P.; Horn, I.; Junkersfeld, J.; Kalinowsky, H.; Klempt, E.; Lang, M.; Pee, H. van; Schmidt, C.; Szczepanek, T.; Thoma, U.; Wendel, C. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- u. Kernphysik, Bonn (Germany); Belogazov, Y.A.; Gridnev, A.B.; Lopatin, I.V.; Schadmand, S.; Sumachev, V.V. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Crede, V.; Wilson, A. [Florida State University, Department of Physics, Tallahassee, FL (United States); Jaegle, I.; Krusche, B.; Mertens, T.; Rostomyan, T. [Universitaet Basel, Department Physik, Basel (Switzerland); Shklyar, V. [Universitaet Giessen, Institut fuer Theoretische Physik, Giessen (Germany); Collaboration: The CBELSA/TAPS Collaboration

    2015-01-01

    ω photoproduction off hydrogen and deuterium has been studied with the tagged photon beam of the ELSA accelerator in Bonn for photon energies up to 2.0 GeV. The ω meson has been identified via the ω → π{sup 0}γ → γγγ decay mode, using the combined setup of the Crystal Barrel/TAPS detector systems. Both inclusive and exclusive analyses have been carried out. Differential and total cross-sections have been derived for ω mesons produced off free protons and off protons and neutrons bound in deuterium. The cross-section for the production off the bound neutron is found to be a factor of ∼ 1.3 larger than the one off the bound proton in the incident beam energy region 1.2 GeV < E{sub γ} < 1.6 GeV. For higher incident beam energies this factor goes down to ∼ 1.1 at 2.0 GeV. The cross-sections of this work have been used as normalization for transparency ratio measurements. (orig.)

  14. Prospects of utilization of sugar beet carbohydrates for biological hydrogen production in the EU

    NARCIS (Netherlands)

    Panagiotopoulos, I.A.; Bakker, R.R.; Vrije, de G.J.; Urbaniec, K.; Koukios, E.G.; Claassen, P.A.M.

    2010-01-01

    Hydrogen can be produced through dark anaerobic fermentation using carbohydrate-rich biomass, and through photofermentation using the organic acids produced from dark fermentation. Sugar beet is an ideal energy crop for fermentative production of hydrogen in the EU due to its environmental profile a

  15. Electricity-Assisted Biological Hydrogen Production from Acetate by Geobacter sulfurreducens

    NARCIS (Netherlands)

    Geelhoed, J.S.; Stams, A.J.M.

    2011-01-01

    Geobacter sulfurreducens is a well-known current-producing microorganism in microbial fuel cells, and is able to use acetate and hydrogen as electron donor. We studied the functionality of G. sulfurreducens as biocatalyst for hydrogen formation at the cathode of a microbial electrolysis cell (MEC).

  16. A new nucleon resonance in eta photoproduction

    CERN Document Server

    Choi, Ki-Seok; Hosaka, Atsushi; Kim, Hyun-Chul

    2007-01-01

    We present in this talk recent investigations on the nucleon-like resonance N*(1675) newly found in eta photoproduction by the GRAAL, Tohoku LNS-gamma and CB-ELSA collaborations. We focus on the production mechanism of the N*(1675), examining its spin and parity theoretically within the framework of the effective Lagrangian method. We expliucitly consider D_{13}(1520), S_{11}(1535), S_{11}(1650), D_{15}(1675), P_{11}(1710), P_{13}(1720) as well as possible background contributions. We calculate the differential cross sections and beam asymmetries for the neutron and proton targets. It turns out that there is manifest isospin asymmetry in eta photoproduction, which can be explained by the asymmetry in the transition magnetic moments: mu_{gamma p p*} =

  17. GlueX: Meson Spectroscopy in Photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Carlos [Norfolk State University, JLAB; Smith, Elton S. [JLAB

    2014-03-01

    The goal of the GlueX experiment \\cite{gluex} is to provide crucial data to help understand the soft gluonic fields responsible for binding quarks in hadrons. Hybrid mesons, and in particular exotic hybrid mesons, provide the ideal laboratory for testing QCD in the confinement regime since these mesons explicitly manifest the gluonic degrees of freedom. Photoproduction is expected to be effective in producing exotic hybrids but there is little data on the photoproduction of light mesons. GlueX will use the new 12-GeV electron beam at Jefferson Lab to produce a 9-GeV beam of linearly polarized photons using the technique of coherent bremsstrahlung. A solenoid-based hermetic detector is under construction, which will be used to collect data on meson production and decays. These data will also be used to study the spectrum of conventional mesons, including the poorly understood excited vector mesons. This talk will give an update on the experiment as well as describe theoretical developments \\cite{Dudek:2011bn} to help understand how these data can provide insights into the fundamental theory of strong interactions.

  18. Inhibitory effects of butyrate on biological hydrogen production with mixed anaerobic cultures.

    Science.gov (United States)

    Zheng, Xian-Jun; Yu, Han-Qing

    2005-01-01

    In this study batch experiments were conducted to investigate the inhibitory effects of butyrate addition on hydrogen production from glucose by using anaerobic mixed cultures. Experimental results showed that addition of butyrate at 4.18 and 6.27 g/l only slightly inhibited hydrogen production, and addition of butyrate at 8.36-12.54 g/l imposed a moderate inhibitory effect on hydrogen production. At addition of 25.08 g/l, butyrate had a strong inhibitory influence on substrate degradation and hydrogen production. The distribution of the volatile fatty acids produced from the acidogeneisis of glucose was significantly influenced by the addition of butyrate. The inhibition of butyrate addition on hydrogen production was described well by a non-competitive and non-linear inhibition model, with the maximum hydrogen production rate of 59.3 ml/g-SS/h, critical added butyrate concentration of 25.08 g/l, and inhibition degree of 0.323, respectively. The C(I,50) values (the butyrate concentration at which bioactivity is reduced by 50%) for hydrogen production rate and yield were estimated as 19.39 and 20.78 g/l of added butyrate, respectively.

  19. Photoproduction in the Energy Range 70-200 GeV

    CERN Multimedia

    2002-01-01

    This experiment continues the photoproduction studies of WA4 and WA57 up to the higher energies made available by the upgrading of the West Hall. An electron beam of energy 200 GeV is used to produce tagged photons in the range 65-180 GeV; The photon beam is incident on a 60 cm liquid hydrogen target in the Omega Spectrometer. A Ring Image Cherenkov detector provides pion/kaon separation up to 150 GeV/c. The Transition Radiation Detector extends the charged pion identification to the momentum range from about 80 GeV/c upwards. The large lead/liquid scintillator calorimeter built by the WA70 collaboration and the new lead/scintillating fibre det (Plug) are used for the detection of the $\\gamma$ rays produced by the interactions of the primary photons in the hydrogen target. \\\\ \\\\ The aim is to make a survey of photoproduction reactions up to photon energies of 200 GeV. The large aperture of the Omega Spectrometer will particularly enable study of fragmentation of the photon to states of high mass, up to @C 9 G...

  20. Beneficial biological effects and the underlying mechanisms of molecular hydrogen - comprehensive review of 321 original articles.

    Science.gov (United States)

    Ichihara, Masatoshi; Sobue, Sayaka; Ito, Mikako; Ito, Masafumi; Hirayama, Masaaki; Ohno, Kinji

    2015-01-01

    Therapeutic effects of molecular hydrogen for a wide range of disease models and human diseases have been investigated since 2007. A total of 321 original articles have been published from 2007 to June 2015. Most studies have been conducted in Japan, China, and the USA. About three-quarters of the articles show the effects in mice and rats. The number of clinical trials is increasing every year. In most diseases, the effect of hydrogen has been reported with hydrogen water or hydrogen gas, which was followed by confirmation of the effect with hydrogen-rich saline. Hydrogen water is mostly given ad libitum. Hydrogen gas of less than 4 % is given by inhalation. The effects have been reported in essentially all organs covering 31 disease categories that can be subdivided into 166 disease models, human diseases, treatment-associated pathologies, and pathophysiological conditions of plants with a predominance of oxidative stress-mediated diseases and inflammatory diseases. Specific extinctions of hydroxyl radical and peroxynitrite were initially presented, but the radical-scavenging effect of hydrogen cannot be held solely accountable for its drastic effects. We and others have shown that the effects can be mediated by modulating activities and expressions of various molecules such as Lyn, ERK, p38, JNK, ASK1, Akt, GTP-Rac1, iNOS, Nox1, NF-κB p65, IκBα, STAT3, NFATc1, c-Fos, and ghrelin. Master regulator(s) that drive these modifications, however, remain to be elucidated and are currently being extensively investigated. PMID:26483953

  1. Biological removal of air loaded with a hydrogen sulfide and ammonia mixture

    Institute of Scientific and Technical Information of China (English)

    CHEN Ying-xu; YIN Jun; FANG Shi

    2004-01-01

    The nuisance impact of air pollutant emissions from wastewater pumping stations is a major issue of concern to China. Hydrogen sulfide and ammonia are commonly the primary odor and are important targets for removal. An alternative control technology, biofiltration, was studied. The aim of this study is to investigate the potential of unit systems packed with compost in terms of ammonia and hydrogen sulfide emissions treatment, and to establish optimal operating conditions for a full-scale conceptual design. The laboratory scale biofilter packed with compost was continuously supplied with hydrogen sulfide and ammonia gas mixtures. A volumetric load of less than 150 gH2S/(m3· d) and 230 gNH3/(m3· d) was applied for about fifteen weeks. Hydrogen sulfide and ammonia elimination occurred in the biofilter simultaneously. The removal efficiency, removal capacity and removal kinetics in the biofilter were studied. The hydrogen sulfide removal efficiency reached was very high above 99%, and ammonia removal efficiency was about 80%. Hydrogen sulfide was oxidized into sulphate. The ammonia oxidation products were nitrite and nitrate. Ammonia in the biofilter was mainly removed by adsorption onto the carrier material and by absorption into the water fraction of the carrier material. High percentages of hydrogen sulfide or ammonia were oxidized in the first section of the column. Through kinetics analysis, the presence of amrronia did not hinder the hydrogen sulfide removal. According to the relationship between pressure drop and gas velocity for the biofilter and Reynolds number, non-Darcy flow can be assumed to represent the flow in the medium.

  2. Diffractive photoproduction of vector mesons at the LHC

    CERN Document Server

    Armesto, Néstor

    2014-01-01

    We confront saturation-based results for diffractive $\\psi(2s)$ and $\\rho$ production at HERA and $J/\\psi$ photoproduction with all available data including recent ones from HERA, ALICE and LHCb, finding a good agreement. We show that the $t$-distribution of differential cross-section of photoproduction of vector mesons offers a unique opportunity to discriminate among saturation and non-saturation models. This is due to emergence of a pronounced dip (or multiple dips) in the $t$-distribution of diffractive photoproduction of vector mesons at relatively large, but potentially accessible $|t|$ that can be traced back to the unitarity features of colour dipole amplitude in the saturation regime. We provide various predictions for exclusive (photo)-production of different vector mesons including the ratio of $\\psi(2s)/J/\\psi$ at HERA, the LHC and at future colliders.

  3. Baryon resonances and polarization transfer in hyperon photoproduction

    CERN Document Server

    Anisovich, A V; Klempt, E; Nikonov, V A; Sarantsev, A V; Thoma, U

    2007-01-01

    A partial wave analysis is presented of data on photoproduction of hyperons including single and double polarization observables. The large spin transfer probability reported by the CLAS collaboration can be successfully described with an isobar partial wave analysis.

  4. Modelling vibrational coherence in the primary rhodopsin photoproduct

    Science.gov (United States)

    Weingart, O.; Garavelli, M.

    2012-12-01

    Molecular dynamics simulations of the rhodopsin photoreaction reveal coherent low frequency oscillations in the primary photoproduct (photorhodopsin), with frequencies slightly higher than observed in the experiment. The coherent molecular motions in the batho-precursor can be attributed to the activation of ground state vibrational modes in the hot photo-product, involving out-of-plane deformations of the carbon skeleton. Results are discussed and compared with respect to spectroscopic data and suggested reaction mechanisms.

  5. Photoproduction models for total cross section and shower development

    Directory of Open Access Journals (Sweden)

    Cornet Fernando

    2015-01-01

    Full Text Available A model for the total photoproduction cross section, based on the ansatz that resummation of infrared gluons limits the rise induced by QCD minijets in all the total cross-sections, is used to simulate extended air showers initiated by cosmic rays with the AIRES simulation program. The impact on common shower observables, especially those related with muon production, is analysed and compared with the corresponding results obtained with previous photoproduction models.

  6. Strangeness Photoproduction at the BGO-OD Experiment

    CERN Document Server

    Jude, T C; Bayadilov, D; Beck, R; Becker, M; Bella, A; Bielefeldt, P; Boese, S; Braghieri, A; Brinkmann, K; Cole, P; Curciarello, F; De Leo, V; Di Salvo, R; Dutz, H; Elsner, D; Fantini, A; Freyermuth, O; Friedrich, S; Frommberger, F; Ganenko, V; Gervino, G; Ghio, F; Giardina, G; Goertz, S; Gridnev, A; Gutz, E; Hammann, D; Hannappel, J; Hartmann, P; Hillert, W; Ignatov, A; Jahn, R; Joosten, R; Klein, F; Koop, K; Krusche, B; Lapik, A; Sandri, P Levi; Lopatin, I V; Mandaglio, G; Messi, F; Messi, R; Metag, V; Moricciani, D; Mushkarenkov, A; Nanova, M; Nedorezov, V; Novinskiy, D; Pedroni, P; Reitz, B; Romaniuk, M; Rostomyan, T; Rudnev, N; Scheluchin, G; Schmieden, H; Stugelev, A; Sumachev, V; Tarakanov, V; Vegna, V; Walther, D; Watts, D; Zaunick, H; Zimmermann, T

    2015-01-01

    BGO-OD is a newly commissioned experiment to investigate the internal structure of the nucleon, using an energy tagged bremsstrahlung photon beam at the ELSA electron facility. The setup consists of a highly segmented BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. BGO-OD is ideal for investigating meson photoproduction. The extensive physics programme for open strangeness photoproduction is introduced, and preliminary analysis presented.

  7. Model discrimination in pseudoscalar-meson photoproduction

    CERN Document Server

    Nys, J; Ireland, D G; Glazier, D I

    2016-01-01

    To learn about a physical system of interest, experimental results must be able to discriminate among models. We introduce a geometrical measure to quantify the distance between models for pseudoscalar-meson photoproduction in amplitude space. Experimental observables, with finite accuracy, map to probability distributions in amplitude space, and the characteristic width scale of such distributions needs to be smaller than the distance between models if the observable data are going to be useful. We therefore also introduce a method for evaluating probability distributions in amplitude space that arise as a result of one or more measurements, and show how one can use this to determine what further measurements are going to be necessary to be able to discriminate among models.

  8. Model discrimination in pseudoscalar-meson photoproduction

    Science.gov (United States)

    Nys, J.; Ryckebusch, J.; Ireland, D. G.; Glazier, D. I.

    2016-08-01

    To learn about a physical system of interest, experimental results must be able to discriminate among models. We introduce a geometrical measure to quantify the distance between models for pseudoscalar-meson photoproduction in amplitude space. Experimental observables, with finite precision, map to probability distributions in amplitude space, and the characteristic width scale of such distributions needs to be smaller than the distance between models if the observable data are going to be useful. We therefore also introduce a method for evaluating probability distributions in amplitude space that arise as a result of one or more measurements, and show how one can use this to determine what further measurements are going to be necessary to be able to discriminate among models.

  9. (→ + - 0) meson photoproduction on proton

    Indian Academy of Sciences (India)

    Swapan Das

    2010-10-01

    The cross-section for the + - 0 invariant mass distribution in the $ p$ reaction in the GeV region is calculated. This reaction is assumed to proceed through the formation of the -meson in the intermediate state, because the production cross-section for this meson in the reaction in the GeV region is significant and it has a large branching ratio (88.8%) in the + − 0 channel. The cross-sections for this reaction are calculated using the energy-dependent reaction amplitude, → (0), extracted from the latest -meson photoproduction data. We use established procedure to calculate other factors, like width and propagator of the -meson, so that our calculation can provide reliable cross-section. The calculated results reproduce the measured + - 0 invariant mass distribution spectra in the reaction.

  10. Photoproduction of eta-mesic 3He

    CERN Document Server

    Pfeiffer, M; Annand, J R M; Beck, R; Caselotti, G; Cherepnya, S N; Föhl, K; Fog, L S; Hornidge, D; Janssen, S; Kashevarov, V; Kondratiev, R; Kotulla, M; Krusche, B; McGeorge, J C; MacGregor, I J D; Mengel, K; Messchendorp, J G; Metag, V; Novotny, R; Rost, M; Sack, S; Sanderson, R; Schadmand, S; Thomas, A; Watts, D P

    2003-01-01

    The photoproduction of eta-mesic 3He has been investigated using the TAPS calorimeter at the Mainz Microtron accelerator facility MAMI. The total inclusive cross section for the reaction gamma+3He->eta+X has been measured for photon energies from threshold to 820 MeV. The total and angular differential coherent eta cross sections have been extracted up to energies of 745 MeV. A resonance-like structure just above the eta production threshold with an isotropic angular distribution suggests the existence of a resonant quasi-bound state. This is supported by studies of a competing decay channel of such a quasi-bound eta-mesic nucleus into pi^0+p+X. A binding energy of (4+-4) MeV and a width of (25+-6) MeV is deduced for the quasi-bound eta-mesic state in 3He.

  11. Photoproduction at High Energy and High Intensity

    CERN Multimedia

    2002-01-01

    The photon beam used for this programme is tagged and provides a large flux up to very high energies (150-200 GeV). It is also hadron-free, since it is obtained by a two-step conversion method. A spectrometer is designed to exploit this beam and to perform a programme of photoproduction with a high level of sensitivity (5-50 events/picobarn).\\\\ \\\\ Priority will be given to the study of processes exhibiting the point-like behaviour of the photon, especially deep inelastic Compton scattering. The spectrometer has two magnets. Charged tracks are measured by MWPC's located only in field-free regions. Three calorimeters provide a large coverage for identifying and measuring electrons and photons. An iron filter downstream identifies muons. Most of the equipment is existing and recuperated from previous experiments.

  12. Double polarisation experiments in meson photoproduction

    CERN Document Server

    ,

    2016-01-01

    One of the remaining challenges within the standard model is to gain a good understanding of QCD in the non-perturbative regime. A key step towards this aim is baryon spectroscopy, investigating the spectrum and the properties of baryon resonances. To gain access to resonances with small $\\pi N$ partial width, photoproduction experiments provide essential information. Partial wave analyses need to be performed to extract the contributing resonances. Here, a complete experiment is required to unambiguously determine the contributing amplitudes. This involves the measurement of carefully chosen single and double polarisation observables. In a joint endeavour by MAMI, ELSA, and Jefferson Laboratory, a new generation of experiments with polarised beams, polarised proton and neutron targets, and $4\\pi$ particle detectors have been performed in recent years. Many results of unprecedented quality were recently published by all three experiments, and included by the various partial wave analysis groups in their analy...

  13. Photoproduction of quarkonium from soft color exchanges

    Energy Technology Data Exchange (ETDEWEB)

    Rathsman, J.

    2000-01-20

    The authors discuss photoproduction of quarkonium states in the models of soft color interactions and the generalized area law for color string reinteractions as implemented in the Monte Carlo program AROMA. The physics of heavy quarks offers many probes for a better understanding of the interplay between perturbative and non-perturbative aspects of quantum chromogynamics. One such question is the production mechanisms for quarkonium states for which a complete understanding is not available presently. The color octet model can describe the large direct production of J/{psi}'s and {psi}'s at the Fermilab Tevatron, which is a factor of {approximately}30 above expectations from the color singlet model, but it does not seem to describe the polarization correctly. In addition, it does not seem to be consistent with data from HERA which agrees quite well with the color singlet model.

  14. High-ET dijet photoproduction at HERA

    International Nuclear Information System (INIS)

    The cross section for high-ET dijet production in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 81.8 pb-1. The events were required to have a virtuality of the incoming pho- ton, Q2, of less than 1 GeV2 and a photon-proton centre-of-mass energy in the range 142γpTjet1>20 GeV and ETjet2>15 GeV and pseudorapidity requirements of -1jet1,2jet<2.5. The measurements show sensitivity to the parton distributions in the photon and proton and effects beyond next-to-leading order in QCD. Hence these data can be used to constrain further the parton densities in the proton and photon. (orig.)

  15. Prompt Photons in Photoproduction at HERA

    CERN Document Server

    Aaron, F D; Alexa, C; Andreev, V; Antunovic, B; Backovic, S; Baghdasaryan, A; Barrelet, E; Bartel, W; Begzsuren, K; Belousov, A; Bizot, J C; Boudry, V; Bozovic-Jelisavcic, I; Bracinik, J; Brandt, G; Brinkmann, M; Brisson, V; Bruncko, D; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Cerny, K; Cerny, V; Chekelian, V; Cholewa, A; Contreras, J G; Coughlan, J A; Cozzika, G; Cvach, J; Dainton, J B; Daum, K; Deak, M; de Boer, Y; Delcourt, B; Del Degan, M; Delvax, J; De Wolf, E A; Diaconu, C; Dodonov, V; Dossanov, A; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eliseev, A; Elsen, E; Falkiewicz, A; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Fischer, D J; Fleischer, M; Fomenko, A; Gabathuler, E; Gayler, J; Ghazaryan, S; Glazov, A; Glushkov, I; Goerlich, L; Gogitidze, N; Gouzevitch, M; Grab, C; Greenshaw, T; Grell, B R; Grindhammer, G; Habib, S; Haidt, D; Helebrant, C; Henderson, R C.W; Hennekemper, E; Henschel, H; Herbst, M; Herrera, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R; Hreus, T; Jacquet, M; Janssen, X; Jonsson, L; Jung, A W; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Kluge, T; Knutsson, A; Kogler, R; Kostka, P; Kraemer, M; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Kruger, K; Kutak, K; Landon, M P.J; Lange, W; Lastovicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Li, G; Lipka, K; Liptaj, A; List, B; List, J; Loktionova, N; Lopez-Fernandez, R; Lubimov, V; Makankine, A; Malinovski, E; Marage, P; Marti, Ll; Martyn, H U; Maxfield, S J; Mehta, A; Meyer, A B; Meyer, H; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Moreau, F; Morozov, A; Morris, J V; Mozer, M U; Mudrinic, M; Muller, K; Murin, P; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nikitin, D; Nowak, G; Nowak, K; Nozicka, M; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Pandurovic, M; Papadopoulou, Th; Pascaud, C; Patel, G D; Pejchal, O; Perez, E; Petrukhin, A; Picuric, I; Piec, S; Pitzl, D; Placakyte, R; Pokorny, B; Polifka, R; Povh, B; Radescu, V; Rahmat, A J; Raicevic, N; Raspiareza, A; Ravdandorj, T; Reimer, P; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rotaru, M; Ruiz Tabasco, J E; Rurikova, Z; Rusakov, S; Salek, D; Sankey, D P.C; Sauter, M; Sauvan, E; Schmitt, S; Schoeffel, L; Schoning, A; Schultz-Coulon, H C; Sefkow, F; Shaw-West, R N; Shtarkov, L N; Shushkevich, S; Sloan, T; Smiljanic, I; Soloviev, Y; Sopicki, P; South, D; Spaskov, V; Specka, A; Staykova, Z; Steder, M; Stella, B; Stoicea, G; Straumann, U; Sunar, D; Sykora, T; Tchoulakov, V; Thompson, G; Thompson, P D; Toll, T; Tomasz, F; Tran, T H; Traynor, D; Trinh, T N; Truol, P; Tsakov, I; Tseepeldorj, B; Turnau, J; Urban, K; Valkarova, A; Vallee, C; Van Mechelen, P; Vargas Trevino, A; Vazdik, Y; Vinokurova, S; Volchinski, V; von den Driesch, M; Wegener, D; Wissing, Ch; Wunsch, E; Zacek, J; Zalesak, J; Zhang, Z; Zhokin, A; Zimmermann, T; Zohrabyan, H; Zomer, F; Zus, R

    2010-01-01

    The production of prompt photons is measured in the photoproduction regime of electron-proton scattering at HERA. The analysis is based on a data sample corresponding to a total integrated luminosity of 340 pb^-1 collected by the H1 experiment. Cross sections are measured for photons with transverse momentum and pseudorapidity in the range 6 < Et < 15 GeV and -1.0 < eta < 2.4, respectively. Cross sections for events with an additional jet are measured as a function of the transverse energy and pseudorapidity of the jet, and as a function of the fractional momenta x_gamma and x_p carried by the partons entering the hard scattering process. The correlation between the photon and the jet is also studied. The results are compared with QCD predictions based on the collinear and on the k_T factorisation approaches.

  16. Photoproduction of heavy quarkonium at the ILC

    Science.gov (United States)

    Chen, Gu; Wu, Xing-Gang; Fu, Hai-Bing; Han, Hua-Yong; Sun, Zhan

    2014-08-01

    We study the photoproduction of the heavy quarkonium at the future International Linear Collider (ILC) within the nonrelativistic QCD theory. We focus on the production channel via the subprocess γγ→|[Q1(n)⟩+Q'+Q¯, where Q and Q' stand for the heavy c or b quark, respectively. |[Q Q1(n)⟩ stands for the color-singlet S-wave quarkonium, i.e., ηc(|[c1(S10)⟩), J/ψ(|[cc¯]1(S31)⟩), Bc(|[c1(S10)⟩), Bc*(|[cb¯]1(S31)⟩), ηb(|[b1(1S0)⟩), and Υ(|[bb¯]1(S31)⟩), respectively. To improve the calculation efficiency, we adopt the improved helicity amplitude approach to deal with the difficulty of calculating the expressions for the yields when the quark masses cannot be neglected. Total and differential photoproduction cross sections, together with their uncertainties, have been presented. It is noted that a sizable number of |cc¯⟩-charmonium and |cb¯⟩-quarkonium events can be generated at the ILC. More specifically, we predict (2.4-0.6+0.8)×106 ηc, (4.7-1.1+1.6)×106 J/ψ, (8.6-1.9+2.3)×103 Bc, (4.6-0.9+1.3)×104 Bc*, (6.6±1.2)×103 ηb, and (1.2±0.2)×103 ϒ events to be generated in one operation year at the ILC under the condition of √S =500 GeV and L ≃1036 cm-2s-1.

  17. Biological hydrogen production from phenol-containing wastewater using Clostridium butyricum

    Energy Technology Data Exchange (ETDEWEB)

    Tai, Jung; Adav, Sunil S.; Lee, Duu-Jong [Department of Chemical Engineering, National Taiwan University, Taipei 10617 (China); Su, Ay [Department of Mechanical Engineering, Fuel Cell Center, Yuan-Ze University, Chungli, 32003 (China)

    2010-12-15

    Toxicity renders certain industrial effluents unfit for recovering its bioenergy content. An enriched single strain, Clostridium butyricum, was herein applied to fermentatively produce hydrogen from glucose in the presence of 200-1500 mg L{sup -1} of phenol. The enriched C. butyricum yielded hydrogen at approximately 1.4 mol H{sub 2} mol{sup -1} glucose in the presence of 200-400 mg L{sup -1} phenol. Significant inhibition of cell metabolism was noted at phenol concentration >1000 mg L{sup -1}. During glucose fermentation, phenol dosed at 200-400 mg L{sup -1} was partly co-degraded. Ethanol and acetate were the primary metabolites, whose yields increased with increasing phenol concentration. The present results revealed the potential to harvest hydrogen from a toxic (phenol-containing) wastewater. (author)

  18. Biological hydrogen production: Simultaneous saccharification and fermentation with nitrogen and phosphorus removal from wastewater effluent

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, Steve; Dixon, Melissa [U.S. Army Edgewood Chemical Biological Center, 5183 Blackhawk Road Building E3160, Aberdeen Proving Ground, MD 21010-5424 (United States)

    2010-09-15

    A simple anaerobic biodegradation process using wastewater treatment plant (WWTP) effluent, shredded paper, and a purge of nitrogen gas was used to produce hydrogen and simultaneously capture nitrogen and phosphorus. Two reactor configurations, a sequencing batch reactor (SBR) and a classic batch reactor (CBR) were tested as simultaneous saccharification and fermentation reactors (enzymatic hydrolysis and fermentation in one tank). The CBR demonstrated greater stability of hydrogen production and simplicity of operation, while the SBR provided better nitrogen and phosphorus removal efficiencies. Nuclear magnetic resonance analyses showed acetic acid to be the main product from both reactors. Optimal CBR conditions were found to be pH 5, 4 g/L loading, 0.45 ml/g Accellerase 1500, and 38 C. Experiments with an argon purge in place of nitrogen and with ammonium chloride spiking suggested that hydrogenase and nitrogenase enzymes contributed similarly to hydrogen production in the cultures. Analysis of a single fermentation showed that hydrogen production occurred relatively early in the course of TOC removal, and that follow-on treatments might extract more energy from the products. (author)

  19. Biological hydrogen and methane production from bagasse bioethanol fermentation residues using a two-stage bioprocess.

    Science.gov (United States)

    Cheng, Hai-Hsuan; Whang, Liang-Ming; Chung, Man-Chien; Chan, Kun-Chi

    2016-06-01

    This study investigated the recovery of H2 and CH4 from bagasse bioethanol fermentation residues (bagasse BEFR) using a two-stage bioprocess. In the hydrogen fermentation bioreactor (HFB), carbohydrate removal efficiency was maintained at 82-93% and the highest hydrogen yield was 8.24mL/gCOD at volumetric loading rate (VLR) of 80kgCOD/m(3)/day. The results indicated a positive correlation between hydrogen yield and butyrate-to-acetate ratio, which might be due to the mechanisms of lactate/acetate utilization for hydrogen production and acetogenesis occurring in the HFB. Remaining volatile fatty acids and alcohols in the HFB effluent were further utilized for methane production in methane fermentation bioreactor (MFB), in which the highest methane yield of 345.2mL/gCOD was attained at VLR of 2.5kgCOD/m(3)/day. Overall, the two-stage bioprocess achieved a maximum COD removal of 81% from bagasse BEFR, and converted 0.3% and 72.8% of COD in the forms of H2 and CH4, respectively. PMID:26774443

  20. Photoproduction of the K+ K0-(1750)

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Ryan Edward

    2003-01-01

    While photoproduction has often been advertised as an important environment in which to study light meson spectroscopy, solid experimental results are sparse. In fact, beyond the relatively straightforward photoproduction of the {rho}, {omega}, and {phi} mesons, the few results of exclusive photoproduction that do exist are poorly understood, and several, perhaps, have even been misinterpreted. After extensively reviewing the sometimes tenuous history of the exclusive photoproduction of the ''{rho}{sup 1}(1600)'', the ''{omega}{pi}{sup 0}(1250)'', the ''{omega}(1650)'', and the ''K{sup +}K{sup -}(1750)'', new results from the E831/FOCUS photoproduction experiment at Fermilab are presented which address the interpretation of the K{sup +}K{sup -}(1750). This enhancement in low-p{sub T} K{sup +}K{sup -} pairs at a mass near 1750 MeV/c{sup 2} has been observed by several previous photoproduction experiments, but, despite several apparent inconsistencies, it has always been interpreted as the J{sup PC} = 1{sup --} {phi}(1680) meson. With nearly two orders of magnitude more events than any previous observation of the K{sup +}K{sup -}(1750), and based on precise measurements of its mass and width, and its absence from the K*K final state, the FOCUS data can finally render this interpretation implausible. In addition, several steps have been taken towards establishing a new interpretation. Based on limited angular analyses of its decay and the beam energy dependence of its production, they argue that, in the absence of any wild interference scenarios, the K{sup +}K{sup -}(1750) has J{sup PC} {ne} 1{sup --}, and, in fact, the most likely assignment appears to be 2{sup ++}. It is hoped that this work can help set the stage for future reevaluations and new insights in photoproduction.

  1. Protective Effect of Selected Medicinal Plants against Hydrogen Peroxide Induced Oxidative Damage on Biological Substrates

    OpenAIRE

    Pai Kotebagilu, Namratha; Reddy Palvai, Vanitha; Urooj, Asna

    2014-01-01

    Oxidative stress is developed due to susceptibility of biological substrates to oxidation by generation of free radicals. In degenerative diseases, oxidative stress level can be reduced by antioxidants which neutralize free radicals. Primary objective of this work was to screen four medicinal plants, namely, Andrographis paniculata, Costus speciosus, Canthium parviflorum, and Abrus precatorius, for their antioxidant property using two biological substrates—RBC and microsomes. The antioxidativ...

  2. Biological hydrogen production from corn-syrup waste using a novel system

    Energy Technology Data Exchange (ETDEWEB)

    Hafez, H.; Nakhla, G.; El Naggar, H. [Civil and Environmental Engineering Department, University of Western Ontario, London, Ontario (Canada)

    2009-07-01

    The reported patent-pending system comprises a novel biohydrogen reactor with a gravity settler for decoupling of SRT from HRT. The biohydrogenator was operated for 100 days at 37 {sup o}C, hydraulic retention time 8 h and solids retention time ranging from 2.2-2.5 days. The feed was a corn-syrup waste generated as a byproduct from an industrial facility for bioethanol production located in southwestern Ontario, Canada. The system was initially started up with a synthetic feed containing glucose at concentration of 8 g/L and other essential inorganics. Anaerobically-digested sludge from the St. Mary's wastewater treatment plant (St. Mary, Ontario, Canada) was used as the seed, and was heat treated at 70 {sup o}C for 30 min to inhibit methanogenesis. After 10 days, when the hydrogen production was steady, the corn-syrup waste was introduced to the system. Glucose was the main constituent in the corn-syrup; its concentration was varied over a period of 90 days from 8 to 25 g/L. The change in glucose concentration was used to study the impact of variable organic loading on the stability of hydrogen production in the biohydrogenator. Hydrogen production rate increased from 10 L H{sub 2}/L{center_dot}d to 34 L H{sub 2}/L{center_dot}d with the increase of organic loading rate (OLR) from 26 to 81 gCOD/L{center_dot}d, while a maximum hydrogen yield of 430 mL H{sub 2}/gCOD was achieved in the system with an overall average of 385 mL H{sub 2}/gCOD. (author)

  3. Biological Hydrogen Production from Corn-Syrup Waste Using a Novel System

    Directory of Open Access Journals (Sweden)

    George Nakhla

    2009-06-01

    Full Text Available The reported patent-pending system comprises a novel biohydrogen reactor with a gravity settler for decoupling of SRT from HRT. The biohydrogenator was operated for 100 days at 37 °C, hydraulic retention time 8 h and solids retention time ranging from 2.2–2.5 days. The feed was a corn-syrup waste generated as a byproduct from an industrial facility for bioethanol production located in southwestern Ontario, Canada. The system was initially started up with a synthetic feed containing glucose at concentration of 8 g/L and other essential inorganics. Anaerobicaly-digested sludge from the St. Mary’s wastewater treatment plant (St. Mary, Ontario, Canada was used as the seed, and was heat treated at 70 °C for 30 min to inhibit methanogens. After 10 days, when the hydrogen production was steady, the corn-syrup waste was introduced to the system. Glucose was the main constituent in the corn-syrup; its concentration was varied over a period of 90 days from 8 to 25 g/L. The change in glucose concentration was used to study the impact of variable organic loading on the stability of hydrogen production in the biohydrogenator. Hydrogen production rate increased from 10 L H2/L·d to 34 L H2/L·d with the increase of organic loading rate (OLR from 26 to 81 gCOD/L·d, while a maximum hydrogen yield of 430 mL H2/gCOD was achieved in the system with an overall average of 385 mL H2/gCOD.

  4. Photoproduction of $\\eta '$-mesons off the deuteron

    CERN Document Server

    Jaegle, I; Fix, A; Huang, F; Nakayama, K; Tiator, L; Anisovich, A V; Bacelar, J C S; Bantes, B; Bartholomy, O; Bayadilov, D E; Beck, R; Beloglazov, Y A; Castelijns, R; Crede, V; Dutz, H; Elsner, D; Ewald, R; Frommberger, F; Funke, C; Gregor, R; Gridnev, A B; Gutz, E; Hillert, W; Hoeffgen, S; Junkersfeld, J; Kalinowsky, H; Kammer, S; Kleber, V; Klein, Frank; Klein, Friedrich; Klempt, E; Kotulla, M; Krusche, B; Lang, M; Loehner, H; Lopatin, I V; Lugert, S; Menze, D; Messchendorp, J G; Metag, V; Nikonov, V A; Nanova, M; Novinski, D V; Novotny, R; Ostrick, M; Pant, L M; van Pee, H; Pfeiffer, M; Roy, A; Sarantsev, A V; Schadmand, S; Schmidt, C; Schmieden, H; Schoch, B; Shende, S V; Sokhoyan, V; Suele, A; Sumachev, V V; Szczepanek, T; Thoma, U; Trnka, D; Varma, R; Walther, D; Wendel, C

    2010-01-01

    Quasi-free photoproduction of $\\eta '$ mesons off nucleons bound in the deuteron has been measured with the combined Crystal Barrel - TAPS detector. The experiment was done at a tagged photon beam of the ELSA electron accelerator in Bonn for incident photon energies from the production threshold up to 2.5 GeV. The $\\eta '$-mesons have been detected in coincidence with recoil protons and recoil neutrons. The quasi-free proton data are in good agreement with the results for free protons, indicating that nuclear effects have no significant impact. The coincidence with recoil neutrons provides the first data for the $\\gamma n \\rightarrow n\\eta '$ reaction. In addition, also first estimates for coherent $\\eta '$-production off the deuteron have been obtained. In agreement with model predictions, the total cross section for this channel is found to be very small, at most at the level of a few nb. The data are compared to model calculations taking into account contributions from nucleon resonances and $t$-channel ex...

  5. Photoproduction of ω mesons off the proton

    Science.gov (United States)

    Wilson, A.; Crede, V.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, B.; Bartholomy, O.; Bayadilov, D.; Beck, R.; Beloglazov, Y. A.; Brinkmann, K. T.; Castelijns, R.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Fuchs, M.; Funke, Chr.; Gregor, R.; Gridnev, A.; Gutz, E.; Hannappel, J.; Hillert, W.; Hoffmeister, P.; Horn, I.; Jaegle, I.; Jude, T.; Junkersfeld, J.; Kalinowsky, H.; Kleber, V.; Klein, Frank; Klein, Friedrich; Klempt, E.; Kotulla, M.; Krusche, B.; Lang, M.; Löhner, H.; Lopatin, I. V.; Lugert, S.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Nanova, M.; Nikonov, V. A.; Novinski, D.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Roy, A.; Sarantsev, A. V.; Schmidt, C.; Schmieden, H.; Shende, S.; Sokhoyan, V.; Sparks, N.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Wendel, Ch.; Wiedner, U.

    2015-10-01

    The differential cross sections and unpolarized spin-density matrix elements for the reaction γp → pω were measured using the CBELSA/TAPS experiment for initial photon energies ranging from the reaction threshold to 2.5 GeV. These observables were measured from the radiative decay of the ω meson, ω →π0 γ. The cross sections cover the full angular range and show the full extent of the t-channel forward rise. The overall shape of the angular distributions in the differential cross sections and unpolarized spin-density matrix elements are in fair agreement with previous data. In addition, for the first time, a beam of linearly-polarized tagged photons in the energy range from 1150 MeV to 1650 MeV was used to extract polarized spin-density matrix elements. These data were included in the Bonn-Gatchina partial wave analysis (PWA). The dominant contribution to ω photoproduction near threshold was found to be the 3 /2+ partial wave, which is primarily due to the sub-threshold N (1720) 3 /2+ resonance. At higher energies, pomeron-exchange was found to dominate whereas π-exchange remained small. These t-channel contributions as well as further contributions from nucleon resonances were necessary to describe the entire dataset: the 1 /2-, 3 /2-, and 5 /2+ partial waves were also found to contribute significantly.

  6. Photoproduction of {\\omega} Mesons off the Proton

    CERN Document Server

    Wilson, A; Anisovich, A V; Bacelar, J C S; Bantes, B; Bartholomy, O; Bayadilov, D; Beck, R; Beloglazov, Y A; Brinkmann, K T; Castelijns, R; Dutz, H; Elsner, D; Ewald, R; Frommberger, F; Fuchs, M; Funke, Chr; Gregor, R; Gridnev, A; Gutz, E; Hannappel, J; Hillert, W; Hoffmeister, P; Horn, I; Jaegle, I; Jude, T; Junkersfeld, J; Kalinowsky, H; Kleber, V; Klein, Frank; Klein, Friedrich; Klempt, E; Kotulla, M; Krusche, B; Lang, M; Löhner, H; Lopatin, I V; Lugert, S; Mertens, T; Messchendorp, J G; Metag, V; Nanova, M; Nikonov, V A; Novinski, D; Novotny, R; Ostrick, M; Pant, L M; van Pee, H; Pfeiffer, M; Roy, A; Sarantsev, A V; Schmidt, C; Schmieden, H; Shende, S; Sokhoyan, V; Sparks, N; Süle, A; Sumachev, V V; Szczepanek, T; Thoma, U; Trnka, D; Varma, R; Walther, D; Wendel, Ch; Wiedner, U

    2015-01-01

    The differential cross sections and unpolarized spin-density matrix elements for the reaction $\\gamma p\\to p\\omega$ were measured using the CBELSA/TAPS experiment for initial photon energies ranging from the reaction threshold to 2.5 GeV. These observables were measured from the radiative decay of the $\\omega$ meson, $\\omega\\to\\pi^0\\gamma$. The cross sections cover the full angular range and show the full extent of the $t$-channel forward rise. The overall shape of the angular distributions in the differential cross sections and unpolarized spin-density matrix elements are in fair agreement with previous data. In addition, for the first time, a beam of linearly-polarized tagged photons in the energy range from 1150 MeV to 1650 MeV was used to extract polarized spin-density matrix elements. These data were included in the Bonn-Gatchina partial wave analysis (PWA). The dominant contribution to $\\omega$ photoproduction near threshold was found to be the $3/2^+$ partial wave, which is primarily due to the sub-thr...

  7. Biological consilience of hydrogen sulfide and nitric oxide in plants: Gases of primordial earth linking plant, microbial and animal physiologies.

    Science.gov (United States)

    Yamasaki, Hideo; Cohen, Michael F

    2016-05-01

    Hydrogen sulfide (H2S) is produced in the mammalian body through the enzymatic activities of cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3MST). A growing number of studies have revealed that biogenic H2S produced in tissues is involved in a variety of physiological responses in mammals including vasorelaxation and neurotransmission. It is now evident that mammals utilize H2S to regulate multiple signaling systems, echoing the research history of the gaseous signaling molecules nitric oxide (NO) and carbon monoxide (CO) that had previously only been recognized for their cytotoxicity. In the human diet, meats (mammals, birds and fishes) and vegetables (plants) containing cysteine and other sulfur compounds are the major dietary sources for endogenous production of H2S. Plants are primary producers in ecosystems on the earth and they synthesize organic sulfur compounds through the activity of sulfur assimilation. Although plant H2S-producing activities have been known for a long time, our knowledge of H2S biology in plant systems has not been updated to the extent of mammalian studies. Here we review recent progress on H2S studies, highlighting plants and bacteria. Scoping the future integration of H2S, NO and O2 biology, we discuss a possible linkage between physiology, ecology and evolutional biology of gas metabolisms that may reflect the historical changes of the Earth's atmospheric composition. PMID:27083071

  8. Advances in the biotechnology of hydrogen production with the microalga Chlamydomonas reinhardtii.

    Science.gov (United States)

    Torzillo, Giuseppe; Scoma, Alberto; Faraloni, Cecilia; Giannelli, Luca

    2015-01-01

    Biological hydrogen production is being evaluated for use as a fuel, since it is a promising substitute for carbonaceous fuels owing to its high conversion efficiency and high specific energy content. The basic advantages of biological hydrogen production over other "green" energy sources are that it does not compete for agricultural land use, and it does not pollute, as water is the only by-product of the combustion. These characteristics make hydrogen a suitable fuel for the future. Among several biotechnological approaches, photobiological hydrogen production carried out by green microalgae has been intensively investigated in recent years. A select group of photosynthetic organisms has evolved the ability to harness light energy to drive hydrogen gas production from water. Of these, the microalga Chlamydomonas reinhardtii is considered one of the most promising eukaryotic H2 producers. In this model microorganism, light energy, H2O and H2 are linked by two excellent catalysts, the photosystem 2 (PSII) and the [FeFe]-hydrogenase, in a pathway usually referred to as direct biophotolysis. This review summarizes the main advances made over the past decade as an outcome of the discovery of the sulfur-deprivation process. Both the scientific and technical barriers that need to be overcome before H2 photoproduction can be scaled up to an industrial level are examined. Actual and theoretical limits of the efficiency of the process are also discussed. Particular emphasis is placed on algal biohydrogen production outdoors, and guidelines for an optimal photobioreactor design are suggested. PMID:24754449

  9. Factorization breaking in dijet photoproduction with a leading neutron

    International Nuclear Information System (INIS)

    The production of dijets with a leading neutron in ep-interactions at HERA is calculated in leading order and next-to-leading order of perturbative QCD using a pion-exchange model. Differential cross sections for deep-inelastic scattering (DIS) and photoproduction are presented as a function of several kinematic variables. By comparing the theoretical predictions for DIS dijets to recent H1 data, the pion flux factor together with the parton distribution functions of the pion is determined. The dijet cross sections in photoproduction show factorization breaking if compared to the H1 photoproduction data. The suppression factor is S=0.48(0.64) for resolved (global) suppression. (orig.)

  10. Dijet Angular Distributions in Direct and Resolved Photoproduction at HERA

    OpenAIRE

    ZEUS Collaboration

    1996-01-01

    Jet photoproduction, where the two highest transverse energy ($\\ETJ$) jets have $\\ETJ$ above 6 GeV and a jet-jet invariant mass above 23~GeV, has been studied with the ZEUS detector at the HERA $ep$ collider. Resolved and direct photoproduction samples have been separated. The cross section as a function of the angle between the jet-jet axis and the beam direction in the dijet rest frame has been measured for the two samples. The measured angular distributions differ markedly from each other....

  11. High-mass dijet cross sections in photoproduction at HERA

    CERN Document Server

    Abe, T; Adamczyk, L; Adamus, M; Aghuzumtsyan, G; Ahn, S H; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Bashkirov, V; Basile, M; Bauerdick, L A T; Bednarek, B; Behrens, U; Bell, M; Bellagamba, L; Benen, A; Bertolin, A; Bhadra, S; Bodmann, B; Bokel, C; Boogert, S; Boos, E G; Borras, K; Boscherini, D; Breitweg, J; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Cartiglia, N; Catterall, C D; Chapin, D; Chekanov, S; Chiochia, V; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cirio, R; Cloth, P; Coldewey, C; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cormack, C; Corradi, M; Corriveau, F; Costa, M; Crittenden, J; Cross, R; D'Agostini, Giulio; Dagan, S; Dal Corso, F; Danilov, P; Dannheim, D; De Pasquale, S; Dementiev, R K; Derrick, M; Deshpande, Abhay A; Desler, K; Devenish, R C E; Dhawan, S; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Engelen, J; Ermolov, P F; Eskreys, Andrzej; Ferrando, J; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fox-Murphy, A; Fricke, U; Fusayasu, T; Gabareen, A; Galea, R; Gallo, E; García, G; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Gilmore, J; Ginsburg, C M; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Göbel, F; Goers, S; Golubkov, Yu A; Goncalo, R; González, O; Göttlicher, P; Grabowska-Bold, I; Graciani, R; Grijpink, S; Grzelak, G; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hanlon, S; Hart, J C; Hartmann, H; Hartner, G F; Hayes, M E; Heaphy, E A; Heath, G P; Heath, H F; Helbich, M; Heusch, C A; Hilger, E; Hillert, S; Hirose, T; Hochman, D; Holm, U; Hughes, V W; Iacobucci, G; Iga, Y; Inuzuka, M; Irrgang, P; Jakob, H P; Jelen, K; Jeoung, H Y; Jones, T W; Kananov, S; Kappes, A; Karshon, U; Katkov, I I; Katz, U F; Kcira, D; Kerger, R; Khein, L A; Kim, C L; Kim, J Y; Kind, O; Kisielewska, D; Kitamura, S; Klimek, K; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korotkova, N A; Korzhavina, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowal, M; Kowalski, H; Kowalski, T; Krakauer, D A; Kreisel, A; Kuze, M; Kuzmin, V A; Labarga, L; Labes, H; Lammers, S; Lane, J B; Lee, J H; Lee, S B; Lee, S W; Lelas, D; Levchenko, B B; Levi, G; Levman, G M; Levy, A; Lightwood, M S; Lim, H; Lim, I T; Limentani, S; Ling, T Y; Liu, X; Löhr, B; Lohrmann, E; Long, K R; Longhin, A; Lopez-Duran Viani, A; Lukina, O Yu; Lupi, A; Ma, K J; Maddox, E; Magill, S; Mankel, R; Margotti, A; Marini, G; Markun, P; Martens, J; Martin, J F; Martínez, M; Maselli, S; Massam, Thomas; Mastroberardino, A; Matsushita, T; Matsuzawa, K; Mattingly, M C K; McCubbin, N A; Mellado, B; Menary, S R; Metlica, F; Meyer, A; Milite, M; Miller, D B; Mindur, B; Mirea, A; Monaco, V; Moritz, M; Musgrave, B; Nagano, K; Nania, R; Nigro, A; Nishimura, T; Notz, D; Nowak, R J; Ochs, A; Oh, B Y; Olkiewicz, K; Pac, M Y; Padhi, S; Paganis, S; Palmonari, F; Parenti, A; Park, I H; Park, S K; Paul, E; Pavel, N; Pawlak, J M; Pelfer, P G; Pellegrino, A; Peroni, C; Pesci, A; Petrucci, M C; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Posocco, M; Proskuryakov, A S; Przybycien, M B; Raach, H; Rautenberg, J; Redondo, I; Reeder, D D; Renner, R; Repond, J; Rigby, M; Robins, S; Rodrigues, E; Rulikowska-Zarebska, E; Ruske, O; Ruspa, M; Sabetfakhri, A; Sacchi, R; Salehi, H; Sar, G; Saull, P R B; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schmidke, W B; Schneekloth, U; Schnurbusch, H; Sciulli, F; Scott, J; Selonke, F; Shche, L M; Skillicorn, I O; Slominski, W; Smalska, B; Smith, W H; Soares, M; Solano, A; Solomin, A N; Son, D; Sosnovtsev, V V; Saint-Laurent, M G; Staiano, A; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Straub, P B; Suchkov, S; Surrow, B; Susinno, G; Suszycki, L; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tandler, J; Tapper, A D; Tapper, R J; Tassi, E; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Tuning, N; Turcato, M; Tymieniecka, T; Ukleja, A; Ukleja, J; Umemori, K; Vázquez, M; Velthuis, J J; Vlasov, N N; Voss, K C; Walczak, R; Walker, R; Weber, A; Wessoleck, H; West, B J; Whitmore, J J; Wichmann, R; Wick, K; Wiggers, L; Wing, M; Wolf, G; Wölfle, S; Yamada, S; Yamashita, T; Yamazaki, Y; Yoshida, R; Youngman, C; Za, L; Zakrzewski, J A; Zeuner, W; Zhautykov, B O; Zichichi, A; Ziegler, A; Zotkin, S A; De Wolf, E; Del Peso, J

    2002-01-01

    Dijet differential cross sections for the reaction e+p -> e+ + jet + jet + X in the photoproduction regime have been measured with the ZEUS detector at HERA using an integrated luminosity of 42.7 pb**{-1}. The cross sections are given for photon-proton centre-of-mass energies in the range 134 e+ Z0 X} < 5.9 pb. Upper limits on the photoproduction of new heavy resonances decaying into two jets are also presented for masses in the range between 60 GeV and 155 GeV.

  12. Beam-helicity asymmetries in double-charged-pion photoproduction on the proton.

    Science.gov (United States)

    Strauch, S; Berman, B L; Adams, G; Ambrozewicz, P; Anghinolfi, M; Asavapibhop, B; Asryan, G; Audit, G; Avakian, H; Bagdasaryan, H; Baillie, N; Ball, J P; Baltzell, N A; Barrow, S; Batourine, V; Battaglieri, M; Beard, K; Bedlinskiy, I; Bektasoglu, M; Bellis, M; Benmouna, N; Bennhold, C; Biselli, A S; Boiarinov, S; Bouchigny, S; Bradford, R; Branford, D; Briscoe, W J; Brooks, W K; Bültmann, S; Burkert, V D; Butuceanu, C; Calarco, J R; Careccia, S L; Carman, D S; Carnahan, B; Chen, S; Cole, P L; Coleman, A; Coltharp, P; Cords, D; Corvisiero, P; Crabb, D; Crannell, H; Cummings, J P; Degtyarenko, P V; Denizli, H; Dennis, L; De Sanctis, E; Deur, A; Devita, R; Dharmawardane, K V; Dhuga, K S; Djalali, C; Dodge, G E; Donnelly, J; Doughty, D; Dragovitsch, P; Dugger, M; Dytman, S; Dzyubak, O P; Egiyan, H; Egiyan, K S; Elouadrhiri, L; Empl, A; Eugenio, P; Fatemi, R; Fedotov, G; Feldman, G; Feuerbach, R J; Fix, A; Forest, T A; Funsten, H; Gavalian, G; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Gothe, R W; Griffioen, K A; Guidal, M; Guler, N; Guo, L; Gyurjyan, V; Hadjidakis, C; Hakobyan, R S; Hardie, J; Heddle, D; Hersman, F W; Hicks, K; Hleiqawi, I; Holtrop, M; Hu, J; Huertas, M; Hyde-Wright, C E; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Ito, M M; Jenkins, D; Jo, H S; Joo, K; Juengst, H G; Kellie, J D; Khandaker, M; Kim, K Y; Kim, K; Kim, W; Klein, A; Klein, F J; Klimenko, A V; Klusman, M; Kossov, M; Kramer, L H; Kubarovsky, V; Kuhn, J; Kuhn, S E; Lachniet, J; Laget, J M; Langheinrich, J; Lawrence, D; Lee, T; Lima, A C S; Livingston, K; Lukashin, K; Manak, J J; Marchand, C; McAleer, S; McKinnon, B; McNabb, J W C; Mecking, B A; Mestayer, M D; Meyer, C A; Mibe, T; Mikhailov, K; Minehart, R; Mirazita, M; Miskimen, R; Mokeev, V; Morrow, S A; Muccifora, V; Mueller, J; Mutchler, G S; Nadel-Turonski, P; Napolitano, J; Nasseripour, R; Niccolai, S; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niyazov, R A; Nozar, M; O'rielly, G V; Osipenko, M; Ostrovidov, A I; Park, K; Pasyuk, E; Paterson, C; Philips, S A; Pierce, J; Pivnyuk, N; Pocanic, D; Pogorelko, O; Polli, E; Pozdniakov, S; Preedom, B M; Price, J W; Prok, Y; Protopopescu, D; Qin, L M; Raue, B A; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Roberts, W; Ronchetti, F; Rosner, G; Rossi, P; Rowntree, D; Rubin, P D; Sabatié, F; Salgado, C; Santoro, J P; Sapunenko, V; Schumacher, R A; Serov, V S; Shafi, A; Sharabian, Y G; Shaw, J; Skabelin, A V; Smith, E S; Smith, L C; Sober, D I; Stavinsky, A; Stepanyan, S S; Stepanyan, S; Stokes, B E; Stoler, P; Strakovsky, I I; Suleiman, R; Taiuti, M; Taylor, S; Tedeschi, D J; Thoma, U; Thompson, R; Tkabladze, A; Tkachenko, S; Todor, L; Tur, C; Ungaro, M; Vineyard, M F; Vlassov, A V; Wang, K; Weinstein, L B; Weygand, D P; Williams, M; Wolin, E; Wood, M H; Yegneswaran, A; Yun, J; Zana, L; Zhang, J

    2005-10-14

    Beam-helicity asymmetries for the two-pion-photoproduction reaction gammap-->ppi(+)pi(-) have been studied for the first time in the resonance region for center-of-mass energies between 1.35 and 2.30 GeV. The experiment was performed at Jefferson Lab with the CEBAF Large Acceptance Spectrometer using circularly polarized tagged photons incident on an unpolarized hydrogen target. Beam-helicity-dependent angular distributions of the final-state particles were measured. The large cross-section asymmetries exhibit strong sensitivity to the kinematics and dynamics of the reaction. The data are compared with the results of various phenomenological model calculations, and show that these models currently do not provide an adequate description for the behavior of this new observable. PMID:16241787

  13. Protective Effect of Selected Medicinal Plants against Hydrogen Peroxide Induced Oxidative Damage on Biological Substrates

    Directory of Open Access Journals (Sweden)

    Namratha Pai Kotebagilu

    2014-01-01

    Full Text Available Oxidative stress is developed due to susceptibility of biological substrates to oxidation by generation of free radicals. In degenerative diseases, oxidative stress level can be reduced by antioxidants which neutralize free radicals. Primary objective of this work was to screen four medicinal plants, namely, Andrographis paniculata, Costus speciosus, Canthium parviflorum, and Abrus precatorius, for their antioxidant property using two biological substrates—RBC and microsomes. The antioxidative ability of three solvent extracts, methanol (100% and 80% and aqueous leaf extracts, was studied at different concentrations by thiobarbituric acid reactive substances method using Fenton’s reagent to induce oxidation in the substrates. The polyphenol and flavonoid content were analyzed to relate with the observed antioxidant effect of the extracts. The phytochemical screening indicated the presence of flavonoids, polyphenols, tannins, and β-carotene in the samples. In microsomes, 80% methanol extract of Canthium and Costus and, in RBC, 80% methanol extract of Costus showed highest inhibition of oxidation and correlated well with the polyphenol and flavonoid content. From the results it can be concluded that antioxidants from medicinal plants are capable of inhibiting oxidation in biological systems, suggesting scope for their use as nutraceuticals.

  14. Protective Effect of Selected Medicinal Plants against Hydrogen Peroxide Induced Oxidative Damage on Biological Substrates.

    Science.gov (United States)

    Pai Kotebagilu, Namratha; Reddy Palvai, Vanitha; Urooj, Asna

    2014-01-01

    Oxidative stress is developed due to susceptibility of biological substrates to oxidation by generation of free radicals. In degenerative diseases, oxidative stress level can be reduced by antioxidants which neutralize free radicals. Primary objective of this work was to screen four medicinal plants, namely, Andrographis paniculata, Costus speciosus, Canthium parviflorum, and Abrus precatorius, for their antioxidant property using two biological substrates-RBC and microsomes. The antioxidative ability of three solvent extracts, methanol (100% and 80%) and aqueous leaf extracts, was studied at different concentrations by thiobarbituric acid reactive substances method using Fenton's reagent to induce oxidation in the substrates. The polyphenol and flavonoid content were analyzed to relate with the observed antioxidant effect of the extracts. The phytochemical screening indicated the presence of flavonoids, polyphenols, tannins, and β-carotene in the samples. In microsomes, 80% methanol extract of Canthium and Costus and, in RBC, 80% methanol extract of Costus showed highest inhibition of oxidation and correlated well with the polyphenol and flavonoid content. From the results it can be concluded that antioxidants from medicinal plants are capable of inhibiting oxidation in biological systems, suggesting scope for their use as nutraceuticals. PMID:25436152

  15. N4-methylation of cytosine drastically favors the formation of (6-4) photoproducts in a TCG context.

    Science.gov (United States)

    Douki, Thierry; Meador, Jarah A; Bérard, Izabel; Wack, Aude

    2015-01-01

    Methylation of cytosine is a common biological process both in prokaryotic and eukaryotic cells. In addition to 5-methylcytosine (5mC), some bacterial species contain in their genome N(4) -methylcytosine (N4mC). Methylation at C5 has been shown to enhance the formation of pyrimidine dimeric photoproducts but nothing is known of the effect of N4 methylation on UV-induced DNA damage. In the present work, we compared the yield and the nature of bipyrimidine photoproducts induced in a series of trinucleotides exhibiting a TXG sequence where X is either T, C, 5mC or N4mC. HPLC associated to tandem mass spectrometry was used to quantify cyclobutane pyrimidine dimers (CPD), (6-4) photoproducts (64PP) and their Dewar valence isomer. Methylation at position N4 was found to drastically increase the reactivity of C upon exposure to both UVC and UVB and to favor the formation of 64PP. In contrast methylation at C5 increased the yield of CPD at the expense of 64PP. In addition, enhancement of photoreactivity by C5 methylation was much higher in the UVB than in the UVC range. These results show the drastic effect of the methylation site on the photochemistry of cytosine. PMID:25319211

  16. Prompt photon production in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Krzysztof

    2010-03-15

    This thesis presents measurement of the production of prompt photons in photoproduction with the H1 experiment at HERA. The analysis is based on the data taken in the years 2004-2007, with a total integrated luminosity of 340 pb{sup -1}. The main difficulty of the measurement comes from the high background of neutral mesons decaying into photons. It is accounted for with the help of multivariate analysis. Prompt photon cross sections are measured with the low negative four-momentum transfer squared Q{sup 2} < 1GeV{sup 2} and in the inelasticity range 0.1 < y < 0.7 for photons with a transverse energy 6 < E{sub T}{sup {gamma}} < 15GeV and in the pseudorapidity range.1.0 < {eta}{sup {gamma}} < 2.4 as a function of photons transverse energy and its pseudorapidity. Cross sections for prompt photon events with an additional hadronic jet are measured as a function of the transverse energy and pseudorapidity of the jet and of the momentum fractions x{sub {gamma}} and x{sub p} of the incident photon and proton carried by the constituents participating in the hard scattering process. Additionally, the transverse correlation between the photon and the jet is studied. The results are compared with predictions of a next-to-leading order calculation and a calculation based on the k{sub T} factorisation approach. Neither of calculations is able to describe all the aspects of the measurement. (orig.)

  17. Biological hydrogen production from corn stover by moderately thermophile Thermoanaerobacterium thermosaccharolyticum W16

    Energy Technology Data Exchange (ETDEWEB)

    Ren, Nan-Qi; Cao, Guang-Li; Guo, Wan-Qian; Wang, Ai-Jie; Zhu, Yu-Hong; Liu, Bing-feng; Xu, Ji-Fei [State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, No. 202 Haihe Road, 2nd Campus of HIT box 2614, Harbin, Hei Longjiang 150090 (China)

    2010-04-15

    This study addressed the utilization of an agro-waste, corn stover, as a renewable lignocellulosic feedstock for the fermentative H{sub 2} production by the moderate thermophile Thermoanaerobacterium thermosaccharolyticum W16. The corn stover was first hydrolyzed by cellulase with supplementation of xylanase after delignification with 2% NaOH. It produced reducing sugar at a yield of 11.2 g L{sup -1} glucose, 3.4 g L{sup -1} xylose and 0.5 g L{sup -1} arabinose under the optimum condition of cellulase dosage 25 U g{sup -1} substrate with supplement xylanase 30 U g{sup -1} substrate. The hydrolyzed corn stover was sequentially introduced to fermentation by strain W16, where, the cell density and the maximum H{sub 2} production rate was comparable to that on simulated medium, which has the same concentration of reducing sugars with hydrolysate. The present results suggest a promising combined hydrogen production process from corn stover with enzymatic hydrolysis stage and fermentation stage using W16. (author)

  18. Genetics and Molecular Biology of Hydrogen Metabolism in Sulfate-Reducing Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Wall, Judy D. [Univ. of Missouri, Columbia, MO (United States)

    2014-12-23

    The degradation of our environment and the depletion of fossil fuels make the exploration of alternative fuels evermore imperative. Among the alternatives is biohydrogen which has high energy content by weight and produces only water when combusted. Considerable effort is being expended to develop photosynthetic systems -- algae, cyanobacteria, and anaerobic phototrophs -- for sustainable H2 production. While promising, this approach also has hurdles such as the harvesting of light in densely pigmented cultures that requires costly constant mixing and large areas for exposure to sunlight. Little attention is given to fermentative H2 generation. Thus understanding the microbial pathways to H2 evolution and metabolic processes competing for electrons is an essential foundation that may expand the variety of fuels that can be generated or provide alternative substrates for fine chemical production. We studied a widely found soil anaerobe of the class Deltaproteobacteria, a sulfate-reducing bacterium to determine the electron pathways used during the oxidation of substrates and the potential for hydrogen production.

  19. Genetics and Molecular Biology of Hydrogen Metabolism in Sulfate-Reducing Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Wall, Judy D. [University of Missouri-Columbia

    2014-12-23

    The degradation of our environment and the depletion of fossil fuels make the exploration of alternative fuels evermore imperative. Among the alternatives is biohydrogen which has high energy content by weight and produces only water when combusted. Considerable effort is being expended to develop photosynthetic systems -- algae, cyanobacteria, and anaerobic phototrophs -- for sustainable H2 production. While promising, this approach also has hurdles such as the harvesting of light in densely pigmented cultures that requires costly constant mixing and large areas for exposure to sunlight. Little attention is given to fermentative H2 generation. Thus understanding the microbial pathways to H2 evolution and metabolic processes competing for electrons is an essential foundation that may expand the variety of fuels that can be generated or provide alternative substrates for fine chemical production. We studied a widely found soil anaerobe of the class Deltaproteobacteria, a sulfate-reducing bacterium to determine the electron pathways used during the oxidation of substrates and the potential for hydrogen production.

  20. Low-energy photoproduction of omega-mesons

    CERN Document Server

    Barth, J; Glander, K H; Hannappel, J; Jöpen, N; Klein, F; Lawall, R; Menze, D; Neuerburg, W; Ostrick, M; Paul, E; Schulday, I; Schwille, W J; Wiegers, B; Ernst, J; Kalinowsky, H; Klempt, E; Link, J; Pee, H V; Klein, F J; Wieland, F W; Wisskirchen, J; Wu, C

    2003-01-01

    The photoproduction of the vector meson omega has been studied between threshold and W=2.4 GeV with the SAPHIR detector at the Bonn electron stretcher ring ELSA. Besides, the total cross-sections angular distributions in the CMS and decay angular distributions in the helicity and Gottfried-Jackson systems have been measured.

  1. Beam asymmetry $\\Sigma$ measurements on the $\\pi^-$ photoproduction off neutrons

    CERN Document Server

    Mandaglio, G; Manganaro, M; Bellini, V; Bocquet, J P; Casano, L; D'Angelo, A; Di Salvo, R; Fantini, A; Franco, D; Gervino, G; Ghio, F; Giardina, G; Girolami, B; Giusa, A; Ignatov, A; Lapik, A; Sandri, P Levi; Lleres, A; Moricciani, D; Mushkarenkov, A N; Nedorezov, V; Randieri, C; Rebreyend, D; Rudnev, N V; Russo, G; Schaerf, C; Sperduto, M L; Sutera, M C; Turinge, A; Vegna, V; Briscoe, W J; Strakovsky, I I

    2010-01-01

    The $\\Sigma$ beam asymmetry in the photoproduction of negative pions from quasi-free neutrons in a deuterium target was measured at Graal in the energy interval 700 - 1500 MeV and a wide angular range, using polarized and tagged photons. The results are compared with recent partial wave analyses.

  2. Hadro and Photoproduction of c and b Hadrons

    International Nuclear Information System (INIS)

    Results in heavy flavor spectroscopy and decay; the baryon sector; lifetimes; and weak decays are reviewed. Charm hadroproduction dynamics (cross section dependence, total charm production cross sections, differential cross sections) are discussed. Charm photoproduction dynamics (A dependence, total cross sections, production characteristics) are considered. Open beauty production in hadron or photon interactions (B production in fixed target experiments and at colliders) is treated

  3. The role of screening corrections in high energy photoproduction

    CERN Document Server

    Gotsman, E; Maor, U

    1995-01-01

    The role of screening corrections, calculated using the eikonal model, is discussed in the context of soft photoproduction. We present a comprehensive calculation considering the total,elastic and diffractive cross sections jointly. We examine the differences between our results and those obtained from the supercritical Pomeron-Reggeon model with no unitarity corrections.

  4. Human repair endonuclease incises DNA at cytosine photoproducts

    International Nuclear Information System (INIS)

    The nature of DNA damage by uvB and uvC irradiation was investigated using a defined sequence of human DNA. A UV-irradiated, 3'-end-labeled, 92 base pair sequence from the human alphoid segment was incubated with a purified human lymphoblast endonuclease that incises DNA at non-dimer photoproducts. Analysis by polyacrylamide gel electrophoresis identified all sites of endonucleolytic incision as cytosines. These were found in regions of the DNA sequence lacking adjacent pyrimidines and therefore are neither cyclobutane pyrimidine dimers nor 6-4'-pyrimidines. Incision at cytosine photoproducts was not detected at loci corresponding to alkali-labile sites in either control or irradiated substrates. This demonstrates that the bands detected after the enzymic reactions were not the result of DNA strand breaks, base loss sites or ring-opened cytosines. The optimal wavelengths for formation of cytosine photoproducts are 270-295 nm, similar to those associated with maximal tumor yields in animal ultraviolet carcinogenesis studies. Irradiation by monochromatic 254 nm light resulted in reduced cytosine photoproduct formation. This human UV endonuclease has an apparently identical substrate specificity to E. coli endonuclease III. Both the human and bacterial enzymes incise cytosine moieties in UV irradiated DNA and modified thymines in oxidized DNA

  5. Inelastic photoproduction of J/Psi mesons at HERA

    OpenAIRE

    Adloff, C; Andreev, V.; Andrieu, B.; Anthonis, T.; Astvatsatourov, A.; Babaev, A.; Bahr, J.; Baranov, P; Barrelet, E.; Bartel, W.; Baumgartner, S.; J. Becker(Bochum Ruhr-University, Bochum, Germany); Beckingham, M.; Beglarian, A.; Behnke, O.

    2002-01-01

    An analysis of inelastic photoproduction of J/Psi mesons is presented using data collected at the ep collider HERA corresponding to an integrated luminosity of above 80pb-1. Differential and double differential cross sections are measured in a wide kinematic region: 60

  6. Integrative Approach for Producing Hydrogen and Polyhydroxyalkanoate from Mixed Wastes of Biological Origin.

    Science.gov (United States)

    Patel, Sanjay K S; Lee, Jung-Kul; Kalia, Vipin C

    2016-09-01

    In this study, an integrative approach to produce biohydrogen (H2) and polyhydroxyalkanoates (PHA) from the wastes of biological origin was investigated. A defined set of mixed cultures was used for hydrolysis and the hydrolysates were used to produce H2. The effluent from H2 production stage was used for PHA production. Under batch culture, a maximum of 62 l H2/kg of pure potato peels (Total solid, TS 2 %, w/v) and 54 l H2/kg of mixed biowastes (MBW1) was recorded. Using effluent from the H2 production stage of biowaste mixture (MBW1), Bacillus cereus EGU43 could produce 195 mg PHA/l and 15.6 % (w/w). Further, supplementation of GM-2 medium (0.1×) and glucose (0.5 %) in H2 production stage effluents, resulted in significant improvements of up to 11 and 41.7 % of PHA contents, respectively. An improvement of 3.9- and 17-fold in PHA yields as compared to with and without integrative H2 production from the MBW1 has been recorded. This integrative approach seems to be a suitable process to improve the yields of H2 and PHA by mixing biowastes. PMID:27407293

  7. Progress in the study of biological effects of hydrogen on higher plants and its promising application in agriculture

    OpenAIRE

    Zeng, Jiqing; Ye, Zhouheng; Sun, Xuejun

    2014-01-01

    While the medical effects of hydrogen have been broadly analyzed, research into the effects of hydrogen on higher plants has often been of lesser concern. Recent studies on the botanical effects of hydrogen have shown that it is involved in signal transduction pathways of plant hormones and can improve the resistance of plants to stressors, such as drought, salinity, cold and heavy metals. In addition, hydrogen could delay postharvest ripening and senescence of fruits. Observational evidence ...

  8. Photochemistry. Chemiexcitation of melanin derivatives induces DNA photoproducts long after UV exposure.

    Science.gov (United States)

    Premi, Sanjay; Wallisch, Silvia; Mano, Camila M; Weiner, Adam B; Bacchiocchi, Antonella; Wakamatsu, Kazumasa; Bechara, Etelvino J H; Halaban, Ruth; Douki, Thierry; Brash, Douglas E

    2015-02-20

    Mutations in sunlight-induced melanoma arise from cyclobutane pyrimidine dimers (CPDs), DNA photoproducts that are typically created picoseconds after an ultraviolet (UV) photon is absorbed at thymine or cytosine. We found that in melanocytes, CPDs are generated for >3 hours after exposure to UVA, a major component of the radiation in sunlight and in tanning beds. These "dark CPDs" constitute the majority of CPDs and include the cytosine-containing CPDs that initiate UV-signature C→T mutations. Dark CPDs arise when UV-induced reactive oxygen and nitrogen species combine to excite an electron in fragments of the pigment melanin. This creates a quantum triplet state that has the energy of a UV photon but induces CPDs by energy transfer to DNA in a radiation-independent manner. Melanin may thus be carcinogenic as well as protective against cancer. These findings also validate the long-standing suggestion that chemically generated excited electronic states are relevant to mammalian biology.

  9. The Enzyme-Mediated Direct Reversal of a Dithymine Photoproduct in Germinating Endospores

    Directory of Open Access Journals (Sweden)

    Lei Li

    2013-06-01

    Full Text Available Spore photoproduct lyase (SPL repairs a special thymine dimer, 5-thyminyl-5,6-dihydrothymine, which is commonly called spore photoproduct, or SP, in germinating endospores. SP is the exclusive DNA photo-damaging product found in endospores; its generation and swift repair by SPL are responsible for the spores’ extremely high UV resistance. Early in vivo studies suggested that SPL utilizes a direct reversal strategy to repair SP in the absence of light. Recently, it has been established that SPL belongs to the radical S-adenosylmethionine (SAM superfamily. The enzymes in this superfamily utilize a tri-cysteine CXXXCXXC motif to bind a [4Fe-4S] cluster. The cluster provides an electron to the S-adenosylmethionine (SAM to reductively cleave its C5'-S bond, generating a reactive 5'-deoxyadenosyl (5'-dA radical. This 5'-dA radical abstracts the proR hydrogen atom from the C6 carbon of SP to initiate the repair process; the resulting SP radical subsequently fragments to generate a putative thymine methyl radical, which accepts a back-donated H atom to yield the repaired TpT. The H atom donor is suggested to be a conserved cysteine141 in B. subtilis SPL; the resulting thiyl radical likely interacts with a neighboring tyrosine99 before oxidizing the 5'-dA to 5'-dA radical and, subsequently, regenerating SAM. These findings suggest SPL to be the first enzyme in the large radical SAM superfamily (>44,000 members to utilize a radical transfer pathway for catalysis; its study should shed light on the mechanistic understanding of the SAM regeneration process in other members of the superfamily.

  10. Heavy quark photoproduction in the semihard approach at HERA and beyond

    CERN Document Server

    Saleev, V A

    1995-01-01

    Processes of heavy quark photoproduction at HERA energies and beyond are investigated using the semihard (k_{\\bot} factorization) approach. Virtuality and longitudinal polarization of gluons in the photon - gluon subprocess as well as the saturation effects in the gluon distribution function at small x have been taken into account. The total cross sections, rapidity and p_{\\bot} distributions of the charm and beauty quark photoproduction have been calculated. The results are compared with ZEUS experimental data for charm photoproduction cross section.

  11. Color Evaporation and Elastic $\\Upsilon$ Photoproduction at DESY HERA

    CERN Document Server

    Ducati, M B G; Mariotto, C B

    2002-01-01

    The diffractive photoproduction of vector mesons is usually described considering the two-gluon (Pomeron) exchange, non-diagonal parton distributions and the contribution of the real part to the cross section. In this letter we analyze the diffractive photoproduction of the $\\Upsilon$ at HERA using an alternative model, the Color Evaporation Model (CEM), where the cross section is simply determined by the boson-gluon cross section and an assumption for the production of the colorless state. We verify that, similarly to the $J/\\Psi$ case, the HERA data for this process can be well described by the CEM. Moreover, we propose the analyzes of the ratio $R = \\sigma_{\\Upsilon} / \\sigma_{J/\\Psi}$ to discriminate between the distinct approaches.

  12. Fragmentation contributions to $J/\\psi$ photoproduction at HERA

    CERN Document Server

    Bodwin, Geoffrey T; Kim, U-Rae; Lee, Jungil

    2015-01-01

    We compute leading-power fragmentation corrections to $J/\\psi$ photoproduction at DESY HERA, making use of the nonrelativistic QCD factorization approach. Our calculations include parton production cross sections through order $\\alpha_s^3$, fragmentation functions though order $\\alpha_s^2$, and leading logarithms of the transverse momentum divided by the charm-quark mass to all orders in $\\alpha_s$. We find that the leading-power fragmentation corrections, beyond those that are included through next-to-leading order in $\\alpha_s$, are small relative to the fixed-order contributions through next-to-leading order in $\\alpha_s$. Consequently, an important discrepancy remains between the experimental measurements of the $J/\\psi$ photoproduction cross section and predictions that make use of nonrelativistic-QCD long-distance matrix elements that are extracted from the $J/\\psi$ hadroproduction cross-section and polarization data.

  13. Measurement of the Photoproduction of Vector and Scalar Bosons

    CERN Multimedia

    2002-01-01

    The original programme of the experiment consisted of a detailed study of projectile fragmentation on nucleons and nuclei with particular attention to diffractive excitation. This programme of research was then specified as the measurement of coherent photoproduction on nuclei up to @=~180~GeV with the following aims: \\item a) photoproduction of charmed particle pairs and measurement of charmed particle lifetimes by means of an active target; \\item b) study of the spectroscopy of the new massive particles with particular attention to the hadronic decay channels, containing charged particles and photons, and to radiative decays. \\end{enumerate}\\\\ \\\\ The apparatus consists of a forward spectrometer for charged particles and photons and of a large angle detector which provides the topology of individual events. The spectrometer subtends a solid angle of @C 40 msr and consists of four bending magnets interspaced by sets of drift chambers, counter hodoscopes and photon detectors. The momentum resolution for charge...

  14. Photoproduction of top in peripheral heavy ion collisions

    CERN Document Server

    Klein, S R; Vogt, R; Klein, Spencer R.; Nystrand, Joakim; Vogt, Ramona

    2001-01-01

    In relativistic heavy ion collisions, top quarks can be produced by photon-gluon fusion when a photon from the Weizs\\"acker-Williams virtual photon field of one nucleus interacts with a gluon in the other nucleus. Photoproduction with heavy ions at the Large Hadron Collider (LHC) will be the first accessible non-hadronic top production channel. We calculate the $t \\bar t$ photoproduction cross sections, pair mass and top quark rapidity distributions in peripheral heavy ion collisions. The cross sections are sensitive to the top quark charge and the large-$Q^2$ gluon distribution in the nucleus. We find a cross section of 94 pb in calcium-calcium collisions, leading to 490 pairs in a one month LHC run. We also find $p$Pb and $p$Ca cross sections of 5.8 and 3.4 pb respectively, resulting in 15 and 88 $t\\bar t$ pairs per month.

  15. The incompleteness of complete pseudoscalar-meson photoproduction

    CERN Document Server

    Vrancx, Tom; Van Cuyck, Tom; Vancraeyveld, Pieter

    2013-01-01

    [Background] A complete set is a minimum set of observables which allows one to determine the underlying reaction amplitudes unambiguously. Pseudoscalar-meson photoproduction from the nucleon is characterized by four such amplitudes and complete sets involve single- and double-polarization observables. [Purpose] Identify complete sets of observables, and study how measurements with finite error bars impact their potential to determine the reaction amplitudes unambiguously. [Method] The authors provide arguments to employ the transversity representation in order to determine the amplitudes in pseudoscalar-meson photoproduction. It is studied whether the amplitudes in the transversity basis for the $\\gamma p \\to K^+\\Lambda$ reaction can be estimated without ambiguity. To this end, data from the GRAAL collaboration and mock data from a realistic model are analyzed. [Results] It is illustrated that the moduli of normalized transversity amplitudes can be determined from precise single-polarization data. Starting f...

  16. Photoproduction of events with rapidity gaps between jets at HERA

    CERN Document Server

    Chekanov, S; Magill, S; Miglioranzi, S; Musgrave, B; Nicholass, D; Repond, J; Yoshida, R; Mattingly, M C K; Jechow, M; Pavel, N; Yagues-Molina, A G; Antonelli, S; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Bindi, M; Boscherini, D; Bruni, A; Bruni, G; Cifarelli, L; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Iacobucci, G; Margotti, A; Nania, R; Polini, A; Rinaldi, L; Sartorelli, G; Zichichi, A; Aghuzumtsyan, G; Bartsch, D; Brock, I; Goers, S; Hartmann, H; Hilger, E; Jakob, H P; Jüngst, M; Kind, O M; Paul, E; Rautenberg, J; Renner, R; Samson, U; Schonberg, V; Wang, M; Wlasenko, M; Brook, N H; Heath, G P; Morris, J D; Namsoo, T; Capua, M; Fazio, S; Mastroberardino, A; Schioppa, M; Susinno, G; Tassi, E; Kim, J Y; Ma, K J; Ibrahim, Z A; Kamaluddin, B; Wan-Abdullah, W A T; Ning, Y; Ren, Z; Sciulli, F; Chwastowski, J; Eskreys, A; Figiel, J; Galas, A; Gil, M; Olkiewicz, K; Stopa, P; Zawiejski, L; Adamczyk, L; Bold, T; Grabowska-Bold, I; Kisielewska, D; Lukasik, J; Przybycien, M B; Suszycki, L; Kotanski, A; Slominski, W; Adler, V; Behrens, U; Bloch, I; Bonato, A; Borras, K; Coppola, N; Fourletova, J; Geiser, A; Gladkov, D; Göttlicher, P; Gregor, I; Haas, T; Hain, W; Horn, C; Kahle, B; Kötz, U; Kowalski, H; Lobodzinska, E; Löhr, B; Mankel, R; Melzer-Pellmann, I A; Montanari, A; Notz, D; Nuncio-Quiroz, A E; Santamarta, R; Schneekloth, U; Spiridonov, A A; Stadie, H; Stösslein, U; Szuba, D; Szuba, J; Theedt, T; Wolf, G; Wrona, K; Youngman, C; Zeuner, W; Schlenstedt, S; Barbagli, G; Gallo, E; Pelfer, P G; Bamberger, A; Dobur, D; Karstens, F; Vlasov, N N; Bussey, P J; Doyle, A T; Dunne, W; Ferrando, J; Saxon, D H; Skillicorn, I O; Gialas, I; Gosau, T; Holm, U; Klanner, R; Lohrmann, E; Salehi, H; Schleper, P; Schörner-Sadenius, T; Sztuk, J; Wichmann, K; Wick, K; Foudas, C; Fry, C; Long, K R; Tapper, A D; Kataoka, M; Matsumoto, T; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Dossanov, A; Pokrovskiy, N S; Zhautykov, B O; Son, D; De Favereau, J; Piotrzkowski, K; Barreiro, F; Glasman, C; Jiménez, M; Labarga, L; Del Peso, J; Ron, E; Soares, M; Terron, J; Zambrana, M; Corriveau, F; Liu, C; Walsh, R; Zhou, C; Tsurugai, T; Antonov, A; Dolgoshein, B A; Rubinsky, I; Sosnovtsev, V; Stifutkin, A; Suchkov, S; Dementiev, R K; Ermolov, P F; Gladilin, L K; Katkov, I I; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Zotkin, D S; Zotkin, S A; Abt, I; Büttner, C; Caldwell, A; Kollar, D; Schmidke, W B; Sutiak, J; Grigorescu, G; Keramidas, A; Koffeman, E; Kooijman, P; Pellegrino, A; Tiecke, H G; Vázquez, M; Wiggers, L; Brümmer, N; Bylsma, B; Durkin, L S; Lee, A; Ling, T Y; Allfrey, P D; Bell, M A; Cooper-Sarkar, A M; Cottrell, A; Devenish, R C E; Foster, B; Korcsak-Gorzo, K; Patel, S; Roberfroid, V; Robertson, A; Straub, P B; Uribe-Estrada, C; Walczak, R; Bellan, P M; Bertolin, A; Brugnera, R; Carlin, R; Ciesielski, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Stanco, L; Turcato, M; Oh, B Y; Raval, A; Ukleja, J; Whitmore, J J; Iga, Y; D'Agostini, G; Marini, G; Nigro, A; Cole, J E; Hart, J C; Abramowicz, H; Gabareen, A; Ingbir, R; Kananov, S; Levy, A; Kuze, M; Hori, R; Kagawa, S; Okazaki, N; Shimizu, S; Tawara, T; Hamatsu, R; Kaji, H; Kitamura, S; Ota, O; Ri, Y D; Ferrero, M I; Monaco, V; Sacchi, R; Solano, A; Arneodo, M; Ruspa, M; Fourletov, S; Martin, J F; Boutle, S K; Butterworth, J M; Gwenlan, C; Jones, T W; Loizides, J H; Sutton, M R; Targett-Adams, C; Wing, M; Brzozowska, B; Ciborowski, J; Grzelak, G; Kulinski, P; Luzniak, P; Malka, J; Nowak, R J; Pawlak, J M; Tymieniecka, T; Ukleja, A; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Giller, I; Hochman, D; Karshon, U; Rosin, M; Brownson, E; Danielson, T; Everett, A; Kcira, D; Reeder, D D; Ryan, P; Savin, A A; Smith, W H; Wolfe, H; Bhadra, S; Catterall, C D; Cui, Y; Hartner, G; Menary, S; Noor, U; Standage, J; Whyte, J

    2006-01-01

    The photoproduction of dijet events, where the two jets with the highest transverse energy are separated by a large gap in pseudorapidity, have been studied with the ZEUS detector using an integrated luminosity of 39 pb$^{-1}$. Rapidity-gap events are defined in terms of the energy flow between the jets, such that the total summed transverse energy in this region is less than some value $E_{\\rm T}^{\\rm CUT}$. The data show a clear excess over the predictions of standard photoproduction models. This is interpreted as evidence for a strongly interacting exchange of a color-singlet object. Monte Carlo models which include such a color-singlet exchange are able to describe the data.

  17. Exclusive measurement of coherent eta photoproduction from the deuteron

    CERN Document Server

    Weiss, J; Ahrens, J; Annand, J R M; Beck, R; Hejny, V; Kellie, J D; Kleber, V; Kotulla, M; Krusche, B; Kuhr, V; Leukel, R; Metag, V; de Leon, V M O; Rambo, F; Schmidt, A; Siodlaczek, U; Ströher, H; Wissmann, F; Wolf, M

    2001-01-01

    Coherent photoproduction of eta mesons from the deuteron has been measured from threshold up to incident photon energies of 750 MeV using the photon spectrometer TAPS at the tagged photon facility at the Mainz microtron MAMI. For the first time, differential coherent cross sections have been deduced from the coincident detection of the eta meson and the recoil deuteron. A missing energy analysis was used for the suppression of background events so that a very clean identification of coherent eta-photoproduction was achieved. The resulting cross sections agree with previous experimental results except for angles around 90 deg in the photon-deuteron cm-system where they are smaller. They are compared to various model calculations.

  18. Photoproduction of η and η' mesons off protons

    Science.gov (United States)

    Crede, V.; McVeigh, A.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, R.; Bartholomy, O.; Bayadilov, D.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Ehmanns, A.; Elsner, D.; Essig, K.; Ewald, R.; Fabry, I.; Fuchs, M.; Funke, Chr.; Gothe, R.; Gregor, R.; Gridnev, A.; Gutz, E.; Höffgen, St.; Hoffmeister, P.; Horn, I.; Jaegle, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Klein, Frank; Klein, Friedrich; Klempt, E.; Konrad, M.; Kotulla, M.; Krusche, B.; Langheinrich, J.; Löhner, H.; Lopatin, I. V.; Lotz, J.; Lugert, S.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Nanova, M.; Nikonov, V. A.; Novinski, D.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Roy, A.; Sarantsev, A. V.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S.; Sokhoyan, V.; Sparks, N.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Weinheimer, Ch.; Wendel, Ch.; Wilson, A.

    2009-11-01

    Total and differential cross sections for η and η'photoproduction off the proton have been determined with the CBELSA/TAPS detector for photon energies between 0.85 and 2.55 GeV. The η mesons are detected in their two neutral decay modes, η→γγ and η→3π0→6γ, and for the first time, cover the full angular range in cosθc.m. of the η meson. These new η photoproduction data are consistent with the earlier CB-ELSA results. The η' mesons are observed in their neutral decay to π0π0η→6γ and also extend the coverage in angular range.

  19. Incoherent photoproduction of pseudoscalar mesons off nuclei at forward angles

    CERN Document Server

    Gevorkyan, S; Gan, L; Larin, I; Khandaker, M

    2009-01-01

    Recent advances in the photon tagging facilities together with the novel, high resolution fast calorimetry made possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths, needed for testing the symmetry breaking effects in QCD, from these measurements at small angles is done by the Primakoff method. This method requires theoretical treatment of all processes participating in these reactions at the same percent level. The most updated description of general processes, including the nuclear coherent amplitude, is done in our previous paper. In this work, based on the framework of Glauber multiple scattering theory, we obtain analytical expressions for the incoherent cross section of the photoproduction of pseudoscalar mesons off nuclei accounting for the mesons absorption in nuclei and Pauli suppression at forward production angles. As illustrations of the obtained formulas, we calculate the incoher...

  20. Photoproduction of Pseudoscalar Mesons off Nuclei at Forward Angles

    CERN Document Server

    Gevorkyan, S; Gan, L; Larin, I; Khandaker, M

    2009-01-01

    With the advent of new photon tagging facilities and novel experimental technologies it has become possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths from these measurements at forward angles is done by the Primakoff method, which requires theoretical treatment of all processes participating in these reactions at the same percent level. In this work we review the theoretical approach to meson photoproduction amplitudes in the electromagnetic and strong fields of nuclei at forward direction. The most updated description of these processes are presented based on the Glauber theory of multiple scattering. In particular, the effects of final state interactions, corrections for light nuclei, and photon shadowing in nuclei are discussed.

  1. Effective Lagrangian Approach to pion photoproduction from the nucleon

    CERN Document Server

    Fernandez-Ramirez, C; Udias, J M

    2006-01-01

    We present a pion photoproduction model on the free nucleon based on an Effective Lagrangian Approach (ELA) which includes the nucleon resonances ($\\Delta(1232)$, N(1440), N(1520), N(1535), $\\Delta (1620)$, N(1650), and $\\Delta (1700)$), in addition to Born and vector meson exchange terms. The model incorporates a new theoretical treatment of spin-3/2 resonances, first introduced by Pascalutsa, avoiding pathologies present in previous models. Other main features of the model are chiral symmetry, gauge invariance, and crossing symmetry. We use the model combined with modern optimization techniques to assess the parameters of the nucleon resonances on the basis of world data on electromagnetic multipoles. We present results for electromagnetic multipoles, differential cross sections, asymmetries, and total cross sections for all one pion photoproduction processes on free nucleons. We find overall agreement with data from threshold up to 1 GeV in laboratory frame.

  2. Low-energy pi pi photoproduction off nuclei

    CERN Document Server

    Mühlich, P; Buss, O; Mosel, U

    2004-01-01

    In the present paper we investigate pi0 pi0 and pi(+/-)pi0 photoproduction off complex nuclei at incident beam energies of 400-460 MeV. Simulations of two pion photoproduction on protons and nuclei are performed by means of a semi-classical BUU transport model including a full coupled-channel treatment of the final state interactions. Elastic scattering of the final state pions with the nucleons in the surrounding nuclear medium is found to yield a downward shift of the pi pi invariant mass distribution. We show that the target mass dependence of the pi0 pi0 invariant mass spectrum as measured by the TAPS collaboration can be explained without introducing medium effects beyond absorption and quasi-elastic scattering of the final state particles. On the other hand, we find considerable discrepancies with the data in the pi(+/-)pi0 channel, which are not understood.

  3. Heavy Quark Photoproduction in k_{perp}-Factorization Approach

    CERN Document Server

    Mariotto, C B; Machado, M V T

    2002-01-01

    We investigate the heavy quark photoproduction based on the rk_{perp}-factorization approach, focusing on the results from the saturation model. The deviations in the results using the unintegrated gluon distribution considering the saturation model and the derivative of the collinear gluon distribution are analysed. Total cross sections and p_T distributions are analysed in detail, setting the deviations between the color dipole approximation and the complete semihard approach.

  4. Kaon photoproduction on the nucleon with constrained parameters

    CERN Document Server

    Nelson, R

    2009-01-01

    The new experimental data of kaon photoproduction on the nucleon, gamma p -> K+ Lambda, have been analyzed by means of a multipoles model. Different from the previous models, in this analysis the resonance decay widths are constrained to the values given by the Particle Data Group (PDG). The result indicates that constraining these parameters to the PDG values could dramatically change the conclusion of the important resonances in this reaction found in the previous studies.

  5. Heavy quark photoproduction in proton-proton collisions

    OpenAIRE

    Goncalves, V. P.; Machado, M. V. T.

    2004-01-01

    We calculate the photoproduction of heavy quarks in proton-proton collisions at RHIC, Tevatron and LHC energies. The integrated cross section and the rapidity distributions for open charm and bottom production are computed employing sound high energy QCD formalisms. For the linear pQCD approaches we consider both the usual collinear factorization and the k_T-factorization formalisms, whereas for the nonlinear QCD (saturation) calculations one considers the Golec-Biernat-Wuesthoff and the Ianc...

  6. Beauty in photoproduction at HERA II with the ZEUS detector

    Energy Technology Data Exchange (ETDEWEB)

    Boutle, Sarah

    2010-02-15

    The production of beauty quarks in ep collisions should be accurately calculable in perturbative Quantum Chromodynamics (QCD) since the large mass of the b quark provides a hard scale. Therefore it is interesting to compare such predictions to results using photoproduction events where a low-virtuality photon, emitted by the incoming lepton, collides with a parton from the incoming proton. A measurement of beauty in photoproduction has been made at HERA with the ZEUS detector using an integrated luminosity of 126 pb{sup -}1. Beauty was identified in events with a muon in the final state by using the transverse momentum of the muon relative to the closest jet. Lifetime information from the silicon vertex detector was also used; the impact parameter of the muon with respect to the primary vertex was exploited to discriminate between signal and background. Cross sections for beauty production as a function of the muon and the jet variables were measured and compared to QCD predictions and to previous measurements. The data were found to be well described by the predictions from next-to-leading-order QCD. The dijet sample of beauty photoproduction events was also used to study higher-order QCD topologies. At leading order, the two jets in the event are produced back-to-back in azimuthal angle, such that {delta}{phi}{sup jj}={phi}{sup j1}-{phi}{sup j2}={pi}. Additional soft radiation causes small azimuthal decorrelations, whilst {delta}{phi}{sup jj} significantly lower than {pi} is evidence of additional hard radiation. In this thesis, the cross section versus {delta}{phi}{sup jj} for beauty photoproduction and the comparison to NLO QCD predictions and Monte Carlo models are presented. (orig.)

  7. Diffractive photoproduction of dijets in ep collisions at HERA

    CERN Document Server

    Chekanov, S; Magill, S; Musgrave, B; Nicholass, D; Repond, J; Yoshida, R; Mattingly, M C K; Jechow, M; Pavel, N; Yagues-Molina, A G; Antonelli, S; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Bindi, M; Boscherini, D; Bruni, A; Bruni, G; Cifarelli, L; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Iacobucci, G; Margotti, A; Nania, R; Polini, A; Sartorelli, G; Zichichi, A; Bartsch, D; Brock, I; Hartmann, H; Hilger, E; Jakob, H P; Jüngst, M; Kind, O M; Nuncio-Quiroz, A E; Paul, E; Renner, R; Samson, U; Schonberg, V; Shehzadi, R; Wlasenko, M; Brook, N H; Heath, G P; Morris, J D; Capua, M; Fazio, S; Mastroberardino, A; Schioppa, M; Susinno, G; Tassi, E; Kim, J Y; Ibrahim, Z A; Kamaluddin, B; Wan-Abdullah, W A T; Ning, Y; Ren, Z; Sciulli, F; Chwastowski, J; Eskreys, A; Figiel, J; Galas, A; Gil, M; Olkiewicz, K; Stopa, P; Zawiejski, L; Adamczyk, L; Bold, T; Grabowska-Bold, I; Kisielewska, D; Lukasik, J; Przybycien, M; Suszycki, L; Kotanski, A; Slominski, W; Adler, V; Behrens, U; Blohm, C; Bonato, A; Borras, K; Ciesielski, R; Coppola, N; Drugakov, V; Fang, S; Fourletova, J; Geiser, A; Gladkov, D; Göttlicher, P; Grebenyuk, J; Gregor, I; Haas, T; Hain, W; Huttmann, A; Kahle, B; Katkov, I I; Klein, U; Kötz, U; Kowalski, H; Lobodzinska, E; Löhr, B; Mankel, R; Melzer-Pellmann, I A; Miglioranzi, S; Montanari, A; Namsoo, T; Notz, D; Rinaldi, L; Roloff, P; Rubinsky, I; Santamarta, R; Schneekloth, U; Spiridonov, A; Szuba, D; Szuba, J; Theedt, T; Wolf, G; Wrona, K; Youngman, C; Zeuner, W; Lohmann, W; Schlenstedt, S; Barbagli, G; Gallo, E; Pelfer, P G; Bamberger, A; Dobur, D; Karstens, F; Vlasov, N N; Bussey, P J; Doyle, A T; Dunne, W; Forrest, M; Saxon, D H; Skillicorn, I O; Gialas, I; Papageorgiu, K; Holm, U; Klanner, R; Lohrmann, E; Schleper, P; Schörner-Sadenius, T; Sztuk, J; Stadie, H; Turcato, M; Foudas, C; Fry, C; Long, K R; Tapper, A D; Matsumoto, T; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Pokrovskiy, N S; Zhautykov, B O; Aushev, V; Borodin, M; Kozulia, A; Lisovyi, M; Son, D; De Favereau, J; Piotrzkowski, K; Barreiro, F; Glasman, C; Jiménez, M; Labarga, L; Del Peso, J; Ron, E; Soares, M; Terron, J; Zambrana, M; Corriveau, F; Liu, C; Walsh, R; Zhou, C; Tsurugai, T; Antonov, A; Dolgoshein, B A; Sosnovtsev, V; Stifutkin, A; Suchkov, S; Dementiev, R K; Ermolov, P F; Gladilin, L K; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Zotkin, D S; Zotkin, S A; Abt, I; Büttner, C; Caldwell, A; Kollar, D; Schmidke, W B; Sutiak, J; Grigorescu, G; Keramidas, A; Koffeman, E; Kooijman, P; Pellegrino, A; Tiecke, H; Vázquez, M; Wiggers, L; Brümmer, N; Bylsma, B; Durkin, L S; Lee, A; Ling, T Y; Allfrey, P D; Bell, M A; Cooper-Sarkar, A M; Devenish, R C E; Ferrando, J; Fos-ter, B; Korcsak-Gorzo, K; Oliver, K; Patel, S; Roberfroid, V; Robertson, A; Straub, P B; Uribe-Estrada, C; Walczak, R; Bellan, P; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Stanco, L; Turcato, M; Oh, B Y; Raval, A; Ukleja, J; Whitmore, J J; Iga, Y; D'Agostini, G; Marini, G; Nigro, A; Cole, J E; Hart, J C; Abramowicz, H; Gabareen, A; Ingbir, R; Kananov, S; Levy, A; Smith, O; Stern, A; Kuze, M; Maeda, J; Hori, R; Kagawa, S; Okazaki, N; Shimizu, S; Tawara, T; Hamatsu, R; Kaji, H; Kitamura, S; Ota, O; Ri, Y D; Ferrero, M I; Monaco, V; Sacchi, R; Solano, A; Arneodo, M; Costa, M; Ruspa, M; Fourletov, S; Martin, J F; Stewart, T P; Boutle, S K; Butterworth, J M; Gwenlan, C; Jones, T W; Loizides, J H; Wing, M; Brzozowska, B; Ciborowski, J; Grzelak, G; Kulinski, P; Luzniak, P; Malka, J; Nowak, R J; Pawlak, J M; Tymieniecka, T; Ukleja, A; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Giller, I; Hochman, D; Karshon, U; Rosin, M; Brownson, E; Danielson, T; Everett, A; Kcira, D; Reeder, D D; Ryan, P; Savin, A A; Smith, W H; Wolfe, H; Bhadra, S; Catterall, C D; Cui, Y; Hartner, G; Menary, S; Noor, U; Standage, J; Whyte, J

    2005-01-01

    Diffractive photoproduction of dijets was measured with the ZEUS detector at the ep collider HERA using an integrated luminosity of 77.2 pb-1. The measurements were made in the kinematic range Q^2 7.5 and 6.5 GeV, respectively, and to lie in the pseudorapidity range -1.5 < eta^jet < 1.5. Differential cross sections were compared to perturbative QCD calculations using available parameterisations of diffractive parton distributions of the proton.

  8. Inclusive parton cross sections in photoproduction and photon structure

    CERN Document Server

    Ahmed, T; Andrieu, B; Appuhn, R D; Arpagaus, M; Aïd, S; Babaev, A; Ban, Y; Baranov, P S; Barrelet, E; Bartel, Wulfrin; Barth, Monique; Bassler, U; Beck, H P; Behrend, H J; Belousov, A; Berger, C; Bergstein, H; Bernardi, G; Bernet, R; Bertrand-Coremans, G H; Besançon, M; Beyer, R; Biddulph, P; Bispham, P; Bizot, J C; Blobel, Volker; Borras, K; Botterweck, F; Boudry, V; Braemer, A; Brasse, F W; Braunschweig, W; Brisson, V; Bruncko, Dusan; Brune, C R; Buchholz, R; Buniatian, A Yu; Burke, S; Burton, M; Buschhorn, G W; Bán, J; Bähr, J; Büngener, L; Bürger, J; Büsser, F W; Campbell, A J; Carli, T; Charles, F; Charlet, M; Chernyshov, V; Clarke, D; Clegg, A B; Clerbaux, B; Colombo, M G; Contreras, J G; Cormack, C; Coughlan, J A; Courau, A; Coutures, C; Cozzika, G; Criegee, L; Cussans, D G; Cvach, J; Dagoret, S; Dainton, J B; Dau, W D; Daum, K; David, M; De Wolf, E A; Del Buono, L; Delcourt, B; Di Nezza, P; Dollfus, C; Dowell, John D; Dreis, H B; Droutskoi, A; Duboc, J; Duhm, H; Düllmann, D; Dünger, O; Ebert, J; Ebert, T R; Eckerlin, G; Efremenko, V; Egli, S; Eichenberger, S; Eichler, R; Eisele, Franz; Eisenhandler, Eric F; Ellison, R J; Elsen, E E; Erdmann, M; Erdmann, W; Erlichmann, H; Evrard, E; Favart, L; Fedotov, A; Feeken, D; Felst, R; Feltesse, Joel; Ferencei, J; Ferrarotto, F; Flamm, K; Fleischer, M; Flieser, M; Flügge, G; Fomenko, A; Fominykh, B A; Forbush, M; Formánek, J; Foster, J M; Franke, G; Fretwurst, E; Gabathuler, Erwin; Gabathuler, K; Gamerdinger, K; Garvey, J; Gayler, J; Gebauer, M; Gellrich, A; Genzel, H; Gerhards, R; Goerlach, U; Gogitidze, N; Goldberg, M; Goldner, D; González-Pineiro, B; Gorelov, I V; Goritchev, P A; Grab, C; Greenshaw, T J; Grindhammer, G; Gruber, A; Gruber, C; Grässler, Herbert; Grässler, R; Görlich, L; Haack, J; Haidt, Dieter; Hajduk, L; Hamon, O; Hampel, M; Hanlon, E M; Hapke, M; Haynes, W J; Heatherington, J; Heinzelmann, G; Henderson, R C W; Henschel, H; Herynek, I; Hess, M F; Hildesheim, W; Hill, P; Hiller, K H; Hilton, C D; Hladky, J; Hoeger, K C; Horisberger, R P; Hudgson, V L; Huet, Patrick; Hufnagel, H; Höppner, M; Hütte, M; Ibbotson, M; Itterbeck, H; Jabiol, M A; Jacholkowska, A; Jacobsson, C; Jaffré, M; Janoth, J; Jansen, T; Johnson, D P; Johnson, L; Jung, H; Jönsson, L B; Kalmus, Peter I P; Kant, D; Kaschowitz, R; Kasselmann, P; Kathage, U; Katzy, J M; Kaufmann, H H; Kazarian, S; Kenyon, Ian Richard; Kermiche, S; Keuker, C; Kiesling, C; Klein, M; Kleinwort, C; Knies, G; Ko, W; Kolanoski, H; Kole, F; Kolya, S D; Korbel, V; Korn, M; Kostka, P; Kotelnikov, S K; Krasny, M W; Krehbiel, H; Krämerkämper, T; Krücker, D; Krüger, U P; Krüner-Marquis, U; Kubenka, J P; Kuhlen, M; Kurca, T; Kurzhöfer, J; Kuznik, B; Köhler, T; Köhne, J H; Küster, H; Lacour, D; Lamarche, F; Lander, R; Landon, M P J; Lange, W; Lanius, P; Laporte, J F; Lebedev, A; Leverenz, C; Levonian, S; Ley, C; Lindner, A; Lindström, G; Link, J; Linsel, F; Lipinski, J; List, B; Lobo, G; Loch, P; Lohmander, H; Lomas, J W; Lubimov, V; López, G C; Lüke, D; Magnussen, N; Malinovskii, E I; Mani, S; Maracek, R; Marage, P; Marks, J; Marshall, R; Martens, J; Martin, R D; Martyn, H U; Martyniak, J; Masson, S; Mavroidis, A; Maxfield, S J; McMahon, S J; Mehta, A; Meier, K; Mercer, D; Merz, T; Meyer, C A; Meyer, H; Meyer, J; Migliori, A; Mikocki, S; Milstead, D; Moreau, F; Morris, J V; Mroczko, E; Murín, P; Müller, G; Müller, K; Nagovitsin, V; Nahnhauer, R; Naroska, Beate; Naumann, T; Newman, P R; Newton, D; Neyret, D; Nguyen, H K; Nicholls, T C; Niebergall, F; Niebuhr, C B; Niedzballa, C; Nisius, R; Nowak, G; Noyes, G W; Nyberg-Werther, M; Oakden, M N; Oberlack, H; Obrock, U; Olsson, J E; Ozerov, D; Panaro, E; Panitch, A; Pascaud, C; Patel, G D; Peppel, E; Phillips, J P; Pichler, C; Pieuchot, A; Pitzl, D; Pope, G; Prell, S; Prosi, R; Pérez, E; Rabbertz, K; Raupach, F; Reimer, P; Reinshagen, S; Ribarics, P; Rick, Hartmut; Riech, V; Riedlberger, J; Riess, S; Rietz, M; Rizvi, E; Robertson, S M; Robmann, P; Roloff, H E; Roosen, R; Rosenbauer, K; Rostovtsev, A A; Rouse, F; Royon, C; Rusakov, S V; Rybicki, K; Rylko, R; Rädel, G; Rüter, K; Sahlmann, N; Salesch, S G; Sankey, D P C; Schacht, P; Schiek, S; Schleper, P; Schmidt, C; Schmidt, D; Schmidt, G; Schröder, V; Schuhmann, E; Schwab, B; Schwind, A; Schöning, A; Sefkow, F; Seidel, M; Sell, R; Semenov, A A; Shekelian, V I; Shevyakov, I; Shooshtari, H; Shtarkov, L N; Siegmon, G; Siewert, U; Sirois, Y; Skillicorn, Ian O; Smirnov, P; Smith, J R; Solochenko, V; Soloviev, Yu V; Spiekermann, J; Spielman, S; Spitzer, H; Starosta, R; Steenbock, M; Steffen, P; Steinberg, R; Stella, B; Stephens, K; Stier, J; Stiewe, J; Stolze, K; Strachota, J; Straumann, U; Struczinski, W; Stösslein, U; Sutton, J P; Sánchez, E; Tapprogge, Stefan; Thiebaux, C; Thompson, G; Truöl, P; Turnau, J; Tutas, J; Uelkes, P; Usik, A; Valkár, S; Valkárová, A; Vallée, C; Van Esch, P; Van Mechelen, P; Vartapetian, A H; Vazdik, Ya A; Verrecchia, P; Villet, G; Wacker, K; Wagener, A; Wagener, M; Walker, I W; Walther, A; Weber, G; Weber, M; Wegener, D; Wegner, A; Wellisch, H P; West, L R; Willard, S; Winde, M; Winter, G G; Wittek, C; Wright, A E; Wulff, N; Wünsch, E; Yiou, T P; Zarbock, D; Zhang, Z; Zhokin, A S; Zimmer, M; Zimmermann, W; Zomer, F; Zuber, K; Zácek, J; de Roeck, A; von Schlippe, W

    1995-01-01

    Photoproduction of 2-jet events is studied with the H1 detector at HERA. Parton cross sections are extracted from the data by an unfolding method using leading order parton-jet correlations of a QCD generator. The gluon distribution in the photon is derived in the fractional momentum range 0.04\\le x_\\gamma \\le 1 at the average factorization scale 75 GeV^2.

  9. Polarization Measurements in Photoproduction with CEBAF Large Acceptance Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    E. Pasyuk

    2010-05-01

    A significant part of the experimental program in Hall-B of the Jefferson Lab is dedicated to the studies of the structure of baryons. CEBAF Large Acceptance Spectrometer (CLAS), availability of circularly and linearly polarized photon beams and recent addition of polarized targets provides remarkable opportunity for single, double and in some cases triple polarization measurements in photoproduction. An overview of the experiments will be presented.

  10. Double pi(0) Photoproduction on the Proton at GRAAL.

    Science.gov (United States)

    Assafiri, Y; Bartalini, O; Bellini, V; Bocquet, J P; Bouchigny, S; Capogni, M; Castoldi, M; D'Angelo, A; Didelez, J P; Di Salvo, R; Fantini, A; Fichen, L; Gervino, G; Ghio, F; Girolami, B; Giusa, A; Guidal, M; Hourany, E; Kouznetsov, V; Kunne, R; Laget, J-M; Lapik, A; Sandri, P Levi; Lleres, A; Moricciani, D; Nedorezov, V; Rebreyend, D; Randieri, C; Renard, F; Rudnev, N; Schaerf, C; Sperduto, M; Sutera, M; Turinge, A; Zucchiatti, A

    2003-06-01

    The double pi(0) photoproduction off the proton has been measured in the beam energy range of 0.65-1.5 GeV. The total and differential cross sections and the Sigma beam asymmetry were extracted. The total cross section measured for the first time in the third resonance region of the nucleon shows a prominent peak. The interpretation of these results by two independent theoretical models infers mostly the selective excitation of P11- and D13-nucleon resonances.

  11. Beauty in photoproduction at HERA II with the ZEUS detector

    International Nuclear Information System (INIS)

    The production of beauty quarks in ep collisions should be accurately calculable in perturbative Quantum Chromodynamics (QCD) since the large mass of the b quark provides a hard scale. Therefore it is interesting to compare such predictions to results using photoproduction events where a low-virtuality photon, emitted by the incoming lepton, collides with a parton from the incoming proton. A measurement of beauty in photoproduction has been made at HERA with the ZEUS detector using an integrated luminosity of 126 pb-1. Beauty was identified in events with a muon in the final state by using the transverse momentum of the muon relative to the closest jet. Lifetime information from the silicon vertex detector was also used; the impact parameter of the muon with respect to the primary vertex was exploited to discriminate between signal and background. Cross sections for beauty production as a function of the muon and the jet variables were measured and compared to QCD predictions and to previous measurements. The data were found to be well described by the predictions from next-to-leading-order QCD. The dijet sample of beauty photoproduction events was also used to study higher-order QCD topologies. At leading order, the two jets in the event are produced back-to-back in azimuthal angle, such that Δφjj=φj1-φj2=π. Additional soft radiation causes small azimuthal decorrelations, whilst Δφjj significantly lower than π is evidence of additional hard radiation. In this thesis, the cross section versus Δφjj for beauty photoproduction and the comparison to NLO QCD predictions and Monte Carlo models are presented. (orig.)

  12. Neutral pion photoproduction off nucleons and nuclei near threshold

    International Nuclear Information System (INIS)

    The modern experimental data on the coherent photoproduction off 4He, 6Li, 12C, 16O, 40Ca and 208Pb are analyzed in terms of the DWIA in the momentum space. It is shown that the elaborated elementary amplitudes do not give a possibility of the simultaneous self-consistent description of the process on free nucleons and nuclei. 36 refs.; 11 figs.; 2 tabs

  13. Autumn Photoproduction of Carbon Monoxide in Jiaozhou Bay,China

    Institute of Scientific and Technical Information of China (English)

    REN Chunyan; YANG Guipeng; LU Xiaolan

    2014-01-01

    Carbon monoxide (CO) plays a significant role in global warming and atmospheric chemistry. Global oceans are net natural sources of atmospheric CO. CO at surface ocean is primarily produced from the photochemical degradation of chromophoric dissolved organic matter (CDOM). In this study, the effects of photobleaching, temperature and the origin (terrestrial or marine) of CDOM on the apparent quantum yields (AQY) of CO were studied for seawater samples collected from Jiaozhou Bay. Our results demonstrat that photobleaching, temperature and the origin of CDOM strongly affected the efficiency of CO photoproduction. The concentration, absorbance and fluorescence of CDOM exponentially decreased with increasing light dose. Terrestrial riverine organic matter could be more prone to photodegradation than the marine algae-derived one. The relationships between CO AQY and the dis-solved organic carbon-specific absorption coefficient at 254 nm for the photobleaching study were nonlinear, whereas those of the original samples were strongly linear. This suggests that:1) terrestrial riverine CDOM was more efficient than marine algae-derived CDOM for CO photoproduction;2) aromatic and olefinic moieties of the CDOM pool were affected more strongly by degradation processes than by aliphatic ones. Water temperature and the origin of CDOM strongly affected the efficiency of CO photoproduction. The photoproduction rate of CO in autumn was estimated to be 31.98μmol m-2 d-1 and the total DOC photomineralization was equivalent to 3.25%-6.35%of primary production in Jiaozhou Bay. Our results indicate that CO photochemistry in coastal areas is important for oceanic carbon cycle.

  14. Beam asymmetry in near threshold omega photoproduction off the proton

    CERN Document Server

    Klein, Frank; Bacelar, J C S; Bantes, B; Bartholomy, O; Bayadilov, D; Beck, R; Beloglasov, Yu A; Castelijns, R; Credé, V; Dutz, H; Ehmanns, A; Elsner, D; Essig, K; Ewald, R; Fabry, I; Fuchs, M; Funke, C; Gregor, R; Gridnev, A B; Gutz, E; Hoffgen, S; Hoffmeister, P; Horn, I; Jaegle, I; Junkersfeld, J; Kalinowsky, H; Kammer, S; Kleber, V; Klein, Friedrich; Klempt, E; Konrad, M; Kotulla, M; Krusche, B; Lang, M; Löhner, H; Lopatin, I V; Lotz, J; Lugert, S; Menze, D; Mertens, T; Messchendorp, J G; Metag, V; Morales, C; Nanova, M; Nikonov, V A; Novinski, D; Novotny, R; Ostrick, M; Pant, L M; Van Pee, H; Pfeiffer, M; Radkov, A; Roy, A; Sarantsev, A V; Schadmand, S; Schmidt, C; Schmieden, H; Schoch, B; Shende, S V; Sokhoyan, V; Sule, A; Sumachev, V V; Szczepanek, T; Thoma, U; Trnka, D; Varma, R; Walther, D; Weinheimer, C; Wendel, C

    2008-01-01

    The photoproduction of omega mesons off protons has been studied at the Bonn ELSA accelerator from threshold to E_gamma = 1700 MeV. Linearly polarized beams were produced via coherent bremsstrahlung. Large photon asymmtries in excess of 50% were obtained, whereas the pion asymmetries from omega \\to pi^0 gamma are close to zero. The asymmetries do characteristically depend on Theta_{cm} rather than |t| and indicate s-channel resonance formation on top of t-channel exchange processes.

  15. Photoproduction of J/ψ in the forward region

    International Nuclear Information System (INIS)

    We study the phenomenology of fixed-target elastic J/ψ photoproduction in the nonrelativistic QCD (NRQCD) factorization formalism. Our goal is to test an essential feature of this formalism emdash the color-octet mechanism. We obtain an order-of-magnitude estimate for a certain linear combination of NRQCD color-octet matrix elements. Our estimate is consistent with other empirical determinations and with the v-scaling rules of NRQCD. copyright 1997 The American Physical Society

  16. Incoherent photoproduction of pseudoscalar mesons off nuclei at forward angles

    OpenAIRE

    Gevorkyan, S; Gasparian, A.; Gan, L.; Larin, I.; Khandaker, M.

    2009-01-01

    Recent advances in the photon tagging facilities together with the novel, high resolution fast calorimetry made possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths, needed for testing the symmetry breaking effects in QCD, from these measurements at small angles is done by the Primakoff method. This method requires theoretical treatment of all processes participating in these...

  17. Photoproduction of Pseudoscalar Mesons off Nuclei at Forward Angles

    OpenAIRE

    Gevorkyan, S; Gasparian, A.; Gan, L.; Larin, I.; Khandaker, M.

    2009-01-01

    With the advent of new photon tagging facilities and novel experimental technologies it has become possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths from these measurements at forward angles is done by the Primakoff method, which requires theoretical treatment of all processes participating in these reactions at the same percent level. In this work we review the theoretica...

  18. Study of the photon remnant in resolved photoproduction at HERA

    International Nuclear Information System (INIS)

    Photoproduction at HERA is studied in ep collisions, with the ZEUS detector, for γp centre-of-mass energies ranging from 130-270 GeV. A sample of events with two high-pT jets (pT>6 GeV, ηT with respect to the beam axis is measured to be 2.1±0.2 GeV, which demonstrates substantial mean transverse momenta for the photon remnant. (orig.)

  19. Kaon Photoproduction Near Threshold in Six Isospin Channels Revisited

    Science.gov (United States)

    Mart, T.

    2016-08-01

    In this talk I review the progress achieved in the investigation of kaon photoproduction on the nucleon near the production threshold. This investigation has been performed by using the so-called isobar model, which makes use of Feynman diagrams for the background terms and the Breit-Wigner multipoles for the resonance terms. The future prospect as well as application of this model in the hadronic sector are also briefly discussed.

  20. Study of the photon remnant in resolved photoproduction at HERA

    International Nuclear Information System (INIS)

    Photoproduction at HERA is studied in ep collisions, using the ZEUS detector, for γp center-of-mass energies ranging from 130-270 GeV. A sample of events with two high-pT jets (pT>6 GeV, ηT with respect to the beam axis, measured to be 2.1±0.2 GeV, is substantial. (orig.)

  1. Biological hydrogen production by immobilized cells of Clostridium tyrobutyricum JM1 isolated from a food waste treatment process.

    Science.gov (United States)

    Jo, Ji Hye; Lee, Dae Sung; Park, Donghee; Park, Jong Moon

    2008-09-01

    A fermentative hydrogen-producing bacterium, Clostridium tyrobutyricum JM1, was isolated from a food waste treating process using 16S rRNA gene sequencing and amplified ribosomal DNA restriction analysis (ARDRA). A fixed-bed bioreactor packed with polyurethane foam as support matrix for the growth of the isolate was operated at different hydraulic retention time (HRT) to evaluate its performance for hydrogen production. The reactor achieved the maximal hydrogen production rate of 7.2 l H(2)l(-1)d(-1) at 2h HRT, where hydrogen content in biogas was 50.0%, and substrate conversion efficiency was 97.4%. The maximum hydrogen yield was 223 ml (g-hexose)(-1) with an influent glucose concentration of 5 g l(-1). Therefore, the immobilized reactor using C. tyrobutyricum JM1 was an effective and stable system for continuous hydrogen production.

  2. Measurement of Inclusive $D_{s}^{pm}$ Photoproduction at HERA

    CERN Document Server

    Breitweg, J; Derrick, Malcolm; Krakauer, D A; Magill, S; Musgrave, B; Pellegrino, A; Repond, J; Stanek, R; Yoshida, R; Mattingly, M C K; Abbiendi, G; Anselmo, F; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Boscherini, D; Bruni, A; Bruni, G; Cara Romeo, G; Castellini, G; Cifarelli, Luisa; Cindolo, F; Contin, A; Coppola, N; Corradi, M; De Pasquale, S; Giusti, P; Iacobucci, G; Laurenti, G; Levi, G; Margotti, A; Massam, Thomas; Nania, R; Palmonari, F; Pesci, A; Polini, A; Sartorelli, G; Zamora-Garcia, Yu E; Zichichi, A; Amelung, C; Bornheim, A; Brock, I; Coboken, K; Crittenden, James Arthur; Deffner, R; Hartmann, H; Heinloth, K; Hilger, E; Irrgang, P; Jakob, H P; Kappes, A; Katz, U F; Kerger, R; Paul, E; Schnurbusch, H; Stifutkin, A; Tandler, J; Voss, K C; Weber, A; Wieber, H; Bailey, D S; Barret, O; Brook, N H; Foster, B; Heath, G P; Heath, H F; McFall, J D; Piccioni, D; Rodrigues, E; Scott, J; Tapper, R J; Capua, M; Mastroberardino, A; Schioppa, M; Susinno, G; Jeoung, H Y; Kim, J Y; Lee, J H; Lim, I T; Ma, K J; Pac, M Y; Caldwell, A; Liu, W; Liu, X; Mellado, B; Paganis, S; Sampson, S; Schmidke, W B; Sciulli, F; Chwastowski, J; Eskreys, Andrzej; Figiel, J; Klimek, K H; Olkiewicz, K; Piotrzkowski, K; Przybycien, M B; Stopa, P; Zawiejski, L; Bednarek, B; Jelen, K; Kisielewska, D; Kowal, A M; Kowalski, T; Rulikowska-Zarebska, E; Suszycki, L; Szuba, D; Kotanski, Andrzej; Bauerdick, L A T; Behrens, U; Bienlein, J K; Burgard, C; Dannheim, D; Desler, K; Drews, G; Fox-Murphy, A; Fricke, U; Göbel, F; Göttlicher, P; Graciani, R; Haas, T; Hain, W; Hartner, G F; Hasell, D; Hebbel, K; Johnson, K F; Kasemann, M; Koch, W; Kötz, U; Kowalski, H; Lindemann, L; Löhr, B; Martínez, M; Milite, M; Monteiro, T; Moritz, M; Notz, D; Pelucchi, F; Petrucci, M C; Rohde, M; Saull, P R B; Savin, A A; Schneekloth, U; Selonke, F; Sievers, M; Stonjek, S; Tassi, E; Wolf, G; Wollmer, U; Youngman, C; Zeuner, W; Coldewey, C; López-Duran-Viani, A; Meyer, A; Schlenstedt, S; Straub, P B; Barbagli, G; Gallo, E; Pelfer, P G; Maccarrone, G D; Votano, L; Bamberger, Andreas; Benen, A; Eisenhardt, S; Markun, P; Raach, H; Wölfle, S; Bussey, Peter J; Doyle, A T; Lee, S W; MacDonald, N; McCance, G J; Saxon, D H; Sinclair, L E; Skillicorn, Ian O; Waugh, R; Bohnet, I; Gendner, N; Holm, U; Meyer-Larsen, A; Salehi, H; Wick, K; Garfagnini, A; Gialas, I; Gladilin, L K; Kcira, D; Klanner, Robert; Lohrmann, E; Poelz, G; Zetsche, F; Goncalo, R; Long, K R; Miller, D B; Tapper, A D; Walker, R; Mallik, U; Cloth, P; Filges, D; Ishii, T; Kuze, M; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Ahn, S H; Lee, S B; Park, S K; Lim, H; Park, I H; Son, D; Barreiro, F; García, G; Glasman, C; González, O; Labarga, L; Del Peso, J; Redondo, I; Terron, J; Barbi, M S; Corriveau, F; Hanna, D S; Ochs, A; Padhi, S; Riveline, M; Stairs, D G; Wing, M; Tsurugai, T; Bashkirov, V; Dolgoshein, B A; Dementev, R K; Ermolov, P F; Golubkov, Yu A; Katkov, I I; Khein, L A; Korotkova, N A; Korzhavina, I A; Kuzmin, V A; Lukina, O Yu; Proskuryakov, A S; Sheheglova, L M; Solomin, A N; Vlasov, N N; Zotkin, S A; Bokel, C; Botje, M; Brümmer, N; Engelen, J; Grijpink, S; Koffeman, E; Kooijman, P M; Schagen, S; Van Sighem, A; Tiecke, H G; Tuning, N; Velthuis, J J; Vossebeld, Joost Herman; Wiggers, L; De Wolf, E; Acosta, D; Bylsma, B; Durkin, L S; Gilmore, J; Ginsburg, C M; Kim, C L; Ling, T Y; Boogert, S; Cooper-Sarkar, A M; Devenish, R C E; Grosse-Knetter, J; Matsushita, T; Ruske, O; Sutton, M R; Walczak, R; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; Dosselli, U; Dusini, S; Limentani, S; Morandin, M; Posocco, M; Stanco, L; Stroili, R; Voci, C; Adamczyk, L; Iannotti, L; Oh, B Y; Okrasinski, J R; Toothacker, W S; Whitmore, J J; Iga, Y; D'Agostini, Giulio; Marini, G; Nigro, A; Cormack, C; Hart, J C; McCubbin, N A; Shah, T P; Epperson, D E; Heusch, C A; Sadrozinski, H F W; Seiden, A; Wichmann, R; Williams, D C; Pavel, N; Abramowicz, H; Dagan, S; Kananov, S; Kreisel, A; Levy, A; Abe, T; Fusayasu, T; Umemori, K; Yamashita, T; Hamatsu, R; Hirose, T; Inuzuka, M; Kitamura, S; Nishimura, T; Arneodo, M; Cartiglia, N; Cirio, R; Costa, M; Ferrero, M I; Maselli, S; Monaco, V; Peroni, C; Ruspa, M; Sacchi, R; Solano, A; Staiano, A; Dardo, M; Bailey, D C; Fagerstroem, C P; Galea, R; Koop, T; Levman, G M; Martin, J F; Orr, R S; Polenz, S; Sabetfakhri, A; Simmons, D; Butterworth, J M; Catterall, C D; Hayes, M E; Heaphy, E A; Jones, T W; Lane, J B; West, B J; Ciborowski, J; Ciesielski, R; Grzelak, G; Nowak, R J; Pawlak, J M; Pawlak, R; Smalska, B; Tymieniecka, T; Wróblewski, A K; Zakrzewski, J A; Adamus, M; Gadaj, T; Deppe, O; Eisenberg, Y; Hochman, D; Karshon, U; Badgett, W F; Chapin, D; Cross, R; Foudas, C; Mattingly, S E K; Reeder, D D; Smith, W H; Vaiciulis, A W; Wildschek, T; Wodarczyk, M; Deshpande, A A; Dhawan, S K; Hughes, V W; Bhadra, S; Cole, J E; Frisken, W R; Hall-Wilton, R; Khakzad, M; Menary, S R

    2000-01-01

    The first measurement of inclusive Ds+- photoproduction at HERA has been performed with the ZEUS detector for photon-proton centre-of-mass energies 130 Ds X) = 3.79 +- 0.59 (stat.) +0.26-0.46 (syst.) +- 0.94 (br.) nb, where the last error arises from the uncertainty in the Ds decay branching ratio. The measurements are compared with inclusive D*+- photoproduction cross sections in the same kinematic region and with QCD calculations. The Ds cross sections lie above a fixed-order next-to-leading order calculation and agree better with a tree-level O(alpha,alpha_s^3) calculation that was tuned to describe the ZEUS D* cross sections. The ratio of Ds+- to D*+- cross sections is 0.41 +- 0.07 (stat.) +0.03-0.05 (syst.) +- 0.10 (br.). From this ratio, the strangeness-suppression factor in charm photoproduction, within the LUND string fragmentation model, has been calculated to be gamma_s = 0.27 +- 0.05 +- 0.07 (br.). The cross-section ratio and gamma_s are in good agreement with those obtained in charm production in...

  3. Diffractive Vector Meson Photoproduction from Dual String Theory

    CERN Document Server

    Freund, Peter G O

    2008-01-01

    We study diffractive vector meson photoproduction using string theory via AdS/CFT. The large $s$ behavior of the cross sections for the scattering of the vector meson $V$ on a proton is dominated by the soft Pomeron, $\\sigma_V\\sim s^{2\\epsilon-2\\alpha'_P/B}$, where from the string theory model of \\cite{nastase2}, $\\epsilon$ is approximately 1/7 below 10 GeV, and 1/11 for higher, but still sub-Froissart, energies. This is due to the production of black holes in the dual gravity. In $\\phi$-photoproduction the mesonic Regge poles do not contribute, so that we deal with a pure Pomeron contribution. This allows for an experimental test. At the gauge theory "Planck scale" of about 1-2 GeV, the ratios of the soft Pomeron contributions to the photoproduction cross-sections of different vector mesons involve not only the obvious quark model factors, but also the Boltzmann factors $e^{-4 M_V/T_0}$, with $T_0$ the temperature of the dual black hole. The presence of these factors is confirmed in the experimental data for...

  4. Biological production of hydrogen from agricultural raw materials and residues with a subsequent methanisation step; Biologische Wasserstoffproduktion aus landwirtschaftlichen Roh- und Reststoffen mit nachfolgender Methanstufe

    Energy Technology Data Exchange (ETDEWEB)

    Meyer, M.; Stegmann, R. [Technische Univ. Hamburg-Harburg, Hamburg (Germany). Inst. fuer AbfallRessourcenWirtschaft

    2007-07-01

    In order to examine the thermophile fermentative production from biohydrogen, discontinuous attempts were accomplished at a temperature of 60 C. As an inoculum, heat-treated sewage sludge was used. Glucose was used as a substrate. The fermenting residues of the hydrogen attempts were used as a substrate in a methane reactor in order to examine a two-stage system. The hydrogen attempts in the anaerobic test system were operated with a hydraulic retention time by 3.3 days and were performed during a period of 300 days. The optimal space load amounts to 5 g (l*d). The production rate at hydrogen amounts to 1.2 Nl/(l{sub R}*d). The yields amount to between 200 and 250 Nml/g oTS. In the case of an overloading of the system with substrate, the hydrogen production decreases drastically due to poor yields. Biological hydrogen production by fermentation possesses the potential to become a component for a lasting emission-free power supply. The thermophile approach ensures a simultaneous hygienization. As a fermenting remainder treatment a downstream methanation stage is possible.

  5. Biologic

    CERN Document Server

    Kauffman, L H

    2002-01-01

    In this paper we explore the boundary between biology and the study of formal systems (logic). In the end, we arrive at a summary formalism, a chapter in "boundary mathematics" where there are not only containers but also extainers ><, entities open to interaction and distinguishing the space that they are not. The boundary algebra of containers and extainers is to biologic what boolean algebra is to classical logic. We show how this formalism encompasses significant parts of the logic of DNA replication, the Dirac formalism for quantum mechanics, formalisms for protein folding and the basic structure of the Temperley Lieb algebra at the foundations of topological invariants of knots and links.

  6. A Search for the LHCb Charmed 'Pentaquark' using Photo-Production of $J/{\\psi}$ at Threshold in Hall C at Jefferson Lab

    CERN Document Server

    Meziani, Z -E; Paolone, M; Chudakov, E; Jones, M; Adhikari, K; Aniol, K; Armstrong, W; Arrington, J; Asaturyan, A; Atac, H; Bae, S; Bhatt, H; Bhetuwal, D; Chen, J -P; Chen, X; Choi, H; Choi, S; Diefenthaler, M; Dunne, J; Dupré, R; Duran, B; Dutta, D; El-Fassi, L; Fu, Q; Gao, H; Go, H; Gu, C; Ha, J; Hafidi, K; Hansen, O; Hattawy, M; Higinbotham, D; Huber, G M; Markowitz, P; Meekins, D; Mkrtchyan, H; Li, W; Li, X; Liu, T; Peng, C; Pentchev, L; Pooser, E; Rehfuss, M; Sparveris, N; Tadevosyan, V; Wang, R; Wesselmann, F R; Wood, S; Xiong, W; Yan, X; Ye, L; Ye, Z; Zafar, A; Zhang, Y; Zhao, F; Zhao, Z; Zhamkochyana, S

    2016-01-01

    We propose to measure the photo-production cross section of $J/{\\psi}$ near threshold, in search of the recently observed LHCb hidden-charm resonances $P_c$(4380) and $P_c$(4450) consistent with 'pentaquarks'. The observation of these resonances in photo-production will provide strong evidence of the true resonance nature of the LHCb states, distinguishing them from kinematic enhancements. A bremsstrahlung photon beam produced with an 11 GeV electron beam at CEBAF covers the energy range of $J/{\\psi}$ production from the threshold photo-production energy of 8.2 GeV, to an energy beyond the presumed $P_c$(4450) resonance. The experiment will be carried out in Hall C at Jefferson Lab using a 50{\\mu}A electron beam incident on a 9% copper radiator. The resulting photon beam passes through a 15 cm liquid hydrogen target, producing $J/{\\psi}$ mesons through a diffractive process in the $t$-channel, or through a resonant process in the $s$- and $u$-channel. The decay $e^+e^-$ pair of the $J/{\\psi}$ will be detected...

  7. Photosynthetic water splitting for hydrogen fuel synthesis

    Science.gov (United States)

    Greenbaum, E.

    Three key advances in photosynthesis research are reported. A significant advance in microalgal water splitting has been made. In the linear, low-intensity region of the light saturation curves, equivalent solar conversion efficiencies of 10% have been measured. A technological advance in the ability to genetically screen individual algal colonies has been made. Successive subcultures of anaerobiosis-stressed Chlamydomonas reinhardtii exhibited enhanced capacity for photoproduction of hydrogen and oxygen.

  8. {eta} meson photoproduction on deuterium; Photoproduction du meson {eta} sur le deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann-Rothe, P.

    1996-05-30

    Measurements of the total and differential cross sections for {eta}-meson photoproduction on a D{sub 2} liquid target from threshold to 1.2 GeV, have been taken using the tagged Bremsstrahlung photon beam produced by the electrons extracted from the ELSA storage ring at Bonn. The reaction was identified by detecting the eta decay products in the neutral meson spectrometer SPES0-2{pi}, while the recoil baryons (proton, neutron or deuteron) were detected by a variety of large angle scintillator detectors. We succeeded to identify completely the final states corresponding to the production of an {eta} meson on a Quasi-Free (QF) proton, a QF neutron and the coherent deuteron. The differential cross sections corresponding to the production of a coherent deuteron n the final state have been measured, from threshold to 800 MeV; they are 6 times smaller the only previous measurement reported by Anderson and Prepost in 1969. This is consistent with an Isoscalar part of the Amplitude much smaller than the Isovector one. The differential cross sections are in good agreement with the theoretical prediction on the impulse approximation mechanism; indicating in particular, fairly small contributions from rescattering terms. A direct measurement of the neutron to proton cross section ratios has been obtained by integrating the counting rates on the corresponding QF peaks and is 0.70 {+-} 0.03, from 700 MeV to 900 MeV, with a small angular dependence. These two results by comparison to the measured free proton data should allow to reconstruct the free neutron cross sections in a rather model-independent way. (authors). 56 refs., 90 figs., 13 tabs.

  9. Measurement of the \\Sigma\\ beam asymmetry for the \\omega\\ photo-production off the proton and the neutron at GRAAL

    CERN Document Server

    Vegna, V; Bartalini, O; Bellini, V; Boquet, J P; Capogni, M; Casano, L E; Castoldi, M; Curciarello, F; De Leo, V; Didelez, J P; Di Salvo, R; Fantini, A; Franco, D; Gervino, G; Ghio, F; Giardina, G; Girolami, B; Giusa, A; Lapik, A; Sandri, P Levi; Lleres, A; Mammoliti, F; Mandaglio, G; Manganaro, M; Moricciani, D; Mushkarenkov, A; Nedorezov, V; Randieri, C; Rebreyend, D; Rudnev, N; Russo, G; Schaerf, C; Sperduto, M L; Sutera, M C; Turinge, A; Zonta, I

    2013-01-01

    We report on new measurements of the beam asymmetry for \\omega\\ photo-production on proton and neutron in Hydrogen and Deuterium targets from the GRAAL collaboration. The beam asymmetry values are extracted from the reaction threshold (E_{\\gamma} = 1.1 GeV in the free nucleon kinematics) up to 1.5 GeV of incoming photon energy. For the first time both the radiative and the three-pion decay channels are simultaneously investigated on the free proton. Results from the two decay channels are in agreement and provide important constraints for the determination of resonant state contributions to the \\omega\\ production mechanism. First experimental results on the deuteron allow the extraction of the \\Sigma\\ beam asymmetry on quasi-free nucleons. Comparison of the results for free and quasi-free kinematics on the proton shows a generally reasonable agreement, similar to the findings in pseudo-scalar meson photo-production reactions. For the first time measurements on quasi-free neutrons are available, showing that b...

  10. Recent results on eta and eta-prime photoproduction on the proton

    Energy Technology Data Exchange (ETDEWEB)

    Barry Ritchie

    2004-06-01

    The experimental situation on eta and eta' photoproduction on the proton is reviewed, emphasizing progress made since 2001. New preliminary results for eta' photoproduction on the proton from Jefferson Lab are presented. Experimental results are compared with several theoretical approaches, with an emphasis on consequences for understanding baryon spectroscopy.

  11. Theoretical estimates of photoproduction cross sections for neutral subthreshold pions in carbon-carbon collisions

    Science.gov (United States)

    Norbury, J. W.; Townsend, L. W.

    1986-01-01

    Using the Weizsacher-Williams method of virtual quanta, total cross section estimates for the photoproduction of neutral subthreshold pins in carbon-carbon collisions at incident energies below 300 MeV/nucleon are made. Comparisons with recent experimental data indicate that the photoproduction mechanism makes an insignificant contribution to these measured cross sections.

  12. Comparative study of biological hydrogen production by pure strains and consortia of facultative and strict anaerobic bacteria.

    Science.gov (United States)

    Hiligsmann, Serge; Masset, Julien; Hamilton, Christopher; Beckers, Laurent; Thonart, Philippe

    2011-02-01

    In this paper, a simple and rapid method was developed in order to assess in comparative tests the production of binary biogas mixtures containing CO(2) and another gaseous compound such as hydrogen or methane. This method was validated and experimented for the characterisation of the biochemical hydrogen potential of different pure strains and mixed cultures of hydrogen-producing bacteria (HPB) growing on glucose. The experimental results compared the hydrogen production yield of 19 different pure strains and sludges: facultative and strict anaerobic HPB strains along with anaerobic digester sludges thermally pre-treated or not. Significant yields variations were recorded even between different strains of the same species by i.e. about 20% for three Clostridium butyricum strains. The pure Clostridium butyricum and pasteurianum strains achieved the highest yields i.e. up to 1.36 mol H(2)/mol glucose compared to the yields achieved by the sludges and the tested Escherichia and Citrobacter strains.

  13. Evidence for an Exotic Baryon State, Theta+(1540), in Photoproduction Reactions from Protons and Deuterons with CLAS

    CERN Document Server

    Kubarovski, V

    2003-01-01

    CLAS photoproduction data on deuterium and hydrogen targets have been analyzed in a search for an exotic baryon state with strangeness S=+1, the \\Theta^+ (originally named the Z^+). This resonance was predicted recently in theoretical work based on the chiral soliton model as a lowest mass member of an anti-decuplet of 5-quark states. The reaction gamma d --> pK^-K^+n, which requires a final state interaction inside the deuteron, was used in the analysis of deuteron data. In the analysis of proton data, the reaction gamma p --> pi^+K^-K^+n was studied. Evidence for the \\Theta^+ state is found in both analyses in the invariant mass distribution of the nK^+. Our results are consistent with previously reported results by LEPS/Spring-8 collaboration (Japan), and by the ITEP (Moscow) group.

  14. The Color Evaporation Model in Diffractive $J/\\psi$ Photoproduction

    CERN Document Server

    Gay-Ducati, M B

    1999-01-01

    Our goal is the study of color effects on the $J/\\psi$ and $D$ mesons production, as well as the study of their elastic production. We use the Color Evaporation Model (CEM), where a single factor takes into account the probability that the $c\\bar{c}$ produced in a color octet state turns into a physical (colorless) quarkonium or continues as a color octet, producing open charm. The main result of this work, besides investigating the range of applicability of the CEM, is to show that this model can be used to describe the elastic processes of $J/\\psi$ and open charm photoproduction without the use of a Pomeron.

  15. Measurement of Three-jet Distributions in Photoproduction at HERA

    CERN Document Server

    Abbiendi, G; Abramowicz, H; Acosta, D; Adamczyk, L; Adamus, M; Ahn, S H; Amelung, C; An Shiz Hong; Anselmo, F; Antonioli, P; Arneodo, M; Bacon, Trevor C; Badgett, W F; Bailey, D C; Bailey, D S; Bamberger, A; Barbagli, G; Bari, G; Barreiro, F; Barret, O; Bashindzhagian, G L; Bashkirov, V; Basile, M; Bauerdick, L A T; Bednarek, B; Behrens, U; Beier, H; Bellagamba, L; Bertolin, A; Bhadra, S; Bienlein, J K; Blaikley, H E; Bohnet, I; Bokel, C; Bornheim, A; Borzemski, P; Boscherini, D; Botje, M; Breitweg, J; Briskin, G; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Burgard, C; Burow, B D; Bussey, P J; Butterworth, J M; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carlin, R; Cartiglia, N; Cashmore, R J; Castellini, G; Catterall, C D; Chapin, D; Chekanov, S; Chwastowski, J; Ciborowski, J; Cifarelli, Luisa; Cindolo, F; Cirio, R; Cloth, P; Coboken, K; Coldewey, C; Cole, J E; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cormack, C; Corradi, M; Corriveau, F; Costa, M; Cottingham, W N; Crittenden, J; Cross, R; D'Agostini, G; Dagan, S; Dal Corso, F; Dardo, M; De Pasquale, S; Deffner, R; Deppe, O; Derrick, M; Deshpande, Abhay A; Desler, K; Devenish, R C E; Dhawan, S; Dolgoshein, B A; Dosselli, U; Doyle, A T; Drews, G; Dulinski, Z; Durkin, L S; Eckert, M; Edmonds, J K; Eisenberg, Y; Eisenhardt, S; Engelen, J; Epperson, D E; Ermolov, P F; Eskreys, Andrzej; Fagerstroem, C P; Fernández, J P; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fricke, U; Frisken, W R; Fusayasu, T; Gadaj, T; Galea, R; Gallo, E; García, G; Garfagnini, A; Gendner, N; Gialas, I; Gilmore, J; Ginsburg, C M; Giusti, P; Gladilin, L K; Glasman, C; Göbel, F; Golubkov, Yu A; Göttlicher, P; Grabosch, H J; Graciani, R; Grosse-Knetter, J; Grothe, M; Grzelak, G; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hanna, D S; Harnew, N; Hart, J C; Hartmann, H; Hartmann, J; Hartner, G F; Hasell, D; Hayes, M E; Heaphy, E A; Heath, G P; Heath, H F; Hebbel, K; Heinloth, K; Heinz, L; Hernández, J M; Heusch, C A; Hilger, E; Hirose, T; Hochman, D; Holm, U; Homma, K; Hong, S J; Howell, G; Hughes, V W; Iacobucci, G; Iannotti, L; Iga, Y; Inuzuka, M; Ishii, T; Jakob, H P; Jelen, K; Jeoung, H Y; Jing, Z; Johnson, K F; Jones, T W; Kananov, S; Kappes, A; Karshon, U; Kasemann, M; Katz, U F; Kcira, D; Kerger, R; Khakzad, M; Khein, L A; Kim, C L; Kim, J Y; Kisielewska, D; Kitamura, S; Klanner, Robert; Klimek, K; Koch, W; Koffeman, E; Kooijman, P; Koop, T; Korotkova, N A; Korzhavina, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowal, H; Kowalski, T; Krakauer, D; Kuze, M; Kuzmin, V A; Labarga, L; Lamberti, L; Lane, J B; Laurenti, G; Lee, J H; Lee, S B; Lee, S W; Levi, G; Levman, G M; Levy, A; Lim, H; Lim, I T; Limentani, S; Lindemann, L; Ling, T Y; Liu, W; Löhr, B; Lohrmann, E; Long, K R; Lopez-Duran Viani, A; Lukina, O Yu; Ma, K J; Maccarrone, G; MacDonald, N; Magill, S; Mallik, U; Margotti, A; Marini, G; Markun, P; Martin, J F; Martínez, M; Maselli, S; Massam, Thomas; Mastroberardino, A; Matsushita, T; Mattingly, M C K; Mattingly, S E K; McCance, G J; McCubbin, N A; McFall, J D; Mellado, B; Menary, S; Meyer, A; Meyer-Larsen, A; Milewski, J; Milite, M; Miller, D B; Monaco, V; Mönig, K; Monteiro, T; Morandin, M; Murray, W N; Musgrave, B; Nagano, K; Nam, S W; Nania, R; Nigro, A; Nishimura, T; Notz, D; Nowak, R J; Noyes, V A; Nylander, P; Ochs, A; Oh, B Y; Okrasinski, J R; Orr, R S; Pac, M Y; Padhi, S; Palmonari, F; Park, I H; Park, S K; Parsons, J A; Paul, E; Pavel, N; Pawlak, J M; Pawlak, R; Pelfer, Pier Giovanni; Pellegrino, A; Pelucchi, F; Peroni, C; Pesci, A; Petrucci, M C; Pfeiffer, M; Piccioni, D; Pin, C; Piotrzkowski, K; Poelz, G; Polenz, S; Polini, A; Posocco, M; Prinias, A; Proskuryakov, A S; Przybycien, M B; Puga, J; Quadt, A; Raach, H; Raso, M; Redondo, I; Reeder, D D; Repond, J; Ritz, S; Riveline, M; Rohde, M; Roldán, J; Rulikowska-Zarebska, E; Ruske, O; Ruspa, M; Ryan, J J; Sabetfakhri, A; Sacchi, R; Sadrozinski, H F W; Salehi, H; Sampson, S; Sartorelli, G; Saull, P R B; Savin, A A; Saxon, D H; Schioppa, M; Schlenstedt, S; Schmidke, W B; Schneekloth, U; Schnurbusch, H; Schwarzer, O; Sciulli, F; Scott, J; Sedgbeer, J K; Seiden, A; Selonke, F; Shah, T P; Shcheglova, L M; Sideris, D; Sievers, M; Simmons, D; Sinclair, L E; Skillicorn, I O; Smalska, B; Smith, W H; Solano, A; Solomin, A N; Son, D; Saint-Laurent, M G; Staiano, A; Stairs, D G; Stanco, L; Stanek, R; Stifutkin, A; Stonjek, S; Straub, P B; Strickland, E; Stroili, R; Surrow, B; Susinno, G; Suszycki, L; Sutton, M R; Suzuki, I; Tapper, A D; Tapper, R J; Tassi, E; Terron, J; Tiecke, H G; Tokushuku, K; Toothacker, W S; Tsurugai, T; Tuning, N; Tymie-, T; Umemori, K; Vaiciulis, A W; Verkerke, W; Voci, C; Vossebeld, Joost Herman; Votano, L; Walczak, R; Walker, R; Wang, S M; Waters, D S; Waugh, R; Weber, A; Westphal, D; Whitmore, J J; Wichmann, R; Wick, K; Wieber, H; Wiggers, L; Wildschek, T; Williams, D C; Wills, H H; Wing, M; Wodarczyk, M; Wolf, G; Wölfle, S; Wollmer, U; Wróblewski, A K; Yamada, S; Yamashita, T; Yamauchi, K; Yamazaki, Y; Yoshida, R; Youngman, C; Za, L; Zajac, J; Zakrzewski, J A; Zamora Garcia, Y; Zetsche, F; Zeuner, W; Zhu, Q; Zichichi, Antonino; Zotkin, S A; De Wolf, E; Del Peso, J; Van Sighem, A

    1998-01-01

    The cross section for the photoproduction of events containing three jets with a three-jet invariant mass of M_3J > 50 GeV has been measured with the ZEUS detector at HERA. The three-jet angular distributions are inconsistent with a uniform population of the available phase space but are well described by parton shower models and O(alpha alpha_s^2) pQCD calculations. Comparisons with the parton shower model indicate a strong contribution from initial state radiation as well as a sensitivity to the effects of colour coherence.

  16. Isobar model analysis of pi0-eta photoproduction on protons

    CERN Document Server

    Fix, A; Lee, A; Ostrick, M

    2010-01-01

    Photoproduction of pi0-eta on protons in the energy range from threshold to 1.4 GeV is discussed. The data for representative angular distributions recently obtained at MAMI C are analyzed using an isobar model. The isobars considered are Delta(1232) and S11(1535) for pi0-p and eta-p states, respectively. In accordance with the results of earlier works the main features of the reaction are explained through the dominance of the D33 wave with a relatively small admixture of positive parity resonances. Comparison with recent experimental results for the photon beam asymmetry is carried out.

  17. Photoproduction of $a_{2}(1320)$ in a Regge model

    CERN Document Server

    Wang, Xiao-Yun

    2015-01-01

    In this work, the photoproduction of $a_{2}(1320)$ off a proton target is investigated within an effective Lagrangian approach and the Regge model. The theoretical result indicates that the shapes of total and differential cross section of the $\\gamma p\\rightarrow a_{2}^{+}n$ reaction within the Feynman (isobar) model are much different from that of Reggeized treatment. The obtained cross section is compared with existing experimental results at low energies. The $a_{2}(1320)$ production cross section at high energies can be tested by the COMPASS experiment, which can provide important information for clarifying the role of Reggeized treatment at that energy range.

  18. Measurement of heavy-quark jet photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max-Planck-Institute for Physics, Munich (Germany); Abt, I. [Max-Planck-Institute for Physics, Munich (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Cracow (PL). Faculty of Physics and Applied Computer Science] (and others)

    2011-04-15

    Photoproduction of beauty and charm quarks in events with at least two jets has been measured with the ZEUS detector at HERA using an integrated luminosity of 133 pb{sup -1}. The fractions of jets containing b and c quarks were extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of jet transverse momentum, p{sup jet}{sub T}, and pseudorapidity, {eta}{sup jet}, were measured. The data are compared with previous measurements and are well described by next-to-leading-order QCD predictions. (orig.)

  19. Complete sets of observables in pseudoscalar-meson photoproduction

    CERN Document Server

    Vrancx, Tom; Nys, Jannes

    2014-01-01

    Pseudoscalar-meson photoproduction is characterized by four complex reaction amplitudes. A complete set is a minimum theoretical set of observables that allow to determine these amplitudes unambiguously. It is studied whether complete sets remain complete when experimental uncertainty is involved. To this end, data from the GRAAL Collaboration and simulated data from a realistic model, both for the $\\gamma p \\to K^+ \\Lambda$ reaction, are analyzed in the transversity representation of the reaction amplitudes. It is found that only the moduli of the transversity amplitudes can be determined without ambiguity but not the relative phases.

  20. Experimental results on heavy flavour hadro- and photo-production

    International Nuclear Information System (INIS)

    Results from experiments on the production of beauty and charm with hadron and photon beams are reviewed. Beauty production experiments are beginning to obtain b anti b cross-sections with hadron beams. Hadroproduction of charm is a somewhat more mature field, although high statistics are still eagerly sought. The situation is most promising with charm photoproduction experiments where total cross-sections, p/sub T/2 and X/sub F/ distributions and other production characteristics are now known in considerable detail

  1. Properties of Ξ hyperons and Ξ photoproduction process

    Directory of Open Access Journals (Sweden)

    Oh Yongseok

    2012-12-01

    Full Text Available In spite of the early efforts for studying Ξ resonances, we still do not have enough information on the properties of these resonances. The number of observed Ξ resonances is much smaller than the quark model predictions, and the predicted mass spectrum shows serious model-dependence. Furthermore, the spin-parity quantum numbers are not known for most observed resonances and the parity of the ground state Ξ has never been measured. In this talk, we review the issue in the Ξ spectrum and present a model for Ξ photoproduction which emphasizes the role of high-spin hyperon resonances.

  2. Measurement of heavy-quark jet photoproduction at HERA

    International Nuclear Information System (INIS)

    Photoproduction of beauty and charm quarks in events with at least two jets has been measured with the ZEUS detector at HERA using an integrated luminosity of 133 pb-1. The fractions of jets containing b and c quarks were extracted using the invariant mass of charged tracks associated with secondary vertices and the decay-length significance of these vertices. Differential cross sections as a function of jet transverse momentum, pjetT, and pseudorapidity, ηjet, were measured. The data are compared with previous measurements and are well described by next-to-leading-order QCD predictions. (orig.)

  3. $a_0(980)$ photoproduction in the coupled channel model

    CERN Document Server

    Bibrzycki, Ł

    2016-01-01

    We calculated the coupled channel photoproduction amplitudes of the scalar isovector resononace $a_0(980)$, which include the $\\pi\\eta$, $K^+K^-$ and $K^0\\overline{K^0}$ intermediate states. Based on them we obtained the mass distribution in the $\\pi\\eta$ channel at photon energy $E_\\gamma$=7 GeV, corresponding to energy accissible in new JLab experiments CLAS12 and GlueX. We also analyzed the shape of mass distribution as a function of the phase of the background amplitude.

  4. Photoproduction and Decay of Light Mesons in CLAS

    Energy Technology Data Exchange (ETDEWEB)

    Amaryan, Moskov Jamalovich [Old Dominion University

    2013-08-01

    We present preliminary experimental results on photoproduction and decay of light mesons measured with CLAS setup at JLAB . This include Dalitz decay of pseudoscalar and vector mesons, radiative decay of pseudoscalar mesons as well hadronic decays of pseudoscalar and vector mesons. The collected high statistics in some of decay channels exceeds the world data by an order of magnitude and some other decay modes are observed for the first time. It is shown how the CLAS data will improve the world data on transition form factors of light mesons, Dalitz plot analyses, branching ratios of rare decay modes and other fundamental properties potentially accessible through the light meson decays.

  5. Beauty photoproduction using decays into electrons at HERA

    International Nuclear Information System (INIS)

    Photoproduction of beauty quarks in events with two jets and an electron associated with one of the jets has been studied with the ZEUS detector at HERA using an integrated luminosity of 120 pb-1. The fractions of events containing b quarks, and also of events containing c quarks, were extracted from a likelihood fit using variables sensitive to electron identification as well as to semileptonic decays. Total and differential cross sections for beauty and charm production were measured and compared with next-to-leading-order QCD calculations and Monte Carlo models. (orig.)

  6. Total photoproduction cross section at very high energy

    International Nuclear Information System (INIS)

    In this paper we apply to the photoproduction total cross section a model we have proposed for purely hadronic processes and which is based on QCD mini-jets and soft gluon re-summation. We compare the predictions of our model with the HERA data as well as with other models. For cosmic rays, our model predicts substantially higher cross sections at TeV energies than models based on factorization, but lower than models based on mini-jets alone, without soft gluons. We discuss the origin of this difference. (orig.)

  7. $\\eta$-$\\eta$' photoproduction and the axial isoscalar neutral coupling

    CERN Document Server

    Bernabeu, J; Vidal, J; Bernabéu, J; González-Sprinberg, G A; Vidal, J

    1995-01-01

    We show that coherent \\eta and \\etap photoproduction by means of the Primakoff Effect on the proton depends on the strange component of the neutral axial current coupling. We construct polarization asymmetries that are sensitive to this coupling through the \\gamma - Z interference. The \\eta^\\prime is not a Goldstone boson of a spontaneously broken chiral symmetry, but a phenomenological analysis of the \\eta and \\eta^\\prime production through chiral perturbation theory allows to calculate the observables of interest. The polarized proton or polarized photon asymmetries are predicted to be close to 10^{-4} for -q^2 \\sim 0.1-0.5\\;\\mbox{\\rm GeV}^2.

  8. Primakoff effect in eta-photoproduction off protons

    CERN Document Server

    Sibirtsev, A; Krewald, S; Meißner, U -G

    2010-01-01

    We analyse data on forward eta-meson photoproduction off a proton target and extract the eta to gamma gamma decay width utilizing the Primakoff effect. The hadronic amplitude that enters into our analysis is strongly constrained because it is fixed from a global fit to available gamma p to p eta data for differential cross sections and polarizations. We compare our results with present information on the two-photon eta-decay from the literature. We provide predictions for future PrimEx experiments at Jefferson Laboratory in order to motivate further studies.

  9. η - η' photoproduction and the axial isoscalar neutral current coupling

    International Nuclear Information System (INIS)

    We show that coherent η and η' photoproduction by means of the Primakoff Effect on the proton depends on the strange component of the neutral axial current coupling. We construct polarization asymmetries that are sensitive to this coupling by the γ-Z interference. The η' is not a Goldstone boson of a spontaneously broken chiral symmetry, but a phenomenological analysis of the η and η' production by chiral perturbation theory allows to calculate the observables of interest. The polarized proton or polarized photon asymmetries are predicted to be close to 10-4 for -q2∝0.1-0.5 GeV2. (orig.)

  10. Primakoff effect in η-photoproduction off protons

    International Nuclear Information System (INIS)

    We analyse data on forward η-meson photoproduction off a proton target and extract the η → γγ decay width utilizing the Primakoff effect. The hadronic amplitude that enters into our analysis is strongly constrained because it is fixed from a global fit to available γp → pη data for differential cross sections and polarizations. We compare our results with present information on the two-photon η-decay from the literature. We provide predictions for future PrimEx experiments at Jefferson Laboratory in order to motivate further studies.

  11. Primakoff effect in eta-photoproduction off protons

    OpenAIRE

    Sibirtsev, A.; Haidenbauer, J.; Krewald, S.; Meißner, U.-G

    2010-01-01

    We analyse data on forward eta-meson photoproduction off a proton target and extract the eta to gamma gamma decay width utilizing the Primakoff effect. The hadronic amplitude that enters into our analysis is strongly constrained because it is fixed from a global fit to available gamma p to p eta data for differential cross sections and polarizations. We compare our results with present information on the two-photon eta-decay from the literature. We provide predictions for future PrimEx experi...

  12. Experimental results on heavy flavour hadro- and photo-production

    Energy Technology Data Exchange (ETDEWEB)

    Purohit, M.V.

    1987-05-01

    Results from experiments on the production of beauty and charm with hadron and photon beams are reviewed. Beauty production experiments are beginning to obtain b anti b cross-sections with hadron beams. Hadroproduction of charm is a somewhat more mature field, although high statistics are still eagerly sought. The situation is most promising with charm photoproduction experiments where total cross-sections, p/sub T//sup 2/ and X/sub F/ distributions and other production characteristics are now known in considerable detail.

  13. Measuring polarized gluon and quark distributions with meson photoproduction

    International Nuclear Information System (INIS)

    The authors calculate polarization asymmetries in photoproduction of high transverse momentum mesons, focusing on charged pions, considering the direct, fragmentation, and resolved photon processes. The results at very high meson momentum measure the polarized quark distributions and are sensitive to differences among the existing models. The results at moderate meson momentum are sensitive to the polarized gluon distribution and can provide a good way to measure it. Suitable data may come as a by-product of deep inelastic experiments to measure g1 or from dedicated experiments

  14. Measuring Polarized Gluon and Quark Distributions with Meson Photoproduction

    CERN Document Server

    Afanasiev, A M; Wahlquist, C; Afanasev, Andrei; Carlson, Carl E.; Wahlquist, Christian

    1998-01-01

    We calculate polarization asymmetries in photoproduction of high transverse momentum mesons, focusing on charged pions, considering the direct, fragmentation, and resolved photon processes. The results at very high meson momentum measure the polarized quark distributions and are sensitive to differences among the existing models. The results at moderate meson momentum are sensitive to the polarized gluon distribution and can provide a good way to measure it. Suitable data may come as a by-product of deep inelastic experiments to measure $g_1$ or from dedicated experiments.

  15. Measurement of the beam asymmetry in neutral pion photoproduction from the proton near Threshold

    International Nuclear Information System (INIS)

    A precise measurement of neutral pion photoproduction with a linearly polarized, tagged, photon beam and almost 4π detector in the threshold region (and higher) was performed at the Mainz Microtron. The Glasgow-Mainz tagged photon facility alon with the Crystal Ball/TAPS detector system and a cryogenic liquid hydrogen target were used to obtain the total and differential cross sections simultaneously with the photon-beam asymmetry. This allowed for a precise determination of the S-wave amplitude, all three P-wave amplitudes and, for the first time, their energy dependence. The unitary cusp in the S-wave amplitude arising from charged pion re-scattering was also examined, leading to the extraction of the cusp function for the real part of the electric dipole amplitude. Results for the photon-beam asymmetry differ from the only previous measurement, which was done with the TAPS detector alone (PRL 87 232501). These data provide the most stringent test to date of the predictions of Chiral Perturbation Theory and its energy region of convergence.

  16. IEA Agreement on the production and utilization of hydrogen: 1996 annual report

    Energy Technology Data Exchange (ETDEWEB)

    Elam, Carolyn C. (National Renewable Energy Lab, Golden, CO (US)) (ed.)

    1997-01-31

    The annual report includes an overview of the IEA Hydrogen Agreement, including a brief summary of hydrogen in general. The Chairman's report provides highlights for the year. Sections are included on hydrogen energy activities in the IEA Hydrogen Agreement member countries, including Canada, European Commission, Germany, Japan, Netherlands, Norway, Spain, Sweden, Switzerland, and the US. Lastly, Annex reports are given for the following tasks: Task 10, Photoproduction of Hydrogen, Task 11, Integrated Systems, and Task 12, Metal Hydrides and Carbon for Hydrogen Storage.

  17. MC rate at NLO for heavy flavour photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Toll, Tobias

    2010-02-15

    A Monte Carlo at next-to-leading order (MC rate at NLO) has been constructed for the production of heavy quark flavours in photoproduction. As such, it is the rst Monte Carlo event generator with next-to-leading order (NLO) accuracy for a process in lepton hadron scattering. In order to construct such an MC rate at NLO, the matrix element for the process has to be calculated at NLO and then be matched with a parton shower. When doing this, it is important that none of the parton configurations produced are doubly counted. In this thesis, the concept of a Monte Carlo event generator will be explained, with emphasis on the HERWIG parton shower. Also, different techniques of calculating matrix elements at NLO accuracy will be explained. It will then be shown how the NLO calculation can be matched with the HERWIG parton shower in an MC rate at NLO without double counting, producing unweighted events at NLO-accuracy. Many comparisons are made between the MC rate at NLO here constructed, the HERWIG Monte Carlo and the FMNR NLO calculation. Also many comparisons are made to HERA data from the H1 and ZEUS experiments. It is shown that all HERA data with heavy quarks produced in photoproduction can be described by the MC rate at NLO program constructed in this thesis. (orig.)

  18. Diffractive photoproduction of D{sup *{+-}}(2010) at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2007-03-15

    Diffractive photoproduction of D{sup *{+-}}(2010) mesons was measured with the ZEUS detector at the ep collider HERA, using an integrated luminosity of 78.6 pb{sup -1}. The D{sup *} mesons were reconstructed in the kinematic range: transverse momentum p{sub T}(D{sup *})>1.9 GeV and pseudorapidity vertical stroke {eta}(D{sup *}) vertical stroke <1.6, using the decay D{sup *+} {yields} D{sup 0}{pi}{sup +}{sub s} followed by D{sup 0} {yields} K{sup -}{pi}{sup +}(+c.c.). Diffractive events were identified by a large gap in pseudorapidity between the produced hadronic state and the outgoing proton. Cross sections are reported for photon-proton centre-of-mass energies in the range 130photoproduction cross section is about 6%. The data are in agree- ment with perturbative QCD calculations based on various parameterisations of diffractive parton distribution functions. The results are consistent with diffractive QCD factorisation. (orig.) ZEUS Collaboration

  19. Constituent-counting rule in photoproduction of hyperon resonances

    CERN Document Server

    Chang, Wen-Chen; Sekihara, Takayasu

    2015-01-01

    We analyze the CLAS data on the photoproduction of hyperon resonances, as well as the available data for the ground state $\\Lambda$ and $\\Sigma ^{0}$ of the CLAS and SLAC-E84 collaborations, by considering constituent-counting rule suggested by perturbative QCD. The counting rule emerges as a scaling behavior of cross sections in hard exclusive reactions with large scattering angles, and it enables us to determine the number of elementary constituents inside hadrons. Therefore, it could be used as a new method for identifying internal constituents of exotic-hadron candidates. From the analyses of the $\\gamma \\, p \\to K^{+} \\Lambda$ and $K^{+} \\Sigma ^{0}$ reactions, we find that the number of the elementary constituents is consistent with $n_{\\gamma} = 1$, $n_{p} = 3$, $n_{K^{+}} = 2$, and $n_{\\Lambda} = n_{\\Sigma ^{0}} = 3$. Then, the analysis is made for the photoproductions of the hyperon resonances $\\Lambda (1405)$, $\\Sigma (1385)^{0}$, and $\\Lambda (1520)$, where $\\Lambda (1405)$ is considered to be a $\\...

  20. Experimental study of $\\eta$ meson photoproduction reaction at MAMI

    CERN Document Server

    Kashevarov, V L

    2015-01-01

    New data for the differential cross sections, polarization observables $T$, $F$, and $E$ in the reaction of $\\eta$ photoproduction on proton from the threshold up to a center-of-mass energy of W=1.9 GeV are presented. The data were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility of the Mainz Microtron MAMI. The polarization measurements were made using a frozen-spin butanol target and circularly polarized photon beam. The results are compared to existing experimental data and different PWA predictions. The data solve a long-standing problem related the angular dependence of older $T$ data close to threshold. The unexpected relative phase motion between $s$- and $d$-wave amplitudes required by the old data is not confirmed. At higher energies, all model predictions fail to reproduce the new polarization data indicating a significant impact on our understanding of the underlying dynamics of $\\eta$ meson photoproduction. Furthermore, we present a fit of the new data and e...

  1. Experimental study of η meson photoproduction reaction at MAMI

    Directory of Open Access Journals (Sweden)

    Kashevarov V. L.

    2015-01-01

    Full Text Available New data for the differential cross sections, polarization observables T, F, and E in the reaction of η photoproduction on proton from the threshold up to a center-of-mass energy of W=1.9 GeV are presented. The data were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility of the Mainz Microtron MAMI. The polarization measurements were made using a frozen-spin butanol target and circularly polarized photon beam. The results are compared to existing experimental data and different PWA predictions. The data solve a long-standing problem related the angular dependence of older T data close to threshold. The unexpected relative phase motion between s- and d-wave amplitudes required by the old data is not confirmed. At higher energies, all model predictions fail to reproduce the new polarization data indicating a significant impact on our understanding of the underlying dynamics of η meson photoproduction. Furthermore, we present a fit of the new data and existing data from GRAAL for ∑ asymmetry based on an expansion in terms of associated Legendre polynomials. A Legendre decomposition shows the sensitivity to small partialwave contributions. The sensitivity of the Legendre coefficients to the nucleon resonance parameters is shown using the ηMAID isobar model.

  2. Photoproduction of {eta}-mesons off the deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Werthmueller, Dominik [Department of Physics, University of Basel (Switzerland)

    2009-07-01

    Photoproduction of {eta}-mesons off a liquid deuterium target has been measured using bremsstrahlung photons produced by MAMI-C with incident energies up to 1.5 GeV. The {eta}-meson was detected through its neutral decays into 2{gamma} and 3{pi}{sup 0}{yields} 6{gamma}, respectively, in a combined setup of the Crystal Ball calorimeter and a TAPS forward wall which results in an almost 4{pi} acceptance. Previous experiments performed by the CBELSA/TAPS and the GRAAL collaborations studying {eta}-photoproduction on the deuteron revealed a bump-like structure of still unknown nature in the quasi-free neutron excitation function around E{sub {gamma}} = 1 GeV that is not found for the proton. The present experiment aimed at a significant improvement of the statistical quality of the data, in particular for {eta}-mesons at backward angles. Preliminary results for the inclusive {gamma}(d, {eta})X, the semi-exclusive {gamma}(d, {eta})NN, and the fully exclusive reactions measured in coincidence with the recoil nucleons are presented.

  3. Diffractive photoproduction of ψ(2 S) mesons at HERA

    Science.gov (United States)

    Adloff, C.; Andreev, V.; Andrieu, B.; Anthonis, T.; Astvatsatourov, A.; Babaev, A.; Bähr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Berger, Ch.; Berndt, T.; Bizot, J. C.; Böhme, J.; Boudry, V.; Braunschweig, W.; Brisson, V.; Bröker, H.-B.; Brown, D. P.; Brückner, W.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Burrage, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Caron, S.; Cassol-Brunner, F.; Clarke, D.; Collard, C.; Contreras, J. G.; Coppens, Y. R.; Coughlan, J. A.; Cousinou, M.-C.; Cox, B. E.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Dau, W. D.; Daum, K.; Davidsson, M.; Delcourt, B.; Delerue, N.; Demirchyan, R.; De Roeck, A.; De Wolf, E. A.; Diaconu, C.; Dingfelder, J.; Dixon, P.; Dodonov, V.; Dowell, J. D.; Droutskoi, A.; Dubak, A.; Duprel, C.; Eckerlin, G.; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Erdmann, W.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Ferron, S.; Fleischer, M.; Fleischmann, P.; Fleming, Y. H.; Flügge, G.; Fomenko, A.; Foresti, I.; Formánek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, S.; Goerlich, L.; Gogitidze, N.; Grab, C.; Grabski, V.; Grässler, H.; Greenshaw, T.; Grindhammer, G.; Hadig, T.; Haidt, D.; Hajduk, L.; Haller, J.; Haynes, W. J.; Heinemann, B.; Heinzelmann, G.; Henderson, R. C. W.; Hengstmann, S.; Henschel, H.; Heremans, R.; Herrera, G.; Herynek, I.; Hildebrandt, M.; Hilgers, M.; Hiller, K. H.; Hladký, J.; Höting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hurling, S.; Ibbotson, M.; İşsever, Ç.; Jacquet, M.; Jaffre, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, C.; Johnson, D. P.; Jones, M. A. S.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnick, O.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I. R.; Kermiche, S.; Kiesling, C.; Kjellberg, P.; Klein, M.; Kleinwort, C.; Kluge, T.; Knies, G.; Koblitz, B.; Kolya, S. D.; Korbel, V.; Kostka, P.; Kotelnikov, S. K.; Koutouev, R.; Koutov, A.; Kroseberg, J.; Krüger, K.; Kuhr, T.; Kurča, T.; Lamb, D.; Landon, M. P. J.; Lange, W.; Laštovička, T.; Laycock, P.; Lebailly, E.; Lebedev, A.; Leißner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstroem, M.; List, B.; Lobodzinska, E.; Lobodzinski, B.; Loginov, A.; Loktionova, N.; Lubimov, V.; Lüders, S.; Lüke, D.; Lytkin, L.; Malden, N.; Malinovski, E.; Malinovski, I.; Mangano, S.; Maraček, R.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.-U.; Martyniak, J.; Maxfield, S. J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, J.; Meyer, P.-O.; Mikocki, S.; Milstead, D.; Mohrdieck, S.; Mondragon, M. N.; Moreau, F.; Morozov, A.; Morris, J. V.; Müller, K.; Murín, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, Th.; Nellen, G.; Newman, P. R.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Olsson, J. E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G. D.; Peez, M.; Perez, E.; Petrukhin, A.; Phillips, J. P.; Pitzl, D.; Pöschl, R.; Potachnikova, I.; Povh, B.; Rädel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Sankey, D. P. C.; Schätzel, S.; Scheins, J.; Schilling, F.-P.; Schleper, P.; Schmidt, D.; Schmidt, D.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schöning, A.; Schörner, T.; Schröder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlák, K.; Sefkow, F.; Shekelyan, V.; Sheviakov, I.; Shtarkov, L. N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Swart, M.; Tchetchelnitski, S.; Thompson, G.; Thompson, P. D.; Tomasz, F.; Traynor, D.; Truöl, P.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J. E.; Tzamariudaki, E.; Udluft, S.; Uraev, A.; Urban, M.; Usik, A.; Valkár, S.; Valkárová, A.; Vallée, C.; Van Mechelen, P.; Vassiliev, S.; Vazdik, Y.; Vest, A.; Vichnevski, A.; Wacker, K.; Wagner, J.; Wallny, R.; Waugh, B.; Weber, G.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; White, G.; Wiesand, S.; Wilksen, T.; Winde, M.; Winter, G.-G.; Wissing, Ch.; Wobisch, M.; Woehrling, E.-E.; Wünsch, E.; Wyatt, A. C.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; zur Nedden, M.; H1 Collaboration

    2002-08-01

    Results on diffractive photoproduction of ψ(2 S) mesons are presented using data collected between 1996 and 2000 with the H1 detector at the HERA ep collider. The data correspond to an integrated luminosity of 77 pb -1. The energy dependence of the diffractive ψ(2 S) cross section is found to be similar to or possibly somewhat steeper than that for J/ ψ mesons. The dependences of the elastic and proton dissociative ψ(2 S) photoproduction cross sections on the squared momentum transfer t at the proton vertex are measured. The t-dependence of the elastic channel, parametrised as ebt, yields belψ(2 S) =(4.31±0.57±0.46) GeV -2, compatible with that of the J/ ψ. For the proton dissociative channel the result bpdψ(2 S) =(0.59±0.13±0.12) GeV -2 is 2.3 standard deviations smaller than that measured for the J/ ψ. With proper account of the individual wavefunctions theoretical predictions based on perturbative QCD are found to describe the measurements well.

  4. Measurement of elastic ρ0 photoproduction at HERA

    International Nuclear Information System (INIS)

    Elastic ρ0 photoproduction has been measured using the ZEUS detector at HERA. Untagged photoproduction events from ep interactions were used to measure the reaction γp→ρ0p (ρ0→π+π-) at photon-proton centre-of-mass energies between 60 and 80 GeV and vertical stroke tvertical stroke 2, where t is the square of the four-momentum transferred at the proton vertex. The differential cross section dσ/dMππ, where Mππ is the invariant mass of the two pions, and the integrated cross section, σsub(γp→ρ0p), are presented; the latter was measured to be 14.7±0.4(stat.)±2.4(syst.) μb. The differential cross section dσ/dt has an approximately exponential shape; a fit of the type A'texp(-b'tvertical stroke tvertical stroke +c'tt2) yields a t-slope b't=9.9±1.2(stat.)±1.4(syst.) μb. The results, when compared to low energy data, show a weak energy dependence of both σsub(γp→ρ0p) and of the t-slope. The ρ0 is produced predominantly with transverse polarisation, demonstrating that s-channel helicity conservation holds at these energies. (orig.)

  5. Low-energy {pi}{pi} photoproduction off nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Muehlich, P.; Alvarez-Ruso, L.; Buss, O.; Mosel, U

    2004-08-12

    In the present Letter we investigate {pi}{sup 0}{pi}{sup 0} and {pi}{sup {+-}}{pi}{sup 0} photoproduction off complex nuclei at incident beam energies of 400-460 MeV. Simulations of two pion photoproduction on protons and nuclei are performed by means of a semi-classical BUU transport model including a full coupled-channel treatment of the final state interactions. Elastic scattering of the final state pions with the nucleons in the surrounding nuclear medium is found to yield a downward shift of the {pi}{pi} invariant mass distribution. We show that the target mass dependence of the {pi}{sup 0}{pi}{sup 0} invariant mass spectrum as measured by the TAPS Collaboration can be explained without introducing medium effects beyond absorption and quasi-elastic scattering of the final state particles. On the other hand, we find considerable discrepancies with the data in the {pi}{sup {+-}}{pi}{sup 0} channel, which are not understood.

  6. Evaluation of feed COD/sulfate ratio as a control criterion for the biological hydrogen sulfide production and lead precipitation

    International Nuclear Information System (INIS)

    The ability of sulfate-reducing bacteria to produce hydrogen sulfide and the high affinity of sulfide to react with divalent metallic cations represent an excellent option to remove heavy metals from wastewater. Different parameters have been proposed to control the hydrogen sulfide production by anaerobic bacteria, such as the organic and sulfate loading rates and the feed COD/SO42- ratio. This work relates the feed COD/SO42- ratio with the hydrogen sulfide production and dissolved lead precipitation, using ethanol as carbon and energy source in an up-flow anaerobic sludge blanket reactor. A maximum dissolved sulfide concentration of 470 ± 7 mg S/L was obtained at a feed COD/SO42- ratio of 2.5, with sulfate and ethanol conversions of approximately 94 and 87%, respectively. The lowest dissolved sulfide concentration (145 ± 10 mg S/L) was observed with a feed COD/SO42- ratio of 0.67. Substantial amounts of acetate (510-1730 mg/L) were produced and accumulated in the bioreactor from ethanol oxidation. Although only incomplete oxidation of ethanol to acetate was observed, the consortium was able to remove 99% of the dissolved lead (200 mg/L) with a feed COD/SO42- ratio of 1.5. It was found that the feed COD/SO42- ratio could be an adequate parameter to control the hydrogen sulfide production and the consequent precipitation of dissolved lead

  7. Field-controlled electron transfer and reaction kinetics of the biological catalytic system of microperoxidase-11 and hydrogen peroxide

    Directory of Open Access Journals (Sweden)

    Yongki Choi

    2011-12-01

    Full Text Available Controlled reaction kinetics of the bio-catalytic system of microperoxidase-11 and hydrogen peroxide has been achieved using an electrostatic technique. The technique allowed independent control of 1 the thermodynamics of the system using electrochemical setup and 2 the quantum mechanical tunneling at the interface between microperoxidase-11 and the working electrode by applying a gating voltage to the electrode. The cathodic currents of electrodes immobilized with microperoxidase-11 showed a dependence on the gating voltage in the presence of hydrogen peroxide, indicating a controllable reduction reaction. The measured kinetic parameters of the bio-catalytic reduction showed nonlinear dependences on the gating voltage as the result of modified interfacial electron tunnel due to the field induced at the microperoxidase-11-electrode interface. Our results indicate that the kinetics of the reduction of hydrogen peroxide can be controlled by a gating voltage and illustrate the operation of a field-effect bio-catalytic transistor, whose current-generating mechanism is the conversion of hydrogen peroxide to water with the current being controlled by the gating voltage.

  8. Evaluation of feed COD/sulfate ratio as a control criterion for the biological hydrogen sulfide production and lead precipitation

    Energy Technology Data Exchange (ETDEWEB)

    Velasco, Antonio [Direccion General del Centro Nacional de Investigacion y Capacitacion Ambiental-Instituto Nacional de Ecologia, Av. San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico)], E-mail: jvelasco@ine.gob.mx; Ramirez, Martha [Direccion General del Centro Nacional de Investigacion y Capacitacion Ambiental-Instituto Nacional de Ecologia, Av. San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico); Volke-Sepulveda, Tania [Departamento de Biotecnologia, UAM-Cuajimalpa, San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico); Gonzalez-Sanchez, Armando [Departamento de Ingenieria de Procesos, Universidad Autonoma Metropolitana-Iztapalapa, UAM-Cuajimalpa, San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico); Revah, Sergio [Departamento de Procesos y Tecnologia, UAM-Cuajimalpa, San Rafael Atlixco 186, Col. Vicentina. Iztapalapa, Mexico 09340, D.F. (Mexico)

    2008-03-01

    The ability of sulfate-reducing bacteria to produce hydrogen sulfide and the high affinity of sulfide to react with divalent metallic cations represent an excellent option to remove heavy metals from wastewater. Different parameters have been proposed to control the hydrogen sulfide production by anaerobic bacteria, such as the organic and sulfate loading rates and the feed COD/SO{sub 4}{sup 2-} ratio. This work relates the feed COD/SO{sub 4}{sup 2-} ratio with the hydrogen sulfide production and dissolved lead precipitation, using ethanol as carbon and energy source in an up-flow anaerobic sludge blanket reactor. A maximum dissolved sulfide concentration of 470 {+-} 7 mg S/L was obtained at a feed COD/SO{sub 4}{sup 2-} ratio of 2.5, with sulfate and ethanol conversions of approximately 94 and 87%, respectively. The lowest dissolved sulfide concentration (145 {+-} 10 mg S/L) was observed with a feed COD/SO{sub 4}{sup 2-} ratio of 0.67. Substantial amounts of acetate (510-1730 mg/L) were produced and accumulated in the bioreactor from ethanol oxidation. Although only incomplete oxidation of ethanol to acetate was observed, the consortium was able to remove 99% of the dissolved lead (200 mg/L) with a feed COD/SO{sub 4}{sup 2-} ratio of 1.5. It was found that the feed COD/SO{sub 4}{sup 2-} ratio could be an adequate parameter to control the hydrogen sulfide production and the consequent precipitation of dissolved lead.

  9. Field-controlled electron transfer and reaction kinetics of the biological catalytic system of microperoxidase-11 and hydrogen peroxide

    OpenAIRE

    Yongki Choi; Siu-Tung Yau

    2011-01-01

    Controlled reaction kinetics of the bio-catalytic system of microperoxidase-11 and hydrogen peroxide has been achieved using an electrostatic technique. The technique allowed independent control of 1) the thermodynamics of the system using electrochemical setup and 2) the quantum mechanical tunneling at the interface between microperoxidase-11 and the working electrode by applying a gating voltage to the electrode. The cathodic currents of electrodes immobilized with microperoxidase-11 showed...

  10. Study of metabolic pathways for hydrogen production in chlamydomonas reinhardtii and transposition on a torus photo bioreactor; Etude des voies metaboliques de production d'hydrogene chez la microalgue Chlamydomonas reinhardtii et transposition en photobioreacteur

    Energy Technology Data Exchange (ETDEWEB)

    Fouchard, S

    2006-04-15

    Considering the recent increase in energy consumption. aide associated environmental risks, new trails are followed today to develop the use of clean and renewable alternative energies. In this context hydrogen seems to be a serious solution and this study, based on micro-algae photosynthetic capacities exploitation, will allow to devise a process for hydrogen production from only water and solar energy without greenhouse gas release. The sulphur deprivation protocol on TAP medium, known to lead to hydrogen production in Chlamydomonas reinhardtii species was particularly studied. At the metabolic level, two important phenomena are induced under these conditions: an over-accumulation of the intracellular starch reserves and a simultaneous alteration of the PsII activity which leads to anoxia and Fe-hydrogenase induction, an enzyme with a strong specific activity responsible for the hydrogen production. The contribution of the two electron transfer pathways implied in the hydrogen production process (PsII-dependent and PSII-independent) as well as the importance of the previously accumulated starch were highlighted here. We also investigated the potential for designing autotrophic protocols for hydrogen photoproduction. Various protocols, considered to be relevant, were then transposed on a torus photo-bioreactor, specifically developed in this study and which allows the control of culture parameters as well as the precise measurement of gas release kinetics, in order to obtain first estimates of productivity of the system. Integration of the physical; aspects of the pilot and biological aspects of the process in a model, finally opens new prospects for subject development, in particular for a reasoned optimization of hydrogen production via this double physiology/process approach. (author)

  11. A montecarlo program for beauty and charm photoproduction at the tevatron energies

    International Nuclear Information System (INIS)

    A montecarlo program is described which simulates the diffractive photoproduction of charm and beauty states for the vertex detector of the E687 experiment at FNAL. The program is now running on the Frascati and Milano VAX computers

  12. Eta photoproduction in a combined analysis of pion- and photon-induced reactions

    CERN Document Server

    Rönchen, D; Haberzettl, H; Haidenbauer, J; Meißner, U -G; Nakayama, K

    2015-01-01

    The $\\eta N$ final state is isospin-selective and thus provides access to the spectrum of excited nucleons without being affected by excited $\\Delta$ states. To this end, the world database on eta photoproduction off the proton up to $E\\sim 2.3$~GeV is analyzed, including data on differential cross sections, and single and double polarization observables. The resonance spectrum and its properties are determined in a combined analysis of eta and pion photoproduction off the proton together with the reactions $\\pi N\\to \\pi N$, $\\eta N$, $K\\Lambda$ and $K\\Sigma$. For the analysis, the so-called J\\"ulich coupled-channel framework is used, incorporating unitarity, analyticity, and effective three-body channels. Parameters tied to photoproduction and hadronic interactions are varied simultaneously. The influence of recent MAMI $T$ and $F$ asymmetry data in eta photoproduction is discussed in detail.

  13. Single-energy amplitudes for pion photoproduction in the first resonance region

    OpenAIRE

    Workman, R. L.

    2010-01-01

    We consider multipole amplitudes for low-energy pion photoproduction, constructed with minimal model dependence, at single energies. Comparisons with fits to the full resonance region are made. Explanations are suggested for the discrepancies and further experiments are motivated.

  14. Aspects of the heavy-quark photoproduction in the semihard approach

    International Nuclear Information System (INIS)

    In this contribution we report on the calculations of heavy-quark photoproduction using the Kperpendicular to-factorization (semihard) approach, emphasizing the results obtained with the phenomenological saturation model. (author)

  15. Photoproduction of $\\omega$ mesons off nuclei and impact of polarization on meson-nucleon interaction

    CERN Document Server

    Chudakov, E; Somov, A

    2015-01-01

    We consider photoproduction of $\\omega$ mesons off complex nuclei to study interactions of transversely and longitudinally polarized vector mesons with nucleons. Whereas the total cross section for interactions of the transversely polarized vector mesons with nucleons $\\sigma_T=\\sigma(V_TN)$ can be obtained from coherent photoproduction, measurements of vector meson photoproduction in the incoherent region provide a unique opportunity to extract the total cross section for longitudinally polarized mesons interacting with nucleons $\\sigma_L=\\sigma(V_LN)$, which has not yet been measured and strongly depends on theoretical approaches. This work is stimulated by the construction of the new experiment GlueX at Jefferson Lab, designed to study the photoproduction of mesons in a large beam energy range up to 12 GeV.

  16. Study of metabolic pathways for hydrogen production in chlamydomonas reinhardtii and transposition on a torus photo bioreactor

    International Nuclear Information System (INIS)

    Considering the recent increase in energy consumption. aide associated environmental risks, new trails are followed today to develop the use of clean and renewable alternative energies. In this context hydrogen seems to be a serious solution and this study, based on micro-algae photosynthetic capacities exploitation, will allow to devise a process for hydrogen production from only water and solar energy without greenhouse gas release. The sulphur deprivation protocol on TAP medium, known to lead to hydrogen production in Chlamydomonas reinhardtii species was particularly studied. At the metabolic level, two important phenomena are induced under these conditions: an over-accumulation of the intracellular starch reserves and a simultaneous alteration of the PsII activity which leads to anoxia and Fe-hydrogenase induction, an enzyme with a strong specific activity responsible for the hydrogen production. The contribution of the two electron transfer pathways implied in the hydrogen production process (PsII-dependent and PSII-independent) as well as the importance of the previously accumulated starch were highlighted here. We also investigated the potential for designing autotrophic protocols for hydrogen photoproduction. Various protocols, considered to be relevant, were then transposed on a torus photo-bioreactor, specifically developed in this study and which allows the control of culture parameters as well as the precise measurement of gas release kinetics, in order to obtain first estimates of productivity of the system. Integration of the physical; aspects of the pilot and biological aspects of the process in a model, finally opens new prospects for subject development, in particular for a reasoned optimization of hydrogen production via this double physiology/process approach. (author)

  17. Exclusive photoproduction of quarkonium at the LHC energies within the color dipole approach

    Energy Technology Data Exchange (ETDEWEB)

    Ducati, M. B. Gay; Griep, M. T.; Machado, M. V. T. [High Energy Physics Phenomenology Group, GFPAE IF-UFRGS, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS (Brazil)

    2015-04-10

    The exclusive photoproduction of ψ(2S) meson was investigated and the coherent and the incoherent contributions were evaluated. The light-cone dipole formalism was considered in this analysis and predictions are done for PbPb collisions at the CERN-LHC energy of 2.76 TeV. A comparison is done to the recent ALICE Collaboration data for the ψ(1S) state photoproduction with good agreement.

  18. Appropriate observables for investigating narrow resonances in kaon photoproduction off a proton

    CERN Document Server

    Mart, T

    2011-01-01

    The existence of non-strange partner of pentaquark, the J^p = 1/2^+ narrow resonance, has been investigated by utilizing kaon photoproduction off a proton. It is found that the corresponding mass is 1650 MeV and the appropriate observables for investigating this resonance are the recoiled hyperon polarization, the beam-recoil double polarization C_x, and differential cross section at backward angles. Future kaon photoproduction experiments at low energies should focus on these observables.

  19. Nonresonant Background in Isobaric Models of Photoproduction of η-Mesons on Nucleons

    Science.gov (United States)

    Tryasuchev, V. A.; Alekseev, B. A.; Yakovleva, V. S.; Kondratyeva, A. G.

    2016-07-01

    Within the framework of isobaric models of pseudoscalar meson photoproduction, the nonresonant background of photoproduction of η-mesons on nucleons is investigated as a function of energy. A bound on the magnitude of the pseudoscalar coupling constant of the η-meson with a nucleon is obtained: g η NN 2 /4π ≤ 0.01, and a bound on vector meson exchange models is also obtained.

  20. Photoproduction of Dijets with High Transverse Momenta at HERA

    CERN Document Server

    Andreev, V; Antunovic, B; Aplin, S; Asmone, A; Astvatsatourov, A; Babaev, A; Backovic, S; Bähr, J; Baghdasaryan, A; Baranov, P; Barrelet, E; Bartel, Wulfrin; Baudrand, S; Baumgartner, S; Becker, J; Beckingham, M; Behnke, O; Behrendt, O; Belousov, A; Berger, C; Berger, N; Bizot, J C; Boenig, M O; Boudry, V; Bracinik, J; Brandt, G; Brisson, V; Bruncko, Dusan; Büsser, F W; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Cassol-Brunner, F; Cerny, K; Cerny, V; Chekelian, V; Contreras, J G; Coughlan, J A; Cox, B E; Cozzika, G; Cvach, J; Dainton, J B; Dau, W D; Daum, K; De Boer, Y; Delcourt, B; Del Degan, M; de Roeck, A; Desch, Klaus; De Wolf, E A; Diaconu, C; Dodonov, V; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, F; Elsen, E; Erdmann, W; Essenov, S; Falkewicz, A; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Finke, L; Fleischer, M; Fleischmann, P; Flucke, G; Fomenko, A; Foresti, I; Franke, G; Frisson, T; Gabathuler, E; Garutti, E; Gayler, J; Gerlich, C; Ghazaryan, S; Ginzburgskaya, S; Glazov, A; Glushkov, I; Görlich, L; Goettlich, M; Gogitidze, N; Gorbounov, S; Goyon, C; Grab, C; Greenshaw, T; Gregori, M; Grell, B R; Grindhammer, G; Gwilliam, C; Haidt, D; Hajduk, L; Hansson, M; Heinzelmann, G; Henderson, R C W; Henschel, H; Herrera-Corral, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R P; Hovhannisyan, A; Hreus, T; Hussain, S; Ibbotson, M; Ismail, M; Jacquet, M; Janauschek, L; Janssen, X; Jemanov, V; Jönsson, L B; Johnson, D P; Jung, A W; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Klimkovich, T; Kluge, T; Knies, G; Knutsson, A; Korbel, V; Kostka, P; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Krüger, K; Kuckens, J; Landon, M P J; Lange, W; Laistoviicka, T; Lastoviicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Lindfeld, L; Lipka, K; Liptaj, A; List, B; List, J; Lobodzinska, E; Loktionova, N; López-Fernandez, R; Lubimov, V; Lucaci-Timoce, A I; Lüders, H; Lüke, D; Lux, T; Lytkin, L; Makankine, A; Malden, N; Malinovskii, E I; Mangano, S; Marage, P; Marshall, R; Martisikova, M; Martyn, H U; Maxfield, S J; Meer, D; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Milstead, D; Mladenov, D; Mohamed, A; Moreau, F; Morozov, A; Morris, J V; Mozer, M U; Müller, K; Murn, P; Nankov, K; Naroska, Beate; Naumann, T; Newman, P R; Niebuhr, C; Nikiforov, A; Nowak, G; Nozicka, M; Oganezov, R; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Papadopoulou, T D; Pascaud, C; Patel, G D; Peng, H; Pérez, E; Perez-Astudillo, D; Perieanu, A; Petrukhin, A; Pitzl, D; Placakyte, R; Portheault, B; Povh, B; Prideaux, P; Rahmat, A J; Raicevic, N; Reimer, P; Rimmer, A; Risler, C; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rurikova, Z; Rusakov, S; Salvaire, F; Sankey, D P C; Sauvan, E; Schatzel, S; Schmidt, S; Schmitt, S; Schmitz, C; Schoeffel, L; Schöning, A; Schultz-Coulon, H C; Sedlak, K; Sefkow, F; Shaw-West, R N; Shevyakov, I; Shtarkov, L N; Sloan, T; Smirnov, P; Soloviev, Yu; South, D; Spaskov, V; Specka, A; Steder, M; Stella, B; Stiewe, J; Strauch, I; Straumann, U; Sunar, D; Tchoulakov, V; Thompson, G; Thompson, P D; Tomasz, F; Traynor, D; Truöl, P; Tsakov, I; Tsipolitis, G; Tsurin, I; Turnau, J; Tzamariudaki, E; Urban, K; Urban, M; Usik, A; Utkin, D; Valkárová, A; Vallée, C; Van Mechelen, P; Vargas-Trevino, A; Vazdik, Ya A; Veelken, C; Vinokurova, S; Volchinski, V; Wacker, K; Wagner, J; Weber, G; Weber, R; Wegener, D; Werner, C; Wessels, M; Wessling, B; Wigmore, C; Wissing, C; Wolf, R; Wünsch, E; Xella, S M; Yan, W; Yeganov, V; Zaicek, J; Zaleisak, J; Zhang, Z; Zhelezov, A; Zhokin, A; Zhu, Y C; Zimmermann, J; Zimmermann, T; Zohrabyan, H; Zomer, F

    2006-01-01

    Differential dijet cross sections are measured in photoproduction in the region of photon virtualities Q^2 < 1 GeV^2 with the H1 detector at the HERA ep collider using an integrated luminosity of 66.6 pb^{-1}. Jets are defined with the inclusive k_T algorithm and a minimum transverse momentum of the leading jet of 25 GeV is required. Dijet cross sections are measured in direct and resolved photon enhanced regions separately. Longitudinal proton momentum fractions up to 0.7 are reached. The data compare well with predictions from Monte Carlo event generators based on leading order QCD and parton showers and with next-to-leading order QCD calculations corrected for hadronisation effects.

  1. Baryon Spectroscopy Through Partial-Wave Analysis and Meson Photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Manley, D. Mark [Kent State Univ., Kent, OH (United States)

    2016-09-08

    The principal goal of this project is the experimental and phenomenological study of baryon spectroscopy. The PI's group consists of himself and three graduate students. This final report summarizes research activities by the PI's group during the period 03/01/2015 to 08/14/2016. During this period, the PI co-authored 11 published journal papers and one proceedings article and presented three invited talks. The PI's general interest is the investigation of the baryon resonance spectrum up to masses of ~2 GeV. More detail is given on two research projects: Neutral Kaon Photoproduction and Partial-Wave Analyses of γp → ηp, γn → ηn, and γp → K⁺Λ.

  2. Multiple parton interactions in photoproduction at HERA/H1

    Energy Technology Data Exchange (ETDEWEB)

    Magro, Lluis Marti

    2009-02-15

    Photoproduction data of HERA-I are analysed by requiring dijets with transverse momenta of at least 5 GeV. The two jets define in azimuth a towards region (leading jet), an away region (usually the 2nd jet) and transverse regions between them. The charged particle and jet with low transverse momentum multiplicity, so called minijets, are measured in these regions as a function of the variables x{sup obs}{sub {gamma}} and P{sup Jet{sub 1T}} (leading jet). The measurement is compared to predictions including parton showers and matrix elements at leading order in {alpha}{sub s}. Some predictions include contributions from multiple parton interactions and use different parton evolution equations. It was found that existing MC programs do not fully describe the measurements but the description can be improved by including multiple parton interactions. (orig.)

  3. Measurement of inclusive prompt photon photoproduction at HERA

    CERN Document Server

    Abbiendi, G; Abramowicz, H; Acosta, D; Adamczyk, L; Adamus, M; Ahn, S H; Amelung, C; An Shiz Hong; Anselmo, F; Antonioli, P; Arneodo, M; Bacon, Trevor C; Badgett, W F; Bailey, D C; Bailey, D S; Bamberger, A; Barbagli, G; Bari, G; Barreiro, F; Barret, O; Bashindzhagian, G L; Bashkirov, V; Basile, M; Bauerdick, L A T; Bednarek, B; Behrens, U; Bellagamba, L; Bertolin, A; Bhadra, S; Bienlein, J K; Blaikley, H E; Bohnet, I; Bokel, C; Boogert, S; Bornheim, A; Borzemski, P; Boscherini, D; Botje, M; Breitweg, J; Brock, I; Brook, N H; Brugnera, R; Bruni, A; Bruni, G; Brümmer, N; Burgard, C; Burow, B D; Bussey, P J; Butterworth, J M; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carlin, R; Cartiglia, N; Cashmore, R J; Castellini, G; Catterall, C D; Chapin, D; Chekanov, S; Chwastowski, J; Ciborowski, J; Cifarelli, Luisa; Cindolo, F; Cirio, R; Cloth, P; Coboken, K; Coldewey, C; Cole, J E; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cor, M; Cormack, C; Corriveau, F; Costa, M; Cottingham, W N; Crittenden, J; Cross, R; D'Agostini, G; Dagan, S; Dal Corso, F; Dardo, M; De Pasquale, S; De Wolf, E; Deffner, R; Del Peso, J; Deppe, O; Derrick, M; Deshpande, Abhay A; Desler, K; Devenish, R C E; Dhawan, S; Dolgoshein, B A; Dondana, S; Dosselli, U; Doyle, A T; Drews, G; Dulinski, Z; Durkin, L S; Dusini, S; Eckert, M; Edmonds, J K; Eisenberg, Y; Eisenhardt, S; Engelen, J; Epperson, D E; Ermolov, P F; Eskreys, Andrzej; Fagerstroem, C P; Fernández, J P; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fox-Murphy, A; Fricke, U; Frisken, W R; Fusayasu, T; Gadaj, T; Galea, R; Gallo, E; García, G; Garfagnini, A; Gendner, N; Gialas, I; Gilmore, J; Ginsburg, C M; Giusti, P; Gladilin, L K; Glasman, C; Göbel, F; Golubkov, Yu A; Grabosch, H J; Graciani, R; Grosse-Knetter, J; Grzelak, G; Göttlicher, P; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hanna, D S; Harnew, N; Hart, H; Hart, J C; Hartmann, J; Hartner, G F; Hasell, D; Hayes, M E; Heaphy, E A; Heath, G P; Heath, H F; Hebbel, K; Heinloth, K; Heinz, L; Hernández, J M; Heusch, C A; Hilger, E; Hirose, T; Hochman, D; Holm, U; Homma, K; Hong, S J; Howell, G; Hughes, V W; Iacobucci, G; Iannotti, L; Iga, Y; Inuzuka, M; Ishii, T; Jakob, H P; Jelen, K; Jeoung, H Y; Jing, Z; Johnson, K F; Jones, T W; Kananov, S; Kappes, A; Karshon, U; Kasemann, M; Katz, U F; Kcira, D; Kerger, R; Khakzad, M; Khein, L A; Kim, C L; Kim, J Y; Kisielewska, D; Kitamura, S; Klanner, Robert; Klimek, K; Ko, I A; Koch, W; Koffeman, E; Kooijman, P; Koop, T; Korotkova, N A; Kotanski, A; Kowal, A M; Kowalski, H; Kowalski, T; Krakauer, D; Kreisel, A; Kuze, M; Kuzmin, V A; Kötz, U; Labarga, L; Lamberti, L; Lane, J B; Laurenti, G; Lee, J H; Lee, S B; Lee, S W; Levi, G; Levman, G M; Levy, A; Lim, H; Lim, I T; Limentani, S; Lindemann, L; Ling, T Y; Liu, W; Lohrmann, E; Long, K R; Lopez-Duran Viani, A; Lukina, O Yu; Löhr, B; Ma, K J; MacDonald, N; Maccarrone, G; Magill, S; Mallik, U; Margotti, A; Marini, G; Markun, P; Martin, J F; Martínez, M; Maselli, S; Massam, Thomas; Mastroberardino, A; Matsushita, T; Mattingly, M C K; Mattingly, S E K; McCance, G J; McCubbin, N A; McFall, J D; Mellado, B; Menary, S R; Meyer, A; Meyer-Larsen, A; Milewski, J; Milite, M; Miller, D B; Monaco, V; Monteiro, T; Morandin, M; Moritz, M; Murray, W N; Musgrave, B; Mönig, K; Nagano, K; Nam, S W; Nania, R; Nigro, A; Nishimura, T; Notz, D; Nowak, R J; Noyes, V A; Nylander, P; Ochs, A; Oh, B Y; Okrasinski, J R; Olkiewicz, K; Orr, R S; Pac, M Y; Padhi, S; Palmonari, F; Park, I H; Park, S K; Parsons, J A; Paul, E; Pavel, N; Pawlak, J M; Pawlak, R; Pelfer, Pier Giovanni; Pellegrino, A; Pelucchi, F; Peroni, C; Pesci, A; Petrucci, M C; Pfeiffer, M; Pic, D; Piotrzkowski, K; Poelz, G; Polenz, S; Polini, A; Posocco, M; Prinias, A; Proskuryakov, A S; Przybycien, M B; Puga, J; Quadt, A; Raach, H; Raso, M; Rautenberg, J; Re, J; Redondo, I; Reeder, D D; Ritz, S; Riveline, M; Rohde, M; Rulikowska-Zarebska, E; Ruske, O; Ruspa, M; Sabetfakhri, A; Sacchi, R; Sadrozinski, H F W; Saint-Laurent, M; Salehi, H; Samp, S; Sartorelli, G; Saull, P R B; Savin, A A; Saxon, D H; Schechter, A; Schioppa, M; Schlenstedt, S; Schmidke, W B; Schneekloth, U; Schnurbusch, H; Schwarzer, O; Sciulli, F; Scott, J; Sedgbeer, J K; Seiden, A; Selonke, F; Shah, T P; Shcheglova, L M; Sideris, D; Sievers, M; Simmons, D; Sinclair, L E; Skillicorn, I O; Smalska, B; Smith, W H; Solano, A; Solomin, A N; Son, D; Staiano, A; Stairs, D G; Stanco, L; Stanek, R; Stifutkin, A; Stonjek, S; Straub, P B; Strickland, E; Stroili, R; Susinno, G; Suszycki, L; Sutton, M R; Suzuki, I; Tandler, J; Tapper, A D; Tapper, R J; Tassi, E; Terron, J; Tiecke, H G; Tokushuku, K; Toothacker, W S; Tsurugai, T; Tuning, N; Tymieniecka, T; Umemori, K; Vaiciulis, A W; Van Sighem, A; Velthuis, J J; Verkerke, W; Voci, C; Vossebeld, Joost Herman; Votano, L; Walczak, R; Walker, R; Wang, S M; Waters, D S; Waugh, R; Weber, A; Whitmore, J J; Wichmann, R; Wick, K; Wieber, H; Wiggers, L; Wildschek, T; Williams, D C; Wing, M; Wodarczyk, M; Wolf, G; Wollmer, U; Wróblewski, A K; Wölfle, S; Yamada, S; Yamashita, T; Yamauchi, K; Yamazaki, Y; Yoshida, R; Youngman, C; Zajac, J; Zakrzewski, J A; Zamora Garcia, Y; Zawiejski, L; Zetsche, F; Zeuner, W; Zhu, Q; Zichichi, A; Zotkin, S A

    2000-01-01

    First inclusive measurements of isolated prompt photons in photoproduction at the HERA ep collider have been made with the ZEUS detector, using an integrated luminosity of 38.4 pb$^{-1}$. Cross sections are given as a function of the pseudorapidity and the transverse energy ($\\eta^\\gamma$, \\eTg) of the photon, for $\\eTg > $ 5 GeV in the $\\gamma p$ centre-of-mass energy range 134-285 GeV. Comparisons are made with predictions from Monte Carlo models having leading-logarithm parton showers, and with next-to-leading-order QCD calculations, using currently available parameterisations of the photon structure. For forward $\\eta^\\gamma$ (proton direction) good agreement is found, but in the rear direction all predictions fall below the data.

  4. High-E_T dijet photoproduction at HERA

    CERN Document Server

    Chekanov, S; Magill, S; Musgrave, B; Nicholass, D; Repond, J; Yoshida, R; Mattingly, M C K; Jechow, USAM; Pavel, N; Yagues-Molina, A G; Antonelli, S; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Bindi, M; Boscherini, D; Bruni, A; Bruni, G; Cifarelli, L; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Iacobucci, G; Margotti, A; Nania, R; Polini, A; Sartorelli, G; Zichichi, A; Bartsch, D; Brock, I; Goers, S; Hartmann, H; Hilger, E; Jakob, H P; Jüngst, M; Kind, O M; Nuncio-Quiroz, A E; Paul, E; Renner, R; Samson, U; Schonberg, V; Shehzadi, R; Wlasenko, M; Brook, N H; Heath, G P; Morris, J D; Wills, H H; Capua, M; Fazio, S; Mastroberardino, A; Schioppa, M; Susinno, G; Tassi, E; Kim, J Y; Ma, K J; Ibrahim, Z A; Kamaluddin, B; Wan-Abdullah, W A T; Ning, Y; Ren, Z; Sciulli, F; Chwastowski, J; Eskreys, A; Figiel, J; Galas, A; Gil, M; Olkiewicz, K; Stopa, P; Zawiejski, L; Adamczyk, L; Bold, T; Grabowska-Bold, I; Kisielewska, D; Lukasik, J; Przybycien, M; Suszycki, L; Kotanski, A; Slominski, W; Adler, V; Behrens, U; Bloch, I; Blohm, C; Bonato, A; Borras, K; Ciesielski, R; Coppola, N; Dossanov, A; Drugakov, V; Fourletova, J; Geiser, A; Gladkov, D; Göttlicher, P; Grebenyuk, J; Gregor, I; Haas, T; Hain, W; Horn, C; Huttmann, A; Kahle, B; Katkov, I I; Klein, U; Kötz, U; Kowalski, H; Lobodzinska, E; Löhr, B; Mankel, R; Melzer-Pellmann, I A; Miglioranzi, S; Montanari, A; Namsoo, T; Notz, D; Rinaldi, L; Roloff, P; Rubinsky, I; Santamarta, R; Schneekloth, U; Spiridonov, A; Stadie, H; Szuba, D; Szuba, J; Theedt, T; Wolf, G; Wrona, K; Youngman, C; Zeuner, W; Lohmann, W; Schlenstedt, S; Barbagli, G; Gallo, E; Pelfer, P G; Bamberger, A; Dobur, D; Karstens, F; Vlasov, N N; Bussey, P J; Doyle, A T; Dunne, W; Ferrando, J; Forrest, M; Saxon, D H; Skillicorn, I O; Gialas, I; Papageorgiu, K; Gosau, T; Holm, U; Klanner, R; Lohrmann, E; Perrey, H; Salehi, H; Schleper, P; Schörner-Sadenius, T; Sztuk, J; Wichmann, K; Wick, K; Foudas, C; Fry, C; Long, K R; Tapper, A D; Kataoka, M; Matsumoto, T; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Pokrovskiy, N S; Zhautykov, B O; Aushev, V; Son, D; De Favereau, J; Piotrzkowski, K; Barreiro, F; Glasman, C; Jiménez, M; Labarga, L; Del Peso, J; Ron, E; Soares, M; Terron, J; Zambrana, M; Corriveau, F; Liu, C; Walsh, R; Zhou, C; Tsurugai, T; Antonov, A; Dolgoshein, B A; Sosnovtsev, V; Stifutkin, A; Suchkov, S; Dementiev, R K; Ermolov, P F; Gladilin, L K; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Zotkin, D S; Zotkin, S A; Abt, I; Büttner, C; Caldwell, A; Kollar, D; Schmidke, W B; Sutiak, J; Grigorescu, G; Keramidas, A; Koffeman, E; Kooijman, P; Pellegrino, A; Tiecke, H; Vázquez, M; Wiggers, L; Brümmer, N; Bylsma, B; Durkin, L S; Lee, A; Ling, T Y; Allfrey, P D; Bell, M A; Cooper-Sarkar, A M; Cottrell, A; Devenish, R C E; Foster, B; Korcsak-Gorzo, K; Patel, S; Roberfroid, V; Robertson, A; Straub, P B; Uribe-, C; Estrada; Walczak, R; Bellan, P; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Stanco, L; Turcato, M; Oh, B Y; Raval, A; Ukleja, J; Whitmore, J J; Iga, Y; D'Agostini, G; Marini, G; Nigro, A; Cole, J E; Hart, J C; Abramowicz, H; Gabareen, A; Ingbir, R; Kananov, S; Levy, A; Kuze, M; Maeda, J; Hori, R; Kagawa, S; Okazaki, N; Shimizu, S; Tawara, T; Hamatsu, R; Kaji, H; Kitamura, S; Ota, O; Ri, Y D; Ferrero, M I; Monaco, V; Sacchi, R; Solano, A; Arneodo, M; Ruspa, M; Fourletov, S; Martin, J F; Boutle, S K; Butterworth, J M; Gwenlan, C; Jones, T W; Loizides, J H; Sutton, M R; Targett-Adams, C; Wing, M; Brzozowska, B; Ciborowski, J; Grzelak, G; Kulinski, P; Luzniak, P; Malka, J; Nowak, R J; Pawlak, J M; Tymieniecka, T; Ukleja, A; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Giller, I; Hochman, D; Karshon, U; Rosin, M; Brownson, E; Danielson, T; Everett, A; Kcira, D; Reeder, D D; Ryan, P; Savin, A A; Smith, W H; Wolfe, H; Bhadra, S; Catterall, C D; Cui, Y; Hartner, G; Menary, S; Noor, U; Standage, J; Whyte, J

    2007-01-01

    The cross section for high-E_T dijet production in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 81.8 pb-1. The events were required to have a virtuality of the incoming photon, Q^2, of less than 1 GeV^2 and a photon-proton centre-of-mass energy in the range 142 20 GeV and E_T(jet2) > 15 GeV and pseudorapidity requirements of -1 < eta(jet1,2) < 3, with at least one of the jets satisfying -1 < eta(jet) < 2.5. The measurements show sensitivity to the parton distributions in the photon and proton and effects beyond next-to-leading order in QCD. Hence these data can be used to constrain further the parton densities in the proton and photon.

  5. Study of Charged Pion Photoproduction on Deuteron with Tagged Photons

    Institute of Scientific and Technical Information of China (English)

    HAN Yun-cheng; N.Chiga; Y.Fujii; K.Futatsukawa; O.Hashimoto; K.Hirose; T.Ishikawa; H.Kanda; M.Kaneta; D.Kawama; Konno; MA Yue; K.Maeda; T.Maruta; N.Maruyama; A.Matsumura; Y.Miyagi; K.Miwa; S.N.Nakamura; A.Sasaki; H.Shimizu; K.Shirotori; K.Suzuki; T.Tamae; H.Tamura; K.Tsukada; WANG Tie-shan; H.Yarnazaki

    2009-01-01

    The reactions γd→π~- pp and γd→npπ~+π~- have been studied in an energy range from 0.8 to 1.1 GeV at the tagged photon facility of Laboratory of Nuclear Science,T ohoku University.Charged pions and protons in the final state were measured by using the Neutral Kaon Spectrometer (NKS2).The analysis of the γd→π~- pp was mainly used to check the acceptance of the NKS2 and to calibrate the tagged photon energy.The photoproduction of the Δ~(++)Δ~- was identified in the γd→npπ~+π~- reaction.Since the data analyses are still in progress,we issue an interim report and preliminary results.

  6. Photoproduction of $\\pi^0$-Mesons on the Nucleon and Deuteron

    CERN Document Server

    Darwish, Eed M; El-Shamy, N T

    2016-01-01

    The photoproduction of $\\pi^0$-mesons from the nucleon and deuteron has been studied for incidents of photon energies up to 1.5 GeV. By using the MAID-2007 model for the process on the nucleon, we predict results for the unpolarized and helicity-dependent total cross sections of the semi-exclusive reaction $\\gamma d\\rightarrow\\pi^0X$ ($X=np+d$) with the inclusion of rescattering effects. We find that rescattering effects yield a substantially large contribution. The extracted results are compared with the available experimental data and a satisfactory agreement is obtained. In addition, the contribution of $\\gamma d\\rightarrow\\pi^0X$ ($X=np+d$) to the finite GDH integral has been evaluated by explicit integration up to 1.5 GeV and a total value of 256.96 $\\mu$b has been obtained. Convergence of the GDH integral has been reached.

  7. Baryon Spectroscopy Through Partial-Wave Analysis and Meson Photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Manley, D. Mark [Kent State Univ., Kent, OH (United States)

    2016-09-08

    The principal goal of this project is the experimental and phenomenological study of baryon spectroscopy. The PI's group consists of himself and three graduate students. This final report summarizes research activities by the PI's group during the period 03/01/2015 to 08/14/2016. During this period, the PI co-authored 11 published journal papers and one proceedings article and presented three invited talks. The PI's general interest is the investigation of the baryon resonance spectrum up to masses of ~ 2 GeV. More detail is given on two research projects: Neutral Kaon Photoproduction and Partial-Wave Analyses of γp → η p, γn → η n, and γp → K⁺ Λ.

  8. Measurement of charm fragmentation fractions in photoproduction at HERA

    International Nuclear Information System (INIS)

    The production of D0, D*+, D+, Ds+ and Λc+ charm hadrons and their antiparticles in ep scattering at HERA has been studied with the ZEUS detector, using a total integrated luminosity of 372 pb-1. The fractions of charm quarks hadronising into a particular charm hadron were derived. In addition, the ratio of neutral to charged D-meson production rates, the fraction of charged D mesons produced in a vector state, and the strangeness-suppression factor have been determined. The measurements have been performed in the photoproduction regime. The charm hadrons were reconstructed in the range of transverse momentum pT > 3.8GeV and pseudorapidity vertical stroke η vertical stroke +e- experiments. The data support the hypothesis that fragmentation is independent of the production process.

  9. Dijet photoproduction at HERA and the structure of the photon

    CERN Document Server

    Abe, T; Adamczyk, L; Adamus, M; Aghuzumtsyan, G; Ahn, S H; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Bashkirov, V; Basile, M; Bauerdick, L A T; Bednarek, B; Behrens, U; Bell, M; Bellagamba, L; Benen, A; Bertolin, A; Bhadra, S; Bodmann, B; Bokel, C; Boogert, S; Boos, E G; Borras, K; Boscherini, D; Breitweg, J; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Cartiglia, N; Catterall, C D; Chapin, D; Chekanov, S; Chiochia, V; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cirio, R; Cloth, P; Coldewey, C; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cormack, C; Corradi, M; Corriveau, F; Costa, M; Crittenden, J; Cross, R; D'Agostini, Giulio; Dagan, S; Dal Corso, F; Danilov, P; Dannheim, D; De Pasquale, S; Dementiev, R K; Derrick, M; Deshpande, Abhay A; Desler, K; Devenish, R C E; Dhawan, S; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Engelen, J; Ermolov, P F; Eskreys, Andrzej; Ferrando, J; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fox-Murphy, A; Fricke, U; Fusayasu, T; Gabareen, A; Galea, R; Gallo, E; García, G; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Gilmore, J; Ginsburg, C M; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Göbel, F; Goers, S; Golubkov, Yu A; Goncalo, R; González, O; Göttlicher, P; Grabowska-Bold, I; Graciani, R; Grijpink, S; Grzelak, G; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hanlon, S; Hart, J C; Hartmann, H; Hartner, G F; Hayes, M E; Heaphy, E A; Heath, G P; Heath, H F; Helbich, M; Heusch, C A; Hilger, E; Hillert, S; Hirose, T; Hochman, D; Holm, U; Hughes, V W; Iacobucci, G; Iga, Y; Inuzuka, M; Irrgang, P; Jakob, H P; Jelen, K; Jeoung, H Y; Jones, T W; Kananov, S; Kappes, A; Karshon, U; Katkov, I I; Katz, U F; Kcira, D; Kerger, R; Khein, L A; Kim, C L; Kim, J Y; Kind, O; Kisielewska, D; Kitamura, S; Klimek, K; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korotkova, N A; Korzhavina, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowal, M; Kowalski, H; Kowalski, T; Krakauer, D; Kreisel, A; Kuze, M; Kuzmin, V A; Labarga, L; Labes, H; Lammers, S; Lane, J B; Lee, J H; Lee, S B; Lee, S W; Lelas, D; Levchenko, B B; Levi, G; Levman, G M; Levy, A; Lightwood, M S; Lim, H; Lim, I T; Limentani, S; Ling, T Y; Liu, X; Löhr, B; Lohrmann, E; Long, K R; Longhin, A; Lopez-Duran Viani, A; Lukina, O Yu; Lupi, A; Ma, K J; Maddox, E; Magill, S; Mankel, R; Margotti, A; Marini, G; Markun, P; Martens, J; Martin, J F; Martínez, M; Maselli, S; Massam, Thomas; Mastroberardino, A; Matsushita, T; Matsuzawa, K; Mattingly, M C K; McCubbin, N A; Mellado, B; Menary, S R; Metlica, F; Meyer, A; Milite, M; Miller, D B; Mindur, B; Mirea, A; Monaco, V; Moritz, M; Musgrave, B; Nagano, K; Nania, R; Nigro, A; Nishimura, T; Notz, D; Nowak, R J; Ochs, A; Oh, B Y; Olkiewicz, K; Pac, M Y; Padhi, S; Paganis, S; Palmonari, F; Parenti, A; Park, I H; Park, S K; Paul, E; Pavel, N; Pawlak, J M; Pelfer, P G; Pellegrino, A; Peroni, C; Pesci, A; Petrucci, M C; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Posocco, M; Proskuryakov, A S; Przybycien, M B; Raach, H; Rautenberg, J; Redondo, I; Reeder, D D; Renner, R; Repond, J; Rigby, M; Robins, S; Rodrigues, E; Rulikowska-Zarebska, E; Ruske, O; Ruspa, M; Sabetfakhri, A; Sacchi, R; Salehi, H; Sar, G; Saull, P R B; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schmidke, W B; Schneekloth, U; Schnurbusch, H; Sciulli, F; Scott, J; Selonke, F; Shche-, L M; Skillicorn, I O; Slominski, W; Smalska, B; Smith, W H; Soares, M; Solano, A; Solomin, A N; Son, D; Sosnovtsev, V V; Saint-Laurent, M G; Staiano, A; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Straub, P B; Suchkov, S; Surrow, B; Susinno, G; Suszycki, L; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tandler, J; Tapper, A D; Tapper, R J; Tassi, E; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Tuning, N; Turcato, M; Tymieniecka, T; Ukleja, A; Ukleja, J; Umemori, K; Vázquez, M; Velthuis, J J; Vlasov, N N; Voss, K C; Walczak, R; Walker, R; Weber, A; Wessoleck, H; West, B J; Whitmore, J J; Wichmann, R; Wick, K; Wiggers, L; Wills, H H; Wing, M; Wolf, G; Wölfle, S; Yamada, S; Yamashita, T; Yamazaki, Y; Yoshida, R; Youngman, C; Za, L; Zakrzewski, J A; Zeuner, W; Zhautykov, B O; Zichichi, A; Ziegler, A; Zotkin, S A; De Wolf, E; Del Peso, J

    2002-01-01

    The dijet cross section in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 38.6 pb$^{-1}$. The events were required to have a virtuality of the incoming photon, $Q^2$, of less than 1 GeV$^2$ and a photon-proton centre-of-mass energy in the range $134 14$ GeV and $E_{T}^{\\rm jet2}>11$ GeV and pseudorapidity requirements of $-1<\\eta^{\\rm jet1,2}<2.4$. The measurements are compared to next-to-leading-order QCD predictions. The data show particular sensitivity to the density of partons in the photon, allowing the validity of the current parameterisations to be tested.

  10. Diffractive photoproduction of dijets in ep collisions at HERA

    International Nuclear Information System (INIS)

    Diffractive photoproduction of dijets was measured with the ZEUS detector at the ep collider HERA using an integrated luminosity of 77.2 pb-1. The measurements were made in the kinematic range Q22, 0.20P2 is the photon virtuality, y is the inelasticity and xP is the fraction of the proton momentum taken by the diffractive exchange. The two jets with the highest transverse energy, EjetT, were required to satisfy EjetT>7.5 and 6.5 GeV, respectively, and to lie in the pseudorapidity range -1.5jet<1.5. Differential cross sections were compared to perturbative QCD calculations using available parameterisations of diffractive parton distributions of the proton. (orig.)

  11. Photoproduction of $\\eta$s and N$*$(1535) electrostrong properties

    CERN Document Server

    Mukhopadhyay, N C; Benmerrouche, M; Mukhopadhyay, Nimai C

    1995-01-01

    From the new Mainz data of eta photoproduction off protons\\cite{ref1} and deuterons\\cite{ref2}, we can extract, via the effective Lagrangian approach (ELA)\\cite{ref3}, the electrostrong parameters \\xi_{p} and \\xi_{n} for the N^*(1535) excitation. These parameters are, in units of 10^{-4} MeV^{-1}, (2.20\\pm 0.15) and (-1.86\\pm 0.20) respectively. They yield the ratio of the helicity amplitudes for the excitation of N^*(1535) by photons off neutrons and protons to be A^{n}_{1/2}/A^{p}_{1/2}=-0.84\\pm 0.15, a quantity of fundamental importance in the baryon structure. Best estimates in the quark model are close to this ratio.

  12. Measurement of Prompt Photon Cross Sections in Photoproduction at HERA

    CERN Document Server

    Andreev, V; Asmone, A; Babaev, A; Backovic, S; Bähr, J; Baranov, P; Barrelet, E; Bartel, Wulfrin; Baumgartner, S; Becker, J; Beckingham, M; Behnke, O; Behrendt, O; Belousov, A; Berger, C; Berger, N; Berndt, T; Bizot, J C; Böhme, J; Boenig, M O; Boudry, V; Bracinik, J; Brisson, V; Broker, H B; Brown, D P; Bruncko, Dusan; Büsser, F W; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Caron, S; Cassol-Brunner, F; Cerny, K; Chekelian, V; Collard, Caroline; Contreras, J G; Coppens, Y R; Coughlan, J A; Cox, B E; Cozzika, G; Cvach, J; Dainton, J B; Dau, W D; Daum, K; Delcourt, B; Demirchyan, R; de Roeck, A; Desch, Klaus; De Wolf, E A; Diaconu, C; Dingfelder, J; Dodonov, V; Dubak, A; Duprel, C; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, F; Ellerbrock, M; Elsen, E; Erdmann, M; Erdmann, W; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Ferencei, J; Fleischer, M; Fleischmann, P; Fleming, Y H; Flucke, G; Flügge, G; Fomenko, A; Foresti, I; Formánek, J; Franke, G; Frising, G; Gabathuler, Erwin; Gabathuler, K; Garutti, E; Garvey, J; Gayler, J; Gerhards, R; Gerlich, C; Ghazaryan, S; Görlich, L; Gogitidze, N; Gorbounov, S; Grab, C; Grässler, Herbert; Greenshaw, T; Gregori, M; Grindhammer, G; Gwilliam, C; Haidt, D; Hajduk, L; Haller, J; Hansson, M; Heinzelmann, G; Henderson, R C W; Henschel, H; Henshaw, O; Heremans, R; Herrera-Corral, G; Herynek, I; Heuer, R D; Hildebrandt, M; Hiller, K H; Hladky, J; Hoting, P; Hoffmann, D; Horisberger, R P; Hovhannisyan, A; Ibbotson, M; Ismail, M; Jacquet, M; Janauschek, L; Janssen, X; Jemanov, V; Jönsson, L B; Johnson, D P; Jung, H; Kant, D; Kapichine, M; Karlsson, M; Katzy, J; Keller, N; Kennedy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Kluge, T; Knies, G; Knutsson, A; Koblitz, B; Korbel, V; Kostka, P; Koutouev, R; Kropivnitskaya, A; Kroseberg, J; Kuckens, J; Kuhr, T; Landon, M P J; Lange, W; Lastoviicka, T; Laycock, P; Lebedev, A; Leiner, B; Lemrani, R; Lendermann, V; Levonian, S; Lindfeld, L; Lipka, K; List, B; Lobodzinska, E; Loktionova, N A; López-Fernandez, R; Lubimov, V; Lüders, H; Lüke, D; Lux, T; Lytkin, L; Makankine, A; Malden, N; Malinovskii, E I; Mangano, S; Marage, P; Marks, J; Marshall, R; Martisikova, M; Martyn, H U; Maxfield, S J; Meer, D; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, J; Michine, S; Mikocki, S; Milcewicz-Mika, I; Milstead, D; Mohamed, A; Moreau, F; Morozov, A; Morozov, I; Morris, J V; Mozer, M U; Müller, K; Murn, P; Nagovizin, V; Naroska, Beate; Naumann, J; Naumann, T; Newman, P R; Niebuhr, C B; Nikiforov, A; Nikitin, D K; Nowak, G; Nozicka, M; Oganezov, R; Olivier, B; Olsson, J E; Ossoskov, G; Ozerov, D; Pascaud, C; Patel, G D; Peez, M; Pérez, E; Perieanu, A; Petrukhin, A; Pitzl, D; Placakyte, R; Pöschl, R; Portheault, B; Povh, B; Raicevic, N; Ratiani, Z; Reimer, P; Reisert, B; Rimmer, A; Risler, C; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A A; Rurikova, Z; Rusakov, S V; Rybicki, K; Sankey, D P C; Sauvan, E; Schatzel, S; Scheins, J; Schilling, F P; Schleper, P; Schmidt, S; Schmitt, S; Schneider, M; Schoeffel, L; Schöning, A; Schröder, V; Schultz-Coulon, H C; Schwanenberger, C; Sedlak, K; Sefkow, F; Shevyakov, I; Shtarkov, L N; Sirois, Y; Sloan, T; Smirnov, P; Soloviev, Yu; South, D; Spaskov, V; Specka, A; Spitzer, H; Stamen, R; Stella, B; Stiewe, J; Strauch, I; Straumann, U; Tchoulakov, V; Thompson, G; Thompson, P D; Tomasz, F; Traynor, D; Truöl, P; Tsipolitis, G; Tsurin, I; Turnau, J; Tzamariudaki, E; Uraev, A; Urban, M; Usik, A; Utkin, D; Valkár, S; Vallée, C; Van Mechelen, P; Vargas-Trevino, A; Vazdik, Ya A; Veelken, C; Vest, A; Vinokurova, S; Volchinski, V; Wacker, K; Wagner, J; Weber, G; Weber, R; Wegener, D; Werner, C; Werner, N; Wessels, M; Wessling, B; Winter, G G; Wissing, C; Woerling, E E; Wolf, R; Wünsch, E; Xella, S M; Yan, W; Zaicek, J; Zaleisak, J; Zhang, Z; Zhokin, A; Zohrabyan, H G; Zomer, F

    2004-01-01

    Results are presented on the photoproduction of isolated prompt photons, inclusively and associated with jets, in the gamma p center of mass energy range 142 4.5 GeV. They are measured differentially as a function of E_T^gamma, E_T^jet, the pseudorapidities eta^gamma and eta^jet and estimators of the momentum fractions x_gamma and x_p of the incident photon and proton carried by the constituents participating in the hard process. In order to further investigate the underlying dynamics, the angular correlation between the prompt photon and the jet in the transverse plane is studied. Predictions by perturbative QCD calculations in next to leading order are about 30% below the inclusive prompt photon data after corrections for hadronisation and multiple interactions, but are in reasonable agreement with the results for prompt photons associated with jets. Comparisons with the predictions of the event generators PYTHIA and HERWIG are also presented.

  13. Dijets in diffractive photoproduction measured with the ZEUS experiment

    International Nuclear Information System (INIS)

    The diffractive photoproduction of dijets in electron-proton scattering has been studied using 77.1 pb-1 of data taken with the ZEUS detector at HERA. The measurements have been made at a centre-of- mass energy √s=318 GeV in the kinematic range 0.2PP is the fraction of the proton momentum taken by the diffractive exchange. The jets have been reconstructed using the kT algorithm. The two jets with the highest transversal energy have been required to satisfy ET>7.5 and 6.5 GeV, respectively, and to be in the pseudorapidity range -1.5<η<1.5. Differential cross sections have been measured and been confronted with the predictions from leading order Monte Carlo simulations and next-to-leading order QCD calculations. (orig.)

  14. A compact process for the treatment of olive mill wastewater by combining wet hydrogen peroxide catalytic oxidation and biological techniques

    Energy Technology Data Exchange (ETDEWEB)

    Azabou, Samia [Laboratoire des BioProcedes, Centre de Biotechnologie de Sfax, BP 1177, 3018 Sfax (Tunisia); Najjar, Wahiba [Laboratoire de Chimie des Materiaux et Catalyse, Faculte des Sciences de Tunis, Campus Universitaire, 2092 Tunis (Tunisia); Bouaziz, Mohamed [Laboratoire des BioProcedes, Centre de Biotechnologie de Sfax, BP 1177, 3018 Sfax (Tunisia); Ghorbel, Abdelhamid [Laboratoire de Chimie des Materiaux et Catalyse, Faculte des Sciences de Tunis, Campus Universitaire, 2092 Tunis (Tunisia); Sayadi, Sami, E-mail: sami.sayadi@cbs.rnrt.tn [Laboratoire des BioProcedes, Centre de Biotechnologie de Sfax, BP 1177, 3018 Sfax (Tunisia)

    2010-11-15

    A system based on combined actions of catalytic wet oxidation and microbial technologies for the treatment of highly polluted OMW containing polyphenols was studied. The wet hydrogen peroxide catalytic oxidation (WHPCO) process has been investigated in the semi-batch mode at atmospheric pressure, using aluminium-iron-pillared inter layer clay ((Al-Fe)PILC), under two different catalytic processes: ((Al-Fe)PILC/H{sub 2}O{sub 2}/ultraviolet radiations) at 25 deg. C and ((Al-Fe)PILC/H{sub 2}O{sub 2}) at 50 deg. C. The results show that raw OMW was resistant to the photocatalytic process. However ((Al-Fe)PILC/H{sub 2}O{sub 2}), system operating at 50 deg. C reduced considerably the COD, colour and total phenolic contents, and thus decreased the inhibition of the marine photobacteria Vibrio fischeri luminescence by 70%. This study also examined the feasibility of coupling WHPCO and anaerobic digestion treatment. Biomethanisation experiments performed with raw OMW or pre-treated OMW proved that pre-treatments with ((Al-Fe)PILC/H{sub 2}O{sub 2}) system, for more than 2 h, resulted in higher methane production. Both untreated OMW as well as 2-h pre-treated OMW revealed as toxic to anaerobic bacteria.

  15. A compact process for the treatment of olive mill wastewater by combining wet hydrogen peroxide catalytic oxidation and biological techniques

    International Nuclear Information System (INIS)

    A system based on combined actions of catalytic wet oxidation and microbial technologies for the treatment of highly polluted OMW containing polyphenols was studied. The wet hydrogen peroxide catalytic oxidation (WHPCO) process has been investigated in the semi-batch mode at atmospheric pressure, using aluminium-iron-pillared inter layer clay ((Al-Fe)PILC), under two different catalytic processes: ((Al-Fe)PILC/H2O2/ultraviolet radiations) at 25 deg. C and ((Al-Fe)PILC/H2O2) at 50 deg. C. The results show that raw OMW was resistant to the photocatalytic process. However ((Al-Fe)PILC/H2O2), system operating at 50 deg. C reduced considerably the COD, colour and total phenolic contents, and thus decreased the inhibition of the marine photobacteria Vibrio fischeri luminescence by 70%. This study also examined the feasibility of coupling WHPCO and anaerobic digestion treatment. Biomethanisation experiments performed with raw OMW or pre-treated OMW proved that pre-treatments with ((Al-Fe)PILC/H2O2) system, for more than 2 h, resulted in higher methane production. Both untreated OMW as well as 2-h pre-treated OMW revealed as toxic to anaerobic bacteria.

  16. Diffractive Higgs boson photoproduction in Ultraperipheral Collisions at LHC

    CERN Document Server

    Ducati, M B Gay

    2010-01-01

    A new production mechanism for the Standard Model Higgs boson in Ultraperipheral Collisions at LHC, which allows Central Exclusive Diffractive production by Double Pomeron Exchange in photon-proton processes, is presented. The Higgs boson is centrally produced by gluon fusion with two Large Rapidity Gaps emerging in the final state, being the main experimental signature for this process. As already studied for Pomeron-Pomeron and two-photon processes, the Higgs boson photoproduction is studied within this new mechanism in proton-proton ($pp$) and proton-nucleus ($pA$) collisions, where each system has a different dynamics to be taken into account. As a result, this mechanism predicts a production cross section for $pp$ collisions of about 1.8 fb, which is similar to that obtained in Pomeron-Pomeron processes. Besides, in $pPb$ collisions the cross sections have increased to about 0.6 pb, being comparable with the results of two-photon processes in $pAu$ collisions. Therefore, as the Rapidity Gap Survival Prob...

  17. Diffractive photoproduction of dijets in ep collisions at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

    2007-09-15

    Diffractive photoproduction of dijets was measured with the ZEUS detector at the ep collider HERA using an integrated luminosity of 77.2 pb{sup -1}. The measurements were made in the kinematic range Q{sup 2}<1 GeV{sup 2}, 0.207.5 and 6.5 GeV, respectively, and to lie in the pseudorapidity range -1.5<{eta}{sup jet}<1.5. Differential cross sections were compared to perturbative QCD calculations using available parameterisations of diffractive parton distributions of the proton. (orig.)

  18. Exclusive photoproduction of J/psi mesons at HERA

    CERN Document Server

    Chekanov, S; Abramowicz, H; Adamczyk, L; Adamus, M; Aghuzumtsyan, G; Ahn, S H; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Bashkirov, V; Basile, M; Bauerdick, L A T; Bednarek, B; Behrens, U; Bell, M; Bellagamba, L; Benen, A; Bertolin, A; Bhadra, S; Bodmann, B; Bokel, C; Boogert, S; Boos, E G; Borras, K; Boscherini, D; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Cartiglia, N; Catterall, C D; Chiochia, V; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cirio, R; Cloth, P; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cormack, C; Corradi, M; Corriveau, F; Costa, M; Crittenden, J; D'Agostini, Giulio; Dagan, S; Dal Corso, F; Danilov, P; Dannheim, D; De Pasquale, S; Dementiev, R K; Derrick, M; Deshpande, Abhay A; Desler, K; Devenish, R C E; Dhawan, S; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Engelen, J; Ermolov, P F; Eskreys, Andrzej; Ferrando, J; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fox-Murphy, A; Fricke, U; Fusayasu, T; Gabareen, A; Galea, R; Gallo, E; García, G; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Gilmore, J; Ginsburg, C M; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Göbel, F; Goers, S; Golubkov, Yu A; Goncalo, R; González, O; Göttlicher, P; Grabowska-Bold, I; Graciani, R; Grijpink, S; Grzelak, G; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hanlon, S; Hart, J C; Hartmann, H; Hartner, G F; Heaphy, E A; Heath, G P; Heath, H F; Helbich, M; Heusch, C A; Hilger, E; Hillert, S; Hirose, T; Hochman, D; Holm, U; Hughes, V W; Iacobucci, G; Iga, Y; Inuzuka, M; Irrgang, P; Jakob, H P; Jelen, K; Jones, T W; Kananov, S; Kappes, A; Karshon, U; Katkov, I I; Katz, U F; Kcira, D; Kerger, R; Khein, L A; Kim, C L; Kim, J Y; Kim, Y K; Kind, O; Kisielewska, D; Kitamura, S; Klimek, K; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korotkova, N A; Korzhavina, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowal, M; Kowalski, H; Kowalski, T; Krakauer, D A; Kreisel, A; Kuze, M; Kuzmin, V A; Labarga, L; Labes, H; Lammers, S; Lane, J B; Lee, J H; Lee, S B; Lee, S W; Lelas, D; Levchenko, B B; Levi, G; Levman, G M; Levy, A; Lightwood, M S; Lim, H; Lim, I T; Limentani, S; Ling, T Y; Liu, X; Löhr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lopez-Duran Viani, A; Lukina, O Yu; Lupi, A; Maddox, E; Magill, S; Mankel, R; Margotti, A; Marini, G; Markun, P; Martin, J F; Martínez, M; Maselli, S; Massam, Thomas; Mastroberardino, A; Matsushita, T; Matsuzawa, K; Mattingly, M C K; McCubbin, N A; Mellado, B; Menary, S R; Metlica, F; Meyer, A; Milite, M; Miller, D B; Mindur, B; Mirea, A; Monaco, V; Moritz, M; Musgrave, B; Nagano, K; Nania, R; Nigro, A; Nishimura, T; Notz, D; Nowak, R J; Ochs, A; Oh, B Y; Olkiewicz, K; Pac, M Y; Padhi, S; Paganis, S; Palmonari, F; Parenti, A; Park, I H; Park, S K; Paul, E; Pavel, N; Pawlak, J M; Pelfer, P G; Pellegrino, A; Peroni, C; Pesci, A; Petrucci, M C; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Posocco, M; Proskuryakov, A S; Przybycien, M B; Raach, H; Rautenberg, J; Redondo, I; Reeder, D D; Renner, R; Repond, J; Rigby, M; Robins, S; Rodrigues, E; Rulikowska-Zarebska, E; Ruske, O; Ruspa, M; Sabetfakhri, A; Sacchi, R; Salehi, H; Sar, G; Saull, P R B; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schmidke, W B; Schneekloth, U; Schnurbusch, H; Sciulli, F; Scott, J; Selonke, F; Shche, L M; Skillicorn, I O; Slominski, W; Smalska, B; Smith, W H; Soares, M; Solano, A; Solomin, A N; Son, D; Sosnovtsev, V V; Saint-Laurent, M G; Staiano, A; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Straub, P B; Suchkov, S; Surrow, B; Susinno, G; Suszycki, L; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tandler, J; Tapper, A D; Tapper, R J; Tassi, E; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Tuning, N; Turcato, M; Tymieniecka, T; Ukleja, A; Ukleja, J; Umemori, K; Vázquez, M; Velthuis, J J; Vlasov, N N; Voss, K C; Walczak, R; Walker, R; Weber, A; Wessoleck, H; West, B J; Whitmore, J J; Wichmann, R; Wick, K; Wiggers, L; Wing, M; Wolf, G; Wölfle, S; Yamada, S; Yamashita, T; Yamazaki, Y; Yoshida, R; Youngman, C; Za, L; Zakrzewski, J A; Zeuner, W; Zhautykov, B O; Zichichi, A; Ziegler, A; Zotkin, S A; De Wolf, E; Del Peso, J

    2002-01-01

    The exclusive photoproduction of J/psi mesons, gamma p->J/psi p, has been studied in ep collisions with the ZEUS detector at HERA, in the kinematic range 20

  19. Measurement of open beauty production in photoproduction at HERA

    CERN Document Server

    Breitweg, J; Derrick, Malcolm; Krakauer, D A; Magill, S; Musgrave, B; Pellegrino, A; Repond, J; Stanek, R; Yoshida, R; Mattingly, M C K; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Boscherini, D; Bruni, A; Bruni, G; Cara Romeo, G; Cifarelli, Luisa; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Giusti, P; Iacobucci, G; Levi, G; Margotti, A; Massam, Thomas; Nania, R; Palmonari, F; Pesci, A; Sartorelli, G; Zichichi, A; Aghuzumtsyan, G; Amelung, C; Brock, I; Coboken, K; Goers, S; Hartmann, H; Heinloth, K; Hilger, E; Irrgang, P; Jakob, H P; Kappes, A; Katz, U F; Kerger, R; Kind, O; Paul, E; Rautenberg, J; Schnurbusch, H; Stifutkin, A; Tandler, J; Voss, K C; Weber, A; Wieber, H; Bailey, D S; Barret, O; Brook, N H; Cole, J E; Foster, B; Heath, G P; Heath, H F; Robins, S A; Rodrigues, E; Scott, J; Tapper, R J; Capua, M; Mastroberardino, A; Schioppa, M; Susinno, G; Jeoung, H Y; Kim, J Y; Lee, J H; Lim, I T; Ma, K J; Pac, M Y; Caldwell, A; Liu, W; Liu, X; Mellado, B; Paganis, S; Sampson, S; Schmidke, W B; Sciulli, F; Chwastowski, J; Eskreys, Andrzej; Figiel, J; Klimek, K H; Olkiewicz, K; Piotrzkowski, K; Przybycien, M B; Stopa, P; Zawiejski, L; Bednarek, B; Jelen, K; Kisielewska, D; Kowal, A M; Kowalski, T; Rulikowska-Zarebska, E; Suszycki, L; Szuba, D; Bauerdick, L A T; Behrens, U; Bienlein, J K; Borras, K; Chiochia, V; Crittenden, James Arthur; Dannheim, D; Desler, K; Drews, G; Fox-Murphy, A; Fricke, U; Göbel, F; Göttlicher, P; Graciani, R; Haas, T; Hain, W; Hartner, G F; Hebbel, K; Hillert, S; Koch, W; Kötz, U; Kowalski, H; Labes, H; Löhr, B; Mankel, R; Martens, J; Martínez, M; Milite, M; Moritz, M; Notz, D; Petrucci, M C; Polini, A; Rohde, M; Savin, A A; Schneekloth, U; Selonke, F; Sievers, M; Stonjek, S; Wolf, G; Wollmer, U; Youngman, C; Zeuner, W; Coldewey, C; López-Duran-Viani, A; Meyer, A; Schlenstedt, S; Straub, P B; Barbagli, G; Gallo, E; Parenti, A; Pelfer, P G; Bamberger, Andreas; Benen, A; Coppola, N; Eisenhardt, S; Markun, P; Raach, H; Wölfle, S; Bussey, Peter J; Bell, M; Doyle, A T; Glasman, C; Lee, S W; Lupi, A; MacDonald, N; McCance, G J; Saxon, D H; Sinclair, L E; Skillicorn, Ian O; Waugh, R; Bodmann, B; Gendner, N; Holm, U; Salehi, H; Wick, K; Yildirim, A; Carli, T; Garfagnini, A; Geiser, A; Gialas, I; Kcira, D; Klanner, Robert; Lohrmann, E; Goncalo, R; Long, K R; Miller, D B; Tapper, A D; Walker, R; Cloth, P; Filges, D; Ishii, T; Kuze, M; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Boos, E G; Pokrovskiy, N S; Zhautykov, B O; Barakbaev, A N; Ahn, S H; Lee, S B; Park, S K; Lim, H; Son, D; Barreiro, F; García, G; González, O; Labarga, L; Del Peso, J; Redondo, I; Terron, J; Vázquez, M E; Barbi, M S; Corriveau, F; Padhi, S; Stairs, D G; Wing, M; Tsurugai, T; Antonov, A; Bashkirov, V; Danilov, M V; Dolgoshein, B A; Gladkov, D; Sosnovtsev, V V; Suchkov, S; Dementiev, R K; Ermolov, P F; Golubkov, Yu A; Katkov, I I; Khein, L A; Korotkova, N A; Korzhavina, I A; Kuzmin, V A; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Solomin, A N; Vlasov, N N; Zotkin, S A; Bokel, C; Botje, M; Brümmer, N; Engelen, J; Grijpink, S; Koffeman, E; Kooijman, P M; Schagen, S; Van Sighem, A; Tassi, E; Tiecke, H G; Tuning, N; Velthuis, J J; Vossebeld, Joost Herman; Wiggers, L; De Wolf, E; Bylsma, B; Durkin, L S; Gilmore, J; Ginsburg, C M; Kim, C L; Ling, T Y; Boogert, S; Cooper-Sarkar, A M; Devenish, R C E; Grosse-Knetter, J; Matsushita, T; Ruske, O; Sutton, M R; Walczak, R; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; Dusini, S; Limentani, S; Longhin, A; Posocco, M; Stanco, L; Turcato, M; Adamczyk, L; Iannotti, L; Oh, B Y; Okrasinski, J R; Saull, P R B; Toothacker, W S; Whitmore, J J; Iga, Y; D'Agostini, Giulio; Marini, G; Nigro, A; Cormack, C; Hart, J C; McCubbin, N A; Shah, T P; Epperson, D E; Heusch, C A; Sadrozinski, H F W; Seiden, A; Wichmann, R; Williams, D C; Park, I H; Pavel, N; Abramowicz, H; Dagan, S; Gabareen, A; Kananov, S; Kreisel, A; Levy, A; Abe, T; Fusayasu, T; Kohno, T; Umemori, K; Yamashita, T; Hamatsu, R; Hirose, T; Inuzuka, M; Kitamura, S; Matsuzawa, K; Nishimura, T; Arneodo, M; Cartiglia, N; Cirio, R; Costa, M; Ferrero, M I; Maselli, S; Monaco, V; Peroni, C; Ruspa, M; Sacchi, R; Solano, A; Staiano, A; Bailey, D C; Fagerstroem, C P; Galea, R; Koop, T; Levman, G M; Martin, J F; Mirea, A; Sabetfakhri, A; Butterworth, J M; Gwenlan, C; Hayes, M E; Heaphy, E A; Jones, T W; Lane, J B; West, B J; Ciborowski, J; Ciesielski, R; Grzelak, G; Nowak, R J; Pawlak, J M; Pawlak, R; Smalska, B; Tymieniecka, T; Wróblewski, A K; Zakrzewski, J A

    2001-01-01

    The production and semi-leptonic decay of heavy quarks have been studied in the photoproduction process $e^+p -> e^+ + {dijet} + e^- + X with the ZEUS detector at HERA using an integrated luminosity of 38.5 ${\\rm pb^{-1}}$. Events with photon-proton centre-of-mass energies, $W_{\\gamma p}$, between 134 and 269 GeV and a photon virtuality, Q^2, less than 1 ${\\rm GeV^2}$ were selected requiring at least two jets of transverse energy $E_T^{\\rm jet1(2)} >7(6)$ GeV and an electron in the final state. The electrons were identified by employing the ionisation energy loss measurement. The contribution of beauty quarks was determined using the transverse momentum of the electron relative to the axis of the closest jet, $p_T^{\\rm rel}$. The data, after background subtraction, were fit with a Monte Carlo simulation including beauty and charm decays. The measured beauty cross section was extrapolated to the parton level with the b quark restricted to the region of transverse momentum $p_T^{b} > p_T^{\\rm min} =$ 5 GeV and ...

  20. The light vector meson photoproduction at large t

    CERN Document Server

    Ivanov, D Yu; Schäfer, A; Szymanowski, L

    2000-01-01

    We have studied in perturbative QCD all independent helicity amplitudes describing the photoproduction of light vector mesons at large $t$. We found a new hard production mechanism which is related to the possibility for a real photon to fluctuate into a massless $q\\bar q$ pair in a chiral-odd spin configuration. Each helicity amplitude is given as a sum of a usual chiral-even contribution (when the helicities of quark and antiquark are antiparallel) and this additional chiral-odd part (where the helicities of quark and antiquark are parallel). The chiral-odd contribution is large, it leads to a dominance of the non spin-flip amplitude in a very broad region of intermediately high $|t|$. All amplitudes are expressed in terms of short distance asymptotics of the light-cone wave functions of vector meson (photon). We demonstrate that for each helicity amplitude there exists a soft non-factorizable contribution. We give arguments that for dominant non spin-flip helicity amplitude the relative contribution of the...

  1. Diffractive dijet photoproduction in ep collisions at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)

    2010-03-15

    Measurements are presented of single and double-differential dijet cross sections in diffractive photoproduction based on a data sample with an integrated luminosity of 47 pb{sup -1}. The events are of the type ep{yields}eXY, where the hadronic system X contains at least two jets and is separated by a large rapidity gap from the system Y, which consists of a leading proton or low-mass proton excitation. The dijet cross sections are compared with QCD calculations at next-to-leading order and with a Monte Carlo model based on leading order matrix elements with parton showers. The measured cross sections are smaller than those obtained from the next-to-leading order calculations by a factor of about 0.6. This suppression factor has no significant dependence on the fraction x{sub {gamma}} of the photon four-momentum entering the hard subprocess. Ratios of the diffractive to the inclusive dijet cross sections are measured for the first time and are compared with Monte Carlo models. (orig.)

  2. Measurement of charm fragmentation fractions in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max-Planck-Institute for Physics, Munich (Germany); Abt, I. [Max-Planck-Institute for Physics, Muinch (Germany); Adamczyk, L. [AGH-Univ. of Science and Technology, Krakow (Poland). Faculty of Physics and Applied Computer Science] [and others; Collaboration: ZEUS Collaboration

    2013-06-15

    The production of D{sup 0}, D{sup *+}, D{sup +}, D{sub s}{sup +} and {Lambda}{sub c}{sup +} charm hadrons and their antiparticles in ep scattering at HERA has been studied with the ZEUS detector, using a total integrated luminosity of 372 pb{sup -1}. The fractions of charm quarks hadronising into a particular charm hadron were derived. In addition, the ratio of neutral to charged D-meson production rates, the fraction of charged D mesons produced in a vector state, and the strangeness-suppression factor have been determined. The measurements have been performed in the photoproduction regime. The charm hadrons were reconstructed in the range of transverse momentum p{sub T} > 3.8GeV and pseudorapidity vertical stroke {eta} vertical stroke <1.6. The charm fragmentation fractions are compared to previous results from HERA and from e{sup +}e{sup -} experiments. The data support the hypothesis that fragmentation is independent of the production process.

  3. Photoproduction ofeta-pi pairs off nucleons and deuterons

    CERN Document Server

    Kaeser, A; Ahrens, J; Annand, J R M; Arends, H J; Bantawa, K; Bartolome, P A; Beck, R; Braghieri, A; Briscoe, W J; Cherepnya, S; Costanza, S; Dieterle, M; Downie, E J; Drexler, P; Fil'kov, L V; Fix, A; Garni, S; Glazier, D I; Hamilton, D; Hornidge, D; Howdle, D; Huber, G M; Jaegle, I; Jude, T C; Kashevarov, V L; Keshelashvili, I; Kondratiev, R; Korolija, M; Krusche, B; Lisin, V; Livingston, K; MacGregor, I J D; Maghrbi, Y; Mancell, J; Manley, D M; Marinides, Z; McGeorge, J C; McNicoll, E; Mekterovic, D; Metag, V; Micanovic, S; Middleton, D G; Mushkarenkov, A; Nikolaev, A; Novotny, R; Oberle, M; Ostrick, M; Otte, P; Oussena, B; Pedroni, P; Pheron, F; Polonski, A; Prakhov, S; Robinson, J; Rostomyan, T; Schumann, S; Sikora, M H; Sober, D; Starostin, A; Strub, Th; Supek, I; Thiel, M; Thomas, A; Unverzagt, M; Walford, N K; Watts, D P; Werthmueller, D; Witthauer, L

    2016-01-01

    Quasi-free photoproduction of $\\pi\\eta$-pairs has been investigated from threshold up to incident photon energies of 1.4 GeV, respectively up to photon-nucleon invariant masses up to 1.9 GeV. Total cross sections, angular distributions, invariant-mass distributions of the $\\pi\\eta$ and meson-nucleon pairs, and beam-helicity asymmetries have been measured for the reactions $\\gamma p\\rightarrow p\\pi^0\\eta$, $\\gamma n\\rightarrow n\\pi^0\\eta$, $\\gamma p\\rightarrow n\\pi^+\\eta$, and $\\gamma n\\rightarrow p\\pi^-\\eta$ from nucleons bound inside the deuteron. For the $\\gamma p$ initial state data for free protons have also been analyzed. Finally, the total cross sections for quasi-free production of $\\pi^0\\eta$ pairs from nucleons bound in $^3$He nuclei have been investigated in view of final state interaction (FSI) effects. The experiments were performed at the tagged photon beam facility of the Mainz MAMI accelerator using an almost $4\\pi$ covering electromagnetic calorimeter composed of the Crystal Ball and TAPS dete...

  4. Near-threshold $J/\\psi$ photoproduction off nuclei

    CERN Document Server

    Paryev, E Ya

    2015-01-01

    We study the $J/\\psi$ photoproduction from nuclei near the kinematic threshold within the first collision model, based on the nuclear spectral function, for incoherent primary photon--nucleon charmonium creation processes. The model takes into account the final $J/\\psi$ absorption, target nucleon binding and Fermi motion, the formation length of $J/\\psi$ mesons as well as the effect of their nuclear mean-field potential on these processes. We calculate the A dependences of the absolute and relative (transparency ratio) charmonium yields as well as its absolute and relative excitation functions within the different scenarios for the $J/\\psi N$ absorption cross section, for the $J/\\psi$ formation length and for $J/\\psi$ in-medium modification. We demonstrate that the studied observables, on the one hand, are not practically affected by the charmonium formation length and mass shift effects and, on the other hand, they are appreciably sensitive to the genuine $J/\\psi N$ absorption cross section at above threshol...

  5. Photoproduction of K\\Lambda on the proton

    CERN Document Server

    Skoupil, Dalibor

    2016-01-01

    Kaon photoproduction on the proton is studied in the resonance region using an isobar model. The higher-spin nucleon (3/2 and 5/2) and hyperon (3/2) resonances were included in the model utilizing the consistent formalism by Pascalutsa and they were found to play an important role in data description. The spin-1/2 and spin-3/2 hyperon resonances in combination with the Born terms contribute significantly to the background part of the amplitude. Various forms of the hadron form factor were considered in the construction and the dipole and multidipole forms were selected as those most suitable for the data description. Model parameters were fitted to new experimental data from CLAS, LEPS, and GRAAL collaborations and two versions of the model, BS1 and BS2, were chosen. Both models provide a good overall description of the data for the c.m. energies from the threshold up to 2.4 GeV. Predicted cross sections of the models at very small kaon angles being consistent with results of the Saclay-Lyon model indicate th...

  6. Vector meson photoproduction studied in its radiative decay channel

    CERN Document Server

    Zhao, Q; Cole, P L; Zhao, Qiang

    2005-01-01

    We provide an analysis of vector meson photoproduction in the channel of the vector meson decaying into a pseudoscalar meson plus a photon, i.e. $V\\to P\\gamma$. It is shown that non-trivial kinematic correlations arise from the measurement of the $P\\gamma$ angular distributions in the overall c.m. system in comparison with those in the vector-meson-rest frame. In terms of the vector meson density matrix elements, the implication of such kinematic correlations in the measurement of polarization observables is discussed. For the $\\omega$ meson production, due to its relatively large branching ratios for $\\omega\\to\\pi^0\\gamma$, additional events from this channel may enrich the information about the reaction mechanism and improve the statistics of the recent measurement of polarized beam asymmetries by the GRAAL Collaboration. For $\\phi\\to \\eta\\gamma$, $\\rho\\to \\pi\\gamma$, and $K^*\\to K\\gamma$, we expect that additional information about the spin structure of the vector meson production vertex can be derived.

  7. A reggeized model for eta and eta-prime photoproduction

    CERN Document Server

    Chiang, W T; Tiator, L; Vanderhaeghen, M; Drechsel, D; Chiang, Wen-Tai; Yang, Shin Nan

    2003-01-01

    A reggeized model for \\eta and \\eta' photoproduction on the nucleon is presented. In this model, t-channel vector meson exchanges are described in terms of Regge trajectories to comply with the correct high energy behavior. We compare this reggeized model with an isobar model (\\eta-MAID), where the t-channel exchanges are described by \\rho and \\omega poles. Both models contain the same resonance contributions, and describe current \\gamma p \\to \\eta p data up to E_\\gamma^{lab} = 2 GeV quite well, but only the reggeized model can be successfully extended to higher energies. For the \\gamma p \\to \\eta' p reaction, only the reggeized model is able to give a satisfactory description. For the differential cross section data from SAPHIR, we find that the observed linear forward rise in cos(theta) near E_\\gamma^{lab} = 1.6 GeV can be well described by the interference of an S11 resonance and the Regge trajectory exchanges without any need for an additional P-wave resonance.

  8. Λ(1520) photoproduction off a proton target with Regge contributions

    Science.gov (United States)

    Nam, Seung-Il; Kao, Chung-Wen

    2010-05-01

    We investigate the Λ(1520,3/2-)≡Λ* photoproduction off the proton target beyond the resonance region within a model including the Regge contributions, the tree-level diagrams with the nucleon and the certain resonance intermediate states, and one contact term. The Reggeized propagators for the K and K* exchanges in the t channel are employed in a gauge-invariant manner. We compute the angular and energy dependences of the cross section and some polarization observables, such as the photon-beam asymmetry and the polarization-transfer coefficients. Our results qualitatively agree with the current experimental data. We find that the Regge contributions are necessary to explain the high-energy data beyond Eγ≈4 GeV, especially for the angular dependences in the forward region. On the contrary, the polarization observables are insensitive to the Regge contributions due to the contact-term dominance, which is a consequence of gauge invariance. We also calculate the K--angle distribution function in the Gottfried-Jackson frame, using the polarization-transfer coefficients in the z direction. We find that it owns a complicated angle and energy dependences in the forward K+ scattering region.

  9. Photoproduction of J/{psi}mesons at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, T.; Aid, S.; Andreev, V.; Andrieu, B.; Appuhn, R.D.; Arpagaus, M.; Babaev, A.; Baehr, J.; Ban, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Barth, M.; Bassler, U.; Beck, H.P.; Behrend, H.J.; Belousov, A.; Berger, C.; Bergstein, H.; Bernardi, G.; Bernet, R.; Bertrand-Coremans, G.; Besancon, M.; Beyer, R.; Biddulph, P.; Bizot, J.C.; Blobel, V.; Borras, K.; Botterweck, F.; Boudry, V.; Braemer, A.; Brasse, F.; Braunschweig, W.; Brisson, V.; Bruncko, D.; Brune, C.; Buchholz, R.; Buengener, L.; Buerger, J.; Buesser, F.W.; Buniatian, A.; Burke, S.; Buschhorn, G.; Campbell, A.J.; Carli, T.; Charles, F.; Clarke, D.; Clegg, A.B.; Colombo, M.; Contreras, J.G.; Coughlan, J.A.; Courau, A.; Coutures, C.; Cozzika, G.; Criegee, L.; Cussans, D.G.; Cvach, J.; Dagoret, S.; Dainton, J.B.; Danilov, M.; Dau, W.D.; Daum, K.; David, M.; Deffur, E.; Delcourt, B.; Del Buono, L.; De Roeck, A.; De Wolf, E.A.; Di Nezza, P.; Dollfus, C.; Dowell, J.D.; Dreis, H.B.; Duboc, J.; Duellmann, D.; Duenger, O.; Duhm, H.; Ebert, J.; Ebert, T.R.; Eckerlin, G.; Efremenko, V.; Egli, S.; Ehrlichmann, H.; Eichenberger, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellison, R.J.; Elsen, E.; Erdmann, M.; Erdmann, W.; Evrard, E.; Favart, L.; Fedotov, A.; Feeken, D.; Felst, R.; Feltesse, J.; Ferencei, J.; Ferrarotto, F.; Flamm, K.; Fleischer, M.; Flieser, M.; Fluegge, G.; Fomenko, A.; Fominykh, B.; Forbush, M.; Formanek, J.; Foster, J.M.; Franke, G.; Fretwurst, E.; Gabathuler, E.; Gabathuler, K.; Gamerdinger, K.; Garvey, J.; Gayler, J.; Gebauer, M.; Gellrich, A.; Genzel, H.; Gerhards, R.; Goerlach, U.; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goldner, D.; Gonzalez-Pineiro, B.; Goodall, A.M.; Gorelov, I.; Goritchev, P.; Grab, C.; Graessler, H.; Graessler, R.; Greenshaw, T.; Grindhammer, G.; Gruber, A.; Gruber, C.; Haack, J.; Haidt, D.; Hajduk, L.; Hamon, O.; Hampel, M.; Hanlon, E.M.; Hapke, M.; Haynes, W.J.; Heatherington, J.; Hedberg, V.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; H1 Collaboration

    1994-08-01

    We present a study of J/{psi} meson production in collisions of 26.7 GeV electrons with 820 GeV protons, performed with the H1-detector at the HERA collider at DESY. The J/{psi} mesons are detected via their leptonic decays both to electrons and muons. Requiring exactly two particles in the detector, a cross section of {sigma}(ep{yields}J/{psi}X)=(8.8{+-}2.0{+-}2.2) nb is determined for 30 GeV{<=}W{sub {gamma}p}{<=}180 GeV and Q{sup 2}< or {approx}4 GeV{sup 2}. Using the flux of quasi-real photons with Q{sup 2}< or {approx}4 GeV{sup 2}, a total photoproduction cross section of {sigma}({gamma}p{yields}J/{psi}X)=(56{+-}13{+-}14) nb is derived at an average W{sub {gamma}p}=90 GeV. The distribution of the squared momentum transfer t from the proton to the J/{psi} can be fitted using an exponential exp(-bvertical stroke tvertical stroke ) below avertical stroke tvertical stroke of 0.75 GeV{sup 2} yielding a slope parameter of b=(4.7{+-}1.9) GeV{sup -2}. (orig.)

  10. Polarization Observables for Kaon Photoproduction from Polarized Protons

    CERN Document Server

    Walford, Natalie K

    2013-01-01

    The search for undiscovered excited states of the nucleon continues to be a focus of experiments at Jefferson Lab.Recent LQCD calculations have confirmed long-standing quark-model predictions of many more states than have so far been identified.A large effort for the N-star program has been launched using the CLAS detector to provide the database that will allow nearly model-independent partial wave analyses to be carried out in the search for such states. Polarization observables play a crucial role in this effort, as they are essential in disentangling overlapping resonant and non-resonant amplitudes. In 2010, double-polarization data were taken at JLab using circularly polarized photons incident on a transversely polarized frozen-spin butanol target. Our current analysis yields preliminary data of the T and F asymmetries for kaon photoproduction final states, which are compared to predictions of recent multipole analyses. This work is the first of its kind and will significantly broaden the world database ...

  11. Photoproduction of {eta}{sup '} -mesons off the deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Jaegle, I.; Mertens, T.; Krusche, B. [Univ. Basel, Dept. Physik, Basel (Switzerland); Fix, A. [Tomsk Polytechnic Univ., Lab. of Mathematical Physics, Tomsk (Russian Federation); Huang, F.; Nakayama, K. [Univ. of Georgia, Dept. of Physics and Astronomy, Athens, GA (United States); Tiator, L. [Univ. Mainz, Inst. fuer Kernphysik, Mainz (Germany); Anisovich, A.V.; Bayadilov, D.E.; Nikonov, V.A.; Novinski, D.V.; Sarantsev, A.V. [Helmholtz-Inst. fuer Strahlen- und Kernphysik der Univ. Bonn, Bonn (Germany); Petersburg Nuclear Physics Inst., Gatchina (Russian Federation); Bacelar, J.C.S.; Castelijns, R.; Loehner, H.; Messchendorp, J.G.; Shende, S.V. [Univ. of Groningen, KVI, Groningen (Netherlands); Bantes, B.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Hillert, W.; Hoeffgen, S.; Kammer, S.; Kleber, V.; Klein, Frank; Klein, Friedrich; Menze, D.; Ostrick, M.; Schmieden, H.; Schoch, B.; Suele, A.; Walther, D. [Physikalisches Inst. der Univ. Bonn, Bonn (Germany); Bartholomy, O.; Beck, R.; Funke, C.; Gutz, E.; Junkersfeld, J.; Kalinowsky, H.; Klempt, E.; Lang, M.; Schmidt, C.; Sokhoyan, V.; Szczepanek, T.; Wendel, C. [Helmholtz-Inst. fuer Strahlen- und Kernphysik der Univ. Bonn, Bonn (Germany); Beloglazov, Y.A.; Gridnev, A.B.; Lopatin, I.V.; Sumachev, V.V. [Petersburg Nuclear Physics Inst., Gatchina (Russian Federation); Crede, V. [Helmholtz-Inst. fuer Strahlen- und Kernphysik der Univ. Bonn, Bonn (Germany); Florida State Univ., Dept. of Physics, Tallahassee, FL (United States); Gregor, R.; Lugert, S.; Metag, V.; Nanova, M.; Novotny, R.; Pant, L.M.; Pfeiffer, M.; Roy, A.; Schadmand, S.; Trnka, D.; Varma, R. [Univ. Giessen, II. Physikalisches Inst., Giessen (Germany); Kotulla, M. [Univ. Basel, Dept. Physik, Basel (Switzerland); Univ. Giessen, II. Physikalisches Inst., Giessen (Germany); Pee, H. van; Thoma, U. [Helmholtz-Inst. fuer Strahlen- und Kernphysik der Univ. Bonn, Bonn (Germany); Univ. Giessen, II. Physikalisches Inst., Giessen (Germany)

    2011-01-15

    Quasi-free photoproduction of {eta}{sup '} -mesons off nucleons bound in the deuteron has been measured with the combined Crystal Barrel - TAPS detector. The experiment was done at a tagged photon beam of the ELSA electron accelerator in Bonn for incident photon energies from the production threshold up to 2.5GeV. The {eta}{sup '} -mesons have been detected in coincidence with recoil protons and recoil neutrons. The quasi-free proton data are in good agreement with the results for free protons, indicating that nuclear effects have no significant impact. The coincidence with recoil neutrons provides the first data for the {gamma}n{yields}n{eta}{sup '} reaction. In addition, also first estimates for coherent {eta}{sup '} -production off the deuteron have been obtained. In agreement with model predictions, the total cross-section for this channel is found to be very small, at most at the level of a few nb. The data are compared to model calculations taking into account contributions from nucleon resonances and t -channel exchanges. (orig.)

  12. Diffractive photoproduction of dijets in ep collisions at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S.; Musgrave, B.; Repond, J.; Yoshida, R. [Argonne National Lab., Argonne, Illinois (United States); Nicholass, D. [Argonne National Lab., Argonne, Illinois (United States)]|[University College London, London (United Kingdom); Mattingly, M.C.K. [Andrews Univ., Berrien Springs, Michigan (United States); Jechow, M.; Pavel, N.; Yaguees Molina, A.G. [Humboldt-Univ. zu Berlin, Inst. fuer Physik, Berlin (Germany); Antonelli, S.; Antonioli, P.; Bari, G.; Basile, M.; Bellagamba, L.; Bindi, M.; Boscherini, D.; Bruni, A.; Bruni, G.; Cifarelli, L.; Cindolo, F.; Contin, A.; Corradi, M.; Iacobucci, G.; Margotti, A.; Nania, R.; Polini, A.; Sartorelli, G.; Zichichi, A. [Univ. and INFN Bologna, Bologna (Italy); De Pasquale, S. [Univ. and INFN Bologna, Bologna (Italy)]|[Univ. of Salerno, Salerno (Italy); Bartsch, D.; Brock, I.; Hartmann, H.; Hilger, E.; Jakob, H.P.; Juengst, M.; Nuncio-Quiroz, A.E.; Paul, E.; Samson, U.; Schoenberg, V.; Shehzadi, R.; Wlasenko, M. [Univ. Bonn, Physikalisches Inst., Bonn (Germany); Kind, O.M. [Univ. Bonn, Physikalisches Inst., Bonn (Germany)]|[Humboldt Univ., Berlin (Germany); Renner, R. [Univ. Bonn, Physikalisches Inst., Bonn (Germany)]|[Bruker AXS, Karlsruhe (Germany); Brook, N.H.; Heath, G.P.; Morris, J.D. [Univ. of Bristol, H.H. Wills Physics Lab., Bristol (United Kingdom); Capua, M.; Fazio, S.; Mastroberardino, A.; Schioppa, M.; Susinno, G.; Tassi, E. [Calabria Univ., Physics Dept. and INFN, Cosenza (Italy); Kim, J.Y. [Chonnam National Univ., Kwangju (Korea); Ibrahim, Z.A.; Kamaluddin, B.; Wan Abdullah, W.A.T. [Univ. Malaya, Jabatan Fizik, Kuala Lumpur (Malaysia); Ning, Y.; Ren, Z.; Sciulli, F. [Columbia Univ., Nevis Labs., Irvington on Hudson, New York (United States); Chwastowski, J.; Eskreys, A.; Figiel, J.; Galas, A.; Gil, M.; Olkiewicz, K.; Stopa, P.; Zawiejski, L. [Polish Academy of Sciences, The Henryk Niewodniczanski Inst. of Nuclear Physics, Cracow (Poland)] [and others

    2008-05-15

    Diffractive photoproduction of dijets was measured with the ZEUS detector at the ep collider HERA using an integrated luminosity of 77.2 pb{sup -1}. The measurements were made in the kinematic range Q{sup 2}<1 GeV{sup 2}, 0.207.5 and 6.5 GeV, respectively, and to lie in the pseudorapidity range -1.5<{eta}{sup jet}<1.5. Differential cross sections were compared to perturbative QCD calculations using available parameterisations of diffractive parton distributions of the proton. (orig.)

  13. Measurement of open beauty production in photoproduction at HERA

    Science.gov (United States)

    ZEUS Collaboration; Breitweg, J.; et al.

    2001-01-01

    The production and semi-leptonic decay of heavy quarks have been studied in the photoproduction process e+p -> e+ + dijet + e- + X with the ZEUS detector at HERA using an integrated luminosity of 38.5 pb -1. Events with photon-proton centre-of-mass energies, Wγ p, between 134 and 269 GeV and a photon virtuality, Q2, less than 1 GeV 2 were selected requiring at least two jets of transverse energy ET jet1(2) >7(6) GeV and an electron in the final state. The electrons were identified by employing the ionisation energy loss measurement. The contribution of beauty quarks was determined using the transverse momentum of the electron relative to the axis of the closest jet, pT rel. The data, after background subtraction, were fit with a Monte Carlo simulation including beauty and charm decays. The measured beauty cross section was extrapolated to the parton level with the b quark restricted to the region of transverse momentum pT^b > pT^min = 5 GeV and pseudorapidity |η b| < 2. The extrapolated cross section is 1.6 +/- 0.4 (stat.)+0.3-0.5 (syst.) +0.2-0.4 (ext.) nb. The result is compared to a perturbative QCD calculation performed to next-to-leading order.

  14. Measurement of double polarisation asymmetries in $\\omega$-photoproduction

    CERN Document Server

    Eberhardt, H; Schmieden, H; Anisovich, A V; Bantes, B; Bayadilov, D; Beck, R; Beloglazov, Yu; Bichow, M; Boese, S; Brinkmann, K -Th; Challand, Th; Crede, V; Diez, F; Drexler, P; Dutz, H; Elsner, D; Ewald, R; Fornet-Ponse, K; Friedrich, St; Frommberger, F; Funke, Ch; Gottschall, M; Gridnev, A; Gruener, M; Gutz, E; Hammann, Ch; Hannappel, J; Hartmann, J; Hillert, W; Hoffmeister, Ph; Honisch, Ch; Jaegle, I; Kaiser, D; Kalinowsky, H; Kalischewski, F; Kammer, S; Keshelashvili, I; Kleber, V; Klein, F; Klempt, E; Koop, K; Krusche, B; Kube, M; Lang, M; Lopatin, I; Maghrbi, Y; Makonyi, K; Metag, V; Meyer, W; Mueller, J; Nanova, M; Nikonov, V; Novotny, R; Piontek, D; Reeve, S; Reicherz, G; Rostomyan, T; Runkel, S; Sarantsev, A; Schaepe, St; Schmidt, Ch; Schmitz, R; Seifen, T; Sokhoyan, V; Sumachev, V; Thiel, A; Thoma, U; Urban, M; van Pee, H; Walther, D; Wendel, Ch; Wiedner, U; Wilson, A; Winnebeck, A

    2015-01-01

    The first measurements of the beam-target-helicity-asymmetries $E$ and $G$ in the photoproduction of $\\omega$-mesons off protons at the CBELSA/TAPS experiment are reported. $E$ ($G$) was measured using circularly (linearly) polarised photons and a longitudinally polarised target. $E$ was measured over the photon energy range from close to threshold ($E_\\gamma = 1108$~MeV) to $E_\\gamma = 2300$~MeV and $G$ at a single energy interval of $1108 < E_\\gamma <1300$~MeV. Both measurements cover the full solid angle. The observables $E$ and $G$ are highly sensitive to the contribution of baryon resonances, with $E$ acting as a helicity filter in the $s$-channel. The new results indicate significant $s$-channel resonance contributions together with contributions from $t$-channel exchange processes. A partial wave analysis reveals strong contributions from the partial waves with spin-parity $J^P=3/2^+, 5/2^+$, and $3/2^-$.

  15. Measurement of double polarisation asymmetries in ω-photoproduction

    Directory of Open Access Journals (Sweden)

    H. Eberhardt

    2015-11-01

    Full Text Available The first measurements of the beam-target-helicity-asymmetries E and G in the photoproduction of ω-mesons off protons at the CBELSA/TAPS experiment are reported. E (G was measured using circularly (linearly polarised photons and a longitudinally polarised target. E was measured over the photon energy range from close to threshold (Eγ=1108 MeV to Eγ=2300 MeV and G at a single energy interval of 1108

  16. Measurement of inclusive jet cross sections in photoproduction at HERA

    CERN Document Server

    Adloff, C; Andrieu, B; Anthonis, T; Astvatsatourov, A; Babaev, A; Bähr, J; Baranov, P S; Barrelet, E; Bartel, Wulfrin; Baumgartner, S; Becker, J; Beckingham, M; Beglarian, A; Behnke, O; Belousov, A; Berger, C; Berndt, T; Bizot, J C; Böhme, J; Boudry, V; Braunschweig, W; Brisson, V; Broker, H B; Brown, D P; Bruncko, Dusan; Büsser, F W; Bunyatyan, A; Burrage, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Caron, S; Cassol-Brunner, F; Chekelian, V; Clarke, D; Collard, Caroline; Contreras, J G; Coppens, Y R; Coughlan, J A; Cousinou, M C; Cox, B E; Cozzika, G; Cvach, J; Dainton, J B; Dau, W D; Daum, K; Davidsson, M; Delcourt, B; Delerue, N; Demirchyan, R A; de Roeck, A; De Wolf, E A; Diaconu, C A; Dingfelder, J; Dixon, P; Dodonov, V; Dowell, John D; Dubak, A; Duprel, C; Eckerlin, G; Eckstein, D; Efremenko, V; Egli, S; Eichler, R; Eisele, Franz; Eisenhandler, Eric F; Ellerbrock, M; Elsen, E; Erdmann, M; Erdmann, W; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Ferencei, J; Ferron, S; Fleischer, M; Fleischmann, P; Fleming, Y H; Flucke, G; Flügge, G; Fomenko, A; Foresti, I; Formánek, J; Franke, G; Frising, G; Gabathuler, Erwin; Gabathuler, K; Garvey, J; Gassner, J; Gayler, J; Gerhards, R; Gerlich, C; Ghazaryan, S; Görlich, L; Gogitidze, N; Grab, C; Grabskii, V; Grässler, Herbert; Greenshaw, T; Grindhammer, G; Haidt, Dieter; Hajduk, L; Haller, J; Heinemann, B; Heinzelmann, G; Henderson, R C W; Hengstmann, S; Henschel, H; Henshaw, O; Heremans, R; Herrera-Corral, G; Herynek, I; Hildebrandt, M; Hilgers, M; Hiller, K H; Hladky, J; Hoting, P; Hoffmann, D; Horisberger, R P; Hovhannisyan, A V; Ibbotson, M; Issever, C; Jacquet, M; Jaffré, M; Janauschek, L; Janssen, X; Jemanov, V; Jönsson, L B; Johnson, C; Johnson, D P; Jones, M A S; Jung, H; Kant, D; Kapichine, M; Karlsson, M; Karschnick, O; Katzy, J; Keil, F; Keller, N; Kennedy, J; Kenyon, Ian Richard; Kiesling, C; Kjellberg, P; Klein, M; Kleinwort, C; Kluge, T; Knies, G; Koblitz, B; Kolya, S D; Korbel, V; Kostka, P; Koutouev, R; Koutov, A; Kroseberg, J; Krüger, K; Kuhr, T; Lamb, D; Landon, M P J; Lange, W; Lastoviicka, T; Laycock, P; Lebailly, E; Lebedev, A; Leiner, B; Lemrani, R; Lendermann, V; Levonian, S; List, B; Lobodzinska, E; Lobodzinski, B; Loginov, A; Loktionova, N A; Lubimov, V; Lüders, S; Lüke, D; Lytkin, L; Malden, N; Malinovskii, E I; Mangano, S; Marage, P; Marks, J; Marshall, R; Martyn, H U; Martyniak, J; Maxfield, S J; Meer, D; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, J; Michine, S; Mikocki, S; Milstead, D; Mohrdieck, S; Mondragón, M N; Moreau, F; Morozov, A; Morris, J V; Müller, K; Murn, P; Nagovizin, V; Naroska, Beate; Naumann, J; Naumann, T; Newman, P R; Niebergall, F; Niebuhr, C B; Nix, O; Nowak, G; Nozicka, M; Olivier, B; Olsson, J E; Ozerov, D; Panassik, V; Pascaud, C; Patel, G D; Peez, M; Pérez, E; Petrukhin, A; Phillips, J P; Pitzl, D; Pöschl, R; Potachnikova, I; Povh, B; Rauschenberger, J; Reimer, P; Reisert, B; Risler, C; Rizvi, E; Robmann, P; Roosen, R; Rostovtsev, A A; Rusakov, S V; Rybicki, K; Sankey, D P C; Sauvan, E; Schatzel, S; Scheins, J; Schilling, F P; Schleper, P; Schmidt, D; Schmidt, S; Schmitt, S; Schneider, M; Schoeffel, L; Schöning, A; Schörner-Sadenius, T; Schröder, V; Schultz-Coulon, H C; Schwanenberger, C; Sedlak, K; Sefkow, F; Shevyakov, I; Shtarkov, L N; Sirois, Y; Sloan, Terence; Smirnov, P; Soloviev, Yu; South, D; Spaskov, V N; Specka, A E; Spitzer, H; Stamen, R; Stella, B; Stiewe, J; Strauch, I; Straumann, U; Chechelnitskii, S; Thompson, G; Thompson, P D; Tomasz, F; Traynor, D; Truöl, P; Tsipolitis, G; Tsurin, I; Turnau, J; Turney, J E; Tzamariudaki, E; Uraev, A; Urban, M; Usik, A; Valkár, S; Valkárová, A; Vallée, C; Van Mechelen, P; Vargas-Trevino, A; Vasilev, S; Vazdik, Ya A; Veelken, C; Vest, A; Vichnevski, A; Volchinski, V; Wacker, K; Wagner, J; Wallny, R; Waugh, B; Weber, G; Weber, R; Wegener, D; Werner, C; Werner, N; Wessels, M; Wiesand, S; Winde, M; Winter, G G; Wissing, C; Wobisch, M; Woerling, E E; Wünsch, E; Wyatt, A C; Zácek, J; Zaleisak, J; Zhang, Z; Zhokin, A; Zomer, F; Zur Nedden, M

    2003-01-01

    Inclusive jet cross sections are measured in photoproduction at HERA using the H1 detector. The data sample of e+ p -> e+ + jet + X events in the kinematic range of photon virtualities Q^2 < 1 GeV^2 and photon-proton centre-of-mass energies 95 < W_gammap < 285 GeV represents an integrated luminosity of 24.1 pb^-1. Jets are defined using the inclusive k_T algorithm. Single- and multi-differential cross sections are measured as functions of jet transverse energy E_T^jet and pseudorapidity \\eta^jet in the domain 5 < E_T^jet < 75 GeV and -1 < \\eta^jet < 2.5. The cross sections are found to be in good agreement with next-to-leading order perturbative QCD calculations corrected for fragmentation and underlying event effects. The cross section differential in E_T^jet, which varies by six orders of magnitude over the measured range, is compared with similar distributions from p pbar colliders at equal and higher energies.

  17. Photoproduction of $\\pi^0$-pairs off protons and off neutrons

    CERN Document Server

    Dieterle, M; Ahrens, J; Annand, J R M; Arends, H J; Bantawa, K; Bartolome, P A; Beck, R; Bekrenev, V; Berghäuser, H; Braghieri, A; Branford, D; Briscoe, W J; Brudvik, J; Cherepnya, S; Costanza, S; Demissie, B; Downie, E J; Drexler, P; Fil'kov, L V; Fix, A; Garni, S; Glazier, D I; Hamilton, D; Heid, E; Hornidge, D; Howdle, D; Huber, G M; Jahn, O; Jude, T C; Käser, A; Kashevarov, V L; Keshelashvili, I; Kondratiev, R; Korolija, M; Krusche, B; Lisin, V; Livingston, K; MacGregor, I J D; Maghrbi, Y; Mancell, J; Manley, D M; Marinides, Z; McGeorge, J C; McNicoll, E; Mekterovic, D; Metag, V; Micanovic, S; Middleton, D G; Mushkarenkov, A; Nikolaev, A; Novotny, R; Ostrick, M; Otte, P; Oussena, B; Pedroni, P; Pheron, F; Polonski, A; Prakhov, S; Robinson, J; Rostomyan, T; Schumann, S; Sikora, M H; Sober, D I; Starostin, A; Strub, Th; Supek, I; Thiel, M; Thomas, A; Unverzagt, M; Walford, N K; Watts, D P; Werthmüller, D; Witthauer, L

    2015-01-01

    Total cross sections, angular distributions, and invariant-mass distributions have been measured for the photoproduction of $\\pi^0\\pi^0$ pairs off free protons and off nucleons bound in the deuteron. The experiments were performed at the MAMI accelerator facility in Mainz using the Glasgow photon tagging spectrometer and the Crystal Ball/TAPS detector. The accelerator delivered electron beams of 1508 and 1557~MeV, which produced bremsstrahlung in thin radiator foils. The tagged photon beam covered energies up to 1400~MeV. The data from the free proton target are in good agreement with previous measurements and were only used to test the analysis procedures. The results for differential cross sections (angular distributions and invariant-mass distributions) for free and quasi-free protons are almost identical in shape, but differ in absolute magnitude up to 15\\%. Thus, moderate final-state interaction effects are present. The data for quasi-free neutrons are similar to the proton data in the second resonance r...

  18. Beauty photoproduction using decays into muons at HERA

    International Nuclear Information System (INIS)

    Inclusive cross-sections for the production of open beauty in ep collisions at HERA are measured. The data were recorded with the ZEUS detector between 1996 and 2000. The measurements are restricted to photoproduction processes, i.e. collision events with small four-momentum transfer squared, Q2∼0. Two jets with transverse momentum pT>7(6) GeV and pseudo-rapidities vertical stroke η vertical stroke <2.5 are required. The flavour is tagged by the identification of muons from semi-leptonic decays of the beauty quark. The variable used to discriminate between beauty and background is the transverse momentum of the muon with respect to the jet axis. The fraction of beauty is determined by a fit of Monte Carlo templates to the data. Cross-sections have been measured as a function of the muon and jet variables as well as a function of dijet correlation variables. Dijet correlations in beauty production have been measured for the first time in ZEUS and are found in agreement with QCD NLO predictions. (orig.)

  19. Rapidity gaps between jets in Photoproduction at HERA

    International Nuclear Information System (INIS)

    Photoproduction events which have two or more jets have been studied in the Wγp range 135 GeVγp<280 GeV with the ZEUS detector at HERA. A class of events is observed with little hadronic activity between the jets. The jets are separated by pseudorapidity intervals (Δη) of up to four units and have transverse energies greater than 6 GeV. A gap is defined as the absence between the jets of particles with transverse energy greater than 300 MeV. The fraction of events containing a gap is measured as a function of Δη. It decreases exponentially as expected for processes in which colour is exchanged between the jets, up to a value of Δη∼3, then reaches a constant value of about 0.1. The excess above the exponential fall-off can be interpreted as evidence for hard diffractive scattering via a strongly interacting colour singlet object. (orig.)

  20. Inelastic Photoproduction of J/Psi Mesons at HERA

    CERN Document Server

    Adloff, C

    2002-01-01

    An analysis of inelastic photoproduction of J/Psi mesons is presented using data collected at the ep collider HERA corresponding to an integrated luminosity of above 80pb-1. Differential and double differential cross sections are measured in a wide kinematic region: 60

  1. Dijets in diffractive photoproduction measured with the ZEUS experiment

    Energy Technology Data Exchange (ETDEWEB)

    Renner, R.

    2006-10-15

    The diffractive photoproduction of dijets in electron-proton scattering has been studied using 77.1 pb{sup -1} of data taken with the ZEUS detector at HERA. The measurements have been made at a centre-of- mass energy {radical}s=318 GeV in the kinematic range 0.27.5 and 6.5 GeV, respectively, and to be in the pseudorapidity range -1.5<{eta}<1.5. Differential cross sections have been measured and been confronted with the predictions from leading order Monte Carlo simulations and next-to-leading order QCD calculations. (orig.)

  2. STRUCTURES OF SOME KEPONE PHOTOPRODUCTS AND RELATED CHLORINATED PENTACYCLODECANES BY CARBON-13 AND PROTON NUCLEAR MAGNETIC RESONANCE

    Science.gov (United States)

    The pesticide Kepone, 1,1a,3,3a,4,5,5a,5b,6-decachlorooctahydro-1,3,4-metheno-2H-cyclobuta(cd)pentalen-2-one, the related compounds mirex, kelevan, a monohydro photoproduct of kelevan, kepone alcohol, kepone hydrate, and the mono- and dihydro photoproducts of Kepone hydrate and t...

  3. Hydrogen production by Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Chaudhuri Surabhi

    2005-12-01

    Full Text Available Abstract The limited fossil fuel prompts the prospecting of various unconventional energy sources to take over the traditional fossil fuel energy source. In this respect the use of hydrogen gas is an attractive alternate source. Attributed by its numerous advantages including those of environmentally clean, efficiency and renew ability, hydrogen gas is considered to be one of the most desired alternate. Cyanobacteria are highly promising microorganism for hydrogen production. In comparison to the traditional ways of hydrogen production (chemical, photoelectrical, Cyanobacterial hydrogen production is commercially viable. This review highlights the basic biology of cynobacterial hydrogen production, strains involved, large-scale hydrogen production and its future prospects. While integrating the existing knowledge and technology, much future improvement and progress is to be done before hydrogen is accepted as a commercial primary energy source.

  4. IEA Agreement on the Production and utilization of hydrogen: 1998 annual report

    Energy Technology Data Exchange (ETDEWEB)

    Elam, Carolyn C. (National Renewable Energy Lab, Golden, CO (US)) (ed.)

    1999-01-31

    The annual report includes an overview of the IEA Hydrogen Agreement, including its guiding principles. The Chairman's report section includes highlights of the agreement for 1998. Annex reports are given on various tasks: Task 10, Photoproduction of Hydrogen, Task 11, Integrated Systems, and Task 12, Metal Hydrides and Carbon for Hydrogen Storage. Lastly, a feature article by Karsten Wurr, E3M Material Consulting, GmbH, Hamburg Germany, is included titled 'Hydrogen in Material Science and Technology: State of the Art and New Tendencies'.

  5. Study of Coherent {pi}{sup 0}-Photoproduction on the Deuteron

    Energy Technology Data Exchange (ETDEWEB)

    El-Zohry Aly, Mohamed Ahmed; Akopov, N. [Yerevan Physics Institute, Br. Alikhanian 2, 0036 Yerevan (Armenia); Darwish, E. [Taibah University (Saudi Arabia)

    2010-07-01

    In the present paper, we consider the coherent neutral-pion photoproduction reaction on the deuteron in the energy region from pion-threshold up to 1 GeV using an enhanced elementary pion photoproduction operator on the free nucleon and a realistic high-precision nucleon-nucleon potential model for the deuteron wave function. Numerical results for total and differential cross sections are presented for which the sensitivity to various models for the elementary pion photoproduction amplitude is investigated. Considerable dependence of the results on the elementary amplitude is found at photon lab-energies close to threshold and above 600 MeV. In addition, the results of differential and total cross sections are compared with the available experimental data and a good agreement was found. (authors)

  6. Phototransformation of Amlodipine in Aqueous Solution: Toxicity of the Drug and Its Photoproduct on Aquatic Organisms

    Directory of Open Access Journals (Sweden)

    Marina DellaGreca

    2007-01-01

    Full Text Available The phototransformation of amlodipine in water was investigated under various conditions. A quantum yield ΦS2.2×10−4 and a half-life time t1/2 0.419 days were calculated when the drug in water (10−4 M was exposed to sunlight. The only photoproduct found was its pyridine derivative. Formation of this product was explained on the basis of a radical cation intermediate. The acute and chronic toxicity of the drug and its photoproduct were evaluated on different organisms of the freshwater chain (Brachionus calyciflorus, Thamnocephalus platyurus, Daphnia magna, Ceriodaphnia dubia. The photoproduct exhibited a stronger toxic potential than the parent drug on the long time for C. dubia.

  7. Use Of A Quartz Crystal Microbalance Rate Monitor To Examine Photoproduct Effects On Resist Dissolution

    Science.gov (United States)

    Hinsberg, W. D.; Willson, C. G.; Kanazawa, K. K.

    1985-04-01

    A new general method for measuring dissolution kinetics of thin films has been developed. This technique employs a quartz crystal microbalance to measure the mass of the dissolving thin film. The method allows the measurement of very rapid dissolution rates, and can also be used to study the dissolution kinetics of thick or opaque films. The technique has several advantages over alternative in situ methods based on optical interferometry or capacitance. This instrument has been used to examine the effects of photoproducts on the dissolution kinetics of positive photoresist. The influence of photolytically generated carboxylic acid, and the nitrogen byproduct entrapped in the film, have been independently assessed by comparing the solubility of films of novolac resin, and films of resin plus carboxylic acid photoproduct, with that of exposed photoresist. Our results indicate that the acid does not significantly influence the solubility of the resin, and that entrapped gaseous photoproducts exert a rate-enhancing effect.

  8. Photoproduction Of eta And eta-prime Mesons From The Proton

    International Nuclear Information System (INIS)

    The excitation spectrum of the proton is comprised of many broad overlapping resonances, making investigations of these resonances very challenging. Two excellent tools in helping deconvolve the spectrum are eta and eta-prime meson photoproduction from the proton. Since the beginning of this new millennium, much progress has been made in measuring eta and eta-prime meson photoproduction from the proton. These new measurements are largely in the form of differential cross sections that now cover the first and second resonance regions. In addition to differential cross section data, there have been a comparatively smaller number of beam asymmetry measurements for eta photoproduction. However, these beam asymmetries cover the energy range up to only about Egamma = 1.5 GeV. In this talk, I will present preliminary Jefferson Lab CLAS data on beam asymmetry for both the eta and eta-prime. I will also discuss how the new measurements will be useful in understanding the structure and exci

  9. Theoretical study on photoproduction of the charged charmoniumlike $Z_{c}^{+}(4200)$

    CERN Document Server

    Wang, Xiao-Yun

    2015-01-01

    In this work, inspired by the observation of charmoniumlike $Z_{c}^{+}(4200)$%, we study the photoproduction of the charged charmoniumlike $Z_{c}^{+}(4200) $ with an effective Lagrangian approach and the Regge trajectories model. The numerical results indicate that the Reggeized treatment can lead to a lower total cross section of the $Z_{c}^{+}(4200)$ photoproduction and the peak position of cross section was moved to the higher energy point when using the Reggeized treatment. Also discussed is the feasibility of searching for the charged charmoniumlike $Z_{c}^{+}(4200)$. The relevant results not only shed light on the further experiment of searching for the charmoniumlike $Z_{c}(4200)$ state via meson photoproduction, but also provide valuable informations for having a better comprehension of properties and producing mechanism of charmoniumlike $Z_{c}(4200)$ state.

  10. Photoproduction of events with rapidity gaps between jets with ZEUS at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Ryan, P.D.

    2006-11-15

    Cross sections for the photoproduction of dijet events, where the two jets with the highest transverse energy are separated by a large gap in pseudorapidity, have been studied with the ZEUS detector using an integrated luminosity of 38.6 pb{sup -1}. Rapidity-gap events are defined in terms of the energy flow between the jets, such that the total summed transverse energy in this region is less than some value E{sup CUT}{sub T}. The data show a clear excess above the predictions of standard photoproduction models. Models which include color-singlet exchange are able to describe the data. (orig.)

  11. Small-x physics and heavy quark photoproduction in the semihard approach at HERA

    CERN Document Server

    Saleev, V A; Saleev, A; Zotov, N P

    1995-01-01

    Processes of hevy quark photoproduction at HERA energies and beyond are investigated using the semihard (k_{\\bot} factorization) approach. The virtuality and longitudinal polarization of gluons in the photon - gluon subprocess as well as the saturation effects in the gluon distribution function at small x have been taken into account. The total cross sections, rapidity and p_{\\bot} distributions of the charm and beauty quark photoproduction have been calculated. We obtained the some differences between the predictions of the standard parton model and the semihard approach used here.

  12. CLAS+FROST: new generation of photoproduction experiments at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Eugene Pasyuk

    2009-12-01

    A large part of the experimental program in Hall B of the Jefferson Lab is dedicated to baryon spectroscopy. Photoproduction experiments are essential part of this program. CEBAF Large Acceptance Spectrometer (CLAS) and availability of circularly and linearly polarized tagged photon beams provide unique conditions for this type of experiments. Recent addition of the Frozen Spin Target (FROST) gives a remarkable opportunity to measure double and triple polarization observables for different pseudo-scalar meson photoproduction processes. For the first time, a complete or nearly complete experiment becomes possible and will allow model independent extraction of the reaction amplitude. An overview of the experiment and its current status is presented.

  13. Studying the Pc(4450 ) resonance in J /ψ photoproduction off protons

    Science.gov (United States)

    Blin, A. N. Hiller; Fernández-Ramírez, C.; Jackura, A.; Mathieu, V.; Mokeev, V. I.; Pilloni, A.; Szczepaniak, A. P.; Joint Physics Analysis Center

    2016-08-01

    A resonancelike structure, the Pc(4450 ), has recently been observed in the J /ψ p spectrum by the LHCb Collaboration. We discuss the feasibility of detecting this structure in J /ψ photoproduction in the CLAS12 experiment at JLab. We present a first estimate of the upper limit for the branching ratio of the Pc(4450 ) to J /ψ p . Our estimates, which take into account the experimental resolution effects, predict that it will be possible to observe a sizable cross section close to the J /ψ production threshold and shed light on the Pc(4450 ) resonance in the future photoproduction measurements.

  14. Prompt photon photoproduction at HERA in the k_T-factorization approach

    CERN Document Server

    Lipatov, A V

    2005-01-01

    We present calculations of the prompt photon photoproduction at HERA collider in the k_T-factorization approach. Both direct and resolved contributions are taken into account. The conservative error analisys is performed. The unintegrated parton densities in a proton and in a photon are determined using the Kimber-Martin-Ryskin prescription. We investigate both inclusive and associated with jet prompt photon photoproduction rates. In particular, we study the angular correlations between produced photon and hadronic jet in the transverse momentum plane which can provide a unique information about non-collinear evolution dynamics. We compare our theoretical predictions with recent experimental data taken by the H1 and ZEUS collaborations.

  15. Light Vector Meson Photoproduction off of 1H at Jefferson Lab and p-w Interference in the Leptonic Decay Channel

    Energy Technology Data Exchange (ETDEWEB)

    Djalali, Chaden [University of Iowa; Paolone, Michael [Temple University, JLAB; Weygand, Dennis; Wood, Mike H. [USC LA, JLAB

    2014-09-01

    Although the phenomena of r – w interference has been studied at great length in pionic decay channel over the past 50 years, a study of the interference in a purely electromagnetic production and decay channel has never been performed on an elementary proton target until now. The only published photo-production data of the r - w leptonic decay channel was obtained in the early seventies on C and Be. An investigation of the r - w interference on a Hydrogen was recently completed at Jefferson Lab with the CLAS detector. The di-lepton spectra was fit with two inter- fering relativistic Breit-Wigner functions, and the interference phase was extracted. Preliminary results will be compared to the previous experimental studies in nuclei.

  16. The Research Situation on the Biological Functions of Hydrogen Sulfide%硫化氢生物学功能的研究概况

    Institute of Scientific and Technical Information of China (English)

    王茂先

    2013-01-01

    Hydrogen sulfide (H2S) has been recognized as a physiological mediator with a variety of bi-ological functions. It is produced by three enzymes,cytathiohineβ-synthase (CBS),cytathiohineγ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3MST) along with cysteine aminotransferase.The mech-anism of release and production, vasorelaxant effect, antioxidative stress and anti-inflammatory response of H2S were reviewed in the article.%硫化氢(H2S)已经被公认为一种生理介质,具有各种各样的生物学功能.胱硫醚β-合成酶(Cytathiohineβ-synthase, CBS)、胱硫醚γ-裂解酶(Cytathiohineγ-lyase, CSE)及3-硫基丙酮酸硫基转移酶(3-Mercaptopyruvate Sulfurtransferase,3MST)可利用半胱氨酸或者同型半胱氨酸生成H2S.本文就H2S的产生及其释放机制、血管舒张作用、抗氧化应激及其抗炎症反应等方面做了综述.

  17. Discovery of novel quinoline-based mTOR inhibitors via introducing intra-molecular hydrogen bonding scaffold (iMHBS): The design, synthesis and biological evaluation.

    Science.gov (United States)

    Ma, Xiaodong; Lv, Xiaoqing; Qiu, Ni; Yang, Bo; He, Qiaojun; Hu, Yongzhou

    2015-12-15

    A series of quinoline derivatives featuring the novelty of introducing intra-molecular hydrogen bonding scaffold (iMHBS) were designed, synthesized and biologically evaluated for their mTOR inhibitory activity, as well as anti-proliferative efficacies against HCT-116, PC-3 and MCF-7 cell lines. As a result, six compounds exhibited significant inhibition against mTOR with IC50 values below 35nM. Compound 15a, the most potent mTOR inhibitor reported herein (IC50=14nM), also displayed the most favorable cellular activities, with the IC50 values of 0.46, 0.61 and 0.24μM against HCT-116, PC-3 and MCF-7, respectively. Besides, several compounds in this series were identified to be selective over class I PI3Ks. Further western blot analysis of 16b, a representative compound in this series, highlighted their advantage in surmounting the S6K/IRS1/PI3K negative feedback loop upon dual inhibition of mTORC1 and mTORC2. In addition to the remarkable activity, 15a demonstrated acceptable stability in simulated gastric fluid (SGF), simulated intestinal fluid (SIF) and liver microsome, thereby being valuable for extensive in vivo investigation.

  18. Study of the Two-pion Photoproduction on the Deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Graham, Lewis P. [Univ. of South Carolina, Columbia, SC (United States)

    2012-12-01

    Understanding the structure of baryons in terms of the fundamental interaction of the constituent quarks and gluons is one of the primary challenges in strong interaction physics. This interaction is governed by Quantum Chromodynamics (QCD), which is a theory for understanding the dynamics of strong. QCD displays the asymptotic freedom of hadrons at very short distances and also the confinement of quarks and gluons inside hadrons. However, solutions of this QCD theory in the non-perturbative domain of the interaction are extremely difficult to achieve, mainly because confinement happens on the hadronic scale on which the coupling constant is large and prevents any perturbative approach. Thus leaving us with strategies such as lattice QCD or formulating QCD sum rules to get around this problem. In exclusive hadron production the yN interaction is recognized for being a powerful method for investigating hadrons and the mysteries that still exist within the strong interaction. From reactions with the nucleon, the strong interaction can be investigated through the transition amplitudes to the N and Delta resonances. More specifically, if an electromagnetic interaction is well known then the intermediate resonance states may be evaluated through meson photoproduction. To gain more detailed insight into this interaction, we look to probe the baryon structure of the nucleon and the photo-excited resonance decays through photon scattering off a deuteron producing two pions in the final state. This photoproduction process off the deuteron will be used to investigate known baryon resonances in the two pion channel. The two pion final state will be investigated for unraveling new information into the photo-coupling strengths. We want to explore final state interactions, search for properties of known resonances, and to explore the possibility of seeing missing states that are predicted by quark models but have not yet been found experimentally. Using the CEBAF Large

  19. Hydrogen energy for beginners

    CERN Document Server

    2013-01-01

    This book highlights the outstanding role of hydrogen in energy processes, where it is the most functional element due to its unique peculiarities that are highlighted and emphasized in the book. The first half of the book covers the great natural hydrogen processes in biology, chemistry, and physics, showing that hydrogen is a trend that can unite all natural sciences. The second half of the book is devoted to the technological hydrogen processes that are under research and development with the aim to create the infrastructure for hydrogen energetics. The book describes the main features of hydrogen that make it inalienable player in processes such as fusion, photosynthesis, and metabolism. It also covers the methods of hydrogen production and storage, highlighting at the same time the exclusive importance of nanotechnologies in those processes.

  20. Relevance of nutrient media composition for hydrogen production in Chlamydomonas.

    Science.gov (United States)

    Gonzalez-Ballester, David; Jurado-Oller, Jose Luis; Fernandez, Emilio

    2015-09-01

    Microalgae are capable of biological H2 photoproduction from water, solar energy, and a variety of organic substrates. Acclimation responses to different nutrient regimes finely control photosynthetic activity and can influence H2 production. Hence, nutrient stresses are an interesting scenario to study H2 production in photosynthetic organisms. In this review, we mainly focus on the H2-production mechanisms in Chlamydomonas reinhardtii and the physiological relevance of the nutrient media composition when producing H2. PMID:25952745

  1. Measurement of antideuteron photoproduction and a search for heavy stable charged particles at HERA

    CERN Document Server

    Aktas, A; Anthonis, T; Asmone, A; Babaev, A; Backovic, S; Bähr, J; Baranov, P; Barrelet, E; Bartel, Wulfrin; Baumgartner, S; Becker, J; Beckingham, M; Behnke, O; Behrendt, O; Belousov, A; Berger, Christoph; Berndt, T; Bizot, J C; Boenig, M O; Böhme, J; Boudry, V; Bracinik, J; Brisson, V; Broker, H B; Brown, D P; Bruncko, Dusan; Bunyatyan, A; Buschhorn, G; Büsser, F W; Bystritskaya, L; Campbell, A J; Caron, S; Cassol-Brunner, F; Cerny, K; Chekelian, V; Collard, Caroline; Contreras, J G; Coppens, Y R; Coughlan, J A; Cox, B E; Cozzika, G; Cvach, J; Dainton, J B; Dau, W D; Daum, K; de Roeck, A; De Wolf, E A; Delcourt, B; Demirchyan, R; Desch, Klaus; Diaconu, C; Dingfelder, J; Dodonov, V; Dubak, A; Duprel, C; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, F; Ellerbrock, M; Elsen, E; Erdmann, M; Erdmann, W; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Ferencei, J; Fleischer, M; Fleischmann, P; Fleming, Y H; Flucke, G; Flügge, G; Fomenko, A; Foresti, I; Formánek, J; Franke, G; Frising, G; Gabathuler, E; Gabathuler, K; Garutti, E; Garvey, J; Gayler, J; Gerhards, R; Gerlich, C; Ghazaryan, S; Görlich, L; Gogitidze, N; Gorbounov, S; Grab, C; Grassler, J; Greenshaw, T; Gregori, M; Grindhammer, G; Gwilliam, C; Haidt, D; Hajduk, L; Haller, J; Hansson, M; Heinzelmann, G; Henderson, R C W; Henschel, H; Henshaw, O; Heremans, R; Herrera-Corral, G; Herynek, I; Heuer, R D; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R P; Hoting, P; Hovhannisyan, A; Ibbotson, M; Ismail, M; Jacquet, M; Janauschek, L; Janssen, X; Jemanov, V; Johnson, D P; Jönsson, L B; Jung, H; Kant, D; Kapichine, M; Karlsson, M; Katzy, J; Keller, N; Kennedy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Klimkovich, T; Kluge, T; Knies, G; Knutsson, A; Koblitz, B; Korbel, V; Kostka, P; Koutouev, R; Kropivnitskaya, A; Kroseberg, J; Kuckens, J; Kuhr, T; Landon, M P J; Lange, W; Lastoviicka, T; Laycock, P; Lebedev, A; Leissner, B; Lemrani, R; Lendermann, V; Levonian, S; Lindfeld, L; Lipka, K; List, B; Lobodzinska, E; Loktionova, N; López-Fernandez, R; Lubimov, V; Lüders, H; Lüke, D; Lux, T; Lytkin, L; Makankine, A; Malden, N; Malinovski, E; Mangano, S; Marage, P; Marks, J; Marshall, R; Martisikova, M; Martyn, H U; Maxfield, S J; Meer, D; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, J; Michine, S; Mikocki, S; Milcewicz, I; Milstead, D; Mohamed, A; Moreau, F; Morozov, A; Morozov, I; Morris, J V; Mozer, M U; Müller, K; Murín, P; Nagovizin, V; Naroska, Beate; Naumann, J; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nikitin, D; Nowak, G; Nozicka, M; Oganezov, R; Olivier, B; Olsson, J E; Ossoskov, G; Ozerov, D; Pascaud, C; Patel, G D; Peez, M; Pérez, E; Perieanu, A; Petrukhin, A; Pitzl, D; Placakyte, R; Portheault, B; Pöschl, R; Povh, B; Raicevic, N; Ratiani, Z; Reimer, P; Reisert, B; Rimmer, A; Risler, C; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rurikova, Z; Rusakov, S; Rybicki, K; Sankey, D P C; Sauvan, E; Schatzel, S; Scheins, J; Schilling, F P; Schleper, P; Schmidt, S; Schmitt, S; Schneider, M; Schoeffel, L; Schöning, A; Schröder, V; Schultz Coulon, H C; Schwanenberger, C; Sedlak, K; Sefkow, F; Shevyakov, I; Shtarkov, L N; Sirois, Y; Sloan, T; Smirnov, P; Soloviev, Yu V; South, D; Spaskov, V; Specka, A; Spitzer, H; Stamen, R; Stella, B; Stiewe, J; Strauch, I; Straumann, U; Tchoulakov, V; Thompson, G; Thompson, P D; Tomasz, F; Traynor, D; Trevino, A V; Truöl, P; Tsipolitis, G; Tsuri, I; Turnau, J; Tzamariudaki, E; Uraev, A; Urban, M; Usik, A; Utkin, D; Valkár, S; Valkárová, A; Vallée, C; Van Mechelen, P; Van Remortel, N; Vazdik, Ya A; Veelken, C; Vest, A; Vinokurova, S; Volchinski, V; Wacker, K; Wagner, J; Weber, G; Weber, R; Wegener, D; Werner, C; Werner, N; Wessels, M; Wessling, B; Winter, G G; Wissing, C; Woerling, E E; Wolf, R; Wünsch, E; Xella, S M; Yan, W; Yeganov, V; Zácek, J; Zaleisak, J; Zhang, Z; Zhokin, A; Zohrabyan, H; Zomer, F; 10.1140/epjc/s2004-01978-x

    2004-01-01

    The cross section for antideuteron photoproduction is measured at HERA at a mean centre-of-mass energy of W/sub gamma p/=200 GeV in the range 0.2

    photoproduction to those in central proton-proton collisions at the CERN ISR but much lower than those in central Au-Au collisions at RHIC. The coalescence parameter B/sub 2/, which characterizes the likelihood of antideuteron production, is measured in photoproduction to be 0.010+or-0.002+or-0.001, which is much higher than in Au-Au collisions at a similar nucleon-nucleon centre-of-mass energy. No significant production of particles heavier than deuterons is observed and upper limits are set on the photoproduction cross sections for such particles.

  2. Bound transcription factor suppresses photoproduct formation in the NF-kappa B promoter.

    Science.gov (United States)

    Ghosh, R; Paniker, L; Mitchell, D L

    2001-01-01

    The relationship between purified transcription factor p50 binding and ultraviolet light-induced DNA damage formation in the NF-kappa B promoter element was investigated. The effect of bound transcription factor on cyclobutane dimer formation was quantified using Maxam-Gilbert analysis of irradiated substrate digested with T4 phage endonuclease V. Two methods were employed for cleaving (6-4) photoproducts. Sites of (6-4) photoproducts cleaved by piperidine showed a general suppression in the presence of bound p50 protein similar to that observed for cyclobutane dimers. In contrast to piperidine, digestion with ultraviolet damage endonuclease (UVDE) from Saccharomyces pombe subsequent to cyclobutane dimer reversal by photolyase displayed a broader spectrum of damaged sites. Whereas some of these sites were suppressed by bound p50 protein, some remained unaffected and one site showed increased (6-4) photoproduct induction. These data illustrate the advantage of UVDE over piperidine for studying (6-4) photoproducts at the sequence level and suggest that this approach may be useful for footprinting transcription factor binding in other promoters.

  3. Measurements of inelastic J/psi and psi' photoproduction at HERA

    CERN Document Server

    Chekanov, S; Magill, S; Musgrave, B; Repond, J; Yoshida, R; Mattingly, M C K; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Boscherini, D; Bruni, A; Bruni, G; Cara Romeo, G; Cifarelli, Luisa; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Giusti, P; Iacobucci, G; Margotti, A; Nania, R; Palmonari, F; Pesci, A; Sartorelli, G; Zichichi, A; Aghuzumtsyan, G; Bartsch, D; Brock, I; Goers, S; Hartmann, H; Hilger, E; Irrgang, P; Jakob, H P; Kappes, A; Katz, U F; Kind, O; Paul, E; Rautenberg, J; Renner, R; Schnurbusch, H; Stifutkin, A; Tandler, J; Voss, K C; Wang, M; Weber, A; Bailey, D S; Brook, N H; Cole, J E; Foster, B; Heath, G P; Heath, H F; Robins, S; Rodrigues, E; Scott, J; Tapper, R J; Wing, M; Capua, M; Mastroberardino, A; Schioppa, M; Susinno, G; Kim, J Y; Kim, Y K; Lee, J H; Lim, I T; Pac, M Y; Caldwell, A; Helbich, M; Liu, X; Mellado, B; Ning, Y; Paganis, S; Ren, Z; Schmidke, W B; Sciulli, F; Chwastowski, J; Eskreys, Andrzej; Figiel, J; Olkiewicz, K; Stopa, P; Zawiejski, L; Adamczyk, L; Bold, T; Grabowska-Bold, I; Kisielewska, D; Kowal, A M; Kowal, M; Kowalski, T; Przybycien, M B; Suszycki, L; Szuba, D; Szuba, J; Kotanski, Andrzej; Slominski, W; Bauerdick, L A T; Behrens, U; Bloch, I; Borras, K; Chiochia, V; Dannheim, D; Derrick, Malcolm; Drews, G; Fourletova, J; Fox-Murphy, A; Fricke, U; Geiser, A; Göbel, F; Göttlicher, P; Gutsche, O; Haas, T; Hain, W; Hartner, G F; Hillert, S; Kötz, U; Kowalski, H; Kramberger, G; Labes, H; Lelas, D; Löhr, B; Mankel, R; Melzer-Pellmann, I A; Moritz, M; Notz, D; Petrucci, M C; Polini, A; Raval, A; Schneekloth, U; Selonke, F; Wessoleck, H; Wichmann, R; Wolf, G; Youngman, C; Zeuner, W; López-Duran-Viani, A; Meyer, A; Schlenstedt, S; Barbagli, G; Gallo, E; Genta, C; Pelfer, P G; Bamberger, Andreas; Benen, A; Coppola, N; Bell, M; Bussey, Peter J; Doyle, A T; Glasman, C; Hanlon, S; Lee, S W; Lupi, A; McCance, G J; Saxon, D H; Skillicorn, Ian O; Gialas, I; Bodmann, B; Carli, T; Holm, U; Klimek, K; Krumnack, N; Lohrmann, E; Milite, M; Salehi, H; Stonjek, S; Wick, K; Ziegler, A; Collins-Tooth, C; Foudas, C; Goncalo, R; Long, K R; Metlica, F; Tapper, A D; Cloth, P; Filges, D; Kuze, M; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Pokrovskiy, N S; Zhautykov, B O; Lim, H; Son, D; Barreiro, F; González, O; Labarga, L; Del Peso, J; Redondo, I; Tassi, E; Terron, J; Vázquez, M; Barbi, M; Bertolin, A; Corriveau, F; Ochs, A; Padhi, S; Stairs, D G; Saint-Laurent, M G; Tsurugai, T; Antonov, A; Danilov, P; Dolgoshein, B A; Gladkov, D; Sosnovtsev, V V; Suchkov, S; Dementev, R K; Ermolov, P F; Golubkov, Yu A; Katkov, I I; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Vlasov, N N; Zotkin, S A; Bokel, C; Engelen, J; Grijpink, S; Koffeman, E; Kooijman, P M; Maddox, E; Pellegrino, A; Schagen, S; Tiecke, H G; Tuning, N; Velthuis, J J; Wiggers, L; De Wolf, E; Brümmer, N; Bylsma, B; Durkin, L S; Ling, T Y; Boogert, S; Cooper-Sarkar, A M; Devenish, R C E; Ferrando, J; Grzelak, G; Matsushita, T; Rigby, M; Ruske, O; Sutton, M R; Walczak, R; Brugnera, R; Carlin, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Parenti, A; Posocco, M; Stanco, L; Turcato, M; Heaphy, E A; Oh, B Y; Saull, P R B; Whitmore, J J; Iga, Y; D'Agostini, Giulio; Marini, G; Nigro, A; Cormack, C; Hart, J C; McCubbin, N A; Heusch, C A; Park, I H; Pavel, N; Abramowicz, H; Gabareen, A; Kananov, S; Kreisel, A; Levy, A; Abe, T; Fusayasu, T; Kagawa, S; Kohno, T; Tawara, T; Yamashita, T; Hamatsu, R; Hirose, T; Inuzuka, M; Kitamura, S; Matsuzawa, K; Nishimura, T; Arneodo, M; Ferrero, M I; Monaco, V; Ruspa, M; Sacchi, R; Solano, A; Galea, R; Koop, T; Levman, G M; Martin, J F; Mirea, A; Sabetfakhri, A; Butterworth, J M; Gwenlan, C; Hall-Wilton, R; Jones, T W; Lightwood, M S; Loizides, J H; West, B J; Ciborowski, J; Ciesielski, R; Nowak, R J; Pawlak, J M; Smalska, B; Sztuk, J; Tymieniecka, T; Ukleja, A; Ukleja, J; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Gladilin, L K; Hochman, D; Karshon, U; Kcira, D; Lammers, S; Li, L; Reeder, D D; Savin, A A; Smith, W H; Deshpande, A A; Dhawan, S; Hughes, V W; Straub, P B; Bhadra, S; Catterall, C D; Fourletov, S; Menary, S R; Soares, M; Standage, J

    2003-01-01

    The cross sections for inelastic photoproduction of J/psi and psi' mesons have been measured in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 38.0 pb-1. The events were required to have 0.1 0.4 is compared to leading-order QCD predictions.

  4. Unique Prediction for High-Energy J/\\psi Photoproduction: Color Transparency and Saturation

    CERN Document Server

    Schildknecht, Dieter

    2016-01-01

    Based on the color-dipole picture, we present a successful parameter-free prediction for the recent high-energy $J/\\psi$ photoproduction data from the Large Hadron Collider. The experimental data provide empirical evidence for the transition from color transparency to saturation.

  5. Effect of Sigma-beam Asymmetry Data on the Neutron in Fits to Single Pion Photoproduction

    CERN Document Server

    Strakovsky, I I; Briscoe, W J; Paris, M W; Workman, R L

    2011-01-01

    We investigate the influence of new GRAAL Sigma-beam asymmetry measurements on the neutron in multipole fits to the single-pion photoproduction database. Results are compared to those found with the addition of a double-polarization quantity associated with the sum rule.

  6. Helicity Asymmetry Measurement for pi0 Photoproduction with FROST

    Energy Technology Data Exchange (ETDEWEB)

    Iwamoto, Hideko [George Washington Univ., Washington, DC (United States)

    2011-08-15

    This thesis reports on the first helicity asymmetry measurement for single neutral pion photoproduction using the CLAS detector in Hall B at the Thomas Jefferson National Accelerator Facility (JLab). This measurement used longitudinally polarized protons and circularly polarized photons at energies between 350 MeV and 2400 MeV. The experimental results are compared to three available model calculations.

  7. Chiral Dynamics and Dubna-Mainz-Taipei Dynamical Model for Pion-Photoproduction Reaction

    CERN Document Server

    Yang, Shin Nan

    2010-01-01

    We demonstrate that the Dubna-Mainz-Taipei (DMT) meson-exchange dynamical model, which starts from an effective chiral Lagrangian, for pion photoproduction provides an excellent and economic framework to describe both the pi^0 threshold production and the Delta deformation, two features dictated by chiral dynamics.

  8. Simulation of diffractive and non diffractive heavy quark photoproduction at the tevatron energies

    International Nuclear Information System (INIS)

    A simulation of diffractive and non diffractive heavy quark photoproduction at the tevatron energies is described. The diffractive process is simulated using the photon-gluon fusion model, while for the non diffractive production the photon hadronic behaviour in the framework is applied

  9. Induction of UV photoproducts and DNA damage by solar simulator UV irradiation

    International Nuclear Information System (INIS)

    The recent increased incidence of skin cancer and the depletion of the ozone layer has increased interest in the ultraviolet (UV) component of natural sunlight and its role in the induction of skin cancer. Previous research on UV radiation has concentrated on UVC (254nm) but, as only UVB and UVA are present in natural sunlight, its relevance is unknown. We have investigated the induction of two forms of direct DNA damage - the pyrimidine dimer and the (6-4) photoproduct - in human DNA repair deficient XP-G (Xeroderma pigmentosum group G) lymphoblastoid cells following exposure to simulated sunlight. As exposure to natural sunlight is highly variable, a solar simulator lamp was used which is known to mimic natural sunlight at midday in Central Europe. Cells were irradiated on ice to minimise DNA repair and the relative induction of pyrimidine dimers and (6-4) photoproducts was measured using specific monoclonal antibodies and a computer assisted image analysis system. A time dependent increase in both cyclobutane dimer and (6-4) photoproduct antibody binding sites was seen. The increases in pyrimidine dimer and (6-4) photoproduct antibody binding sites differed to that reported with natural sunlight in the UK but was similar to that seen with a similar solar simulator lamp

  10. Measurement of anti-deuteron photoproduction and a search for heavy stable charged particles at HERA

    International Nuclear Information System (INIS)

    The cross section for anti-deuteron photoproduction is measured at HERA at a mean centre-of-mass energy of Wγp = 200 GeV in the range 0.2 T/M T and y are the mass, transverse momentum and rapidity in the laboratory frame of the anti-deuteron, respectively. The numbers of anti-deuterons per event are found to be similar in photoproduction to those in central proton-proton collisions at the CERN ISR but much lower than those in central Au-Au collisions at RHIC. The coalescence parameter B2, which characterizes the likelihood of anti-deuteron production, is measured in photoproduction to be 0.010 ± 0.002 ± 0.001, which is much higher than in Au-Au collisions at a similar nucleon-nucleon centre-of-mass energy. No significant production of particles heavier than deuterons is observed and upper limits are set on the photoproduction cross sections for such particles. (orig.)

  11. Measurement of Anti-Deuteron Photoproduction and a Search for Heavy Stable Charged Particles at HERA

    CERN Document Server

    Aktas, A; Anthonis, T; Asmone, A; Babaev, A; Backovic, S; Bähr, J; Baranov, P; Barrelet, E; Bartel, Wulfrin; Baumgartner, S; Becker, J; Beckingham, M; Behnke, O; Behrendt, O; Belousov, A; Berger, C; Berger, N; Berndt, T; Bizot, J C; Böhme, J; Boenig, M O; Boudry, V; Bracinik, J; Brisson, V; Broker, H B; Brown, D P; Bruncko, Dusan; Büsser, F W; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Caron, S; Cassol-Brunner, F; Cerny, K; Chekelian, V; Collard, Caroline; Contreras, J G; Coppens, Y R; Coughlan, J A; Cox, B E; Cozzika, G; Cvach, J; Dainton, J B; Dau, W D; Daum, K; Delcourt, B; Demirchyan, R; de Roeck, A; Desch, Klaus; De Wolf, E A; Diaconu, C; Dingfelder, J; Dodonov, V; Dubak, A; Duprel, C; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, F; Ellerbrock, M; Elsen, E; Erdmann, M; Erdmann, W; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Ferencei, J; Fleischer, M; Fleischmann, P; Fleming, Y H; Flucke, G; Flügge, G; Fomenko, A; Foresti, I; Formánek, J; Franke, G; Frising, G; Gabathuler, Erwin; Gabathuler, K; Garutti, E; Garvey, J; Gayler, J; Gerhards, R; Gerlich, C; Ghazaryan, S; Görlich, L; Gogitidze, N; Gorbounov, S; Grab, C; Grässler, Herbert; Greenshaw, T; Gregori, M; Grindhammer, G; Gwilliam, C; Haidt, Dieter; Hajduk, L; Haller, J; Hansson, M; Heinzelmann, G; Henderson, R C W; Henschel, H; Henshaw, O; Heremans, R; Herrera-Corral, G; Herynek, I; Heuer, R D; Hildebrandt, M; Hiller, K H; Hoting, P; Hoffmann, D; Horisberger, R P; Hovhannisyan, A V; Ibbotson, M; Ismail, M; Jacquet, M; Janauschek, L; Janssen, X; Jemanov, V; Jönsson, L B; Johnson, D P; Jung, H; Kant, D; Kapichine, M; Karlsson, M; Katzy, J; Keller, N; Kennedy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Klimkovich, T; Kluge, T; Knies, G; Knutsson, A; Koblitz, B; Korbel, V; Kostka, P; Koutouev, R; Kropivnitskaya, A; Kroseberg, J; Kuckens, J; Kuhr, T; Landon, M P J; Lange, W; Lastoviicka, T; Laycock, P; Lebedev, A; Leiner, B; Lemrani, R; Lendermann, V; Levonian, S; Lindfeld, L; Lipka, K; List, B; Lobodzinska, E; Loktionova, N A; López-Fernandez, R; Lubimov, V; Lüders, H; Lüke, D; Lux, T; Lytkin, L; Makankine, A; Malden, N; Malinovskii, E I; Mangano, S; Marage, P; Marks, J; Marshall, R; Martisikova, M; Martyn, H U; Maxfield, S J; Meer, D; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, J; Michine, S; Mikocki, S; Milcewicz, I; Milstead, D; Mohamed, A; Moreau, F; Morozov, A; Morozov, I; Morris, J V; Mozer, M U; Müller, K; Murn, P; Nagovizin, V; Naroska, Beate; Naumann, J; Naumann, T; Newman, P R; Niebuhr, C B; Nikiforov, A; Nikitin, D K; Nowak, G; Nozicka, M; Oganezov, R; Olivier, B; Olsson, J E; Ossoskov, G; Ozerov, D; Pascaud, C; Patel, G D; Peez, M; Pérez, E; Perieanu, A; Petrukhin, A; Pitzl, D; Placakyte, R; Pöschl, R; Portheault, B; Povh, B; Raicevic, N; Ratiani, Z; Reimer, P; Reisert, B; Rimmer, A; Risler, C; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A A; Rurikova, Z; Rusakov, S V; Rybicki, K; Sankey, D P C; Sauvan, E; Schatzel, S; Scheins, J; Schilling, F P; Schleper, P; Schmidt, S; Schmitt, S; Schneider, M; Schoeffel, L; Schöning, A; Schröder, V; Schultz-Coulon, H C; Schwanenberger, C; Sedlak, K; Sefkow, F; Shevyakov, I; Shtarkov, L N; Sirois, Y; Sloan, T; Smirnov, P; Soloviev, Yu; South, D; Spaskov, V; Specka, A; Spitzer, H; Stamen, R; Stella, B; Stiewe, J; Strauch, I; Straumann, U; Tchoulakov, V; Thompson, G; Thompson, P D; Tomasz, F; Traynor, D; Truöl, P; Tsipolitis, G; Tsurin, I; Turnau, J; Tzamariudaki, E; Uraev, A; Urban, M; Usik, Distiller 3011 page 2A; Utkin, D; Valkár, S; Valkárová, A; Vallée, C; Van Mechelen, P; Van, N; Remortel; Vargas-Trevino, A; Vazdik, Ya A; Veelken, C; Vest, A; Vinokurova, S; Volchinski, V; Wacker, K; Wagner, J; Weber, G; Weber, R; Wegener, D; Werner, C; Werner, N; Wessels, M; Wessling, B; Winter, G G; Wissing, C; Woerling, E E; Wolf, R; Wünsch, E; Xella, S M; Yan, W; Yeganov, V; Zaicek, J; Zaleisak, J; Zhang, Z; Zhokin, A; Zohrabyan, H G; Zomer, F

    2004-01-01

    The cross section for anti-deuteron photoproduction is measured at HERA at a mean centre-of-mass energy of W_{\\gamma p} = 200 GeV in the range 0.2 < p_T/M < 0.7 and |y| < 0.4, where M, p_T and y are the mass, transverse momentum and rapidity in the laboratory frame of the anti-deuteron, respectively. The numbers of anti-deuterons per event are found to be similar in photoproduction to those in central proton-proton collisions at the CERN ISR but much lower than those in central Au-Au collisions at RHIC. The coalescence parameter B_2, which characterizes the likelihood of anti-deuteron production, is measured in photoproduction to be 0.010 \\pm 0.002 \\pm 0.001, which is much higher than in Au-Au collisions at a similar nucleon-nucleon centre-of-mass energy. No significant production of particles heavier than deuterons is observed and upper limits are set on the photoproduction cross sections for such particles.

  12. Spectrally resolved efficiencies of carbon monoxide (CO photoproduction in the western Canadian Arctic: particles versus solutes

    Directory of Open Access Journals (Sweden)

    G. Song

    2013-06-01

    Full Text Available Spectrally resolved efficiency (i.e. apparent quantum yield, AQY of carbon monoxide (CO photoproduction is a useful indicator of substrate photoreactivity and a crucial parameter for modeling CO photoproduction rates in the water column. Recent evidence has suggested that CO photoproduction from particles in marine waters is significant compared to the well-known CO production from chromophoric dissolved organic matter (CDOM photodegradation. Although CDOM-based CO AQY spectra have been extensively determined, little is known of this information on the particulate phase. Using water samples collected from the Mackenzie estuary, shelf, and Canada Basin in the southeastern Beaufort Sea, the present study for the first time quantified the AQY spectra of particle-based CO photoproduction and compared them with the concomitantly determined CDOM-based CO AQY spectra. CO AQYs of both particles and CDOM decreased with wavelength but the spectral shape of the particulate AQY was flatter in the visible regime. This feature resulted in a disproportionally higher visible light-driven CO production by particles, thereby increasing the ratio of particle- to CDOM-based CO photoproduction with depth in the euphotic zone. In terms of depth-integrated production in the euphotic zone, CO formation from CDOM was dominated by the ultraviolet (UV, 290–400 nm radiation whereas UV and visible light played roughly equal roles in CO production from particles. Spatially, CO AQY of bulk particulate matter (i.e. the sum of organics and inorganics augmented from the estuary and shelf to the basin while CO AQY of CDOM trended inversely. Water from the deep chlorophyll maximum layer revealed higher CO AQYs than did surface water for both particles and CDOM. CO AQY of bulk particulate matter exceeded that of CDOM on the shelf and in the basin, but the sequence reversed in the estuary. Without consideration of the potential role of metal oxides (e.g. iron oxides in particle

  13. Spectrally resolved efficiencies of carbon monoxide (CO photoproduction in the Western Canadian Arctic: particles versus solutes

    Directory of Open Access Journals (Sweden)

    G. Song

    2012-11-01

    Full Text Available Spectrally resolved efficiency (i.e. apparent quantum yield, AQY of carbon monoxide (CO photoproduction is a useful indicator of substrate photoreactivity and a crucial parameter for modeling CO photoproduction rates in the water column. Recent evidence has suggested that CO photoproduction from particles in marine waters is significant compared to the well-known CO production from chromophoric dissolved organic matter (CDOM photodegradation. Although CDOM-based CO AQY spectra have been extensively determined, little is known of this information on the particulate phase. Using water samples collected from the Mackenzie estuary, shelf, and Canada Basin in the Southeastern Beaufort Sea, the present study for the first time quantified the AQY spectra of particle-based CO photoproduction and compared them with the concomitantly determined CDOM-based CO AQY spectra. CO AQYs of both particles and CDOM decreased with wavelength but the spectral shape of the particulate AQY was flatter in the visible regime. This feature resulted in a disproportionally higher visible light-driven CO production by particles, thereby increasing the ratio of particle- to CDOM-based CO photoproduction with depth in the euphotic zone. In terms of depth-integrated production in the euphotic zone, CO formation from CDOM was dominated by the ultraviolet (UV, 290–400 nm radiation whereas UV and visible light played roughly equal roles in CO production from particles. Spatially, CO AQY of bulk particulate matter (i.e. the sum of organics and inorganics augmented from the estuary to shelf to basin while CO AQY of CDOM trended inversely. Water from the deep chlorophyll maximum layer revealed higher CO AQYs than did surface water for both particles and CDOM. CO AQY of bulk particulate matter exceeded that of CDOM on the shelf and in the basin but the sequence reversed in the estuary. Mineral absorption-corrected CO AQY of particulate organic matter (POM was, however, greater than

  14. Diffractive Photoproduction of Psi(2S) in Photon-Pomeron Reactions in PbPb Collisions at the CERN LHC

    CERN Document Server

    Ducati, M B Gay; Machado, M V T

    2014-01-01

    This work investigates the exclusive photoproduction of $\\psi(2S)$ meson off nuclei evaluating the coherent and the incoherent contributions. The theoretical framework used in the present analysis is the light-cone dipole formalism and predictions are done for PbPb collisions at the CERN-LHC energy of 2.76 TeV. A comparison is done to the recent ALICE Collaboration data for the $\\psi(1S)$ state photoproduction.

  15. In vitro residual anti-bacterial activity of difloxacin, sarafloxacin and their photoproducts after photolysis in water

    Energy Technology Data Exchange (ETDEWEB)

    Kusari, Souvik; Prabhakaran, Deivasigamani; Lamshoeft, Marc [Institut fuer Umweltforschung (INFU), Technische Universitaet Dortmund, Otto-Hahn-Strasse 6, D-44221 Dortmund (Germany); Spiteller, Michael, E-mail: m.spiteller@infu.uni-dortmund.d [Institut fuer Umweltforschung (INFU), Technische Universitaet Dortmund, Otto-Hahn-Strasse 6, D-44221 Dortmund (Germany)

    2009-10-15

    Fluoroquinolones like difloxacin (DIF) and sarafloxacin (SARA) are adsorbed in soil and enter the aquatic environment wherein they are subjected to photolytic degradation. To evaluate the fate of DIF and SARA, their photolysis was performed in water under stimulated natural sunlight conditions. DIF primarily degrades to SARA. On prolonged photodegradation, seven photoproducts were elucidated by HR-LC-MS/MS, three of which were entirely novel. The residual anti-bacterial activities of DIF, SARA and their photoproducts were studied against a group of pathogenic strains. DIF and SARA revealed potency against both Gram-positive and -negative bacteria. The photoproducts also exhibited varying degrees of efficacies against the tested bacteria. Even without isolating the individual photoproducts, their impact on the aquatic environment could be assessed. Therefore, the present results call for prudence in estimating the fate of these compounds in water and in avoiding emergence of resistance in bacteria caused by the photoproducts of DIF and SARA. - Assessment of the residual anti-bacterial efficacies of difloxacin, sarafloxacin and their photoproducts in water, and estimating their impact on the aquatic environment in inducing resistance to microorganisms.

  16. Production of hydrogen in non oxygen-evolving systems: co-produced hydrogen as a bonus in the photodegradation of organic pollutants and hydrogen sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Sartoretti, C. Jorand; Ulmann, M.; Augustynski, J. (Electrochemistry Laboratory, Department of Chemistry, University of Geneva (CH)); Linkous, C.A. (Florida Solar Energy Center, University of Central Florida (US))

    2000-01-01

    This report was prepared as part of the documentation of Annex 10 (Photoproduction of Hydrogen) of the IEA Hydrogen Agreement. Subtask A of this Annex concerned photo-electrochemical hydrogen production, with an emphasis on direct water splitting. However, studies of non oxygen-evolving systems were also included in view of their interesting potential for combined hydrogen production and waste degradation. Annex 10 was operative from 1 March 1995 until 1 October 1998. One of the collaborative projects involved scientists from the Universities of Geneva and Bern, and the Federal Institute of Technology in Laussane, Switzerland. A device consisting of a photoelectrochemical cell (PEC) with a WO{sub 3} photoanode connected in series with a so-called Grazel cell (a dye sensitized liquid junction photovoltaic cell) was developed and studied in this project. Part of these studies concerned the combination of hydrogen production with degradation of organic pollutants, as described in Chapter 3 of this report. For completeness, a review of the state of the art of organic waste treatment is included in Chapter 2. Most of the work at the University of Geneva, under the supervision of Prof. J. Augustynski, was focused on the development and testing of efficient WO{sub 3} photoanodes for the photoelectrochemical degradation of organic waste solutions. Two types of WO{sub 3} anodes were developed: non transparent bulk photoanodes and non-particle-based transparent film photoanodes. Both types were tested for degradation and proved to be very efficient in dilute solutions. For instance, a solar-to-chemical energy conversion efficiency of 9% was obtained by operating the device in a 0.01M solution of methanol (as compared to about 4% obtained for direct water splitting with the same device). These organic compounds are oxidized to CO{sub 2} by the photocurrent produced by the photoanode. The advantages of this procedure over conventional electrolytic degradation are that much (an

  17. J/psi Photo-production at Large z in Soft Collinear Effective Theory

    CERN Document Server

    Fleming, S; Mehen, T; Fleming, Sean; Leibovich, Adam K.; Mehen, Thomas

    2005-01-01

    One of the outstanding problems in J/\\psi physics is a systematic understanding of the differential photo-production cross section dsigma/dz(gamma + p -> J/psi + X), where z= E_psi/E_gamma in the proton rest frame. The theoretical prediction based on the non-relativistic QCD (NRQCD) factorization formalism has a color-octet contribution which grows rapidly in the endpoint region, z -> 1, spoiling perturbation theory. In addition there are subleading operators which are enhanced by powers of 1/(1-z) and they must be resummed to all orders. Here an update of a systematic analysis is presented. The approach used to organize the endpoint behavior of the photo-production cross section is based on a combination of NRQCD and soft collinear effective theory. While a final result is not yet available, an intermediate result indicates that better agreement between theory and data will be achieved in this framework.

  18. Leading neutron energy and pT distributions in deep inelastic scattering and photoproduction at HERA

    CERN Document Server

    Chekanov, S; Abt, I; Adamczyk, L; Adamus, M; Adler, V; Allfrey, P D; Antonelli, S; Antonioli, P; Antonov, A; Arneodo, M; Bamberger, A; Barakbaev, A N; Barbagli, G; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bell, M A; Bellagamba, L; Bellan, P; Bertolin, A; Bhadra, S; Bindi, M; Bloch, I; Blohm, C; Bold, T; Bonato, A; Boos, E G; Borras, K; Boscherini, D; Boutle, S K; Brock, I; Brook, N H; Brownson, E; Brugnera, R; Bruni, A; Bruni, G; Brzozowska, B; Brümmer, N; Bussey, P J; Butterworth, J M; Bylsma, B; Büttner, C; Caldwell, A; Capua, M; Carlin, R; Catterall, C D; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, L; Cindolo, F; Cole, J E; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Cottrell, A; Cui, Y; D'Agostini, G; Dal Corso, F; Danielson, T; De Favereau, J; De Pasquale, S; Del Peso, J; Dementiev, R K; Derrick, M; Devenish, R C E; Dobur, D; Dolgoshein, B A; Dossanov, A; Doyle, A T; Dunne, W; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, A; Estrada; Everett, A; Fazio, S; Ferrando, J; Ferrero, M I; Figiel, J; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fry, C; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Gialas, I; Gil, M; Giller, I; Gladilin, L K; Gladkov, D; Glasman, C; Goers, S; Gosau, T; Grabowska-Bold, I; Gregor, I; Grigorescu, G; Grzelak, G; Gwenlan, C; Göttlicher, P; Haas, T; Hain, W; Hamatsu, R; Hart, J C; Hartmann, H; Hartner, G; Heath, G P; Hilger, E; Hochman, D; Holm, U; Hori, R; Horn, C; Iacobucci, G; Ibrahim, Z A; Iga, Y; Ingbir, R; Jakob, H P; Jechow, M; Jiménez, M; Jones, T W; Jüngst, M; Kagawa, S; Kahle, B; Kaji, H; Kamaluddin, B; Kananov, S; Karshon, U; Karstens, F; Kataoka, M; Katkov, I I; Kcira, D; Keramidas, A; Khein, L A; Kim, J Y; Kind, O M; Kisielewska, D; Kitamura, S; Klanner, R; Klein, U; Koffeman, E; Kollar, D; Kooijman, P; Korcsak-Gorzo, K; Korzhavina, I A; Kotanski, A; Kowalski, H; Kulinski, P; Kuze, M; Kuzmin, V A; Kötz, U; Labarga, L; Lee, A; Levchenko, B B; Levy, A; Limentani, S; Ling, T Y; Liu, C; Lobodzinska, E; Lohmann, W; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukasik, J; Lukina, O Yu; Luzniak, P; Löhr, B; Ma, K J; Magill, S; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Mastroberardino, A; Matsumoto, T; Mattingly, M C K; Melzer-Pellmann, I A; Menary, S; Miglioranzi, S; Monaco, V; Montanari, A; Morris, J D; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nicholass, D; Nigro, A; Ning, Y; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Okazaki, N; Olkiewicz, K; Ota, O; Patel, S; Paul, E; Pavel, N; Pawlak, J M; Pelfer, P G; Pellegrino, A; Piotrzkowski, K; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycien, M; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Ri, Y D; Rinaldi, L; Roberfroid, V; Robertson, A; Ron, E; Rosin, M; Rubinsky, I; Ruspa, M; Ryan, P; Sacchi, R; Salehi, H; Samson, U; San, R; Sartorelli, G; Savin, A A; Saxon, D H; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schonberg, V; Schörner-Sadenius, T; Sciulli, F; Shcheglova, L M; Shehzadi, R; Shimizu, S; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V; Spiridonov, A; Stadie, H; Stanco, L; Standage, J; Stifutkin, A; Stopa, P; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutiak, J; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tapper, A D; Targett-Adams, C; Tassi, E; Tawara, T; Terron, J; Theedt, T; Tiecke, H; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Ukleja, A; Ukleja, J; Uribe-, C; Vlasov, N N; Vázquez, M; Walczak, R; Walsh, R; Wan-Abdullah, W A T; Whitmore, J J; Whyte, J; Wichmann, K; Wick, K; Wiggers, L; Wing, M; Wlasenko, M; Wolf, G; Wolfe, H; Wrona, K; Yagues-Molina, A G; Yamada, S; Yamazaki, Y; Yoshida, R; Youngman, C; Zambrana, M; Zarnecki, A F; Zaw, I; Zeuner, W; Zhautykov, B O; Zhou, C; Zichichi, A; Zotkin, D S; Zotkin, S A

    2007-01-01

    The production of energetic neutrons in $ep$ collisions has been studied with the ZEUS detector at HERA. The neutron energy and $p_T^2$ distributions were measured with a forward neutron calorimeter and tracker in a $40 \\pb^{-1}$ sample of inclusive deep inelastic scattering (DIS) data and a $6 \\pb^{-1}$ sample of photoproduction data. The neutron yield in photoproduction is suppressed relative to DIS for the lower neutron energies and the neutrons have a steeper $p_T^2$ distribution, consistent with the expectation from absorption models. The distributions are compared to HERA measurements of leading protons. The neutron energy and transverse-momentum distributions in DIS are compared to Monte Carlo simulations and to the predictions of particle exchange models. Models of pion exchange incorporating absorption and additional secondary meson exchanges give a good description of the data.

  19. Three- and four-jet final states in photoproduction at HERA

    CERN Document Server

    Chekanov, S; Magill, S; Musgrave, B; Nicholass, D; Repond, J; Yoshida, R; Mattingly, M C K; Jechow, M; Pavel, N; Yagues-Molina, A G; Antonelli, S; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Bindi, M; Boscherini, D; Bruni, A; Bruni, G; Cifarelli, L; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Iacobucci, G; Margotti, A; Nania, R; Polini, A; Sartorelli, G; Zichichi, A; Bartsch, D; Brock, I; Hartmann, H; Hilger, E; Jakob, H P; Jüngst, M; Kind, O M; Nuncio-Quiroz, A E; Paul, E; Renner, R; Samson, U; Schonberg, V; Shehzadi, R; Wlasenko, M; Brook, N H; Heath, G P; Morris, J D; Capua, M; Fazio, S; Mastroberardino, A; Schioppa, M; Susinno, G; Tassi, E; Kim, J Y; Ma, K J; Ibrahim, Z A; Kamaluddin, B; Wan-Abdullah, W A T; Ning, Y; Ren, Z; Sciulli, F; Chwastowski, J; Eskreys, A; Figiel, J; Galas, A; Gil, M; Olkiewicz, K; Stopa, P; Zawiejski, L; Adamczyk, L; Bold, T; Grabowska-Bold, I; Kisielewska, D; Lukasik, J; Przybycien, M; Suszycki, L; Kotanski, A; Slominski, W; Adler, V; Behrens, U; Bloch, I; Blohm, C; Bonato, A; Borras, K; Ciesielski, R; Coppola, N; Dossanov, A; Drugakov, V; Fourletova, J; Geiser, A; Gladkov, D; Göttlicher, P; Grebenyuk, J; Gregor, I; Haas, T; Hain, W; Horn, C; Huttmann, A; Kahle, B; Katkov, I I; Klein, U; Kötz, U; Kowalski, H; Lobodzinska, E; Löhr, B; Mankel, R; Melzer-Pellmann, I A; Miglioranzi, S; Montanari, A; Namsoo, T; Notz, D; Rinaldi, L; Roloff, P; Rubinsky, I; Santamarta, R; Schneekloth, U; Spiridonov, A; Stadie, H; Szuba, D; Szuba, J; Theedt, T; Wolf, G; Wrona, K; Youngman, C; Zeuner, W; Lohmann, W; Schlenstedt, S; Barbagli, G; Gallo, E; Pelfer, P G; Bamberger, A; Dobur, D; Karstens, F; Vlasov, N N; Bussey, P J; Doyle, A T; Dunne, W; Forrest, M; Saxon, D H; Skillicorn, I O; Gialas, I; Papageorgiu, K; Gosau, T; Holm, U; Klanner, R; Lohrmann, E; Salehi, H; Schleper, P; Schörner-Sadenius, T; Sztuk, J; Wichmann, K; Wick, K; Foudas, C; Fry, C; Long, K R; Tapper, A D; Kataoka, M; Matsumoto, T; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Pokrovskiy, N S; Zhautykov, B O; Aushev, V; Borodin, M; Kozulia, A; Lisovyi, M; Son, D; De Favereau, J; Piotrzkowski, K; Barreiro, F; Glasman, C; Jiménez, M; Labarga, L; Del Peso, J; Ron, E; Soares, M; Terron, J; Zambrana, M; Corriveau, F; Liu, C; Walsh, R; Zhou, C; Tsurugai, T; Antonov, A; Dolgoshein, B A; Sosnovtsev, V; Stifutkin, A; Suchkov, S; Dementiev, R K; Ermolov, P F; Gladilin, L K; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Zotkin, D S; Zotkin, S A; Abt, I; Büttner, C; Caldwell, A; Kollar, D; Schmidke, W B; Sutiak, J; Grigorescu, G; Keramidas, A; Koffeman, E; Kooijman, P; Pellegrino, A; Tiecke, H; Vázquez, M; Wiggers, L; Brümmer, N; Bylsma, B; Durkin, L S; Lee, A; Ling, T Y; Allfrey, P D; Bell, M A; Cooper-Sarkar, A M; Devenish, R C E; Ferrando, J; Fos-ter, B; Korcsak-Gorzo, K; Oliver, K; Patel, S; Roberfroid, V; Robertson, A; Straub, P B; Uribe-Estrada, C; Walczak, R; Bellan, P; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Stanco, L; Turcato, M; Oh, B Y; Raval, A; Ukleja, J; Whitmore, J J; Iga, Y; D'Agostini, Distiller 3011 page IVG; Marini, G; Nigro, A; Cole, J E; Hart, J C; Abramowicz, H; Gabareen, A; Ingbir, R; Kananov, S; Levy, A; Kuze, M; Maeda, J; Hori, R; Kagawa, S; Okazaki, N; Shimizu, S; Tawara, T; Hamatsu, R; Kaji, H; Kitamura, S; Ota, O; Ri, Y D; Ferrero, M I; Monaco, V; Sacchi, R; Solano, A; Arneodo, M; Ruspa, M; Fourletov, S; Martin, J F; Boutle, S K; Butterworth, J M; Gwenlan, C; Jones, T W; Loizides, J H; Sutton, M R; Wing, M; Brzozowska, B; Ciborowski, J; Grzelak, G; Kulinski, P; Luzniak, P; Malka, J; Nowak, R J; Pawlak, J M; Tymieniecka, T; Ukleja, A; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Giller, I; Hochman, D; Karshon, U; Rosin, M; Brownson, E; Danielson, T; Everett, A; Kcira, D; Reeder, D D; Ryan, P; Savin, A A; Smith, W H; Wolfe, H; Bhadra, S; Catterall, C D; Cui, Y; Hartner, G; Menary, S; Noor, U; Standage, J; Whyte, J

    2007-01-01

    Three- and four-jet final states have been measured in photoproduction at HERA using the ZEUS detector with an integrated luminosity of 121 pb^-1. The results are presented for jets with transverse energy E_T^jet>6 GeV and pseudorapidity |eta^jet|50 GeV, where M_nj is the invariant mass of the n-jet system. The four-jet photoproduction cross section has been measured for the first time and represents the highest-order process studied at HERA. Both the three- and four-jet cross sections have been compared with leading-logarithmic parton-shower Monte Carlo models, with and without multi-parton interactions. The three-jet cross sections have been compared to an order(alpha alpha_s^2) perturbative QCD calculation.

  20. Upper limits for the photoproduction cross section for the Phi--(1860) pentaquark state off the deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Hovanes Egiyan

    2012-01-01

    We searched for the {Phi}{sup --}(1860) pentaquark in the photoproduction process off the deuteron in the {Xi}{sup -} {pi}{sup -} decay channel using CLAS. The invariant mass spectrum of the {Xi}{sup -} {pi}{sup -} system does not indicate any statistically significant enhancement near the reported mass M = 1.860 GeV. The statistical analysis of the sideband-subtracted mass spectrum yields a 90% confidence level upper limit of 0.7 nb for the photoproduction cross section of {Phi}{sup --}(1860) with a consecutive decay into {Xi}{sup -} {pi}{sup -} in the photon energy range 4.5 GeV < E{sub {gamma}} < 5.5 GeV.

  1. Photoproduction of vector mesons: from ultraperipheral to semi-central heavy ion collisions

    CERN Document Server

    Klusek-Gawenda, M

    2016-01-01

    We discuss nuclear cross sections for $AA \\to AAV$ and $AA \\to AAVV$ reactions with one or two vector mesons in the final state. Our analysis is done in the impact parameter space equivalent photon approximation. This approach allows to consider the above processes taking into account distance between colliding nuclei. We consider both ultraperipheral and semi-central collisions. We are a first group which undertook a study of single $J/\\psi$ photoproduction for different centrality bins. We show that one can describe new ALICE experimental data by including geometrical effects of collisions in the flux factor. Next, total and differential cross section for double-scattering mechanism in the exclusive $AA \\to AAVV$ reaction in ultrarelativistic ultraperipheral heavy ion collisions is presented. In this context we consider double photoproduction and photon-photon processes. Simultaneously, we get very good agreement of our results with STAR (RHIC), CMS and ALICE (LHC) experimental data for single $\\rho^0$ and ...

  2. Observation of the positive-strangeness pentaquark $\\Theta^+$ in photoproduction with the SAPHIR detector at ELSA

    CERN Document Server

    Barth, J; Ernst, J; Glander, K H; Hannappel, J; Jöpen, N; Kalinowsky, H; Klein, F; Klempt, E; Lawall, R; Link, J; Menze, D W; Neuerburg, W; Ostrick, M; Paul, E; Van Pee, H; Schulday, I; Schwille, W J; Wiegers, B; Wieland, F W; Wisskirchen, J; Wu, C

    2003-01-01

    The positive--strangeness baryon resonance $\\Theta^+$ is observed in photoproduction of the $\\rm nK^+K^0_s$ final state with the SAPHIR detector at the Bonn ELectron Stretcher Accelerator ELSA. It is seen as a peak in the $\\rm nK^+$ invariant mass distribution with a $4.8\\sigma$ confidence level. We find a mass $\\rm M_{\\Theta^+} = 1540\\pm 4\\pm 2$ MeV and an upper limit of the width $\\rm \\Gamma_{\\Theta^+} < 25$ MeV at 90% c.l. The photoproduction cross section for $\\rm\\bar K^0\\Theta^+$ is in the order of 300 nb. From the absence of a signal in the $\\rm pK^+$ invariant mass distribution in $\\rm\\gamma p\\to pK^+K^-$ at the expected strength we conclude that the $\\Theta^+$ must be isoscalar.

  3. Beam asymmetry Σ in η′ photoproduction off the proton at the GRAAL experiment

    Directory of Open Access Journals (Sweden)

    Mandaglio G.

    2014-06-01

    Full Text Available The only recent η′ photoproduction data off proton available in literature are the differential and total cross sections published by the CLAS and CB-ELSA-TAPS Collaborations. However, the wide information about reaction cross sections are not sufficient to understand the role of resonances involved in the process. Different theoretical works stressed the importance to measure also polarization observables in order to solve the ambiguities in the choice of the parameters used in their models. We present the analysis of η′ photoproduction off the proton analysis, identifying the investigated meson by the π+π−η, π0π0η, and γγ decay modes by using the GRAAL apparatus; and we show the preliminary GRAAL results on the beam asymmetry Σ at beam energy of 1475 MeV.

  4. Evidence for a narrow N(1685) resonance in eta photoproduction off the nucleon

    CERN Document Server

    Kuznetsov, V; Boiko, T; Jang, J; Kim, A; Kim, W; Lee, H S; Ni, A; Yang, G -S

    2008-01-01

    Revised analysis of Sigma beam asymmetry for eta photoproduction off the free proton from GRAAL is presented. New analysis reveals a narrow structure near W ~1.685 GeV. We describe this structure by the contribution of a narrow resonance with quantum numbers P_{11}, or P_{13}, or D_{13}. Being considered together with the recent observations of a bump-like structure at W~1.68 GeV in the quasi-free eta photoproduction off the neutron, this result provides an evidence for a narrow (Gamma < 25 MeV) N*(1685) resonance. Properties of this possible new nucleon state, namely the mass, the narrow width, and the much stronger photocoupling to the neutron, are similar to those predicted for the non-strange member of anti-decouplet of exotic baryons.

  5. Studying the P_c(4450) resonance in J/psi photoproduction off protons

    CERN Document Server

    Blin, A N Hiller; Jackura, A; Mathieu, V; Mokeev, V I; Pilloni, A; Szczepaniak, A P

    2016-01-01

    A resonance-like structure, the P_c(4450), has recently been observed in the J/psi p spectrum by the LHCb collaboration. We discuss the feasibility of detecting this structure in J/psi photoproduction in the CLAS12 experiment at JLab. We present a first estimate of the upper limit for the branching ratio of the P_c(4450) to J/psi p. Our estimates, which take into account the experimental resolution effects, predict that it will be possible to observe a sizable cross section close to the J/psi production threshold and shed light on the P_c(4450) resonance in the future photoproduction measurements.

  6. Photoproduction of the rho(0) meson on the proton at large momentum transfer.

    Science.gov (United States)

    Battaglieri, M; Anciant, E; Anghinolfi, M; De Vita, R; Golovach, E; Laget, J M; Mokeev, V; Ripani, M; Adams, G; Amaryan, M J; Armstrong, D S; Asavapibhop, B; Asryan, G; Audit, G; Auger, T; Avakian, H; Barrow, S; Beard, K; Bektasoglu, M; Berman, B L; Bianchi, N; Biselli, A S; Boiarinov, S; Branford, D; Briscoe, W J; Brooks, W K; Burkert, V D; Calarco, J R; Capitani, G P; Carman, D S; Carnahan, B; Cazes, A; Cetina, C; Cole, P L; Coleman, A; Cords, D; Corvisiero, P; Crabb, D; Crannell, H; Cummings, J P; DeSanctis, E; Degtyarenko, P V; Demirchyan, R; Denizli, H; Dennis, L; Dharmawardane, K V; Dhuga, K S; Djalali, C; Dodge, G E; Doughty, D; Dragovitsch, P; Dugger, M; Dytman, S; Eckhause, M; Egiyan, H; Egiyan, K S; Elouadrhiri, L; Farhi, L; Feuerbach, R J; Ficenec, J; Forest, T A; Freyberger, A P; Frolov, V; Funsten, H; Gaff, S J; Gai, M; Gilad, S; Gilfoyle, G P; Giovanetti, K L; Griffioen, K; Guidal, M; Guillo, M; Gyurjyan, V; Hancock, D; Hardie, J; Heddle, D; Hersman, F W; Hicks, K; Hicks, R S; Holtrop, M; Hyde-Wright, C E; Ito, M M; Joo, K; Kelley, J H; Khandaker, M; Kim, W; Klein, A; Klein, F J; Klusman, M; Kossov, M; Kramer, L H; Kuang, Y; Kuhn, S E; Lawrence, D; Lucas, M; Lukashin, K; Major, R W; Manak, J J; Marchand, C; McAleer, S; McCarthy, J; McNabb, J W; Mecking, B A; Mestayer, M D; Meyer, C A; Mikhailov, K; Minehart, R; Mirazita, M; Miskimen, R; Muccifora, V; Mueller, J; Mutchler, G S; Napolitano, J; Nelson, S O; Niczyporuk, B B; Niyazov, R A; O'Brien, J T; Opper, A K; Peterson, G; Philips, S A; Pivnyuk, N; Pocanic, D; Pogorelko, O; Polli, E; Preedom, B M; Price, J W; Protopopescu, D; Qin, L M; Raue, B A; Reolon, A R; Riccardi, G; Ricco, G; Ritchie, B G; Ronchetti, F; Rossi, P; Rowntree, D; Rubin, P D; Sabourov, K; Salgado, C; Sanzone-Arenhovel, M; Sapunenko, V; Schumacher, R A; Serov, V S; Shafi, A; Sharabian, Y G; Shaw, J; Skabelin, A V; Smith, E S; Smith, T; Smith, L C; Sober, D I; Spraker, M; Stavinsky, A; Stepanyan, S; Stoler, P; Taiuti, M; Taylor, S; Tedeschi, D J; Todor, L; Thompson, R; Vineyard, M F; Vlassov, A V; Weinstein, L B; Weisberg, A; Weller, H; Weygand, D P; Whisnant, C S; Wolin, E; Wood, M; Yegneswaran, A; Yun, J; Zhang, B; Zhao, J; Zhou, Z

    2001-10-22

    The differential cross section, d sigma/dt, for rho(0) meson photoproduction on the proton above the resonance region was measured up to a momentum transfer -t = 5 GeV2 using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The rho(0) channel was extracted from the measured two charged-pion cross sections by fitting the pi(+)pi(-) and p pi(+) invariant masses. The low momentum transfer region shows the typical diffractive pattern expected from Reggeon exchange. The flatter behavior at large -t cannot be explained solely in terms of QCD-inspired two-gluon exchange models. The data indicate that other processes, like quark interchange, are important to fully describe rho photoproduction. PMID:11690264

  7. Photoproduction of the rho^0 Meson on the Proton at Large Momentum Transfer

    Energy Technology Data Exchange (ETDEWEB)

    M. Battaglieri; E. Anciant; M. Anghinolfi; R. De Vita; E. Golovach; J. M. Laget; V. Mokeev; M. Ripani; G. Adams; M. J. Amaryan; D. S. Armstrong; B. Asavapibhop; G. Asryan; G. Audit; T. Auger; H. Avakian; S. Barrow; K. Beard; M. Bektasoglu; B. L. Berman; N. Bianchi; A. S. Biselli; S. Boiarinov; D. Branford; W. J. Briscoe; W. K. Brooks; V. D. Burkert; J. R. Calarco; G. P. Capitani; D. S. Carman; B. Carnahan; A. Cazes; C. Cetina; P. L. Cole; A. Coleman; D. Cords; P. Corvisiero; D. Crabb; H. Crannell; J. P. Cummings; E. DeSanctis; P. V. Degtyarenko; R. Demirchyan; H. Denizli; L. Dennis; K. V. Dharmawardane; K. S. Dhuga; C. Djalali; G. E. Dodge; D. Doughty; P. Dragovitsch; M. Dugger; S. Dytman; M. Eckhause; H. Egiyan; K. S. Egiyan; L. Elouadrhiri; L. Farhi; R. J. Feuerbach; J. Ficenec; T. A. Forest; A. P. Freyberger; V. Frolov; H. Funsten; S. J. Gaff; M. Gai; S. Gilad; G. P. Gilfoyle; K. L. Giovanetti; K. Griffioen; M. Guidal; M. Guillo; V. Gyurjyan; D. Hancock; J. Hardie; D. Heddle; F. W. Hersman; K. Hicks; R. S. Hicks; M. Holtrop; C. E. Hyde-Wright; M. M. Ito; K. Joo; J. H. Kelley; M. Khandaker; W. Kim; A. Klein; F. J. Klein; M. Klusman; M. Kossov; L. H. Kramer; Y. Kuang; S. E. Kuhn; D. Lawrence; M. Lucas; K. Lukashin; R. W. Major; J. J. Manak; C. Marchand; S. McAleer; J. McCarthy; J. W. C. McNabb; B. A. Mecking; M. D. Mestayer; C. A. Meyer; K. Mikhailov; R. Minehart; M. Mirazita; R. Miskimen; V. Muccifora; J. Mueller; G. S. Mutchler; J. Napolitano; S. O. Nelson; B. B. Niczyporuk; R. A. Niyazov; J. T. O' Brien; A. K. Opper; G. Peterson; S. A. Philips; N. Pivnyuk; D. Pocanic; O. Pogorelko; E. Polli; B. M. Preedom; J. W. Price; D. Protopopescu; L. M. Qin; B. A. Raue; A. R. Reolon; G. Riccardi; G. Ricco; B. G. Ritchie; F. Ronchetti; P. Rossi; D. Rowntree; P. D. Rubin; K. Sabourov; C. Salgado; M. Sanzone-Arenhovel; V. Sapunenko; R. A. Schumacher; V. S. Serov; A. Shafi; Y. G. Sharabian; J. Shaw; A. V. Skabelin; E. S. Smith; T. Smith; L. C. Smith; D. I. Sober; M. Spraker; A. Stavinsky; S. Stepanyan; P. Stoler; M. Taiuti; S. Taylor; D. J. Tedeschi; L. Todor; R. Thompson; M. F. Vineyard; A. V. Vlassov; L. B. Weinstein; A. Weisberg; H. Weller; D. P. Weygand; C. S. Whisnant; E. Wolin; M. Wood; A. Yegneswaran; J. Yun; B. Zhang; J. Zhao; Z. Zhou

    2001-10-01

    The differential cross section, d{sigma}/dt, for p0 meson photoproduction on the proton above the resonance region was measured up to a momentum transfer -t = 5 GeV2 using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The p0 channel was extracted from the measured two charged-pion cross sections by fitting the {pi}+{pi}- and p{pi}+ invariant masses. The low momentum transfer region shows the typical diffractive pattern expected from Reggeon exchange. The flatter behavior at large -t cannot be explained solely in terms of QCD-inspired two-gluon exchange models. The data indicate that other processes, like quark interchange, are important to fully describe p photoproduction.

  8. Exclusive Photoproduction of Upsilon in pPb collisions with the CMS

    CERN Document Server

    Chudasama, Ruchi; Bhabha Atomic Res. Ctr., Srinagar

    2016-01-01

    Results of exclusive photoproduction of Upsilon states in Ultraperipheral collisions (UPC) of protons and ions with the CMS experiment are presented, which provides a clean probe of the gluon distribution at small values of parton fractional momenta $x \\approx 10^{-2} 10^{4}$ at central rapidities (|y| $< 2.5$). The three Upsilon states (1S, 2S, 3S) are measured in the dimuon decay channel along with the photon-photon decaying to dimuon QED continuum at $\\sqrt{s_{NN}}=5.02$~TeV for integrated luminosity of $L_{int} = 35$ nb$^{-1}$. The total Upsilon photoproduction cross sections at different photon-proton center of mass energy $W_{\\gamma p}$ and t-differential distributions are presented and compared with other experimental results as well as theoretical predictions.

  9. Incoherent photoproduction of ϕ-meson from deuteron at low energies

    Directory of Open Access Journals (Sweden)

    Kiswandhi Alvin

    2014-06-01

    Full Text Available The LEPS and CLAS data of the incoherent photoproduction of ϕ meson from deuteron at low energies are studied with a model for ϕ meson photoproduction from nucleon consisting of Pomeron, π, and η meson exchanges in the t-channel, and a postulated resonance, with parameters fitted to recent LEPS data on ϕ production from proton near threshold. The resonance was introduced to explain an observed bump in the forward differential cross section. Within impulse approximation, we find that the Fermi motion, final state interaction, and the resonance excitation all give important contributions to improve the agreement with data. However, discrepancies remain. Contributions from ϕ production via spectator nucleon by other mesons like π,ρ, and ϕ produced from the first nucleon need to be calculated in order to gain insight on the medium effects as well as the existence of the postulated nucleon resonance.

  10. The nuclear matter effects in π0 photoproduction at high energies

    International Nuclear Information System (INIS)

    The in-medium influence on π0 photoproduction from spin zero nuclei is carefully studied in the GeV range using a straightforward Monte Carlo analysis. The calculation takes into account the relativistic nuclear recoil for coherent mechanisms (electromagnetic and nuclear amplitudes) plus a time dependent multi-collisional intranuclear cascade approach (MCMC) to describe the transport properties of mesons produced in the surroundings of the nucleon. A detailed analysis of the meson energy spectra for the photoproduction on 12C at 5.5 GeV indicates that both the Coulomb and nuclear coherent events are associated with a small energy transfer to the nucleus (π0 > or ∼ 20. Such consistent Monte Carlo approach provides a suitable method to clean up nuclear backgrounds in some recent high precision experiments, such as the Prim Ex experiment at the Jefferson Laboratory Facility. (author)

  11. Double-polarization observable G in neutral-pion photoproduction off the proton

    CERN Document Server

    Thiel, A; Lang, M; Afzal, F; Anisovich, A V; Bantes, B; Bayadilov, D; Beck, R; Bichow, M; Brinkmann, K -T; Böse, S; Crede, V; Dieterle, M; Dutz, H; Elsner, D; Ewald, R; Fornet-Ponse, K; Friedrich, St; Frommberger, F; Funke, Ch; Goertz, St; Gottschall, M; Gridnev, A; Grüner, M; Gutz, E; Hammann, D; Hammann, Ch; Hannappel, J; Hartmann, J; Hillert, W; Hoffmeister, Ph; Honisch, Ch; Jude, T; Kaiser, D; Kalinowsky, H; Kalischewski, F; Kammer, S; Keshelashvili, I; Klassen, P; Kleber, V; Klein, F; Klempt, E; Koop, K; Krusche, B; Kube, M; Lopatin, I; Mahlberg, Ph; Makonyi, K; Metag, V; Meyer, W; Müller, J; Müllers, J; Nanova, M; Nikonov, V; Piontek, D; Reeve, S; Reicherz, G; Runkel, S; Sarantsev, A; Schmidt, Ch; Schmieden, H; Seifen, T; Sokhoyan, V; Spieker, K; Thoma, U; Urban, M; van Pee, H; Walther, D; Wendel, Ch; Wilson, A; Winnebeck, A; Witthauer, L

    2016-01-01

    This paper reports on a measurement of the double-polarization observable G in $\\pi^0$ photoproduction off the proton using the CBELSA/TAPS experiment at the ELSA accelerator in Bonn. The observable G is determined from reactions of linearly-polarized photons with longitudinally-polarized protons. The polarized photons are produced by bremsstrahlung off a properly oriented diamond radiator. A frozen spin butanol target provides the polarized protons. The data cover the photon energy range from 617 to 1325 MeV and a wide angular range. The experimental results for G are compared to predictions by the Bonn-Gatchina (BnGa), J\\"ulich-Bonn (J\\"uBo), MAID and SAID partial wave analyses. Implications of the new data for the pion photoproduction multipoles are discussed.

  12. Eta-photoproduction in a gauge-invariant chiral unitary framework

    CERN Document Server

    Ruic, Dino; Meissner, Ulf-G

    2011-01-01

    We analyse photoproduction of eta mesons off the proton in a gauge-invariant chiral unitary framework. The interaction kernel for meson-baryon scattering is derived from the leading order chiral effective Lagrangian and iterated in a Bethe-Salpeter equation. The recent precise threshold data from the Crystal Ball at MAMI can be described rather well and the complex pole corresponding to the S11(1535) is extracted. An extension of the kernel is also discussed.

  13. Exclusive J/psi and Upsilon photoproduction and the low x gluon

    CERN Document Server

    Jones, S P; Ryskin, M G; Teubner, T

    2016-01-01

    We discuss the potential to constrain the small-$x$ PDFs using the exclusive production of heavy vector mesons. The calculation of $J/\\psi$ and $\\Upsilon$ photoproduction at NLO in collinear factorisation is described. The different behaviour of the NLO corrections for $J/\\psi$ and $\\Upsilon$ is highlighted and we outline what might be expected from the inclusion of these processes in a PDF fit.

  14. Measurement of J/{psi} photoproduction at large momentum transfer at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., Argonne, IL (US)] (and others)

    2009-09-15

    The proton-dissociative diffractive photoproduction of J/{psi} mesons has been studied in ep collisions with the ZEUS detector at HERA using an integrated luminosity of 112 pb{sup -1}. The cross section is presented as a function of the photon- proton centre-of-mass energy and of the squared four-momentum transfer at the proton vertex. The results are compared to perturbative QCD calculations. (orig.)

  15. Scaled momentum distributions of charged particles in dijet photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., Argonne, IL (US)] (and others)

    2009-04-15

    The scaled momentum distributions of charged particles in jets have been measured for dijet photoproduction with the ZEUS detector at HERA using an integrated luminosity of 359 pb{sup -1}. The distributions are compared to predictions based on perturbative QCD carried out in the framework of the modified leading-logarithmic approximation (MLLA) and assuming local parton-hadron duality (LPHD). The universal MLLA scale, {lambda}{sub eff}, and the LPHD parameter, {kappa}{sup ch}, are extracted. (orig.)

  16. Neutral pion photoproduction on protons in fully covariant ChPT with Delta(1232) loop contributions

    CERN Document Server

    Blin, Astrid Hiller; Vacas, Manuel Vicente

    2015-01-01

    We study the neutral pion photoproduction at near-threshold energies in fully covariant chiral perturbation theory up to O(p^3). When including only nucleonic virtual states in the model, the convergence is too slow. Therefore we test the model when introducing the Delta(1232) resonance as an additional degree of freedom. Some low-energy constants were fitted, converging to values in good agreement with those expected from literature.

  17. J/ψ photoproduction in ultra-peripheral heavy ion collisions with the ALICE experiment

    Directory of Open Access Journals (Sweden)

    Rodríguez Cahuantzi M.

    2014-04-01

    Full Text Available During the 2011 Pb-Pb run, dedicated triggers were used by the ALICE Collaboration to enrich ultra-peripheral collisions (UPC to measure the J/ψ production cross section and its rapidity dependence at a centre of mass energy of 2.76 TeV per nucleon pair. In this article, the ongoing studies on J/ψ photoproduction in UPC events are presented.

  18. Photoproduction of isolated photons, inclusively and with a jet, at HERA

    International Nuclear Information System (INIS)

    The photoproduction of isolated photons, both inclusive and together with a jet, has been measured with the ZEUS detector at HERA using an integrated luminosity of 374 pb-1. Differential cross sections are presented in the isolated-photon transverse-energy and pseudorapidity ranges 6TγγTjetjet22. Differential cross sections are also presented for inclusive isolated photon production as functions of the transverse energy and pseudorapidity of the photon. Higher-order theoretical calculations are compared to the results.

  19. Correlations between D and D-bar mesons in high energy photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Gottschalk, Erik E.; Link, J.; Reyes, M.; Yager, P.M.; Anjos, J.; Bediaga, I.; Gobel, C.; Magnin, J.; Massafferri, A.; Miranda, J.M. de; Pepe, I.M.; Reis, A.C. dos; Carrillo, S.; Casimiro, E.; Cuautle, E.; Sanchez-Hernandez, A.; Uribe, C.; Vasquez, F.; Agostino, L.; Cinquini, L.; Cumalat, J.P.; O' Reilly, B.; Ramirez, J.E.; Segoni, I.; Butler, J.N.; Cheung, H.W.K.; Chiodini, G.; Gaines, I.; Garbincius, P.H.; Garren, L.A.; Gottschalk, E.E.; Kasper, P.H.; Kreymer, A.E.; Kutschke, R.; Benussi, L.; Bianco, S.; Fabbri, F.L.; Zallo, A.; Cawlfield, C.; Kim, D.Y.; Park, K.S.; Rahimi, A.; Wiss, J.; Gardner, R.; Kryemadhi, A.; Chang, K.H.; Chung, Y.S.; Kang, J.S.; Ko, B.R.; Kwak, J.W.; Lee, K.B.; Cho, K.; Park, H.; Alimonti, G.; Barberis, S.; Cerutti, A.; Boschini, M.; D' Angelo, P.; DiCorato, M.; Dini, P.; Edera, L.; Erba, S.; Giammarchi, M.; Inzani, P.; Leveraro, F.; Malvezzi, S.; Menasce, D.; Mezzadri, M.; Moroni, L.; Pedrini, D.; Pontoglio, C.; Prelz, F.; Rovere, M.; Sala, S.; Davenport, T.F.; Arena, V.; Boca, G.; Bonomi, G.; Gianini, G.; Liguori, G.; Merlo, M.M.; Pantea, D.; Ratti, S.P.; Vitulo, P.; Hernandez, H.; Lopez, A.M.; Mendez, H.; Mendez, L.; Montiel, E.; Olaya, D.; Paris, A.; Quinones, J.; Rivera, C.; Xiong, W.; Zhang, Y.; Wilson, J.R.; Handler, T.; Mitchell, R.; Engh, D.; Hosack, M.; Johns, W.E.; Nehring, M.; Sheldon, P.D.; Stenson, K.; Vaadering, E.W.; Webster, M.; Sheaff, M

    2003-04-01

    Over 7000 events containing a fully reconstructed D D-bar pair have been extracted from data recorded by the FOCUS photoproduction experiment at Fermilab. Preliminary results from a study of correlations between D and D-bar mesons are presented. Correlations are used to study perturbative QCD predictions and investigate non-perturbative effects. We also present a preliminary result on the production of {psi}(3770)

  20. Amplitude extraction in pseudoscalar-meson photoproduction: towards a situation of complete information

    OpenAIRE

    Nys, Jannes; Vrancx, Tom; Ryckebusch, Jan

    2015-01-01

    A complete set for pseudoscalar-meson photoproduction is a minimum set of observables from which one can determine the underlying reaction amplitudes unambiguously. The complete sets considered in this work involve single- and double-polarization observables. It is argued that for extracting amplitudes from data, the transversity representation of the reaction amplitudes offers advantages over alternate representations. It is shown that with the available single-polarization data for the p({\\...

  1. $\\eta -\\eta^\\prime$ Photoproduction and the Axial Isoscalar Neutral Current Coupling

    OpenAIRE

    Bernabéu, J.; González-Sprinberg, G. A.; Vidal, J.

    1995-01-01

    We show that coherent $\\eta$ and $\\etap$ photoproduction by means of the Primakoff Effect on the proton depends on the strange component of the neutral axial current coupling. We construct polarization asymmetries that are sensitive to this coupling through the $\\gamma - Z$ interference. The $\\eta^\\prime$ is not a Goldstone boson of a spontaneously broken chiral symmetry, but a phenomenological analysis of the $\\eta$ and $\\eta^\\prime$ production through chiral perturbation theory allows to ca...

  2. Measurement of J/ψ photoproduction at large momentum transfer at HERA

    International Nuclear Information System (INIS)

    The proton-dissociative diffractive photoproduction of J/ψ mesons has been studied in ep collisions with the ZEUS detector at HERA using an integrated luminosity of 112 pb-1. The cross section is presented as a function of the photon- proton centre-of-mass energy and of the squared four-momentum transfer at the proton vertex. The results are compared to perturbative QCD calculations. (orig.)

  3. Exclusive photoproduction of a $\\gamma\\,\\rho$ pair with a large invariant mass

    CERN Document Server

    Boussarie, R; Szymanowski, L; Wallon, S

    2016-01-01

    Exclusive photoproduction of a $\\gamma\\,\\rho$ pair in the kinematics where the pair has a large invariant mass and the final nucleon has a small transverse momentum is described in the collinear factorization framework. The scattering amplitude is calculated at leading order in $\\alpha_s$ and the differential cross sections for the process where the $\\rho-$meson is either longitudinally or transversely polarized are estimated in the kinematics of the JLab 12-GeV experiments.

  4. Photoproduction of the eta prime meson in the effective Lagrangian approach

    Energy Technology Data Exchange (ETDEWEB)

    Mukhopadhyay, N.C.; Zhang, J.F. [Rensselaer Polytechnic Inst., Troy, NY (United States); Benmerrouche, M. [Univ. of Saskatchewan, Saskaton (Canada)

    1994-04-01

    In the framework of the effective Lagrangian approach, the authors study the {eta}{prime} photoproduction off protons, of great interest at CEBAF I and II. They calculate the contributions from the leading nucleon Born terms, vector meson exchanges, and estimate the resonance contributions, using the transition amplitudes from the recent quark model estimates by Capstick and Roberts. They discuss implications for the CEBAF experiments.

  5. Nuclear shadowing in photoproduction of ρ mesons in ultraperipheral nucleus collisions at RHIC and the LHC

    Directory of Open Access Journals (Sweden)

    L. Frankfurt

    2016-01-01

    Full Text Available We argue that with an increase of the collision energy, elastic photoproduction of ρ mesons on nuclei becomes affected by the significant cross section of photon inelastic diffraction into large masses, which results in the sizable inelastic nuclear shadowing correction to σγA→ρA and the reduced effective ρ-nucleon cross section. We take these effects into account by combining the vector meson dominance model, which we upgrade to include the contribution of high-mass fluctuations of the photon according to QCD constraints, and the Gribov–Glauber approximation for nuclear shadowing, where the inelastic nuclear shadowing is included by means of cross section fluctuations. The resulting approach allows us to successfully describe the data on elastic ρ photoproduction on nuclei in heavy ion UPCs in the 7 GeVphotoproduction in Pb–Pb UPCs at sNN=5.02 TeV in Run 2 at the LHC, dσPbPb→ρPbPb(y=0/dy=560±25 mb.

  6. Effective lagrangian approach to the theory of eta photoproduction in the N$^{*}$(1535) region

    CERN Document Server

    Benmerrouche, M; Zhang, J F; Benmerrouche, M; Mukhopadhyay, N C; Zhang, J F

    1995-01-01

    We investigate eta photoproduction in the N^{*}(1535) resonance region within the effective Lagrangian approach (ELA), wherein leading contributions to the amplitude at the tree level are taken into account. These include the nucleon Born terms and the leading t-channel vector meson exchanges as the non-resonant pieces. In addition, we consider five resonance contributions in the s- and u- channel; besides the dominant N^{*}(1535), these are: N^{*}(1440), N^{*}(1520),N^{*}(1650) and N^{*}(1710). The amplitudes for the \\pi^\\circ and the \\eta photoproduction near threshold have significant differences, even as they share common contributions, such as those of the nucleon Born terms. Among these differences, the contribution to the \\eta photoproduction of the s-channel excitation of the N^{*}(1535) is the most significant. We find the off-shell properties of the spin-3/2 resonances to be important in determining the background contributions. Fitting our effective amplitude to the available data base allows us to...

  7. Hydrogen sensor

    Science.gov (United States)

    Duan, Yixiang; Jia, Quanxi; Cao, Wenqing

    2010-11-23

    A hydrogen sensor for detecting/quantitating hydrogen and hydrogen isotopes includes a sampling line and a microplasma generator that excites hydrogen from a gas sample and produces light emission from excited hydrogen. A power supply provides power to the microplasma generator, and a spectrometer generates an emission spectrum from the light emission. A programmable computer is adapted for determining whether or not the gas sample includes hydrogen, and for quantitating the amount of hydrogen and/or hydrogen isotopes are present in the gas sample.

  8. Quantum Biology

    CERN Document Server

    Sergi, Alessandro

    2009-01-01

    A critical assessment of the recent developments of molecular biology is presented. The thesis that they do not lead to a conceptual understanding of life and biological systems is defended. Maturana and Varela's concept of autopoiesis is briefly sketched and its logical circularity avoided by postulating the existence of underlying {\\it living processes}, entailing amplification from the microscopic to the macroscopic scale, with increasing complexity in the passage from one scale to the other. Following such a line of thought, the currently accepted model of condensed matter, which is based on electrostatics and short-ranged forces, is criticized. It is suggested that the correct interpretation of quantum dispersion forces (van der Waals, hydrogen bonding, and so on) as quantum coherence effects hints at the necessity of including long-ranged forces (or mechanisms for them) in condensed matter theories of biological processes. Some quantum effects in biology are reviewed and quantum mechanics is acknowledge...

  9. Hydrogen system (hydrogen fuels feasibility)

    International Nuclear Information System (INIS)

    This feasibility study on the production and use of hydrogen fuels for industry and domestic purposes includes the following aspects: physical and chemical properties of hydrogen; production methods steam reforming of natural gas, hydrolysis of water; liquid and gaseous hydrogen transportation and storage (hydrogen-hydride technology); environmental impacts, safety and economics of hydrogen fuel cells for power generation and hydrogen automotive fuels; relevant international research programs

  10. Hydrogen production employing Spirulina maxima 2342: A chemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Juantorena, A.U.; Santoyo, E.; Gamboa, S.A.; Lastres, O.D. [Centro de Investigacion en Energia, UNAM, Temixco 62580, Morelos (Mexico); Sebastian, P.J. [Centro de Investigacion en Energia, UNAM, Temixco 62580, Morelos (Mexico); Cuerpo Academico de Energia, UP Chiapas, Tuxtla Gutierrez, Chiapas (Mexico); Sanchez-Escamilla, D. [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); Bustos, A. [Centro de Ciencias Fisicas, UNAM, Ave. Universidad, Cuernavaca, Morelos (Mexico); Eapen, D. [Investigacion y Desarrollo en Agroindustria, UP Chiapas, Tuxtla Gutierrez, Chiapas (Mexico)

    2007-10-15

    The biomass of the cyanobacteria, Spirulina maxima 2342, was autotrophically obtained in a 20 l bioreactor under illumination and air bubbling and analyzed for its photobiological hydrogen production capability. A volume of 250 ml of Spirulina sp. taken from the reactor was used as culture sample for performing the experiments. An illumination-agitation process was employed to induce the hydrogen photoproduction reaction. The hydrogen produced in this process was quantified by gas chromatography technique using Molesieve 5 A(16ft x (1)/(8)in) column and a thermal conductivity detector (with a detector temperature of 110{sup o}C and a column temperature of 60{sup o}C). The culture samples were finally observed in an electron microscope to evaluate the effect of vacuum on the Spirulina sp. cells. (author)

  11. Coherent photoproduction of vector mesons in heavy ion ultraperipheral collisions: update for Run 2 at the LHC

    CERN Document Server

    Guzey, V; Zhalov, M

    2016-01-01

    We make predictions for the cross sections of coherent photoproduction of $\\rho$, $\\phi$, $J/\\psi$, $\\psi(2S)$, and $\\Upsilon(1S)$ mesons in Pb-Pb UPCs at $\\sqrt{s_{NN}}=5.02$ TeV in the kinematics of Run 2 at the LHC extending the approaches successfully describing the available Pb-Pb UPC data at $\\sqrt{s_{NN}}=2.76$ TeV. Our results illustrate the important roles of hadronic fluctuations of the photon and inelastic nuclear shadowing in photoproduction of light vector mesons on nuclei and the large leading twist nuclear gluon shadowing in photoproduction of quarkonia on nuclei. We show that the ratio of $\\psi(2S)$ and $J/\\psi$ photoproduction cross sections in Pb-Pb UPCs is largely determined by the ratio of these cross sections on the proton. We also argue that UPCs with electromagnetic excitations of the colliding ions followed by the forward neutron emission allows one to significantly increase the range of photon energies accessed in vector meson photoproduction on nuclei.

  12. Measurement of the helium-3 Panofsky ratio and of π+ photoproduction near the threshold for deuterium and helium-3

    International Nuclear Information System (INIS)

    Photoproduction measurements near the threshold are described for two and three-nucleon systems. The experimental techniques used gave the photoproduction cross section value with a precision of a few percent. This accuracy is essential when observing the contribution of multi-nucleon effects which represents a correction to the dominant contribution foreseen by the operator of one-body photoproduction. The method of relative measurement with respect to the elementary process of photoproduction on the proton gives a direct comparison of the experimental result with the momentum approximation at the +-1.5% precision level. No coherent description of multi-nucleon contributions, the overall effect of which should be relatively small in view of the above observation, exists at present. Only the part of these contributions corresponding to the rescattering of the pion has been estimated using a simple model of multiple scattering by fixed nucleons, but more detailed calculations would be needed to confirm these results. The other exchange current terms would also have to be evaluated in order to situate the interpretation of photoproduction results at the same level as that of electron scattering data

  13. Coherent photoproduction of vector mesons in ultraperipheral heavy ion collisions: Update for run 2 at the CERN Large Hadron Collider

    Science.gov (United States)

    Guzey, V.; Kryshen, E.; Zhalov, M.

    2016-05-01

    We make predictions for the cross sections of coherent photoproduction of ρ ,ϕ ,J /ψ ,ψ (2 S ) , and Υ (1 S ) mesons in Pb-Pb ultraperipheral collisions (UPCs) at √{sN N}=5.02 TeV in the kinematics of run 2 at the Large Hadron Collider extending the approaches successfully describing the available Pb-Pb UPC data at √{sN N}=2.76 TeV . Our results illustrate the important roles of hadronic fluctuations of the photon and inelastic nuclear shadowing in photoproduction of light vector mesons on nuclei and the large leading twist nuclear gluon shadowing in photoproduction of quarkonia on nuclei. We show that the ratio of ψ (2 S ) and J /ψ photoproduction cross sections in Pb-Pb UPCs is largely determined by the ratio of these cross sections on the proton. We also argue that UPCs with electromagnetic excitations of the colliding ions followed by the forward neutron emission allows one to significantly increase the range of photon energies accessed in vector meson photoproduction on nuclei.

  14. Relationships between H{sub 2} photoproduction and different electron transport pathways in sulfur-deprived Chlamydomonas reinhardtii

    Energy Technology Data Exchange (ETDEWEB)

    Antal, Taras K.; Volgusheva, Alena A.; Kukarskih, Galina P.; Krendeleva, Tatyana E.; Rubin, Andrej B. [Faculty of Biology, Moscow State University, Vorobyevi Gory 119992, Moscow (Russian Federation)

    2009-11-15

    In this study the relationships between photosystem (PS) II dependent and independent pathways of H{sub 2} photoproduction, cyclic electron transport around PS I, chloro- and mitorespiration, and transmembrane {delta}pH were examined by inhibitor analysis in S deprived Chlamydomonas reinhardtii. The rate of non-photochemical reduction of plastoquinones in photosynthetic membranes was significantly diminished under starvation which may explain the minor contribution of the PS II independent pathway of H{sub 2} photoproduction in starved cells. The suppressive effect of the herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea on the long-term H{sub 2} photoproduction was shown to be entirely attributed to the inhibition of electron transport in PS II, whereas non-specific interactions did not take place. Ferredoxin-quinone reductase - dependent cyclic electron transport around PS I slowed down H{sub 2} photoproduction more than two fold. This result was related to the competition between ferredoxin-quinone reductase and hydrogenase for the reduced ferredoxin and to the decrease in transmembrane {delta}pH induced by the cyclic electron flow. The {delta}pH gradient was shown to down regulate the PS II independent pathway of H{sub 2} photoproduction in starved cells. (author)

  15. Optimization of culture conditions for biological hydrogen production by Citrobacter freundii CWBI952 in batch, sequenced-batch and semicontinuous operating mode

    Energy Technology Data Exchange (ETDEWEB)

    Hamilton, Christopher; Hiligsmann, Serge; Beckers, Laurent; Masset, Julien; Thonart, Philippe [Walloon Centre of Industrial Biology, Bd du Rectorat, 29, B.40 - P.70, B-4000 Liege (Belgium); Wilmotte, Annick [Center for Protein Engineering, Institute of Chemistry, B.6-P.14, B-4000 Liege (Belgium)

    2010-02-15

    Investigations were carried out to determine the effect of the pH, the nitrogen source, iron and the dilution rate (h{sup -1}) on fermentative hydrogen production from glucose by the newly isolated strain Citrobacter freundii CWBI952. The hydrogen production rate (HPR), hydrogen yield, biomass and soluble metabolites were monitored at 30 C in 100 mL serum bottles and in a 2.3 L bioreactor operated in batch, sequenced-batch and semicontinuous mode. The results indicate that hydrogen production activity, formate biosynthesis and glucose intake rates are very sensitive to the culture pH, and that additional formate bioconversion and production of hydrogen with lower biomass yields can be obtained at pH 5.9. In a further series of cultures casein peptone was replaced by (NH{sub 4}){sub 2}SO{sub 4}, a low cost alternative nitrogen source. The ammonia-based substitute was found to be suitable for H{sub 2} production when a concentration of 0.045 g/L FeSO{sub 4} was provided. Optimal overall performances (ca. an HPR of 33.2 mL H{sub 2}/L h and a yield of 0.83mol{sub H{sub 2}}/mol{sub glucose}) were obtained in the semicontinuous culture applying the previously optimized parameters for pH, nitrogen, and iron with a dilution rate of 0.012 h{sup -1} and degassing of biogas by N{sub 2} at a 28 mL/min flow rate. (author)

  16. Quantum Biology

    Directory of Open Access Journals (Sweden)

    Alessandro Sergi

    2009-06-01

    Full Text Available A critical assessment of the recent developmentsof molecular biology is presented.The thesis that they do not lead to a conceptualunderstanding of life and biological systems is defended.Maturana and Varela's concept of autopoiesis is briefly sketchedand its logical circularity avoided by postulatingthe existence of underlying living processes,entailing amplification from the microscopic to the macroscopic scale,with increasing complexity in the passage from one scale to the other.Following such a line of thought, the currently accepted model of condensed matter, which is based on electrostatics and short-ranged forces,is criticized. It is suggested that the correct interpretationof quantum dispersion forces (van der Waals, hydrogen bonding, and so onas quantum coherence effects hints at the necessity of includinglong-ranged forces (or mechanisms for them incondensed matter theories of biological processes.Some quantum effects in biology are reviewedand quantum mechanics is acknowledged as conceptually important to biology since withoutit most (if not all of the biological structuresand signalling processes would not even exist. Moreover, it is suggested that long-rangequantum coherent dynamics, including electron polarization,may be invoked to explain signal amplificationprocess in biological systems in general.

  17. Chemical, mineralogical and molecular biological characterization of the rocks and fluids from a natural gas storage deep reservoir as a baseline for the effects of geological hydrogen storage

    Science.gov (United States)

    Morozova, Daria; Kasina, Monika; Weigt, Jennifer; Merten, Dirk; Pudlo, Dieter; Würdemann, Hilke

    2014-05-01

    Planned transition to renewable energy production from nuclear and CO2-emitting power generation brings the necessity for large scale energy storage capacities. One possibility to store excessive energy produced is to transfer it to chemical forms like hydrogen which can be subsequently injected and stored in subsurface porous rock formations like depleted gas reservoirs and presently used gas storage sites. In order to investigate the feasibility of the hydrogen storage in the subsurface, the collaborative project H2STORE ("hydrogen to store") was initiated. In the scope of this project, potential reactions between microorganism, fluids and rocks induced by hydrogen injection are studied. For the long-term experiments, fluids of natural gas storage are incubated together with rock cores in the high pressure vessels under 40 bar pressure and 40° C temperature with an atmosphere containing 5.8% He as a tracer gas, 3.9% H2 and 90.3% N2. The reservoir is located at a depth of about 2 000 m, and is characterized by a salinity of 88.9 g l-1 NaCl and a temperature of 80° C and therefore represents an extreme environment for microbial life. First geochemical analyses showed a relatively high TOC content of the fluids (about 120 mg l-1) that were also rich in sodium, potassium, calcium, magnesium and iron. Remarkable amounts of heavy metals like zinc and strontium were also detected. XRD analyses of the reservoir sandstones revealed the major components: quartz, plagioclase, K-feldspar, anhydrite and analcime. The sandstones were intercalated by mudstones, consisting of quartz, plagioclase, K-feldspar, analcime, chlorite, mica and carbonates. Genetic profiling of amplified 16S rRNA genes was applied to characterize the microbial community composition by PCR-SSCP (PCR-Single-Strand-Conformation Polymorphism) and DGGE (Denaturing Gradient Gel Electrophoresis). First results indicate the presence of microorganisms belonging to the phylotypes alfa-, beta- and gamma

  18. 超声波光生物制氢反应器启动及产氢特性%Characteristics of Start-Up and Hydrogen Production in Ultrasonic Photo-Biological Reactor

    Institute of Scientific and Technical Information of China (English)

    谢学旺; 朱恂; 赵旭; 廖强; 王永忠

    2012-01-01

    实验研究了超声波光生物制氢反应器的启动工艺以及反应器的产氢特性,探讨了超声时间和超声功率对反应器产氢性能的影响。超声波光生物反应器的启动实验进行了96h,此时反应器光合细菌生物量和反应液pH值趋于稳定,启动完成。在系统稳定运行后,随着超声时间、超声功率的增大,超声波光生物制氢反应器的产氢速率和产氢得率呈先增加后降低的趋势,然而葡萄糖去除率却随着超声时间的增加而增大。%Experimental study on the start-up process and hydrogen production in an ultrasonic photo-biological reactor were conducted in the present study and the effects of ultrasonic time and ultrasonic output power on hydrogen production performance of the bioreactor were investigated. The biomass and pH value of the culture were adopted as indexes to evaluate the start-up process of the bioreactor, and they kept stable after 96 h of start-up, which indicated the start-up process succeeded. In the stable operation stage, the hydrogen production rate and hydrogen yield of the ultrasonic bioreactor firstly increased and then dropped with increases in the ultrasonic time and output power, respectively. However, the glucose removal rate always increased with increasing ultrasonic time.

  19. Hydrogen Production by Thermophilic Fermentation

    NARCIS (Netherlands)

    Niel, van E.W.J.; Willquist, K.; Zeidan, A.A.; Vrije, de T.; Mars, A.E.; Claassen, P.A.M.

    2012-01-01

    Of the many ways hydrogen can be produced, this chapter focuses on biological hydrogen production by thermophilic bacteria and archaea in dark fermentations. The thermophiles are held as promising candidates for a cost-effective fermentation process, because of their relatively high yields and broad

  20. Hydrogen Evolution from Napiergrass by the Combination of Biological Treatment and a Pt-Loaded TiO2-Photocatalytic Reaction

    Directory of Open Access Journals (Sweden)

    Masahide Yasuda

    2011-12-01

    Full Text Available Ethanol and pentose were produced from lignocellulosic napiergrass by the simultaneous saccharification and fermentation process (SSF using hydrolytic enzyme and S. Cerevisiae. After the ethanol was removed, the pentose solution was subjected to photocatalytic hydrogen evolution with Pt-loaded TiO2 under UV-irradiation. This process converted 100 g of napiergrass into 12.3 g of ethanol and 1.76 g of hydrogen whose total combustion energy of (∆H was 615 kJ. This was close to the ∆H (639 kJ of the pentose (13.6 g and hexose (27.4 g obtained by the cellulose-saccharification of 100 g of napiergrass.

  1. Jet shapes in charm photoproduction and deeply inelastic scattering at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Grell, Brian Rosenvold

    2010-09-15

    This analysis investigates charm production processes in photoproduction and deeply inelastic scattering. The analysed data was collected with the H1 detector at the HERA accelerator in the years 1999-2000 for photoproduction and 2004-2007 for deeply inelastic scattering, corresponding to integrated luminosities of 83 pb{sup -1}, respectively 348 pb{sup -1}. Dijet events are selected with jet transverse momenta of at least 5 GeV, respectively 4 GeV, in the central rapidity region. One jet is tagged by a D{sup *} meson to be initiated by a charm quark. The other is studied with respect to its mean integrated jet shape in order to deduce to which fraction it is initiated by a quark or a gluon. The jet shape is described by the fraction {psi}(r) of the jet energy inside a cone of radius r around the jet axis; it is found that for r=0:6, {psi}(r) is most sensitive to differences between charm and light quark or gluon jets. The shape is measured as a function of various kinematic variables such as the jet energy and pseudorapidity, photon virtuality and x{sub {gamma}}{sup obs}, the fraction of the photon momentum entering the hard interaction. The photoproduction data is compared to Pythia, the DIS data to RapGap Monte Carlo simulations. In the Monte Carlo calculation, direct and resolved photon processes are simulated separately to compare samples with an enriched fraction of quark, respectively gluon initiated jets. Deviations at low x{sub {gamma}}{sup obs} are observed for higher values of Q{sup 2}, where direct and resolved expectations are nearly identical, hinting at an overestimation of gluon initiated jets. In most regions of phase space though, the resolution of the measurement excels the difference between direct and resolved predictions, allowing a distinction of such event samples. (orig.)

  2. Jet shapes in charm photoproduction and deeply inelastic scattering at HERA

    International Nuclear Information System (INIS)

    This analysis investigates charm production processes in photoproduction and deeply inelastic scattering. The analysed data was collected with the H1 detector at the HERA accelerator in the years 1999-2000 for photoproduction and 2004-2007 for deeply inelastic scattering, corresponding to integrated luminosities of 83 pb-1, respectively 348 pb-1. Dijet events are selected with jet transverse momenta of at least 5 GeV, respectively 4 GeV, in the central rapidity region. One jet is tagged by a D* meson to be initiated by a charm quark. The other is studied with respect to its mean integrated jet shape in order to deduce to which fraction it is initiated by a quark or a gluon. The jet shape is described by the fraction ψ(r) of the jet energy inside a cone of radius r around the jet axis; it is found that for r=0:6, ψ(r) is most sensitive to differences between charm and light quark or gluon jets. The shape is measured as a function of various kinematic variables such as the jet energy and pseudorapidity, photon virtuality and xγobs, the fraction of the photon momentum entering the hard interaction. The photoproduction data is compared to Pythia, the DIS data to RapGap Monte Carlo simulations. In the Monte Carlo calculation, direct and resolved photon processes are simulated separately to compare samples with an enriched fraction of quark, respectively gluon initiated jets. Deviations at low xγobs are observed for higher values of Q2, where direct and resolved expectations are nearly identical, hinting at an overestimation of gluon initiated jets. In most regions of phase space though, the resolution of the measurement excels the difference between direct and resolved predictions, allowing a distinction of such event samples. (orig.)

  3. Measurement of charm and beauty dijet cross sections in photoproduction at HERA using the H1 vertex detector

    International Nuclear Information System (INIS)

    A measurement of charm and beauty dijet photoproduction cross sections at the ep collider HERA is presented. The lifetime signature of c- and b-flavoured hadrons is exploited to determine the fractions of events in the sample containing charm or beauty. Differential dijet cross sections for charm and beauty, and their relative contributions to the flavour inclusive dijet photoproduction cross section, are measured. Taking into account the theoretical uncertainties, the charm cross sections are consistent with a QCD calculation in next-to-leading order, the predicted cross sections for beauty production being somewhat lower than the measurement. (author)

  4. Report on strangeness photoproduction experiments performed with the Neutral Kaon Spectrometer 2

    CERN Document Server

    Beckford, B; Doi, D; Fujibayashi, J; Fujii, T; Fujii, Y; Futatsukawa, K; Gogami, T; Hashimoto, O; Han, Y C; Hirose, K; Hirose, S; Honda, R; Honda, R; Hosomi, K; Iguchi, A; Ishikawa, T; Kanda, H; Kaneta, M; Kaneko, Y; Kato, S; Kawama, D; Kawasaki, T; Kiyokawa, S; Koike, T; Maeda, K; Makabe, K; Maruyama, N; Matsubara, M; Miwa, K; Miyagi, Y; Nagao, S; Nakamura, S N; Okuyama, A; Shirotori, K; Sugihara, K; Suzuki, K; Tamae, T; Tamura, H; Terada, N; Tsukada, K; Yagi, K; Yamamoto, F; Yamamoto, T O; Yamazaki, H; Yonemoto, Y

    2012-01-01

    An experiment designed to investigate the strangeness photoproduction process using a tagged photon beam in the energy range of 0.90 -1.08 GeV incident on a liquid deuterium target was successfully performed. The purpose of the experiment was to measure the production of neutral kaons and the lambda particles on a deuteron. The generation of photo produced particles was verified by the measurement of their decayed charged particles in the Neutral Kaon Spectrometer 2. The reconstructed invariant mass distributions were achieved by selecting events where two or more particles tracks were identified. Preliminary results are presented here.

  5. Measurement of Charm and Beauty Photoproduction at HERA using D* mu Correlations

    CERN Document Server

    Aktas, A; Anthonis, T; Asmone, A; Babaev, A; Backovic, S; Bähr, J; Baranov, P; Barrelet, E; Bartel, Wulfrin; Baumgartner, S; Becker, J; Beckingham, M; Behnke, O; Behrendt, O; Belousov, A; Berger, C; Berger, N; Berndt, T; Bizot, J C; Böhme, J; Boenig, M O; Boudry, V; Bracinik, J; Brisson, V; Broker, H B; Brown, D P; Bruncko, Dusan; Büsser, F W; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Caron, S; Cassol-Brunner, F; Cerny, K; Chekelian, V; Contreras, J G; Coppens, Y R; Coughlan, J A; Cox, B E; Cozzika, G; Cvach, J; Dainton, J B; Dau, W D; Daum, K; Delcourt, B; Demirchyan, R; de Roeck, A; Desch, Klaus; De Wolf, E A; Diaconu, C; Dingfelder, J; Dodonov, V; Dubak, A; Duprel, C; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, F; Ellerbrock, M; Elsen, E; Erdmann, W; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Ferencei, J; Fleischer, M; Fleischmann, P; Fleming, Y H; Flucke, G; Flügge, G; Fomenko, A; Foresti, I; Formánek, J; Franke, G; Frising, G; Gabathuler, Erwin; Gabathuler, K; Garutti, E; Garvey, J; Gayler, J; Gerhards, R; Gerlich, C; Ghazaryan, S; Ginzburgskaya, S; Görlich, L; Gogitidze, N; Gorbounov, S; Grab, C; Grässler, Herbert; Greenshaw, T; Gregori, M; Grindhammer, G; Gwilliam, C; Haidt, D; Hajduk, L; Haller, J; Hansson, M; Heinzelmann, G; Henderson, R C W; Henschel, H; Henshaw, O; Herrera-Corral, G; Herynek, I; Heuer, R D; Hildebrandt, M; Hiller, K H; Hoting, P; Hoffmann, D; Horisberger, R P; Hovhannisyan, A; Ibbotson, M; Ismail, M; Jacquet, M; Janauschek, L; Janssen, X; Jemanov, V; Jönsson, L B; Johnson, D P; Jung, H; Kant, D; Kapichine, M; Karlsson, M; Katzy, J; Keller, N; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Klimkovich, T; Kluge, T; Knies, G; Knutsson, A; Koblitz, B; Korbel, V; Kostka, P; Koutouev, R; Kropivnitskaya, A; Kroseberg, J; Krüger, K; Kuckens, J; Landon, M P J; Lange, W; Lastoviicka, T; Laycock, P; Lebedev, A; Leiner, B; Lemrani, R; Lendermann, V; Levonian, S; Lindfeld, L; Lipka, K; List, B; Lobodzinska, E; Loktionova, N; López-Fernandez, R; Lubimov, V; Lüders, H; Lüke, D; Lux, T; Lytkin, L; Makankine, A; Malden, N; Malinovskii, E I; Mangano, S; Marage, P; Marks, J; Marshall, R; Martisikova, M; Martyn, H U; Maxfield, S J; Meer, D; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, J; Mikocki, S; Milcewicz-Mika, I; Milstead, D; Mohamed, A; Moreau, F; Morozov, A; Morris, J V; Mozer, M U; Müller, K; Murn, P; Nagovizin, V; Nankov, K; Naroska, Beate; Naumann, J; Naumann, T; Newman, P R; Niebuhr, C B; Nikiforov, A; Nikitin, D K; Nowak, G; Nozicka, M; Oganezov, R; Olivier, B; Olsson, J E; Ozerov, D; Paramonov, A A; Pascaud, C; Patel, G D; Peez, M; Pérez, E; Perieanu, A; Petrukhin, A; Pitzl, D; Placakyte, R; Pöschl, R; Portheault, B; Povh, B; Raicevic, N; Reimer, P; Reisert, B; Rimmer, A; Risler, C; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rurikova, Z; Rusakov, S V; Rybicki, K; Sankey, D P C; Sauvan, E; Schatzel, S; Scheins, J; Schilling, F P; Schleper, P; Schmidt, S; Schmitt, S; Schneider, M; Schoeffel, L; Schöning, A; Schröder, V; Schultz-Coulon, H C; Schwanenberger, C; Sedlak, K; Sefkow, F; Shevyakov, I; Shtarkov, L N; Sirois, Y; Sloan, T; Smirnov, P; Soloviev, Yu; South, D; Spaskov, V; Specka, A; Spitzer, H; Stamen, R; Stella, B; Stiewe, J; Strauch, I; Straumann, U; Tchoulakov, V; Thompson, G; Thompson, P D; Tomasz, F; Traynor, D; Truöl, P; Tsipolitis, G; Tsurin, I; Turnau, J; Tzamariudaki, E; Uraev, A; Urban, M; Usik, A; Utkin, D; Valkár, S; Valkárová, A; Vallée, C; Van Mechelen, P; Van Remortel, N; Vargas-Trevino, A; Vazdik, Ya A; Veelken, C; Vest, A; Vinokurova, S; Volchinski, V; Wacker, K; Wagner, J; Weber, G; Weber, R; Wegener, D; Werner, C; Werner, N; Wessels, M; Wessling, B; Winter, G G; Wissing, C; Woerling, E E; Wolf, R; Wünsch, E; Xella, S M; Yan, W; Yeganov, V; Zaicek, J; Zaleisak, J; Zhang, Z; Zhelezov, A; Zhokin, A; Zohrabyan, H G; Zomer, F

    2005-01-01

    A measurement of charm and beauty photoproduction at the electron proton collider HERA is presented based on the simultaneous detection of a D*^{\\pm} meson and a muon. The correlation between the D* meson and the muon serves to separate the charm and beauty contributions and the analysis provides comparable sensitivity to both. The total and differential experimental cross sections are compared to LO and NLO QCD calculations. The measured charm cross section is in good agreement with QCD predictions including higher order effects while the beauty cross section is higher.

  6. Inclusive Photoproduction of rho^0, K^{*0} and phi Mesons at HERA

    CERN Document Server

    Aaron, F D; Andreev, V; Antunovic, B; Aplin, S; Asmone, A; Astvatsatourov, A; Backovic, S; Baghdasaryan, A; Barrelet, E; Bartel, W; Begzsuren, K; Behnke, O; Belousov, A; Berger, N; Bizot, J C; Boudry, V; Bozovic-Jelisavcic, I; Bracinik, J; Brandt, G; Brinkmann, M; Brisson, V; Bruncko, D; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Cassol-Brunner, F; Cerny, K; Cerny, V; Chekelian, V; Cholewa, A; Contreras, J G; Coughlan, J A; Cozzika, G; Cvach, J; Dainton, J B; Daum, K; Deák, M; de Boer, Y; Delcourt, B; Del Degan, M; Delvax, J; De Roeck, A; De Wolf, E A; Diaconu, C; Dodonov, V; Dossanov, A; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eliseev, A; Elsen, E; Falkiewicz, A; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Fischer, D -J; Fleischer, M; Fomenko, A; Gabathuler, E; Gayler, J; Ghazaryan, S; Glazov, A; Glushkov, I; Goerlich, L; Gogitidze, N; Gouzevitch, M; Grab, C; Greenshaw, T; Grell, B R; Grindhammer, G; Habib, S; Haidt, D; Hansson, M; Helebrant, C; Henderson, R C W; Hennekemper, E; Henschel, H; Herbst, M; Herrera, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R; Hreus, T; Jacquet, M; Janssen, M E; Janssen, X; Jemanov, V; Jönsson, L; Jung, A W; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Kluge, T; Knutsson, A; Kogler, R; Korbel, V; Kostka, P; Kraemer, M; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Krüger, K; Kutak, K; Landon, M P J; Lange, W; Lastovicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Li, G; Lipka, K; Liptaj, A; List, B; List, J; Loktionova, N; Lopez-Fernandez, R; Lubimov, V; Lytkin, L; Makankine, A; Malinovski, E; Marage, P; Marti, Ll; Martyn, H -U; Maxfield, S J; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Moreau, F; Morozov, A; Morris, J V; Mozer, M U; Mudrinic, M; Müller, K; Murín, P; Naroska, B; Naumann, Th; Newman, P R; Niebuhr, C; Nikiforov, A; Nowak, G; Nowak, K; Nozicka, M; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Pandurovic, M; Papadopoulou, Th; Pascaud, C; Patel, G D; Pejchal, O; Perez, E; Petrukhin, A; Picuric, I; Piec, S; Pitzl, D; Placakyte, R; Polifka, R; Povh, B; Preda, T; Radescu, V; Rahmat, A J; Raicevic, N; Raspiareza, A; Ravdandorj, T; Reimer, P; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rotaru, M; Ruiz Tabasco, J E; Rurikova, Z; Rusakov, S; Sálek, D; Sankey, D P C; Sauter, M; Sauvan, E; Schmitt, S; Schmitz, C; Schoeffel, L; Schöning, A; Schultz-Coulon, H -C; Sefkow, F; Shaw-West, R N; Sheviakov, I; Shtarkov, L N; Shushkevich, S; Sloan, T; Smiljanic, I; Soloviev, Y; Sopicki, P; South, D; Spaskov, V; Specka, A; Staykova, Z; Steder, M; Stella, B; Stoicea, G; Straumann, U; Sunar, D; Sykora, T; Tchoulakov, V; Thompson, G; Thompson, P D; Toll, T; Tomasz, F; Tran, T H; Traynor, D; Trinh, T N; Truöl, P; Tsakov, I; Tseepeldorj, B; Turnau, J; Urban, K; Valkárová, A; Vallée, C; Van Mechelen, P; Vargas Trevino, A; Vazdik, Y; Vinokurova, S; Volchinski, V; von den Driesch, M; Wegener, D; Wissing, Ch; Wünsch, E; Zácek, J; Zálesák, J; Zhang, Z; Zhokin, A; Zimmermann, T; Zohrabyan, H; Zomer, F

    2009-01-01

    Inclusive non-diffractive photoproduction of rho(770)^0, K^*(892)^0 and phi(1020) mesons is investigated with the H1 detector in ep collisions at HERA. The corresponding average \\gamma p centre-of-mass energy is 210 GeV. The mesons are measured in the transverse momentum range 0.5

  7. Measurement of the transverse target and beam-target asymmetries in $\\eta$ meson photoproduction at MAMI

    CERN Document Server

    Akondi, C S; Arends, H J; Beck, R; Bernstein, A; Borisov, N; Braghieri, A; Briscoe, W J; Cherepnya, S; Collicott, C; Costanza, S; Downie, E J; Dieterle, M; Fix, A; Fil'kov, L V; Garni, S; Glazier, D I; Gradl, W; Gurevich, G; Barrientos, P Hall; Hamilton, D; Hornidge, D; Howdle, D; Huber, G M; Kashevarov, V L; Keshelashvili, I; Kondratiev, R; Korolija, M; Krusche, B; Lazarev, A; Lisin, V; Livingston, K; MacGregor, I J D; Mancel, J; Manley, D M; Martel, P; McNicoll, E F; Meyer, W; Middleton, D; Miskimen, R; Mushkarenkov, A; Nefkens, B M K; Neganov, A; Nikolaev, A; Oberle, M; Ostrick, M; Ortega, H; Ott, P; Otte, P B; Oussena, B; Pedroni, P; Polonski, A; Polyanski, V V; Prakhov, S; Reicherz, G; Rostomyan, T; Sarty, A; Schumann, S; Steffen, O; Strakovsky, I I; Strub, Th; Supek, I; Tiator, L; Thomas, A; Unverzagt, M; Usov, Yu A; Watts, D P; Werthmüller, D; Witthauer, L; Wolfes, M

    2014-01-01

    We present new data for the transverse target asymmetry T and the very first data for the beam-target asymmetry F in the $\\vec \\gamma \\vec p\\to\\eta p$ reaction up to a center-of-mass energy of W=1.9 GeV. The data were obtained with the Crystal-Ball/TAPS detector setup at the Glasgow tagged photon facility of the Mainz Microtron MAMI. All existing model predictions fail to reproduce the new data indicating a significant impact on our understanding of the underlying dynamics of $\\eta$ meson photoproduction. The peculiar nodal structure observed in existing T data close to threshold is not confirmed.

  8. Revealing transversity GPDs through the photoproduction of a photon and a ρ meson

    Directory of Open Access Journals (Sweden)

    Boussarie R.

    2016-01-01

    Full Text Available Photoproduction of a pair of particles with large invariant mass is a natural extension of collinear QCD factorization theorems which have been much studied for deeply virtual Compton scattering and deeply virtual meson production. We discuss the production of a photon and a meson, where the wide angle Compton scattering on a meson subprocess factorizes from generalized parton distribution. We calculate at dominant twist and leading order in αs, the production cross-section of a transversely polarized ρ meson which is sensitive to chiral-odd GPDs, and show that it may be measurable in near future JLab experiments.

  9. The GlueX experiment: Search for gluonic excitations via photoproduction at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Eugenio, Paul [Florida State U.

    2013-07-01

    Studies of meson spectra via strong decays provide insight regarding QCD at the confinement scale. These studies have led to phenomenological models for QCD such as the constituent quark model. However, QCD allows for a much richer spectrum of meson states which include extra states such as exotics, hybrids, multi-quarks, and glueballs. First discussion of the status of exotic meson searches is given followed by an overview of the progress at Jefferson Lab to double the energy of the machine to 12 GeV, which will allow us to access photoproduction of mesons in search for gluonic excited states.

  10. Mm/submm Study of Gas-Phase Photoproducts from Methanol Interstellar Ice Analogues

    Science.gov (United States)

    Mesko, AJ; Smith, Houston Hartwell; Milam, Stefanie N.; Widicus Weaver, Susanna L.

    2016-06-01

    Icy grain reactions have gained quite the popularity in the astrochemistry community to explain the formation of complex organic molecules. Through temperature programmed desorption and photolysis experiments we use rotational spectroscopy to measure the gas-phase products of icy grain reactions. Previous results include testing detection limits of the system by temperature programmed desorption of methanol and water ices, photochemistry of gas-phase methanol, and detection of photodesorbed water from a pure water ice surface. Current work that will be discussed focuses on the detection of gas-phase CO and other photoproducts from an ice surface.

  11. Inelastic quarkonium photoproduction in hadron-hadron interactions at LHC energies

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, V.P. [Universidade Federal de Pelotas, Instituto de Fisica e Matematica, Pelotas, RS (Brazil); Machado, M.M. [Ciencia e Tecnologia, IF - Farroupilha, Instituto Federal de Educacao, Sao Borja, RS (Brazil)

    2014-04-15

    In this paper we study the inelastic quarkonium photoproduction in coherent pp/p Pb/PbPb interactions. Considering the ultra-relativistic hadrons as a source of photons, we estimate the total h{sub 1}+h{sub 2} → h x V+X (V=J/Ψ and Υ) cross sections and rapidity distributions at LHC energies. Our results demonstrate that the experimental analysis of this process can be used to understand the underlying mechanism governing heavy quarkonium production. (orig.)

  12. Revealing transversity GPDs through the photoproduction of a photon and a $\\rho$ meson

    CERN Document Server

    Boussarie, R; Szymanowski, L; Wallon, S

    2016-01-01

    Photoproduction of a pair of particles with large invariant mass is a natural extension of collinear QCD factorization theorems which have been much studied for deeply virtual Compton scattering and deeply virtual meson production. We discuss the production of a photon and a meson, where the wide angle Compton scattering on a meson subprocess factorizes from generalized parton distribution. We calculate at dominant twist and leading order in $\\alpha_s$, the production cross-section of a transversely polarized $\\rho$ meson which is sensitive to chiral-odd GPDs, and show that it may be measurable in near future JLab experiments.

  13. Radiative decay of $K^-p$ system and photoproduction of $\\Lambda(1405)$

    OpenAIRE

    Choi, Tae Keun; Kim, Kyung Sik; Yu, Byung Geel

    2009-01-01

    The properties of the $\\Lambda(1405)$ resonance have been investigated from radiative decay of $K^- p\\to Y\\gamma$ and photoproduction $\\gamma p\\to K^+\\Lambda(1405)$ within the framework of the isobar model. For a consistent result with recently measured branching ratios, the axial vector meson $K_1(1270)$ is taken into account. Strong and electromagnetic coupling constants of $\\Lambda(1405)$ are extracted from these branching ratios and are applied to the analysis of $K^+\\Lambda(1405)$ photop...

  14. Evidence for nucleon-resonance excitation in omega-meson photoproduction.

    Science.gov (United States)

    Ajaka, J; Assafiri, Y; Bouchigny, S; Didelez, J P; Fichen, L; Guidal, M; Hourany, E; Kouznetsov, V; Kunne, R; Mushkarenkov, A N; Nedorezov, V; Rudnev, N; Turinge, A; Zhao, Q

    2006-04-01

    The photoproduction of the omega meson has been studied at GRAAL from threshold up to a photon energy of 1.5 GeV. The differential cross sections and beam asymmetries have been measured precisely at all angles. The total cross section is also obtained. Systematic enhancements of the differential cross section at large angles and nonzero beam asymmetries at intermediate angles provide clear evidence for s- and u-channel resonant processes. The data are compared to the results of hadron and quark models.

  15. Complete sets of observables in pseudoscalar-meson photo-production

    Directory of Open Access Journals (Sweden)

    Vrancx Tom

    2014-06-01

    Full Text Available Pseudoscalar-meson photoproduction is characterized by four complex reaction amplitudes. A complete set is a minimum theoretical set of observables that allow to determine these amplitudes unambiguously. It is studied whether complete sets remain complete when experimental uncertainty is involved. To this end, data from the GRAAL Collaboration and simulated data from a realistic model, both for the γp → K+Λ reaction, are analyzed in the transversity representation of the reaction amplitudes. It is found that only the moduli of the transversity amplitudes can be determined without ambiguity but not the relative phases.

  16. Further studies of the photoproduction of isolated photons with a jet at HERA

    International Nuclear Information System (INIS)

    In this extended analysis using the ZEUS detector at HERA, the photoproduction of isolated photons together with a jet is measured for different ranges of the fractional photon energy, xγmeas, contributing to the photon-jet final state. Cross sections are evaluated in the photon transverse-energy and pseudorapidity ranges 6TγγTjetjet-1. The kinematic observables studied comprise the transverse energy and pseudorapidity of the photon and the jet, the azimuthal difference between them, the fraction of proton energy taking part in the interaction, and the difference between the pseudorapidities of the photon and the jet. Higher-order theoretical calculations are compared to the results.

  17. Studies of correlations between D and ${\\bar D}$ mesons in high energy photoproduction

    CERN Document Server

    Link, J M; Anjos, J C; Bediaga, I; Göbel, C; Magnin, J; Massafferri, A; De Miranda, J M; Pepe, I M; Polycarpo, E; Dos Reis, A C; Carrillo, S; Casimiro, E; Cuautle, E; Sánchez-Hernández, A; Uribe, C; Vázquez, F; Agostino, L; Cinquini, L; Cumalat, J P; O'Reilly, B; Segoni, I; Wahl, M; Butler, J N; Cheung, H W K; Chiodini, G; Gaines, I; Garbincius, P H; Garren, L A; Gottschalk, E E; Kasper, P H; Kreymer, A E; Kutschke, R; Wang, M; Benussi, L; Bertani, M; Bianco, S; Fabbri, Franco Luigi; Zallo, A; Reyes, M; Cawlfield, C; Kim, D Y; Rahimi, A; Wiss, J; Gardner, R; Kryemadhi, A; Chung, Y S; Kang, J S; Ko, B R; Kwak, J W; Lee, K B; Cho, K; Park, H; Alimonti, G; Barberis, S; Boschini, M; Cerutti, A; D'Angelo, P; Di Corato, M; Dini, P; Edera, L; Erba, S; Giammarchi, M; Inzani, P; Leveraro, F; Malvezzi, S; Menasce, D; Mezzadri, M; Moroni, L; Pedrini, D; Pontoglio, C; Prelz, F; Rovere, M; Sala, S; Davenport, T F; Arena, V; Boca, G; Bonomi, G; Gianini, G; Liguori, G; Lopes-Pegna, D; Merlo, M M; Pantea, D; Ratti, S P; Riccardi, C; Vitulo, P; Hernández, H; López, A M; Luiggi, E; Méndez, H; Paris, A; Quinones, J; Ramírez, J E; Zhang, Y; Wilson, J R; Handler, T; Mitchell, R; Engh, D; Hosack, M; Johns, W E; Nehring, M S; Sheldon, P D; Stenson, K; Vaandering, E W; Webster, M; Sheaff, M

    2003-01-01

    Studies of $D{\\bar D}$ correlations for a large sample of events containing fully and partially reconstructed pairs of charmed $D$ mesons recorded by the Fermilab photoproduction experiment FOCUS (FNAL-E831) are presented. Correlations between $D$ and ${\\bar D}$ mesons are used to study heavy quark production dynamics. We present results for fully and partially reconstructed charm pairs and comparisons to a recent version of \\textsc{Pythia} with default parameter settings. We also comment on the production of $\\psi(3770)$ in our data.

  18. SAID Analysis of Meson Photoproduction : Determination of Neutron and Proton EM Couplings

    CERN Document Server

    Strakovsky, Igor; Kudryavtsev, Alexander; Tarasov, Vladimir; Workman, Ron

    2014-01-01

    We present an overview of the GW SAID group effort to analyze on new pion photoproduction on both proton- and neutron-targets. The main database contribution came from the recent CLAS and MAMI unpolarized and polarized measurements. The differential cross section for the processes gamma n --> pi- p was extracted from new measurements accounting for Fermi motion effects in the impulse approximation (IA) as well as NN and piN effects beyond the IA. The EM coupling results are compared to other recent studies.

  19. SAID analysis of meson photoproduction: Determination of neutron and proton EM couplings

    Directory of Open Access Journals (Sweden)

    Strakovsky Igor

    2014-06-01

    Full Text Available We present an overview of the GW SAID group effort to analyze on new pion photoproduction on both proton- and neutron-targets. The main database contribution came from the recent CLAS and MAMI unpolarized and polarized measurements. The differential cross section for the processes γn → π−p was extracted from new measurements accounting for Fermi motion effects in the impulse approximation (IA as well as NN- and πN effects beyond the IA. The electromagnetic coupling results are compared to other recent studies.

  20. Photoproduction of isolated photons, inclusively and with a jet, at HERA

    International Nuclear Information System (INIS)

    The photoproduction of isolated photons, both inclusive and together with a jet, has been measured with the ZEUS detector at HERA using an integrated luminosity of 374 pb−1. Differential cross sections are presented in the isolated-photon transverse-energy and pseudorapidity ranges 6TγγTjetjet22. Differential cross sections are also presented for inclusive isolated-photon production as functions of the transverse energy and pseudorapidity of the photon. Higher-order theoretical calculations are compared to the results

  1. Diffractive J/ψ photoproduction as a probe of the gluon density

    International Nuclear Information System (INIS)

    We use perturbative QCD beyond the leading Ln Q2 approximation, to show how measurements of diffractive J/ψ production at HERA can provide a sensitive probe of the gluon density of the proton at small values of Bjorken x. We estimate both the effect of the relativistic motion of the c and c within the J/ψ and of the rescattering of the cc quark pair on the proton. We find that the available data for diffractive J/ψ photoproduction can discriminate between the gluon distributions of the most recent sets of partons. (author). 18 refs., 9 figs., 1 tab

  2. Study of charm photoproduction using a silicon vertex detector. Measurement of the lifetime of D mesons

    International Nuclear Information System (INIS)

    In this thesis, we were interested in fully reconstructed charmed events, using the results from NA14/2 experiment at CERN. A filtering program, using the active target information, have been developed. D+ and D0 lifetimes have been measured using samples of events with a very good signal to noise ratio. We find values in good agreement with previous experimental results. In addition, the study of the silicon recoil nucleus in the detector enables us, to set a limit on the coherent charm photoproduction cross section

  3. Eta-eta' Photoproduction and the axial isoscalar neutral current coupling

    OpenAIRE

    Bernabeu, J.; González Sprinberg, Gabriel A.; Vidal Perona, Jorge

    1995-01-01

    We show that coherentη andη′ photoproduction by means of the Primakoff Effect on the proton depends on the strange component of the neutral axial current coupling. We construct polarization asymmetries that are sensitive to this coupling through theγ−Z interference. Theη′ is not a Goldstone boson of a spontaneously broken chiral symmetry, but a phenomenological analysis of theη andη′ production through chiral perturbation theory allows to calculate the observables of interest. The polarized p...

  4. Diffractive photoproduction of $j/\\psi$ mesons with large momentum transfer at HERA

    OpenAIRE

    Aktas, A.; Andreev, V.; Anthonis, T.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baranov, P; Barrelet, E.; Bartel, W.; Baumgartner, S.; J. Becker(Bochum Ruhr-University, Bochum, Germany); Beckingham, M.; Beglarian, A.; Behnke, O.

    2003-01-01

    The diffractive photoproduction of J/psi mesons is measured with the H1 detector at the ep collider HERA using an integrated luminosity of 78 pb^-1. The differential cross section d sigma(gamma p -> J/psi Y) / d t is studied in the range 2 < |t| < 30 GeV^2, where t is the square of the four-momentum transferred at the proton vertex. The cross section is also presented as a function of the photon-proton centre-of-mass energy W in three t intervals, spanning the range 50 < W < 200 GeV. A fast r...

  5. Measurement of charm and beauty photoproduction at HERA using Dμ correlations

    Science.gov (United States)

    H1 Collaboration; Aktas, A.; Andreev, V.; Anthonis, T.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bähr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Brown, D. P.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J. G.; Coughlan, J. A.; Cox, B. E.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Dau, W. D.; Daum, K.; Delcourt, B.; Demirchyan, R.; de Roeck, A.; Desch, K.; de Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Fleming, Y. H.; Flucke, G.; Fomenko, A.; Foresti, I.; Formánek, J.; Franke, G.; Frising, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grindhammer, G.; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Henshaw, O.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, H.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Koutouev, R.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Kückens, J.; Landon, M. P. J.; Lange, W.; Laštovička, T.; Laycock, P.; Lebedev, A.; Leißner, B.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Lüke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Plačakytė, R.; Portheault, B.; Povh, B.; Prideaux, P.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D. P. C.; Sauvan, E.; Schätzel, S.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schröder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlák, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L. N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Tomasz, F.; Traynor, D.; Truöl, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, M.; Usik, A.; Utkin, D.; Valkár, S.; Valkárová, A.; Vallée, C.; van Mechelen, P.; van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Vujicic, B.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Wigmore, C.; Winter, G.-G.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zimmermann, J.; Zohrabyan, H.; Zomer, F.

    2005-08-01

    A measurement of charm and beauty photoproduction at the electron proton collider HERA is presented based on the simultaneous detection of a D meson and a muon. The correlation between the D meson and the muon serves to separate the charm and beauty contributions and the analysis provides comparable sensitivity to both. The total and differential experimental cross sections are compared to LO and NLO QCD calculations. The measured charm cross section is in good agreement with QCD predictions including higher order effects while the beauty cross section is higher.

  6. Measurement of charm and beauty photoproduction at HERA using D* μ correlations

    Science.gov (United States)

    Aktas, A.; Andreev, V.; Anthonis, T.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bähr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Brown, D. P.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J. G.; Coughlan, J. A.; Cox, B. E.; Cozzika, G.; Cvach, J.; Dainton, J. B.; Dau, W. D.; Daum, K.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E. A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, G.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, W.; Essenov, S.; Falkewicz, A.; Faulkner, P. J. W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Fleming, Y. H.; Flucke, G.; Fomenko, A.; Foresti, I.; Formánek, J.; Franke, G.; Frising, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grindhammer, G.; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R. C. W.; Henschel, H.; Henshaw, O.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jönsson, L.; Johnson, D. P.; Jung, H.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kenyon, I. R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Koutouev, R.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Kückens, J.; Landon, M. P. J.; Lange, W.; Laštovička, T.; Laycock, P.; Lebedev, A.; Leißner, B.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Lüke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxfield, S. J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A. B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, P. R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J. E.; Osman, S.; Ozerov, D.; Palichik, V.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Plačakytė, R.; Portheault, B.; Povh, B.; Prideaux, P.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D. P. C.; Sauvan, E.; Schätzel, S.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schröder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlák, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L. N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, G.; Thompson, P. D.; Tomasz, F.; Traynor, D.; Truöl, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, M.; Usik, A.; Utkin, D.; Valkár, S.; Valkárová, A.; Vallée, C.; Van Mechelen, P.; Van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Vujicic, B.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Wigmore, C.; Winter, G.-G.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zimmermann, J.; Zohrabyan, H.; Zomer, F.; H1 Collaboration

    2005-08-01

    A measurement of charm and beauty photoproduction at the electron proton collider HERA is presented based on the simultaneous detection of a D*± meson and a muon. The correlation between the D* meson and the muon serves to separate the charm and beauty contributions and the analysis provides comparable sensitivity to both. The total and differential experimental cross sections are compared to LO and NLO QCD calculations. The measured charm cross section is in good agreement with QCD predictions including higher order effects while the beauty cross section is higher.

  7. Spin-dipole excitations of 6Li in charged pion photoproduction

    International Nuclear Information System (INIS)

    In the framework of bound shell model the photoproduction cross sections of charged pions on 6Li are calculated when spin-isospin dipole resonance is excited. It is shown that the transition strenqth concentrates in several energy regions. Such a gross-structure of the excitation spectrum is gaverned by the confiqurational splittinq of the resonance. The excitation spectrum in 6Li(γ, π)-reaction is compared with the 6Li(π, γ), (e, e') and (n, p) reaction spe;tra where spin-isospin transitions are dominating too

  8. 基于生物电化学原理的生物制氢研究进展%Advances in biological hydrogen production based on bio-electrochemical principles

    Institute of Scientific and Technical Information of China (English)

    邸志珲; 张婧卓; 周启星; 曾文炉; 李凤祥

    2016-01-01

    Clean energy resources obtained as great relief to the pressure of energy and environment.And bio-electrochemistry as a separate discipline involves the integration of biology,electrochemistry and chemistry etc,aimed at biological systems and the related controls and applications.On the molecular level,bio-electrochemical researches focus on electrochemical phenomena of charged particles (or non-charged particles)movements.In the energy and environment research field,bio-electrochemistry mainly concerns the chemical energy recovery from organic pollutants,for instance,microbial electrolysis cells (MECs)recover hydrogen energy and treat organic pollutants.This paper introduces the basic principles of MECs for hydrogen production,electrode materials,hydrogen production assessment, and effect comparisons of different types of MECs constructions for hydrogen production.The problems MECs confronted in engineering practice research trends and future prospective is proposed,simultaneously.%清洁能源对于缓解能源环境压力有重要意义,而生物电化学研究在清洁能源领域受到人们重视。生物电化学是以生物体系的研究及其控制和应用为目的,并融合了生物学、电化学和化学等多门学科交叉形成的一门独立的学科,是在分子水平上研究生物体系荷电粒子(可能包括非荷电粒子)运动过程所产生的电化学现象的科学。在能源环境领域,生物电化学研究环境有机污染物化学能回收,如微生物电解池(microbial electrolysis cells,MECs),氢能的回收同时完成污染物的处理。本文介绍了微生物电解池制氢的基本原理、电极材料产氢评价指标;MECs系统不同结构对产氢效能的影响的比较,MECs实际应用中所存在的问题;提出了今后微生物电解池在制氢方面的发展趋势和研究方向及在制氢方面的应用前景。

  9. Non-linear dynamics of stable carbon and hydrogen isotope signatures based on a biological kinetic model of aerobic enzymatic methane oxidation.

    Science.gov (United States)

    Vavilin, Vasily A; Rytov, Sergey V; Shim, Natalia; Vogt, Carsten

    2016-06-01

    The non-linear dynamics of stable carbon and hydrogen isotope signatures during methane oxidation by the methanotrophic bacteria Methylosinus sporium strain 5 (NCIMB 11126) and Methylocaldum gracile strain 14 L (NCIMB 11912) under copper-rich (8.9 µM Cu(2+)), copper-limited (0.3 µM Cu(2+)) or copper-regular (1.1 µM Cu(2+)) conditions has been described mathematically. The model was calibrated by experimental data of methane quantities and carbon and hydrogen isotope signatures of methane measured previously in laboratory microcosms reported by Feisthauer et al. [ 1 ] M. gracile initially oxidizes methane by a particulate methane monooxygenase and assimilates formaldehyde via the ribulose monophosphate pathway, whereas M. sporium expresses a soluble methane monooxygenase under copper-limited conditions and uses the serine pathway for carbon assimilation. The model shows that during methane solubilization dominant carbon and hydrogen isotope fractionation occurs. An increase of biomass due to growth of methanotrophs causes an increase of particulate or soluble monooxygenase that, in turn, decreases soluble methane concentration intensifying methane solubilization. The specific maximum rate of methane oxidation υm was proved to be equal to 4.0 and 1.3 mM mM(-1) h(-1) for M. sporium under copper-rich and copper-limited conditions, respectively, and 0.5 mM mM(-1) h(-1) for M. gracile. The model shows that methane oxidation cannot be described by traditional first-order kinetics. The kinetic isotope fractionation ceases when methane concentrations decrease close to the threshold value. Applicability of the non-linear model was confirmed by dynamics of carbon isotope signature for carbon dioxide that was depleted and later enriched in (13)C. Contrasting to the common Rayleigh linear graph, the dynamic curves allow identifying inappropriate isotope data due to inaccurate substrate concentration analyses. The non-linear model pretty adequately described experimental

  10. Mass analyzed threshold ionization of hydrogen bonded clusters of biological molecules: the 3-methylindole·C6H6 complex

    International Nuclear Information System (INIS)

    The mass analyzed threshold ionization (MATI) technique has been used for measuring the adiabatic ionization energy of the 3-methylindole·C6H6 cluster (58 018 cm-1) and the binding energies in its ground ionic (4448 cm-1) and ground neutral state (1775 cm-1). We compare our results with those recently obtained for the 3-methylindole·H2O and the indole·C6H6 cluster. The small influence of methylation on the binding energies confirms the π-hydrogen bonding character in the 3-methylindole·C6H6 complex

  11. Hydrogen Production

    Energy Technology Data Exchange (ETDEWEB)

    None

    2014-09-01

    This 2-page fact sheet provides a brief introduction to hydrogen production technologies. Intended for a non-technical audience, it explains how different resources and processes can be used to produce hydrogen. It includes an overview of research goals as well as “quick facts” about hydrogen energy resources and production technologies.

  12. Measurement of diffractive photoproduction of vector mesons at large momentum transfer at HERA

    CERN Document Server

    Abbiendi, G; Abramowicz, H; Acosta, D; Adamczyk, L; Adamus, M; Ahn, S H; Amelung, C; An Shiz Hong; Anselmo, F; Antonioli, P; Arneodo, M; Bacon, Trevor C; Badgett, W F; Bailey, D C; Bailey, D S; Bamberger, A; Barbagli, G; Bari, G; Barreiro, F; Barret, O; Bashindzhagian, G L; Bashkirov, V; Basile, M; Bauerdick, L A T; Bednarek, B; Behrens, U; Bellagamba, L; Bertolin, A; Bhadra, S; Bienlein, J K; Blaikley, H E; Bohnet, I; Bokel, C; Boogert, S; Bornheim, A; Borzemski, P; Boscherini, D; Botje, M; Breitweg, J; Brock, I; Brook, N H; Brugnera, R; Bruni, A; Bruni, G; Brümmer, N; Burgard, C; Burow, B D; Bussey, P J; Butterworth, J M; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carlin, R; Cartiglia, N; Cashmore, R J; Castellini, G; Catterall, C D; Chapin, D; Chekanov, S; Chwastowski, J; Ciborowski, J; Cifarelli, Luisa; Cindolo, F; Cirio, R; Cloth, P; Coboken, K; Coldewey, C; Cole, J E; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cor, M; Cormack, C; Corriveau, F; Costa, M; Cottingham, W N; Crittenden, J; Cross, R; D'Agostini, G; Dagan, S; Dal Corso, F; Dardo, M; De Pasquale, S; De Wolf, E; Deffner, R; Del Peso, J; Deppe, O; Derrick, M; Deshpande, Abhay A; Desler, K; Devenish, R C E; Dhawan, S; Dolgoshein, B A; Dondana, S; Dosselli, U; Doyle, A T; Drews, G; Dulinski, Z; Durkin, L S; Dusini, S; Eckert, M; Edmonds, J K; Eisenberg, Y; Eisenhardt, S; Engelen, J; Epperson, D E; Ermolov, P F; Eskreys, Andrzej; Fagerstroem, C P; Fernández, J P; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fox-Murphy, A; Fricke, U; Frisken, W R; Fusayasu, T; Gadaj, T; Galea, R; Gallo, E; García, G; Garfagnini, A; Gendner, N; Gialas, I; Gilmore, J; Ginsburg, C M; Giusti, P; Gladilin, L K; Glasman, C; Göbel, F; Golubkov, Yu A; Grabosch, H J; Graciani, R; Grosse-Knetter, J; Grzelak, G; Göttlicher, P; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hanna, D S; Harnew, N; Hart, H; Hart, J C; Hartmann, J; Hartner, G F; Hasell, D; Hayes, M E; Heaphy, E A; Heath, G P; Heath, H F; Hebbel, K; Heinloth, K; Heinz, L; Hernández, J M; Heusch, C A; Hilger, E; Hirose, T; Hochman, D; Holm, U; Homma, K; Hong, S J; Howell, G; Hughes, V W; Iacobucci, G; Iannotti, L; Iga, Y; Inuzuka, M; Ishii, T; Jakob, H P; Jelen, K; Jeoung, H Y; Jing, Z; Johnson, K F; Jones, T W; Kananov, S; Kappes, A; Karshon, U; Kasemann, M; Katz, U F; Kcira, D; Kerger, R; Khakzad, M; Khein, L A; Kim, C L; Kim, J Y; Kisielewska, D; Kitamura, S; Klanner, Robert; Klimek, K; Ko, I A; Koch, W; Koffeman, E; Kooijman, P; Koop, T; Korotkova, N A; Kotanski, A; Kowal, A M; Kowalski, H; Kowalski, T; Krakauer, D; Kreisel, A; Kuze, M; Kuzmin, V A; Kötz, U; Labarga, L; Lamberti, L; Lane, J B; Laurenti, G; Lee, J H; Lee, S B; Lee, S W; Levi, G; Levman, G M; Levy, A; Lim, H; Lim, I T; Limentani, S; Lindemann, L; Ling, T Y; Liu, W; Lohrmann, E; Long, K R; Lopez-Duran Viani, A; Lukina, O Yu; Löhr, B; Ma, K J; MacDonald, N; Maccarrone, G; Magill, S; Mallik, U; Margotti, A; Marini, G; Markun, P; Martin, J F; Martínez, M; Maselli, S; Massam, Thomas; Mastroberardino, A; Matsushita, T; Mattingly, M C K; Mattingly, S E K; McCance, G J; McCubbin, N A; McFall, J D; Mellado, B; Menary, S R; Meyer, A; Meyer-Larsen, A; Milewski, J; Milite, M; Miller, D B; Monaco, V; Monteiro, T; Morandin, M; Moritz, M; Murray, W N; Musgrave, B; Mönig, K; Nagano, K; Nam, S W; Nania, R; Nigro, A; Nishimura, T; Notz, D; Nowak, R J; Noyes, V A; Nylander, P; Ochs, A; Oh, B Y; Okrasinski, J R; Olkiewicz, K; Orr, R S; Pac, M Y; Padhi, S; Palmonari, F; Park, I H; Park, S K; Parsons, J A; Paul, E; Pavel, N; Pawlak, J M; Pawlak, R; Pelfer, Pier Giovanni; Pellegrino, A; Pelucchi, F; Peroni, C; Pesci, A; Petrucci, M C; Pfeiffer, M; Pic, D; Piotrzkowski, K; Poelz, G; Polenz, S; Polini, A; Posocco, M; Prinias, A; Proskuryakov, A S; Przybycien, M B; Puga, J; Quadt, A; Raach, H; Raso, M; Rautenberg, J; Re, J; Redondo, I; Reeder, D D; Ritz, S; Riveline, M; Rohde, M; Rulikowska-Zarebska, E; Ruske, O; Ruspa, M; Sabetfakhri, A; Sacchi, R; Sadrozinski, H F W; Saint-Laurent, M; Salehi, H; Samp, S; Sartorelli, G; Saull, P R B; Savin, A A; Saxon, D H; Schechter, A; Schioppa, M; Schlenstedt, S; Schmidke, W B; Schneekloth, U; Schnurbusch, H; Schwarzer, O; Sciulli, F; Scott, J; Sedgbeer, J K; Seiden, A; Selonke, F; Shah, T P; Shcheglova, L M; Sideris, D; Sievers, M; Simmons, D; Sinclair, L E; Skillicorn, I O; Smalska, B; Smith, W H; Solano, A; Solomin, A N; Son, D; Staiano, A; Stairs, D G; Stanco, L; Stanek, R; Stifutkin, A; Stonjek, S; Straub, P B; Strickland, E; Stroili, R; Susinno, G; Suszycki, L; Sutton, M R; Suzuki, I; Tandler, J; Tapper, A D; Tapper, R J; Tassi, E; Terron, J; Tiecke, H G; Tokushuku, K; Toothacker, W S; Tsurugai, T; Tuning, N; Tymieniecka, T; Umemori, K; Vaiciulis, A W; Van Sighem, A; Velthuis, J J; Verkerke, W; Voci, C; Vossebeld, Joost Herman; Votano, L; Walczak, R; Walker, R; Wang, S M; Waters, D S; Waugh, R; Weber, A; Whitmore, J J; Wichmann, R; Wick, K; Wieber, H; Wiggers, L; Wildschek, T; Williams, D C; Wing, M; Wodarczyk, M; Wolf, G; Wollmer, U; Wróblewski, A K; Wölfle, S; Yamada, S; Yamashita, T; Yamauchi, K; Yamazaki, Y; Yoshida, R; Youngman, C; Zajac, J; Zakrzewski, J A; Zamora Garcia, Y; Zawiejski, L; Zetsche, F; Zeuner, W; Zhu, Q; Zichichi, A; Zotkin, S A

    2000-01-01

    Elastic and proton-dissociative photoproduction of $\\rho^0$, $\\phi$ and $J/\\psi$ vector mesons ($\\gamma p\\to Vp$, $\\gamma p\\to VN$, respectively) have been measured in e^+p interactions at HERA up to -t=3 GeV$^2$, where t is the four-momentum transfer squared at the photon-vector meson vertex. The analysis is based on a data sample in which photoproduction reactions were tagged by detection of the scattered positron in a special-purpose calorimeter. This limits the photon virtuality, Q^2, to values less than 0.01 GeV$^2$, and selects a $\\gamma p$ average center-of-mass energy of = 94 GeV. Results for the differential cross sections, d$\\sigma$/d$t$, for $\\rho^0$, $\\phi$ and $J/\\psi$ mesons are presented and compared to the results of recent QCD calculations. Results are also presented for the t-dependence of the pion-pair invariant-mass distribution in the $\\rho^0$ mass region and of the spin-density matrix elements determined from the decay-angle distributions. The Pomeron trajectory has been derived from me...

  13. Production of K+K- and ppbar pairs in high energy photoproduction

    International Nuclear Information System (INIS)

    Using the Fermilab broad-band neutral beam and a multi-particle spectrometer, we have investigated the channels: photon + d→K+-(ppbar) (n, p, d, or X). In K+K- production, we make precise measurements of the elastic phi photoproduction cross section between 35 GeV and 85 GeV. Between these limits, we see the elastic cross section rise by 25%. At K+- masses higher than the phi, we see an enhancement centered at 1.72 +- .02 GeV, with a width of .12 +- .05 GeV. We measure the cross section to be 8.0 +- 2.8 nb/nucleon, with an additional systematic error of 16%. Measurements are made of its production characteristics. The most probable interpretation of this state is a radial excitation of the phi, or phi-prime. Production of ppbar pairs is measured. The ppbar mass spectrum displays no obvious peaks, either in elastic or inelastic photoproduction. Limits are set for previously reported possible states in ppbar electroproduction, which are significantly below the reported cross sections. 57 refs

  14. Measurement of dijet photoproduction for events with a leading neutron at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, B. [Argonne National Lab., Argonne, IL (US)] (and others)

    2009-09-15

    Differential cross sections for dijet photoproduction and this process in association with a leading neutron, e{sup +}+p{yields}e{sup +}+jet+jet+X(+n), have been measured with the ZEUS detector at HERA using an integrated luminosity of 40 pb{sup -1}. The fraction of dijet events with a leading neutron was studied as a function of different jet and event variables. Single- and double-differential cross sections are presented as a function of the longitudinal fraction of the proton momentum carried by the leading neutron, x{sub L}, and of its transverse momentum squared, p{sub T}{sup 2}. The dijet data are compared to inclusive DIS and photoproduction results; they are all consistent with a simple pion-exchange model. The neutron yield as a function of x{sub L} was found to depend only on the fraction of the proton beam energy going into the forward region, independent of the hard process. No firm conclusion can be drawn on the presence of rescattering effects. (orig)

  15. High-energy photoproduction of states containing heavy quarks and other rare phenomena

    International Nuclear Information System (INIS)

    We propose to study the photoproduction of states containing heavy quarks, charm and beauty, using a multiparticle spectrometer at the Tevatron. The apparatus is similar to that used in E87 and E401, but is upgraded to have a much larger acceptance, better γ and π0 reconstruction capabilities, and a prompt decay vertex detector. To achieve high sensitivity to low cross sections, the experiment must run in a wide band photon beam, preferably the new beam proposed for the Proton East area. The experiment has two phases. Phase 1 is a 500 hour run with a thick target (1 interaction length) and a beam dump. This phase will produce a large sample of dimuon decays of T's and J/PSI's with energies up to 450 GeV and will measure the size of beauty photoproduction through the detection of multimuon final states. Phase 2 is a 1500 hour run with an open geometry and a 10% interaction length target. We will collect very large samples (> 106) of charm particle events and will search for specific B-meson and B-baryon final states. The power of the spectrometer and the flexibility of the trigger scheme we employ enables us to do sensitive searches for completely new phenomena with less bias than other experiments

  16. Exclusive $\\rho^0$ Meson Photoproduction with a Leading Neutron at HERA

    CERN Document Server

    ,

    2016-01-01

    A first measurement is presented of exclusive photoproduction of $\\rho^0$ mesons associated with leading neutrons at HERA. The data were taken with the H1 detector in the years 2006 and 2007 at a centre-of-mass energy of 319 GeV and correspond to an integrated luminosity of 1.16/pb. The $\\rho^0$ mesons with transverse momenta $p_T$0.35, are detected in the Forward Neutron Calorimeter having a polar angular acceptance < 0.75 mrad. Single- and double-differential cross sections are measured as a function of several variables. The data are interpreted in terms of a double peripheral process, involving pion exchange at the proton vertex followed by elastic photoproduction of a $\\rho^0$ meson on the virtual pion. In the framework of one-pion-exchange dominance the elastic cross section of photon-pion scattering is extracted. The value of this cross section indicates significant absorptive corrections for the exclusive reaction $\\gamma p \\to \\rho^0 n \\pi^+$.

  17. Sunlight-induced degradation of fluoroquinolones in wastewater effluent: Photoproducts identification and toxicity.

    Science.gov (United States)

    Sturini, Michela; Speltini, Andrea; Maraschi, Federica; Pretali, Luca; Ferri, Elida Nora; Profumo, Antonella

    2015-09-01

    The photodegradation of Ciprofloxacin (CIP), Enrofloxacin (ENR), Danofloxacin (DAN), Marbofloxacin (MAR) and Levofloxacin (LEV), five widely used fluoroquinolones (FQs), was studied in urban WWTP secondary effluent, under solar light. The degradation profiles and the kinetic constants were determined at the micrograms per litre levels (20-50 μg L(-1)). The photo-generated products were identified by high-pressure liquid chromatography coupled to electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS). The toxicity of the photoproducts was assessed by Vibrio fischeri light emission inhibition assay performed on irradiated and not-irradiated FQs solutions, at environmentally significant concentrations. Attention was focused on the evaluation of the photoproducts contribution to the overall biotoxic effect of these emerging pollutants. Data from chronic exposure experiments (24-48 h) were primarily considered. Results confirmed the major usefulness of chronic toxicity data with respect to the acute assay ones and proved the not negligible biotoxicity of the FQs photodegradation products. PMID:25966937

  18. Quasi-free photoproduction of {eta}-mesons off the deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Jaegle, I.; Krusche, B.; Dieterle, M.; Keshelashvili, I.; Kotulla, M.; Maghrbi, Y.; Mertens, T.; Oberle, M.; Pheron, F.; Werthmueller, D.; Witthauer, L. [Univ. Basel (Switzerland). Dept. Physik; Anisovich, A.V.; Bayadilov, D.E.; Nikonov, V.A.; Novinski, D.V.; Sarantsev, A.V. [Helmholtz-Inst. fuer Strahlen- und Kernphysik der Univ. Bonn (Germany); Petersburg Nuclear Physics Inst., Gatchina (Russian Federation); Bacelar, J.C.S.; Castelijns, R.; Loehner, H.; Messchendorp, J.G. [Univ. of Groningen, KVI, Groningen (Netherlands); Bantes, B.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Hillert, W.; Hoeffgen, S.; Kammer, S.; Kleber, V.; Klein, Frank; Klein, Friedrich; Konrad, M.; Menze, D.; Schmieden, H.; Schoch, B.; Suele, A.; Walther, D. [Physikalisches Inst. der Universitaet Bonn (Germany); Bartholomy, O.; Beck, R.; Funke, C.; Gutz, E.; Hoffmeister, P.; Horn, I.; Junkersfeld, J.; Kalinowsky, H.; Klempt, E.; Lang, M.; Schmidt, C.; Sokhoyan, V.; Szczepanek, T.; Wendel, C. [Helmholtz-Inst. fuer Strahlen- und Kernphysik der Univ. Bonn (Germany); Beloglazov, Y.A.; Gridnev, A.B.; Lopatin, I.V.; Sumachev, V.V. [Petersburg Nuclear Physics Inst., Gatchina (Russian Federation); Crede, V. [Florida State Univ., Dept. of Physics, Tallahassee, FL (United States); Gothe, R. [Physikalisches Inst. der Univ. Bonn (Germany); Univ. of South Carolina (United States); Gregor, R.; Lugert, S.; Metag, V.; Nanova, M.; Novotny, R.; Pfeiffer, M.; Trnka, D. [Univ. Giessen, II. Physikalisches Inst., Giessen (Germany); Ostrick, M. [Physikalisches Inst. der Univ. Bonn (Germany); University of Mainz (Germany); Pant, L.M. [Univ. Giessen, II. Physikalisches Inst., Giessen (Germany); BARC, Nuclear Physics Div., Mumbai (India); Pee, H. van; Thoma, U. [Helmholtz-Inst. fuer Strahlen- und Kernphysik der Univ. Bonn (Germany); Univ. Giessen (Germany); Roy, A.; Varma, R. [Univ. Giessen (Germany); Indian Inst. of Technology, Mumbai (India). Dept. of Physics] [and others

    2011-08-15

    Precise data for quasi-free photoproduction of {eta}-mesons off the deuteron have been measured at the Bonn ELSA accelerator with the combined Crystal Barrel/TAPS detector for incident photon energies up to 2.5GeV. The {eta}-mesons have been detected in coincidence with recoil protons and neutrons. Possible nuclear effects like Fermi motion and re-scattering can be studied via a comparison of the quasi-free reaction off the bound proton to {eta}-production off the free proton. No significant effects beyond the folding of the free cross-section with the momentum distribution of the bound protons have been found. These Fermi motion effects can be removed by an analysis using the invariant mass of the {eta}-nucleon pairs reconstructed from the final-state four-momenta of the particles. The total cross-section for quasi-free {eta}-photoproduction off the neutron reveals even without correction for Fermi motion a pronounced bump-like structure around 1GeV of incident photon energy, which is not observed for the proton. This structure is even narrower in the invariant-mass spectrum of the {eta}-neutron pairs. Position and width of the peak in the invariant-mass spectrum are W {approx} 1665 MeV and FWHM {gamma} {approx} 25 MeV. The data are compared to the results of different models. (orig.)

  19. Quasi-free photoproduction of eta-mesons off the deuteron

    CERN Document Server

    Jaegle, I; Anisovich, A V; Bacelar, J C S; Bantes, B; Bartholomy, O; Bayadilov, D E; Beck, R; Beloglazov, Y A; Castelijns, R; Crede, V; Dieterle, M; Dutz, H; Elsner, D; Ewald, R; Frommberger, F; Funke, C; Gothe, R; Gregor, R; Gridnev, A B; Gutz, E; Hillert, W; Hoeffgen, S; Hoffmeister, P; Horn, I; Junkersfeld, J; Kalinowsky, H; Kammer, S; Keshelashvili, I; Kleber, V; Klein, Frank; Klein, Friedrich; Klempt, E; Konrad, M; Kotulla, M; Lang, M; Loehner, H; Lopatin, I V; Lugert, S; Maghrbi, Y; Menze, D; Mertens, T; Messchendorp, J G; Metag, V; Nikonov, V A; Nanova, M; Novinski, D V; Novotny, R; Oberle, M; Ostrick, M; Pant, L M; van Pee, H; Pfeiffer, M; Pheron, F; Roy, A; Sarantsev, A V; Schadmand, S; Schmidt, C; Schmieden, H; Schoch, B; Shende, S V; Sokhoyan, V; Suele, A; Sumachev, V V; Szczepanek, T; Thoma, U; Trnka, D; Varma, R; Walther, D; Wendel, C; Werthmueller, D; Witthauer, L

    2011-01-01

    Precise data for quasi-free photoproduction of $\\eta$ mesons off the deuteron have been measured at the Bonn ELSA accelerator with the combined Crystal Barrel/TAPS detector for incident photon energies up to 2.5 GeV. The $\\eta$-mesons have been detected in coincidence with recoil protons and neutrons. Possible nuclear effects like Fermi motion and re-scattering can be studied via a comparison of the quasi-free reaction off the bound proton to $\\eta$-production off the free proton. No significant effects beyond the folding of the free cross section with the momentum distribution of the bound protons have been found. These Fermi motion effects can be removed by an analysis using the invariant mass of the $\\eta$-nucleon pairs reconstructed from the final state four-momenta of the particles. The total cross section for quasi-free $\\eta$-photoproduction off the neutron reveals even without correction for Fermi motion a pronounced bump-like structure around 1 GeV of incident photon energy, which is not observed for...

  20. Regge approach to charged-pion photoproduction at invariant energies above 2 GeV

    Energy Technology Data Exchange (ETDEWEB)

    Sibirtsev, A; Haidenbauer, J; Krewald, S; Lee, T S.H.; Meissner, U -G; Thomas, A W

    2007-10-01

    A Regge model with absorptive corrections is employed in a global analysis of the world data on positive and negative pion photoproduction for photon energies from 3 to 8~GeV. In this region resonance contributions are expected to be negligible so that the available experimental information on differential cross sections and single polarization observables at $-t{\\leq}2$ GeV$^2$ allows us to determine the non-resonant part of the reaction amplitude reliably. The model amplitude is then used to predict observables for photon energies below $3$ GeV. Differences between our predictions and data in this energy region are systematically examined as possible signals for the presence of excited baryons. We find that the data available for the polarized photon asymmetry show promising resonance signatures at invariant energies around 2~GeV. With regard to differential cross sections the analysis of negative pion photoproduction data, obtained recently at JLab, indicates likewise the presence of resonance structures around 2~GeV.

  1. Regge poles and cuts in π0 photoproduction and related reactions

    International Nuclear Information System (INIS)

    A previous analysis of intermediate- and high-energy photoproduction data using finite-energy sum rules and fixed-t dispersion relations is extended to enable effects due to Regge poles and cuts to be distinguished. This is achieved by requiring Regge poles to be evasive and to have nonsense wrong signature zeros, whereas cuts are parametrised by effective two-pole forms and are taken to be self-conspiring with minimal structure in their residues. These constraints, together with phase information provided by data on the Primakoff effect, enable an essentially unique separation of pole and cut effects to be made. The results are conpared with popular cut models of hadronic reactions relevant at accelerator energies, and with the universal impact parameter hypothesis. None of these are able to reproduce all the features found in the amplitudes. Finally, it is shown how the results can cast light on the puzzling absence of dips in eta0 photoproduction and π0 electroproduction, by making plausible assumptions about the isospin and q2 dependences of our amplitudes, respectively. (Auth.)

  2. Photoproduction of D*± mesons in electron-proton collisions at HERA

    International Nuclear Information System (INIS)

    At the electron-proton collider HERA the inclusive D*± meson photoproduction cross section has been measured with the H1 detector in two different, but partly overlapping, kinematical regions. For the first, where (Wγp)∼200 GeV and Q22, the result is σ(γp→c anti cX)=(13.2±2.2-1.7+22.1-4.8+9.9)μb. The second measurement for Q22 yields σ(γp→c anti cX)=(9.3±2.1-1.8+1.9-3.2+6.9)μb at pp>∼142 GeV and σ(γp→c anti cX)=(20.6±5.5-3.9+4.37.215.4)μb at γp>∼230 GeV, respectively. The third error accounts for an additional uncertainty due to the proton and photon parton density parametrizations. Differential cross sections are presented as a function of the D*± transverse momentum and rapidity. The results compare reasonably well with next-to-leading order QCD calculations. Evidence for diffractive photoproduction of charm quarks is presented. (orig.)

  3. 生物制氢混合培养系统启动与运行的人工操作%THE ARTIFICAL MANIPULATION OF THE START-UP AND OPERATION FOR BIOLOGICAL HYDROGEN PRODUCTION REACTOR

    Institute of Scientific and Technical Information of China (English)

    王兵; 李永峰; 朱雷雷; 郜爽; 曹莉; 白旭峰

    2011-01-01

    采用连续流搅拌槽式反应系统(CSTR)作为反应装置,以糖蜜废水为发酵底物,污水处理厂剩余污泥为反应的启动污泥,着重对pH和氧化还原电位(ORP)调控下生物制氢反应器乙醇型发酵的启动进行了研究.结果表明:在温度为(35±1)℃,水力停留时间(HRT)为6h,进水COD为4000mg/L时,通过调节ORP和系统pH值可在约33d实现生物制氢反应器中微生物的主要代谢类型为乙醇型发酵,并实现稳定产氢.%A continuous stirred tank reactor (CSTR) seeded with anaerobic activated sludge was developed for hydrogen production using molasses wastewater. Emphasis was placed on the start-up of ethanol-type fermentation in biological hydrogen production reactor with ORP and pH. It is found that the temperature of ( 35 ± 1) X. , hydraulic retention time (HRT) of 6h, influent COD of 4000mg/L, the reactor could start-up the ethanol-type fermentation with ORP and pH in 33 days and realize hydrogen production in stable condition.

  4. Hydrogen economy

    Energy Technology Data Exchange (ETDEWEB)

    Pahwa, P.K.; Pahwa, Gulshan Kumar

    2013-10-01

    In the future, our energy systems will need to be renewable and sustainable, efficient and cost-effective, convenient and safe. Hydrogen has been proposed as the perfect fuel for this future energy system. The availability of a reliable and cost-effective supply, safe and efficient storage, and convenient end use of hydrogen will be essential for a transition to a hydrogen economy. Research is being conducted throughout the world for the development of safe, cost-effective hydrogen production, storage, and end-use technologies that support and foster this transition. This book discusses hydrogen economy vis-a-vis sustainable development. It examines the link between development and energy, prospects of sustainable development, significance of hydrogen energy economy, and provides an authoritative and up-to-date scientific account of hydrogen generation, storage, transportation, and safety.

  5. Photoproduction of the scalar mesons $f_0(500)$ and $f_0(980)$ off the nucleon

    CERN Document Server

    Lee, Je-Hee; Ryu, Hui-Young; Yu, Byung-Geel

    2016-01-01

    We investigate photoproduction of the scalar mesona off the nucleon, using the effective Lagrangians and the Regge approach. We first study $f_0(980)$ photoproduction, replacing the Feynman propagator with the Regge ones for the $\\rho$-meson exchange in the $t$-channel. The model parameters are fixed by reproducing the experimental data on the differential cross section. We then apply the same method to $f_0(500)$ or $\\sigma$ photoproduction with the same parameters for the Regge propagator. Since the threshold energy of the $f_0(500)$ production is rather low, $N^*$ resonances, which can decay into the nucleon and two pions in the isoscalar and scalar state, can come into play in the $s$-channel. To examine the effects of the $N^*$ resonances, we set up two models to look into the respective contribution of the $N^*$ resonances. We find that in particular $N^*(1440)$ and $N^*(1680)$ play important roles in $f_0(500)$ photoproduction. We discuss the physical implications of the present results.

  6. Novel Biological Conversion of Hydrogen and Carbon Dioxide Directly into Biodiesel: Cooperative Research and Development Final Report, CRADA Number: CRD-10-408

    Energy Technology Data Exchange (ETDEWEB)

    Maness, P. C.

    2014-06-01

    OPX Biotechnologies, Inc. (OPX), the National Renewable Energy Laboratory (NREL), and Johnson Matthey will develop and optimize a novel, engineered microorganism that directly produces biodiesel from renewable hydrogen (H2) and carbon dioxide (CO2). The proposed process will fix CO2 utilizing H2 to generate an infrastructure-compatible, energy-dense fuel at costs of less than $2.50 per gallon, with water being produced as the primary byproduct. NREL will perform metabolic engineering on the bacterium Cupriavidus necator (formerly Ralstonia eutropha) and a techno-economic analysis to guide future scale-up work. H2 and CO2 uptakes rates will be genetically increased, production of free fatty acids will be enhanced and their degradation pathway blocked in order to meet the ultimate program goals.

  7. Diffractive photoproduction of radially excited psi(2S) mesons in photon-Pomeron reactions in PbPb collisions at the CERN LHC

    CERN Document Server

    Ducati, M B Gay; Machado, M V T

    2013-01-01

    In this work we investigate the photoproduction of radially excited vector mesons off nuclei in heavy ion relativistic collisions. In particular, we analyze the exclusive photoproduction of psi(2S) off nuclei, evaluating the coherent and the incoherent contributions to that process. The theoretical framework used in the present analysis is the light-cone dipole formalism and predictions are done for PbPb collisions at the CERN-LHC energy of 2.76 TeV. The theoretical uncertainties are analyzed and comparison is also done to the recent ALICE Collaboration data for the psi(1S) state photoproduction.

  8. Search for an exotic S=-2, Q=-2 baryon resonance at a mass near 1862 MeV in quasi-real photoproduction

    CERN Document Server

    Airapetian, A; Akopov, Z; Amarian, M; Ammosov, V V; Andrus, A; Aschenauer, E C; Augustyniak, W; Avakian, R; Avetisian, A; Avetissian, E; Bailey, P; Baturin, V; Baumgarten, C; Beckmann, M; Belostotskii, S; Bernreuther, S; Bianchi, N; Blok, H P; Böttcher, Helmut B; Borisov, A; Bouwhuis, M; Brack, J; Brüll, A; Bryzgalov, V V; Capitani, G P; Chiang, H C; Ciullo, G; Contalbrigo, M; Dalpiaz, P F; De Leo, R; De Nardo, L; De Sanctis, E; Devitsin, E G; Di Nezza, P; Düren, M; Ehrenfried, M; Elalaoui-Moulay, A; Elbakian, G M; Ellinghaus, F; Elschenbroich, U; Ely, J; Fabbri, R; Fantoni, A; Feshchenko, A; Felawka, L; Fox, B; Franz, J; Frullani, S; Gärber, Y; Gapienko, G; Gapienko, V; Garibaldi, F; Garrow, K; Garutti, E; Gaskell, D; Gavrilov, G E; Karibian, V; Graw, G; Grebenyuk, O; Greeniaus, L G; Hafidi, K; Hartig, M; Hasch, D; Heesbeen, D; Henoch, M; Hertenberger, R; Hesselink, W H A; Hillenbrand, A; Hoek, M; Holler, Y; Hommez, B; Iarygin, G; Ivanilov, A; Izotov, A; Jackson, H E; Jgoun, A; Kaiser, R; Kinney, E; Kiselev, A; Königsmann, K C; Kopytin, M; Korotkov, V A; Kozlov, V; Krauss, B; Krivokhizhin, V G; Lagamba, L; Lapikas, L; Laziev, A; Lenisa, P; Liebing, P; Lindemann, T; Lipka, K; Lorenzon, W; Lü, J; Maiheu, B; Makins, N C R; Marianski, B; Marukyan, H O; Masoli, F; Mexner, V; Meyners, N; Miklukho, O; Miller, C A; Miyachi, Y; Muccifora, V; Nagaitsev, A; Nappi, E; Naryshkin, Yu; Nass, A; Negodaev, M A; Nowak, Wolf-Dieter; Oganessyan, K; Ohsuga, H; Orlandi, G; Pickert, N; Potashov, S Yu; Potterveld, D H; Raithel, M; Reggiani, D; Reimer, P E; Reischl, A; Reolon, A R; Riedl, C; Rith, K; Rosner, G; Rostomyan, A; Rubacek, L; Ryckbosch, D; Salomatin, Yu I; Sanjiev, I; Savin, I; Scarlett, C; Schäfer, A; Schill, C; Schnell, G; Schüler, K P; Schwind, A; Seele, J; Seidl, R; Seitz, B; Shanidze, R G; Shearer, C; Shibata, T A; Shutov, V B; Simani, M C; Sinram, K; Stancari, M D; Statera, M; Steffens, E; Steijger, J J M; Stewart, J; Stösslein, U; Tait, P; Tanaka, H; Taroian, S P; Tchuiko, B; Terkulov, A R; Tkabladze, A V; Trzcinski, A; Tytgat, M; Vandenbroucke, A; Van der Nat, P B; van der Steenhoven, G; Vetterli, Martin C; Vikhrov, V; Vincter, M G; Visser, J; Vogel, C; Vogt, M; Volmer, J; Weiskopf, C; Wendland, J; Wilbert, J; Ybeles-Smit, G V; Yen, S; Zihlmann, B; Zohrabyan, H G; Zupranski, P

    2004-01-01

    A search for an exotic baryon resonance with $S=-2, Q=-2$ has been performed in quasi-real photoproduction on a deuterium target through the decay channel $\\Xi^- \\pi^- \\to \\Lambda \\pi^- \\pi^- \\to p \\pi^- \\pi^- \\pi^-$. No evidence for a previously reported $\\Xi^{--}(1860)$ resonance is found in the $\\Xi^- \\pi^-$invariant mass spectrum. An upper limit for the photoproduction cross section of 2.1 nb is found at the 90% confidence level. The photoproduction cross section for the $\\Xi^{0}(1530)$ is found to be between 9 and 24 nb.

  9. Purdue Hydrogen Systems Laboratory

    International Nuclear Information System (INIS)

    The Hydrogen Systems Laboratory in a unique partnership between Purdue University's main campus in West Lafayette and the Calumet campus was established and its capabilities were enhanced towards technology demonstrators. The laboratory engaged in basic research in hydrogen production and storage and initiated engineering systems research with performance goals established as per the USDOE Hydrogen, Fuel Cells, and Infrastructure Technologies Program. In the chemical storage and recycling part of the project, we worked towards maximum recycling yield via novel chemical selection and novel recycling pathways. With the basic potential of a large hydrogen yield from AB, we used it as an example chemical but have also discovered its limitations. Further, we discovered alternate storage chemicals that appear to have advantages over AB. We improved the slurry hydrolysis approach by using advanced slurry/solution mixing techniques. We demonstrated vehicle scale aqueous and non-aqueous slurry reactors to address various engineering issues in on-board chemical hydrogen storage systems. We measured the thermal properties of raw and spent AB. Further, we conducted experiments to determine reaction mechanisms and kinetics of hydrothermolysis in hydride-rich solutions and slurries. We also developed a continuous flow reactor and a laboratory scale fuel cell power generation system. The biological hydrogen production work summarized as Task 4.0 below, included investigating optimal hydrogen production cultures for different substrates, reducing the water content in the substrate, and integrating results from vacuum tube solar collector based pre and post processing tests into an enhanced energy system model. An automated testing device was used to finalize optimal hydrogen production conditions using statistical procedures. A 3 L commercial fermentor (New Brunswick, BioFlo 115) was used to finalize testing of larger samples and to consider issues related to scale up. Efforts

  10. Purdue Hydrogen Systems Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Jay P Gore; Robert Kramer; Timothee L Pourpoint; P. V. Ramachandran; Arvind Varma; Yuan Zheng

    2011-12-28

    The Hydrogen Systems Laboratory in a unique partnership between Purdue University's main campus in West Lafayette and the Calumet campus was established and its capabilities were enhanced towards technology demonstrators. The laboratory engaged in basic research in hydrogen production and storage and initiated engineering systems research with performance goals established as per the USDOE Hydrogen, Fuel Cells, and Infrastructure Technologies Program. In the chemical storage and recycling part of the project, we worked towards maximum recycling yield via novel chemical selection and novel recycling pathways. With the basic potential of a large hydrogen yield from AB, we used it as an example chemical but have also discovered its limitations. Further, we discovered alternate storage chemicals that appear to have advantages over AB. We improved the slurry hydrolysis approach by using advanced slurry/solution mixing techniques. We demonstrated vehicle scale aqueous and non-aqueous slurry reactors to address various engineering issues in on-board chemical hydrogen storage systems. We measured the thermal properties of raw and spent AB. Further, we conducted experiments to determine reaction mechanisms and kinetics of hydrothermolysis in hydride-rich solutions and slurries. We also developed a continuous flow reactor and a laboratory scale fuel cell power generation system. The biological hydrogen production work summarized as Task 4.0 below, included investigating optimal hydrogen production cultures for different substrates, reducing the water content in the substrate, and integrating results from vacuum tube solar collector based pre and post processing tests into an enhanced energy system model. An automated testing device was used to finalize optimal hydrogen production conditions using statistical procedures. A 3 L commercial fermentor (New Brunswick, BioFlo 115) was used to finalize testing of larger samples and to consider issues related to scale up

  11. Hydrogen Spectrum

    Science.gov (United States)

    Murdin, P.

    2000-11-01

    The series of absorption or emission lines that are characteristic of the hydrogen atom. According to the Bohr theory of the hydrogen atom, devised by Danish physicist Neils Bohr (1885-1962) in 1913, the hydrogen atom can be envisaged as consisting of a central nucleus (a proton) around which a single electron revolves. The electron is located in one of a number of possible permitted orbits, each...

  12. Photoproduction of ω mesons off nuclei and impact of polarization on the meson-nucleon interaction

    Energy Technology Data Exchange (ETDEWEB)

    Chudakov, Eugene A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Gevorkyan, Sergey [Joint Inst. for Nuclear Research (JINR), Dubna (Russian Federation); Somov, Alexander [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-01-01

    We consider photoproduction of omega mesons off complex nuclei to study interactions of transversely and longitudinally polarized vector mesons with nucleons. Whereas the total cross section for interactions of the transversely polarized vector mesons with nucleons sigma_T = sigma(V_T N) can be obtained from coherent photoproduction, measurements of vector meson photoproduction in the incoherent region provide a unique opportunity to extract the not-yet-measured total cross section for longitudinally polarized mesons sigma_L = sigma(V_L N). The predictions for the latter strongly depend on the theoretical approaches. This work is stimulated by the construction of the new experiment GlueX at Jefferson Lab, designed to study the photoproduction of mesons in a large beam energy range up to 12 GeV.

  13. Elastic and Proton-Dissociative Photoproduction of J/psi Mesons at HERA

    CERN Document Server

    Alexa, C; Baghdasaryan, A; Baghdasaryan, S; Bartel, W; Begzsuren, K; Belousov, A; Belov, P; Boudry, V; Bozovic-Jelisavcic, I; Brandt, G; Brinkmann, M; Brisson, V; Britzger, D; Buniatyan, A; Bylinkin, A; Bystritskaya, L; Campbell, A J; Cantun Avila, K B; Ceccopieri, F; Cerny, K; Chekelian, V; Contreras, J G; Cvach, J; Dainton, J B; Daum, K; De Wolf, E A; Diaconu, C; Dobre, M; Dodonov, V; Dossanov, A; Eckerlin, G; Egli, S; Elsen, E; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Fischer, D J; Fleischer, M; Fomenko, A; Gabathuler, E; Gayler, J; Ghazaryan, S; Glazov, A; Goerlich, L; Gogitidze, N; Gouzevitch, M; Grab, C; Grebenyuk, A; Greenshaw, T; Grindhammer, G; Habib, S; Haidt, D; Henderson, R C W; Hennekemper, E; Herbst, M; Herrera, G; Hildebrandt, M; Hiller, K H; Hladky, J; Hoffmann, D; Horisberger, R; Hreus, T; Huber, F; Jacquet, M; Janssen, X; Jonsson, L; Jung, H; Kapichine, M; Kiesling, C; Klein, M; Kleinwort, C; Kogler, R; Kostka, P; Kramer, M; Kretzschmar, J; Kruger, K; Landon, M P J; Lange, W; Laycock, P; Lebedev, A; Levonian, S; Lipka, K; List, B; List, J; Lobodzinski, B; Lopez-Fernandez, R; Lubimov, V; Malinovski, E; Martyn, H U; Maxfield, S J; Mehta, A; Meyer, A B; Meyer, H; Meyer, J; Mikocki, S; Milcewicz-Mika, I; Morozov, A; Morris, J V; Muller, K; Naumann, Th; Newman, P R; Niebuhr, C; Nikitin, D; Nowak, G; Nowak, K; Olsson, J E; Ozerov, D; Pahl, P; Palichik, V; Pandurovic, M; Pascaud, C; Patel, G D; Perez, E; Petrukhin, A; Picuric, I; Pirumov, H; Pitzl, D; Placakyte, R; Pokorny, B; Polifka, R; Radescu, V; Raicevic, N; Ravdandorj, T; Reimer, P; Rizvi, E; Robmann, P; Roosen, R; Rostovtsev, A; Rotaru, M; Ruiz Tabasco, J E; Rusakov, S; Salek, D; Sankey, D P C; Sauter, M; Sauvan, E; Schmitt, S; Schoeffel, L; Schoning, A; Schultz-Coulon, H C; Sefkow, F; Shushkevich, S; Soloviev, Y; Sopicki, P; South, D; Spaskov, V; Specka, A; Staykova, Z; Steder, M; Stella, B; Stoicea, G; Straumann, U; Sykora, T; Thompson, P D; Traynor, D; Truol, P; Tsakov, I; Tseepeldorj, B; Turnau, J; Valkarova, A; Vallee, C; Van Mechelen, P; Vazdik, Y; Wegener, D; Wunsch, E; Zacek, J; Zalesak, J; Zhang, Z; Zlebcik, R; Zohrabyan, H; Zomer, F

    2013-01-01

    Cross sections for elastic and proton-dissociative photoproduction of J/psi mesons are measured with the H1 detector in positron-proton collisions at HERA. The data were collected at $ep$ centre-of-mass energies sqrt{s} approx 318 GeV and sqrt{s} approx 225 GeV, corresponding to integrated luminosities of L = 130 pb^{-1} and L = 10.8 pb^{-1}, respectively. The cross sections are measured as a function of the photon-proton centre-of-mass energy in the range 25< Wgp < 110 GeV. Differential cross sections $\\mathrm{d}\\sigma / \\mathrm{d}t$, where $t$ is the squared four-momentum transfer at the proton vertex, are measured in the range $|t| < 1.2 \\, \\gevsq$ for the elastic process and $|t| < 8 \\, \\gevsq$ for proton dissociation. The results are compared to other measurements. The $\\Wgp$ and $t$-dependences are parametrised using phenomenological fits.

  14. Inclusive D* Meson Cross Sections and D* Jet Correlations in Photoproduction at HERA

    CERN Document Server

    Aktas, A; Anthonis, T; Antunovic, B; Aplin, S; Asmone, A; Astvatsatourov, A; Babaev, A; Backovic, S; Baghdasaryan, A; Baranov, P; Barrelet, E; Bartel, Wulfrin; Baudrand, S; Baumgartner, S; Beckingham, M; Behnke, O; Behrendt, O; Belousov, A; Berger, N; Bizot, J C; Boenig, M O; Boudry, V; Bracinik, J; Brandt, G; Brisson, V; Bruncko, D; Büsser, F W; Bunyatyan, A; Buschhorn, G; Bystritskaya, L; Campbell, A J; Caron, S; Cassol-Brunner, F; Cerny, K; Cerny, V; Chekelian, V; Contreras, J G; Coughlan, J A; Cox, B E; Cozzika, G; Cvach, J; Dainton, J B; Dau, W D; Daum, K; De Boer, Y; Delcourt, B; Del Degan, M; de Roeck, A; De Wolf, E A; Diaconu, C; Dodonov, V; Dubak, A; Eckerlin, G; Efremenko, V; Egli, S; Eichler, R; Eisele, F; Eliseev, A; Elsen, E; Essenov, S; Falkewicz, A; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Feltesse, J; Ferencei, J; Finke, L; Fleischer, M; Flucke, G; Fomenko, A; Franke, G; Frisson, T; Gabathuler, E; Garutti, E; Gayler, J; Gerlich, C; Ghazaryan, S; Ginzburgskaya, S; Glazov, A; Glushkov, I; Görlich, L; Goettlich, M; Gogitidze, N; Gorbounov, S; Grab, C; Greenshaw, T; Gregori, M; Grell, B R; Grindhammer, G; Gwilliam, C; Habib, S; Haidt, D; Hansson, M; Heinzelmann, G; Henderson, R C W; Henschel, H; Herrera-Corral, G; Hildebrandt, M; Hiller, K H; Hoffmann, D; Horisberger, R P; Hovhannisyan, A; Hreus, T; Hussain, S; Ibbotson, M; Ismail, M; Jacquet, M; Janssen, X; Jemanov, V; Jönsson, L B; Johnson, D P; Jung, A W; Jung, H; Kapichine, M; Katzy, J; Kenyon, I R; Kiesling, C; Klein, M; Kleinwort, C; Klimkovich, T; Kluge, T; Knies, G; Knutsson, A; Korbel, V; Kostka, P; Krastev, K; Kretzschmar, J; Kropivnitskaya, A; Krüger, K; Landon, M P J; Lange, W; Lastoviicka-Medin, G; Laycock, P; Lebedev, A; Leibenguth, G; Lendermann, V; Levonian, S; Lindfeld, L; Lipka, K; Liptaj, A; List, B; List, J; Lobodzinska, E; Loktionova, N; López-Fernandez, R; Lubimov, V; Lucaci-Timoce, A I; Lüders, H; Lux, T; Lytkin, L; Makankine, A; Malden, N; Malinovskii, E I; Marage, P; Marshall, R; Marti, L; Martisikova, M; Martyn, H U; Maxfield, S J; Mehta, A; Meier, K; Meyer, A B; Meyer, H; Meyer, J; Michels, V; Mikocki, S; Milcewicz-Mika, I; Milstead, D; Mladenov, D; Mohamed, A; Moreau, F; Morozov, A; Morris, J V; Mozer, M U; Müller, K; Murn, P; Nankov, K; Naroska, B; Naumann, T; Newman, P R; Niebuhr, C; Nikiforov, A; Nowak, G; Nowak, K; Nozicka, M; Oganezov, R; Olivier, B; Olsson, J E; Osman, S; Ozerov, D; Palichik, V; Panagoulias, I; Papadopoulou, T D; Pascaud, C; Patel, G D; Peng, H; Pérez, E; Perez-Astudillo, D; Perieanu, A; Petrukhin, A; Pitzl, D; Placakyte, R; Portheault, B; Povh, B; Prideaux, P; Rahmat, A J; Raicevic, N; Reimer, P; Rimmer, A; Risler, C; Rizvi, E; Robmann, P; Roland, B; Roosen, R; Rostovtsev, A; Rurikova, Z; Rusakov, S; Salvaire, F; Sankey, D P C; Sauter, M; Sauvan, E; Schmidt, S; Schmitt, S; Schmitz, C; Schoeffel, L; Schöning, A; Schultz-Coulon, H C; Sefkow, F; Shaw-West, R N; Shevyakov, I; Shtarkov, L N; Sloan, T; Smirnov, P; Soloviev, Yu; South, D; Spaskov, V; Specka, A; Steder, M; Stella, B; Stiewe, J; Stoilov, A; Straumann, U; Sunar, D; Tchoulakov, V; Thompson, G; Thompson, P D; Toll, T; Tomasz, F; Traynor, D; Trinh, T N; Truöl, P; Tsakov, I; Tsipolitis, G; Tsurin, I; Turnau, J; Tzamariudaki, E; Urban, K; Urban, M; Usik, A; Utkin, D; Valkárová, A; Vallée, C; Van Mechelen, P; Vargas, A; Trevino; Vazdik, Ya A; Veelken, C; Vinokurova, S; Volchinski, V; Wacker, K; Weber, G; Weber, R; Wegener, D; Werner, C; Wessels, M; Wessling, B; Wissing, C; Wolf, R; Wünsch, E; Xella, S M; Yan, W; Yeganov, V; Zaicek, J; Zaleisak, J; Zhang, Z; Zhelezov, A; Zhokin, A; Zhu, Y C; Zimmermann, J; Zimmermann, T; Zohrabyan, H; Zomer, F

    2007-01-01

    Differential photoproduction cross sections are measured for events containing D* mesons. The data were taken with the H1 detector at the ep collider HERA and correspond to an integrated luminosity of 51.1 pb-1. The kinematic region covers small photon virtualities Q^2 < 0.01 GeV^2 and photon-proton centre-of-mass energies of 171 < W_gammap < 256 GeV. The details of the heavy quark production process are further investigated in events with one or two jets in addition to the D* meson. Differential cross sections for D* jet production are determined and the correlations between the D* meson and the jet(s) are studied. The results are compared with perturbative QCD predictions applying collinear- or kt -factorisation.

  15. Measurement of Di-jet Cross-Sections in Photoproduction and Photon Structure

    CERN Document Server

    Adloff, C; Andrieu, B; Arkadov, V; Astvatsaturov, A R; Ayyaz, I; Babaev, A; Bähr, J; Baranov, P S; Barrelet, E; Bartel, Wulfrin; Bassler, U; Bate, P; Beglarian, A; Behnke, O; Beier, C; Belousov, A; Benisch, T; Berger, C; Bernardi, G; Berndt, T; Bertrand-Coremans, G; Bizot, J C; Borras, K; Boudry, V; Braunschweig, W; Brisson, V; Broker, H B; Brown, D P D; Brückner, W; Bruel, P; Bruncko, Dusan; Bürger, J; Büsser, F W; Bunyatyan, A; Burke, S; Burkhardt, H; Burrage, A; Buschhorn, G W; Campbell, A J; Cao, J; Carli, T; Caron, S; Chabert, E; Clarke, D; Clerbaux, B; Collard, Caroline; Contreras, J G; Coughlan, J A; Cousinou, M C; Cox, B E; Cozzika, G; Cvach, J; Dainton, J B; Dau, W D; Daum, K; David, M; Davidsson, M; Delcourt, B; Delerue, N; Demirchyan, R A; de Roeck, A; De Wolf, E A; Diaconu, C A; Dixon, P; Dodonov, V; Donovan, K T; Dowell, John D; Droutskoi, A; Duprel, C; Ebert, J; Eckerlin, G; Eckstein, D; Efremenko, V; Egli, S; Eichler, R; Eisele, Franz; Eisenhandler, Eric F; Ellerbrock, M; Elsen, E E; Erdmann, M; Faulkner, P J W; Favart, L; Fedotov, A; Felst, R; Feltesse, Joel; Ferencei, J; Ferrarotto, F; Ferron, S; Fleischer, M; Flügge, G; Fomenko, A; Foresti, I; Formánek, J; Foster, J M; Franke, G; Gabathuler, Erwin; Gabathuler, K; Garvey, J; Gassner, J; Gayler, J; Gerhards, R; Kazarian, S; Glazov, A; Görlich, L; Gogitidze, N; Goldberg, M; Goodwin, C; Gorelov, I V; Grab, C; Grässler, Herbert; Greenshaw, T; Griffiths, R K; Grindhammer, G; Hadig, T; Haidt, Dieter; Hajduk, L; Haustein, V; Haynes, W J; Heinemann, B; Heinzelmann, G; Henderson, R C W; Hengstmann, S; Henschel, H; Heremans, R; Herrera-Corral, G; Herynek, I; Hilgers, M; Hiller, K H; Hilton, C D; Hladky, J; Hoting, P; Hoffmann, D; Hoprich, W; Horisberger, R P; Hurling, S; Ibbotson, M; Issever, C; Jacquet, M; Jaffré, M; Janauschek, L; Jansen, D M; Janssen, X; Jemanov, V; Jönsson, L B; Johnson, D P; Jones, M A S; Jung, H; Kastli, H K; Kant, D; Kapichine, M; Karlsson, M; Karschnick, O; Kaufmann, O; Kausch, M; Keil, F; Keller, N; Kennedy, J; Kenyon, Ian Richard; Kermiche, S; Kiesling, C; Klein, M; Kleinwort, C; Knies, G; Koblitz, B; Kolanoski, H; Kolya, S D; Korbel, V; Kostka, P; Kotelnikov, S K; Krasny, M W; Krehbiel, H; Kroseberg, J; Krücker, D; Krüger, K; Küpper, A; Kuhr, T; Kurca, T; Kutuev, R K; Lachnit, W A; Lahmann, R; Lamb, D; Landon, M P J; Lange, W; Lastoviicka, T; Lebedev, A; Leiner, B; Lemaître, V; Lemrani, R; Lendermann, V; Levonian, S; Lindstrøm, M; Lobo, G; Lobodzinska, E; Lobodzinski, B; Loktionova, N A; Lubimov, V; Lüders, S; Lüke, D; Lytkin, L K; Magnussen, N; Mahlke-Krüger, H; Malden, N; Malinovskii, E I; Maracek, R; Marage, P; Marks, J; Marshall, R; Martyn, H U; Martyniak, J; Maxfield, S J; McMahon, T R; Mehta, A; Meier, K; Merkel, P; Metlica, F; Meyer, A; Meyer, H; Meyer, J; Meyer, P O; Mikocki, S; Milstead, D; Mkrtchyan, T; Mohr, R F; Mohrdieck, S; Mondragón, M N; Moreau, F; Morozov, A; Morris, J V; Müller, D; Müller, K; Murn, P; Nagovizin, V; Naroska, Beate; Naumann, J; Naumann, T; Negri, I; Newman, P R; Nguyen, H K; Nicholls, T C; Niebergall, F; Niebuhr, C B; Nix, O; Nowak, G; Nunnemann, T; Olsson, J E; Ozerov, D; Panassik, V; Pascaud, C; Passaggio, S; Patel, G D; Pérez, E; Phillips, J P; Pitzl, D; Pöschl, R; Potachnikova, I; Povh, B; Rabbertz, K; Rädel, G; Rauschenberger, J; Reimer, P; Reisert, B; Reyna, D; Riess, S; Rizvi, E; Robmann, P; Roosen, R; Rostovtsev, A A; Royon, C; Rusakov, S V; Rybicki, K; Sankey, D P C; Scheins, J; Schilling, F P; Schleif, S; Schleper, P; Schmidt, D; Schoeffel, L; Schöning, A; Schörner-Sadenius, T; Schröder, V; Schultz-Coulon, H C; Sedlak, K; Sefkow, F; Shekelian, V I; Shevyakov, I; Shtarkov, L N; Siegmon, G; Sievers, P; Sirois, Y; Sloan, Terence; Smirnov, P; Smith, M; Solochenko, V; Soloviev, Yu V; Spaskov, V N; Specka, A E; Spitzer, H; Stamen, R; Steinhart, J; Stella, B; Stellberger, A; Stiewe, J; Straumann, U; Struczinski, W; Sutton, J P; Swart, M; Tasevsky, M; Chernyshov, V; Chechelnitskii, S; Thompson, G; Thompson, P D; Tobien, N; Traynor, D; Truöl, P; Tsipolitis, G; Turnau, J; Turney, J E; Tzamariudaki, E; Udluft, S; Usik, A; Valkár, S; Valkárová, A; Vallée, C; Van Mechelen, P; Vazdik, Ya A; Villet, G; Von Dombrowski, S; Wacker, K; Wallny, R; Walter, T; Waugh, B; Weber, G; Weber, M; Wegener, D; Wegner, A; Wengler, T; Werner, M; West, L R; White, G; Wiesand, S; Wilksen, T; Winde, M; Winter, G G; Wissing, C; Wobisch, M; Wollatz, H; Wünsch, E; Zaicek, J; Zaleisak, J; Zhang, Z; Zhokin, A S; Zini, P; Zomer, F; Zsembery, J; Zur Nedden, M

    2000-01-01

    The production of hard di-jet events in photoproduction at HERA is dominatedby resolved photon processes in which a parton in the photon with momentumfraction x_gamma is scattered from a parton in the proton. These processes aresensitive to the quark and gluon content of the photon. The differential di-jetcross-section dsigma/dlog(x_gamma) is presented here, measured in taggedphotoproduction at HERA using data taken with the H1 detector, corresponding toan integrated luminosity of 7.2 pb^(-1). Using a restricted data sample at hightransverse jet energy, E_(T,jet)>6 GeV, the effective parton densityf_gamma,eff(x_gamma) = [q(x_gamma) + bar(q)(x_gamma) +9/4g(x_gamma)] in thephoton in leading order QCD is measured down to x_gamma=0.05 from which thegluon density in the photon is derived.

  16. Measurement of charm fragmentation ratios and fractions in photoproduction at HERA

    CERN Document Server

    Chekanov, S; Magill, S; Miglioranzi, S; Musgrave, B; Repond, J; Yoshida, R; Mattingly, M C K; Pavel, N; Yagues-Molina, A G; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Boscherini, D; Bruni, A; Bruni, G; Cara Romeo, G; Cifarelli, L; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Giusti, P; Iacobucci, G; Margotti, A; Montanari, A; Nania, R; Palmonari, F; Pesci, A; Polini, A; Rinaldi, L; Sartorelli, G; Zichichi, A; Aghuzumtsyan, G; Bartsch, D; Brock, I; Goers, S; Hartmann, H; Hilger, E; Irrgang, P; Jakob, H P; Kind, O M; Meyer, U; Paul, E; Rautenberg, J; Renner, R; Wang, M; Wlasenko, M; Bailey, D S; Brook, N H; Cole, J E; Heath, G P; Namsoo, T; Robins, S; Capua, M; Fazio, S; Mastroberardino, A; Schioppa, M; Susinno, G; Tassi, E; Kim, J Y; Ma, K J; Helbich, M; Ning, Y; Ren, Z; Schmidke, W B; Sciulli, F; Chwastowski, J; Eskreys, Andrzej; Figiel, J; Galas, A; Gil, M; Olkiewicz, K; Stopa, P; Szuba, D; Zawiejski, L; Adamczyk, L; Bold, T; Grabowska-Bold, I; Kisielewska, D; Lukasik, J; Przybycien, M B; Suszycki, L; Szuba, J; Kotanski, A; Slominski, W; Adler, V; Behrens, U; Bloch, I; Borras, K; Drews, G; Fourletova, J; Geiser, A; Gladkov, D; Göttlicher, P; Gutsche, O; Haas, T; Hain, W; Horn, C; Kahle, B; Kötz, U; Kowalski, H; Kramberger, G; Lim, H; Löhr, B; Mankel, R; Melzer-Pellmann, I A; Nguyen, C N; Notz, D; Nuncio-Quiroz, A E; Raval, A; Santamarta, R; Schneekloth, U; Stadie, H; Stösslein, U; Wolf, G; Youngman, C; Zeuner, W; Schlenstedt, S; Barbagli, G; Gallo, E; Genta, C; Pelfer, P G; Bamberger, A; Benen, A; Karstens, F; Dobur, D; Vlasov, N N; Bussey, P J; Doyle, A T; Dunne, W; Ferrando, J; McKenzie, J H; Saxon, D H; Skillicorn, I O; Gialas, I; Carli, T; Gosau, T; Holm, U; Krumnack, N; Lohrmann, E; Milite, M; Salehi, H; Schleper, P; Schörner-Sadenius, T; Stonjek, S; Wichmann, K; Wick, K; Ziegler, A; Ziegler, Ar; Collins-Tooth, C; Foudas, C; Fry, C; Goncalo, R; Long, K R; Tapper, A D; Kataoka, M; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Barakbaev, A N; Boos, E G; Pokrovskiy, N S; Zhautykov, B O; Son, D; De Favereau, J; Piotrzkowski, K; Barreiro, F; Glasman, C; Jiménez, M; Labarga, L; Del Peso, J; Terron, J; Zambrana, M; Corriveau, F; Liu, C; Plamondon, M; Robichaud-Véronneau, A; Walsh, R; Zhou, C; Tsurugai, T; Antonov, A; Dolgoshein, B A; Rubinsky, I; Sosnovtsev, V V; Stifutkin, A; Suchkov, S; Dementiev, R K; Ermolov, P F; Gladilin, L K; Katkov, I I; Khein, L A; Korzhavina, I A; Kuzmin, V A; Levchenko, B B; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Zotkin, D S; Zotkin, S A; Abt, I; Büttner, C; Caldwell, A; Liu, X; Sutiak, J; Coppola, N; Grigorescu, G; Keramidas, A; Koffeman, E; Kooijman, P; Maddox, E; Tiecke, H G; Vázquez, M; Wiggers, L; Brümmer, N; Bylsma, B; Durkin, L S; Lee, A; Ling, T Y; Allfrey, P D; Bell, M A; Cooper-Sarkar, A M; Cottrell, A; Devenish, R C E; Foster, B; Gwenlan, C; Kohno, T; Korcsak-Gorzo, K; Patel, S; Roberfroid, V; Straub, P B; Walczak, R; Bellan, P M; Bertolin, A; Brugnera, R; Carlin, R; Ciesielski, R; Dal Corso, F; Dusini, S; Garfagnini, A; Limentani, S; Longhin, A; Stanco, L; Turcato, M; Heaphy, E A; Metlica, F; Oh, B Y; Whitmore, J J; Iga, Y; D'Agostini, G; Marini, G; Nigro, A; Hart, J C; Abramowicz, H; Gabareen, A; Kananov, S; Kreisel, A; Levy, A; Kuze, M; Kagawa, S; Tawara, T; Hamatsu, R; Kaji, H; Kitamura, S; Matsuzawa, K; Ota, O; Ri, Y D; Costa, M; Ferrero, M I; Monaco, V; Sacchi, R; Solano, A; Arneodo, M; Ruspa, M; Fourletov, S; Martin, J F; Butterworth, J M; Hall-Wilton, R; Jones, T W; Loizides, J H; Sutton, M R; Targett-Adams, C; Wing, M; Ciborowski, J; Grzelak, G; Kulinski, P; Luzniak, P; Malka, J; Nowak, R J; Pawlak, J M; Sztuk, J; Tymieniecka, T; Ukleja, A; Ukleja, J; Zarnecki, A F; Adamus, M; Plucinsky, P P; Eisenberg, Y; Hochman, D; Karshon, U; Lightwood, M S; Brownson, E; Danielson, T; Everett, A; Kcira, D; Lammers, S; Li, L; Reeder, D D; Rosin, M; Ryan, P; Savin, A A; Smith, W H; Dhawan, S; Bhadra, S; Catterall, C D; Cui, Y; Hartner, G; Menary, S; Noor, U; Soares, M; Standage, J; Whyte, J

    2005-01-01

    The production of D^*+, D^0, D^+, D_s^+ and Lambda_c^+ charm hadrons and their antiparticles in ep scattering at HERA was measured with the ZEUS detector using an integrated luminosity of 79 pb^-1. The measurement has been performed in the photoproduction regime with the exchanged-photon virtuality Q^2 3.8 GeV and pseudorapidity |eta(D, Lambda_c)| D, Lambda_c), were derived in the given kinematic range. The measured open-charm fragmentation fractions are consistent with previous results, although the measured f(c -> D^*+) is smaller and f(c -> Lambda_c^+) is larger than those obtained in e^+e^- annihilations. These results generally support the hypothesis that fragmentation proceeds independently of the hard sub-process.

  17. Measurement of dijet cross sections for events with a leading neutron in photoproduction at HERA

    CERN Document Server

    Breitweg, J; Derrick, Malcolm; Krakauer, D A; Magill, S; Musgrave, B; Pellegrino, A; Repond, J; Stanek, R; Yoshida, R; Antonioli, P; Bari, G; Basile, M; Bellagamba, L; Boscherini, D; Bruni, A; Bruni, G; Cara Romeo, G; Cifarelli, Luisa; Cindolo, F; Contin, A; Corradi, M; De Pasquale, S; Giusti, P; Iacobucci, G; Levi, G; Margotti, A; Massam, Thomas; Nania, R; Palmonari, F; Pesci, A; Bornheim, A; Brock, I; Coboken, K; Crittenden, James Arthur; Deffner, R; Heinloth, K; Hilger, E; Irrgang, P; Jakob, H P; Kappes, A; Katz, U F; Kerger, R; Paul, E; Rautenberg, J; Schnurbusch, H; Stifutkin, A; Tandler, J; Voss, K C; Weber, A; Wieber, H; Bailey, D S; Barret, O; Brook, N H; Foster, B; Heath, G P; Heath, H F; Rodrigues, E; Scott, J; Tapper, R J; Capua, M; Mastroberardino, A; Schioppa, M; Susinno, G; Jeoung, H Y; Kim, J Y; Lee, J H; Lim, I T; Ma, K J; Pac, M Y; Caldwell, A; Liu, W; Liu, X; Mellado, B; Paganis, S; Sampson, S; Schmidke, W B; Chwastowski, J; Eskreys, Andrzej; Figiel, J; Klimek, K H; Olkiewicz, K; Piotrzkowski, K; Stopa, P; Zawiejski, L; Bednarek, B; Jelen, K; Kisielewska, D; Kowal, A M; Kowalski, T; Przybycien, M B; Suszycki, L; Szuba, D; Bauerdick, L A T; Behrens, U; Bienlein, J K; Borras, K; Chiochia, V; Dannheim, D; Desler, K; Drews, G; Fox-Murphy, A; Fricke, U; Göbel, F; Goers, S; Göttlicher, P; Graciani, R; Haas, T; Hain, W; Hartner, G F; Hebbel, K; Hillert, S; Koch, W; Kötz, U; Kowalski, H; Labes, H; Löhr, B; Mankel, R; Martens, J; Martínez, M; Milite, M; Moritz, M; Notz, D; Petrucci, M C; Polini, A; Rohde, M; Savin, A A; Schneekloth, U; Selonke, F; Sievers, M; Stonjek, S; Wolf, G; Wollmer, U; Youngman, C; Zeuner, W; Coldewey, C; López-Duran-Viani, A; Meyer, A; Schlenstedt, S; Straub, P B; Barbagli, G; Gallo, E; Parenti, A; Pelfer, P G; Bamberger, Andreas; Benen, A; Coppola, N; Eisenhardt, S; Markun, P; Raach, H; Wölfle, S; Bussey, Peter J; Bell, M; Doyle, A T; Glasman, C; Lee, S W; Lupi, A; MacDonald, N; McCance, G J; Saxon, D H; Sinclair, L E; Skillicorn, Ian O; Waugh, R; Bohnet, I; Gendner, N; Holm, U; Meyer-Larsen, A; Salehi, H; Wick, K; Carli, T; Garfagnini, A; Gialas, I; Gladilin, L K; Kcira, D; Klanner, Robert; Lohrmann, E; Goncalo, R; Long, K R; Miller, D B; Tapper, A D; Walker, R; Cloth, P; Filges, D; Ishii, T; Kuze, M; Nagano, K; Tokushuku, K; Yamada, S; Yamazaki, Y; Ahn, S H; Lee, S B; Park, S K; Lim, H; Son, D; Barreiro, F; García, G; González, O; Labarga, L; Del Peso, J; Redondo, I; Terron, J; Vázquez, M E; Barbi, M S; Corriveau, F; Hanna, D S; Ochs, A; Padhi, S; Stairs, D G; Wing, M; Tsurugai, T; Antonov, A; Bashkirov, V; Danilov, M V; Dolgoshein, B A; Gladkov, D; Sosnovtsev, V V; Suchkov, S; Dementev, R K; Ermolov, P F; Golubkov, Yu A; Katkov, I I; Khein, L A; Korotkova, N A; Korzhavina, I A; Kuzmin, V A; Lukina, O Yu; Proskuryakov, A S; Shcheglova, L M; Solomin, A N; Vlasov, N N; Zotkin, S A; Bokel, C; Botje, M; Brümmer, N; Engelen, J; Grijpink, S; Koffeman, E; Kooijman, P M; Schagen, S; Van Sighem, A; Tassi, E; Tiecke, H G; Tuning, N; Velthuis, J J; Vossebeld, Joost Herman; Wiggers, L; De Wolf, E; Bylsma, B; Durkin, L S; Gilmore, J; Ginsburg, C M; Kim, C L; Ling, T Y; Boogert, S; Cooper-Sarkar, A M; Devenish, R C E; Grosse-Knetter, J; Matsushita, T; Ruske, O; Sutton, M R; Walczak, R; Bertolin, A; Brugnera, R; Carlin, R; Dal Corso, F; Dusini, S; Limentani, S; Longhin, A; Posocco, M; Stanco, L; Turcato, M; Adamczyk, L; Iannotti, L; Oh, B Y; Okrasinski, J R; Saull, P R B; Toothacker, W S; Whitmore, J J; Iga, Y; D'Agostini, Giulio; Marini, G; Nigro, A; Cormack, C; Hart, J C; McCubbin, N A; Shah, T P; Epperson, D E; Heusch, C A; Sadrozinski, H F W; Seiden, A; Wichmann, R; Williams, D C

    2000-01-01

    Differential cross sections for dijet photoproduction in association with a leading neutron using the reaction e^+ + p --> e^+ + n + jet + jet + X_r have been measured with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb^{-1}. The fraction of dijet events with a leading neutron in the final state was studied as a function of the jet kinematic variables. The cross sections were measured for jet transverse energies E^{jet}_T > 6 GeV, neutron energy E_n > 400 GeV, and neutron production angle theta_n < 0.8 mrad. The data are broadly consistent with factorization of the lepton and hadron vertices and with a simple one-pion-exchange model.

  18. Photoproduction of $D^{*\\pm}$ mesons associated with a leading neutron

    CERN Document Server

    Abramowicz, H; Adamus, M; Adler, V; Aghuzumtsyan, G; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bell, M; Bellagamba, L; Benen, A; Bertolin, A; Bhadra, S; Bloch, I; Bold, T; Boos, E G; Borras, K; Boscherini, D; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Catterall, C D; Chekanov, S; Chiochia, V; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cloth, P; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cormack, C; Corradi, M; Corriveau, F; Cottrell, A; D'Agostini, Giulio; Dal Corso, F; Danilov, P; Dannheim, D; De Pasquale, S; Dementiev, R K; Derrick, M; Deshpande, A A; Devenish, R C E; Dhawan, S; Dobur, D; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, Andrzej; Ferrando, J; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fricke, U; Fusayasu, T; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Gliga, S; Goers, S; Golubkov, Yu A; Goncalo, R; González, O; Gosau, T; Göttlicher, P; Grabowska-Bold, I; Grijpink, S; Grzelak, G; Gutsche, O; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hamilton, J; Hanlon, S; Hart, J C; Hartmann, H; Hartner, G; Heaphy, E A; Heath, G P; Helbich, M; Heusch, C A; Hilger, E; Hillert, S; Hirose, T; Hochman, D; Holm, U; Iacobucci, G; Iga, Y; Inuzuka, M; Irrgang, P; Jakob, P; Jones, T W; Kagawa, S; Kahle, B; Kaji, H; Kananov, S; Karstens, F; Kataoka, M; Katkov, I I; Kcira, D; Khein, L A; Kim, J Y; Kim, Y K; Kind, O; Kisielewska, D; Kitamura, S; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korzhav--, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowal, M; Kowalski, H; Kowalski, T; Krakauer, D A; Kramberger, G; Kreisel, A; Krumnack, N; Kuze, M; Kuzmin, V A; Labarga, L; Labes, H; Lainesse, J; Lammers, S; Lee, J H; Lelas, D; Levchenko, B B; Levy, A; Li, L; Lightwood, M S; Lim, H; Lim, I T; Limentani, S; Ling, T Y; Liu, X; Löhr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukina, O Yu; Luzniak, P; Maddox, E; Magill, S; Mankel, R; Margotti, A; Marini, G; Martin, J F; Mastroberardino, A; Matsuzawa, K; Mattingly, M C K; McCubbin, N A; Mellado, B; Melzer-Pellmann, I A; Menary, S R; Metlica, F; Meyer, U; Miglioranzi, S; Milite, M; Mirea, A; Monaco, V; Montanari, A; Mus, B; Nagano, K; Namsoo, T; Nania, R; Nguyen, C N; Nigro, A; Ning, Y; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Olkiewicz, K; Pac, M Y; Padhi, S; Paganis, S; Palmonari, F; Parenti, A; Park, I H; Patel, S; Paul, E; Pavel, N; Pawlak, J M; Pelfer, P G; Pellegrino, A; Pesci, A; Piotrzkowski, K; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Posocco, M; Proskuryakov, A S; Przybycien, M B; Rautenberg, J; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Riveline, U Karshon M; Robins, S; Rosin, M; Rurua, L; Ruspa, M; Sacchi, R; Salehi, H; Sartorelli, G; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Sciulli, F; Shcheglova, L M; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V V; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Stösslein, U; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tandler, J; Tapper, A D; Targett-Adams, C; Tassi, E; Tawara, T; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Ukleja, A; Ukleja, J; Vázquez, M; Velthuis, J J; Vlasov, N N; Voss, K C; Walczak, R; Walsh, R; Wang, M; Weber, A; Whitmore, J J; Wichmann, K; Wick, K; Wiggers, L; Wing, M; Wolf, G; Yamada, S; Yamashita, T; Yamazaki, Y; Yoshida, R; Youngman, C; Zambrana, M; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zichichi, A; Ziegler, A; Zotkin, S A; De Wolf, E; Del Peso, J

    2004-01-01

    The photoproduction of $D^{*\\pm} (2010)$ mesons associated with a leading neutron has been observed with the ZEUS detector in $ep$ collisions at HERA using an integrated luminosity of 80 pb$^{-1}$. The neutron carries a large fraction, {$x_L>0.2$}, of the incoming proton beam energy and is detected at very small production angles, {$\\theta_n 1.9$ GeV}, which is large compared to the average transverse momentum of the neutron of 0.22 GeV. The ratio of neutron-tagged to inclusive $D^*$ production is $8.85\\pm 0.93({\\rm stat.})^{+0.48}_{-0.61}({\\rm syst.})\\%$ in the photon-proton center-of-mass energy range {$130

  19. Measurement of proton-dissociative diffractive photoproduction of vector mesons at large momentum transfer at HERA

    CERN Document Server

    Abe, T; Adamczyk, L; Adamus, M; Aghuzumtsyan, G; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Bashkirov, V; Basile, M; Bauerdick, L A T; Bednarek, B; Behrens, U; Bell, M; Bellagamba, L; Benen, A; Bertolin, A; Bhadra, S; Bodmann, B; Bokel, C; Boogert, S; Boos, E G; Borras, K; Boscherini, D; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Cartiglia, N; Catterall, C D; Chekanov, S; Chiochia, V; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cirio, R; Cloth, P; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Cormack, C; Corradi, M; Corriveau, F; Costa, M; Crittenden, J; D'Agostini, Giulio; Dagan, S; Dal Corso, F; Danilov, P; Dannheim, D; De Pasquale, S; Dementiev, R K; Derrick, M; Deshpande, Abhay A; Devenish, R C E; Dhawan, S; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Engelen, J; Ermolov, P F; Eskreys, Andrzej; Ferrando, J; Ferrero, M I; Figiel, J; Filges, D; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fox-Murphy, A; Fricke, U; Fusayasu, T; Gabareen, A; Galea, R; Gallo, E; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Gilmore, J; Ginsburg, C M; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Göbel, F; Goers, S; Golubkov, Yu A; Goncalo, R; González, O; Göttlicher, P; Grabowska-Bold, I; Grijpink, S; Grzelak, G; Gutsche, O; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hanlon, S; Hart, J C; Hartmann, H; Hartner, G F; Heaphy, E A; Heath, G P; Heath, H F; Helbich, M; Heusch, C A; Hilger, E; Hillert, S; Hirose, T; Hochman, D; Holm, U; Hughes, V W; Iacobucci, G; Iga, Y; Inuzuka, M; Irrgang, P; Jakob, H P; Jelen, K; Jones, T W; Kananov, S; Kappes, A; Karshon, U; Katkov, I I; Katz, U F; Kcira, D; Kerger, R; Khein, L A; Kim, C L; Kim, J Y; Kim, Y K; Kind, O; Kisielewska, D; Kitamura, S; Klimek, K; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korzhav, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowal, M; Kowalski, H; Kowalski, T; Krakauer, D A; Kreisel, A; Krumnack, N; Kuze, M; Kuzmin, V A; Labarga, L; Labes, H; Lammers, S; Lane, J B; Lee, J H; Lee, S W; Lelas, D; Levchenko, B B; Levi, G; Levman, G M; Levy, A; Li, L; Lightwood, M S; Lim, H; Lim, I T; Limentani, S; Ling, T Y; Liu, X; Löhr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lopez-Duran Viani, A; Lukina, O Yu; Lupi, A; Maddox, E; Magill, S; Mankel, R; Margotti, A; Marini, G; Martin, J F; Martínez, M; Maselli, S; Mastroberardino, A; Mat, T; Matsuzawa, K; Mattingly, M C K; Mc, G J; McCubbin, N A; Mellado, B; Menary, S R; Metlica, F; Meyer, A; Milite, M; Miller, D B; Mindur, B; Mirea, A; Monaco, V; Moritz, M; Musgrave, B; Nagano, K; Nania, R; Nigro, A; Nishimura, T; Notz, D; Nowak, R J; Ochs, A; Oh, B Y; Olkiewicz, K; Pac, M Y; Padhi, S; Paganis, S; Palmonari, F; Parenti, A; Park, I H; Paul, E; Pavel, N; Pawlak, J M; Pelfer, P G; Pellegrino, A; Pellmann, I A; Peroni, C; Pesci, A; Petrucci, M C; Piotrzkowski, K; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Posocco, M; Proskuryakov, A S; Przybycien, M B; Raach, H; Rautenberg, J; Raval, A; Redondo, I; Reeder, D D; Renner, R; Repond, J; Rigby, M; Robins, S; Rodrigues, E; Rulikowska-Zarebska, E; Ruske, O; Ruspa, M; Sabetfakhri, A; Sacchi, R; Salehi, H; Sartorelli, G; Saull, P R B; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schmidke, W B; Schneekloth, U; Schnurbusch, H; Sciulli, F; Scott, J; Selonke, F; Shcheglova, L M; Skillicorn, I O; Slominski, W; Smalska, B; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V V; Saint-Laurent, M G; Staiano, A; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Straub, P B; Suchkov, S; Surrow, B; Susinno, G; Suszycki, L; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tandler, J; Tap, A D; Tapper, R J; Tassi, E; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Tuning, N; Turcato, M; Tymieniecka, T; Ukleja, A; Ukleja, J; Umemori, K; Vázquez, M; Velthuis, J J; Vlasov, N N; Voss, K C; Walczak, R; Walker, R; Weber, A; Wes, H; West, B J; Whitmore, J J; Wichmann, R; Wick, K; Wiggers, L; Wing, M; Wolf, G; Yamada, S; Yamashita, T; Yamazaki, Y; Yoshida, R; Youngman, C; Zakrzewski, J A; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zichichi, A; Ziegler, A; Zotkin, S A; De Wolf, E; Del Peso, J

    2003-01-01

    Diffractive photoproduction of vector mesons, gamma p --> V Y, where Y is a proton-dissociative system, has been measured in ep interactions with the ZEUS detector at HERA using an integrated luminosity of 25 pb^-1. The differential cross section, ds/dt, is presented for -t phi Y)/dt to ds_(gamma p --> rho^0 Y)/dt and ds_(gamma p --> J/psi Y)/dt to ds_(gamma p --> rho^0 Y)/dt increase with increasing -t. Decay-angle analyses for rho^0, phi and J/psi mesons have been carried out. For the rho^0 and phi mesons, contributions from single and double helicity flip are observed. The results are compared to expectations of theoretical models.

  20. Beauty photoproduction measured from inclusive dijet events in ep collisions at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Yagues, Ana [DESY, Hamburg (Germany)

    2008-07-01

    The production of b quarks is being studied in dijet events in photoproduction (Q{sup 2}<1 GeV{sup 2}) with the ZEUS detector at HERA using an integrated luminosity of 133 pb{sup -1}. The installed micro-vertex detector (MVD) is used to determine the beauty fraction from measurements of the secondary vertex position with respect to the primary vertex. The heavy mass of the beauty quark and its long lifetime is exploited to separate beauty signal from background. The beauty fraction is extracted statistically using the decay length significance and invariant mass distributions. The total cross section and differential cross sections d{sigma}/dp{sup b}{sub T} and d{sigma}/d{eta}{sup b} are measured and compared to previous measurements and next-to-leading order OCD predictions.

  1. Measurement of beauty photoproduction using decays into muons in di-jet events at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Haas, Tobias; Geiser, Achim [Deutsches Elektronen-Synchrotron - DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Reisert, Burkard [Max Planck Institute for Physics - Werner-Heisenberg-Institut, Foehringer Ring 6, 80805 Muenchen (Germany); Tassi, Enrico [Dipartimento di Fisica, Universita della Calabria, Via P. Bucci 31C, 87036 Rende - CS (Italy)

    2010-07-01

    Beauty photoproduction in di-jet events has been measured at HERA with the ZEUS detector using an integrated luminosity of 126 pb{sup -1}. Beauty was identified in events with a muon in the final state by using the transverse momentum of the muon relative to the closest jet. Lifetime information from the silicon vertex detector was also used; the impact parameter of the muon with respect to the primary vertex was exploited to discriminate between signal and background. Cross sections for beauty production as a function of the muon and the jet variables as well as di-jet correlations are compared to QCD predictions and to previous measurements. The data are well described by predictions from next-to-leading-order QCD. (author)

  2. Measurement of beauty photoproduction using decays into muons in dijet events at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Lab., Argonne, IL (US)] (and others)

    2008-12-15

    Beauty photoproduction in dijet events has been measured at HERA with the ZEUS detector using an integrated luminosity of 126 pb{sup -1}. Beauty was identified in events with a muon in the final state by using the transverse momentum of the muon relative to the closest jet. Lifetime information from the silicon vertex detector was also used; the impact parameter of the muon with respect to the primary vertex was exploited to discriminate between signal and background. Cross sections for beauty production as a function of the muon and the jet variables as well as dijet correlations are compared to QCD predictions and to previous measurements. The data are well described by predictions from next-to-leading-order QCD. (orig.)

  3. Measurement of beauty and charm photoproduction using inclusive secondary vertexing with the ZEUS detector at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Schoenberg, Verena Ellen

    2010-04-15

    Photoproduction of heavy quarks in events with two jets has been measured with the ZEUS detector at HERA using data recorded in the years 2006-2007 corresponding to an integrated luminosity of 128 pb{sup -1}. The beauty and charm content was extracted using the decay-length significance of the b and c hadrons and the invariant mass of the decay vertices. Differential cross sections as a function of P{sup Jet}{sub T} and {eta}{sup Jet} were compared with the PYTHIA leading order plus parton shower Monte Carlo and QCD predictions calculated at next-to-leading order. In order to study the theoretical description of higher-order effects correlations between the two highest energy jets were also investigated. (orig.)

  4. First measurement of coherent $\\phi$-meson photoproduction on deuteron at low energies

    Energy Technology Data Exchange (ETDEWEB)

    Tsutomu Mibe; Haiyan Gao; Kenneth Hicks; Kevin Kramer; Stepan Stepanyan; David Tedeschi; Moscov Amaryan; Pawel Ambrozewicz; Marco Anghinolfi; G. Asryan; Gerard Audit; Harutyun Avakian; Hovhannes Baghdasaryan; Nathan Baillie; Jacques Ball; Nathan Baltzell; Marco Battaglieri; Ivan Bedlinski; Ivan Bedlinskiy; Matthew Bellis; Nawal Benmouna; Barry Berman; Angela Biselli; Lukasz Blaszczyk; Sylvain Bouchigny; Sergey Boyarinov; Robert Bradford; Derek Branford; William Briscoe; William Brooks; Stephen Bueltmann; Volker Burkert; Cornel Butuceanu; John Calarco; Sharon Careccia; Daniel Carman; Shifeng Chen; Philip Cole; Patrick Collins; Philip Coltharp; Donald Crabb; Hall Crannell; Volker Crede; John Cummings; Natalya Dashyan; Rita De Masi; Raffaella De Vita; Enzo De Sanctis; Pavel Degtiarenko; Alexandre Deur; Kahanawita Dharmawardane; Richard Dickson; Chaden Djalali; Gail Dodge; Joseph Donnelly; David Doughty; Michael Dugger; Oleksandr Dzyubak; Hovanes Egiyan; Kim Egiyan; Lamiaa Elfassi; Latifa Elouadrhiri; Paul Eugenio; Gleb Fedotov; Gerald Feldman; Herbert Funsten; Michel Garcon; Gagik Gavalian; Gerard Gilfoyle; Kevin Giovanetti; Francois-Xavier Girod; John Goetz; Atilla Gonenc; Christopher Gordon; Ralf Gothe; Keith Griffioen; Michel Guidal; Nevzat Guler; Lei Guo; Vardan Gyurjyan; Cynthia Hadjidakis; Kawtar Hafidi; Hayk Hakobyan; Rafael Hakobyan; Charles Hanretty; John Hardie; F. Hersman; Ishaq Hleiqawi; Maurik Holtrop; Charles Hyde; Charles Hyde-Wright; Yordanka Ilieva; David Ireland; Boris Ishkhanov; Eugeny Isupov; Mark Ito; David Jenkins; Hyon-Suk Jo; John Johnstone; Kyungseon Joo; Henry Juengst; Narbe Kalantarians; James Kellie; Mahbubul Khandaker; Wooyoung Kim; Andreas Klein; Franz Klein; Alexei Klimenko; Mikhail Kossov; Zebulun Krahn; Laird Kramer; V. Kubarovsky; Joachim Kuhn; Sebastian Kuhn; Sergey Kuleshov; Viacheslav Kuznetsov; Jeff Lachniet; Jean Laget; Jorn Langheinrich; David Lawrence; Tsung-shung Lee; Ji Li; Kenneth Livingston; Haiyun Lu; Marion MacCormick; Claude Marchand; Nikolai Markov; Paul Mattione; Bryan McKinnon; Bernhard Mecking; Joseph Melone; Mac Mestayer; Curtis Meyer; Konstantin Mikhaylov; Ralph Minehart; Marco Mirazita; Rory Miskimen; Viktor Mokeev; Kei Moriya; Steven Morrow; M. Moteabbed; E. Munevar; Gordon Mutchler; P. Nadel-Turonski; Rakhsha Nasseripour; Silvia Niccolai; Gabriel Niculescu; Maria-Ioana Niculescu; Bogdan Niczyporuk; Megh Niroula; Rustam Niyazov; Mina Nozar; Mikhail Osipenko; Alexander Ostrovidov; K. Park; Evgueni Pasyuk; Craig Paterson; S. Anefalos Pereira; Joshua Pierce; Nikolay Pivnyuk; Dinko Pocanic; Oleg Pogorelko; S. Pozdniakov; John Price; Yelena Prok; Dan Protopopescu; Brian Raue; Gregory Riccardi; Giovanni Ricco; Marco Ripani; Barry Ritchie; Federico Ronchetti; Guenther Rosner; Patrizia Rossi; Franck Sabatie; Julian Salamanca; Carlos Salgado; Joseph Santoro; Vladimir Sapunenko; Reinhard Schumacher; Vladimir Serov; Youri Sharabian; Dmitri Sharov; Nikolay Shvedunov; Elton Smith; Lee Smith; Daniel Sober; Daria Sokhan; A. Stavinsky; Samuel Stepanyan; B.E. Stokes; Paul Stoler; I.I. Strakovsky; Steffen Strauch; Mauro Taiuti; Ulrike Thoma; Avtandil Tkabladze; Svyatoslav Tkachenko; Luminita Todor; Clarisse Tur; Maurizio Ungaro; Michael Vineyard; Alexander Vlassov; Daniel Watts; Lawrence Weinstein; Dennis Weygand; M. Williams; Elliott Wolin; Michael Wood; Amrit Yegneswaran; Lorenzo Zana; Jixie Zhang; Bo Zhao; Zhiwen Zhao

    2007-11-01

    The cross section and decay angular distributions for the coherent \\phi meson photoproduction on the deuteron have been measured for the first time up to a squared four-momentum transfer t =(p_{\\gamma}-p_{\\phi})^2 =-2 GeV^2/c^2, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cross sections are compared with predictions from a re-scattering model. In a framework of vector meson dominance, the data are consistent with the total \\phi-N cross section \\sigma_{\\phi N} at about 10 mb. If vector meson dominance is violated, a larger \\sigma_{\\phi N} is possible by introducing larger t-slope for the \\phi N \\to \\phi N process than that for the \\gamma N \\to \\phi N process. The decay angular distributions of the \\phi are consistent with helicity conservation.

  5. Study of the Hyperon-Nucleon Interaction in Exclusive Λ Photoproduction off the Deuteron

    Energy Technology Data Exchange (ETDEWEB)

    Zachariou, Nicholas [Univ. of Edinburgh, Scotland (United Kingdom); Ilieva, Yordanka [Univ. of South Carolina, Columbia, SC (United States); Cao, Tongtong [Univ. of South Carolina, Columbia, SC (United States)

    2016-03-01

    The study of final-state interactions in exclusive hyperon photoproduction off the deuteron is a promising approach to extract information about the hyperon-nucleon (YN) interaction. First preliminary results on the azimuthal asymmetry ∑, as well as the polarization transfer coeffcients Ox, Oz, Cx, and Cz for the reaction γd → K+ Λn initiated with linearly and circularly polarized photon beam are presented. The data were taken with the CLAS detector in Hall B of Jefferson Lab during the E06-103 experiment. The large kinematic coverage of the CLAS, combined with the exceptionally high quality of the experimental data, allows identifying and selecting final-state interaction events to extract single- and double-polarization observables and their kinematical dependencies.

  6. DIFFERENTIAL CROSS SECTION ANALYSIS IN KAON PHOTOPRODUCTION USING ASSOCIATED LEGENDRE POLYNOMIALS

    Energy Technology Data Exchange (ETDEWEB)

    P. T. P. HUTAURUK, D. G. IRELAND, G. ROSNER

    2009-04-01

    Angular distributions of differential cross sections from the latest CLAS data sets,6 for the reaction γ + p→K+ + Λ have been analyzed using associated Legendre polynomials. This analysis is based upon theoretical calculations in Ref. 1 where all sixteen observables in kaon photoproduction can be classified into four Legendre classes. Each observable can be described by an expansion of associated Legendre polynomial functions. One of the questions to be addressed is how many associated Legendre polynomials are required to describe the data. In this preliminary analysis, we used data models with different numbers of associated Legendre polynomials. We then compared these models by calculating posterior probabilities of the models. We found that the CLAS data set needs no more than four associated Legendre polynomials to describe the differential cross section data. In addition, we also show the extracted coefficients of the best model.

  7. First measurement of coherent $\\phi$-meson photoproduction on deuteron at low energies

    CERN Document Server

    Mibe, T; Hicks, K; Krämer, K; Stepanyan, S; Tedeschi, D J; Amaryan, M J; Ambrozewicz, P; Anghinolfi, M; Asryan, G; Audit, G; Avakian, H; Bagdasaryan, H; Baillie, N; Ball, J P; Baltzell, N A; Battaglieri, M; Bedlinskiy, I; Bellis, M; Benmouna, N; Berman, B L; Biselli, A S; Blaszczyk, L; Bouchigny, S; Boiarinov, S; Bradford, R; Branford, D; Briscoe, W J; Brooks, W K; Bültmann, S; Burkert, V D; Butuceanu, C; Calarco, J R; Careccia, S L; Carman, D S; Chen, S; Cole, P L; Collins, P; Coltharp, P; Crabb, D; Crannell, H; Credé, V; Cummings, J P; Dashyan, N B; De Masi, R; De Vita, R; De Sanctis, E; Degtyarenko, P V; Deur, A; Dharmawardane, K V; Dickson, R; Djalali, C; Dodge, G E; Donnelly, J; Doughty, D; Dugger, M; Dzyubak, O P; Egiyan, H; Egiyan, K S; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Feldman, G; Funsten, H; Garçon, M; Gavalian, G; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Gonenc, A; Gordon, C I O; Gothe, R W; Griffioen, K A; Guidal, M; Guler, N; Guo, L; Gyurjyan, V; Hadjidakis, C; Hafidi, K; Hakobyan, H; Hakobyan, R S; Hanretty, C; Hardie, J; Hersman, F W; Hleiqawi, I; Holtrop, M; Hyde-Wright, C E; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Isupov, E L; Ito, M M; Jenkins, D; Jo, H S; Johnstone, J R; Joo, K; Jüngst, H G; Kalantarians, N; Kellie, J D; Khandaker, M; Kim, W; Klein, A; Klein, F J; Klimenko, A V; Kossov, M; Krahn, Z; Kramer, L H; Kubarovski, V; Kühn, J; Kuhn, S E; Kuleshov, S V; Kuznetsov, V; Lachniet, J; Laget, J M; Langheinrich, J; Lawrence, D; Lee, T; Li, Ji; Livingston, K; Lu, H Y; MacCormick, M; Marchand, C; Markov, N; Mattione, P; McKinnon, B; Mecking, B A; Melone, J J; Mestayer, M D; Meyer, C A; Mikhailov, K; Minehart, R C; Mirazita, M; Miskimen, R; Mokeev, V; Moriya, K; Morrow, S A; Moteabbed, M; Munevar, E; Mutchler, G S; Nadel-Turonski, P; Nasseripour, R; Niccolai, S; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niroula, M R; Niyazov, R A; Nozar, M; Osipenko, M; Ostrovidov, A I; Park, K; Pasyuk, E; Paterson, C; Anefalos Pereira, S; Pierce, J; Pivnyuk, N; Pocanic, D; Pogorelko, O I; Pozdniakov, S; Price, J W; Prok, Y; Protopopescu, D; Raue, B A; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Ronchetti, F; Rosner, G; Rossi, P; Sabatie, F; Salamanca, J; Salgado, C; Santoro, J P; Sapunenko, V; Schumacher, R A; Serov, V S; Sharabyan, Yu G; Sharov, D; Shvedunov, N V; Smith, E S; Smith, L C; Sober, D I; Sokhan, D; Stavinsky, A V; Stepanyan, S S; Stokes, B E; Stoler, P; Strakovsky, I I; Strauch, S; Taiuti, M; Thoma, U; Tkabladze, A; Tkachenko, S I; Todor, L; Tur, C; Ungaro, M; Vineyard, M F; Vlassov, A V; Watts, D P; Weinstein, L B; Weygand, D P; Williams, M; Wolin, E; Wood, M H; Yegneswaran, A; Zana, L; Zhang, J; Zhao, B; Zhao, Z W; al, et

    2007-01-01

    The cross section and decay angular distributions for the coherent \\phi meson photoproduction on the deuteron have been measured for the first time up to a squared four-momentum transfer t =(p_{\\gamma}-p_{\\phi})^2 =-2 GeV^2/c^2, using the CLAS detector at the Thomas Jefferson National Accelerator Facility. The cross sections are compared with predictions from a re-scattering model. In a framework of vector meson dominance, the data are consistent with the total \\phi-N cross section \\sigma_{\\phi N} at about 10 mb. If vector meson dominance is violated, a larger \\sigma_{\\phi N} is possible by introducing larger t-slope for the \\phi N \\to \\phi N process than that for the \\gamma N \\to \\phi N process. The decay angular distributions of the \\phi are consistent with helicity conservation.

  8. Measurement of beauty and charm photoproduction using inclusive secondary vertexing with the ZEUS detector at HERA

    International Nuclear Information System (INIS)

    Photoproduction of heavy quarks in events with two jets has been measured with the ZEUS detector at HERA using data recorded in the years 2006-2007 corresponding to an integrated luminosity of 128 pb-1. The beauty and charm content was extracted using the decay-length significance of the b and c hadrons and the invariant mass of the decay vertices. Differential cross sections as a function of PJetT and ηJet were compared with the PYTHIA leading order plus parton shower Monte Carlo and QCD predictions calculated at next-to-leading order. In order to study the theoretical description of higher-order effects correlations between the two highest energy jets were also investigated. (orig.)

  9. Differential cross section analysis in kaon photoproduction using associated legendre polynomials

    CERN Document Server

    Hutauruk, P T P; Rosner, G

    2009-01-01

    Angular distributions of differential cross sections from the latest CLAS data sets \\cite{bradford}, for the reaction ${\\gamma}+p {\\to} K^{+} + {\\Lambda}$ have been analyzed using associated Legendre polynomials. This analysis is based upon theoretical calculations in Ref. \\cite{fasano} where all sixteen observables in kaon photoproduction can be classified into four Legendre classes. Each observable can be described by an expansion of associated Legendre polynomial functions. One of the questions to be addressed is how many associated Legendre polynomials are required to describe the data. In this preliminary analysis, we used data models with different numbers of associated Legendre polynomials. We then compared these models by calculating posterior probabilities of the models. We found that the CLAS data set needs no more than four associated Legendre polynomials to describe the differential cross section data. In addition, we also show the extracted coefficients of the best model.

  10. Measurement of inelastic J/ψ and ψ' photoproduction at HERA

    International Nuclear Information System (INIS)

    The cross sections for inelastic photoproduction of J/ψ and ψ' mesons have been measured in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 468 pb-1 collected in the period 1996-2007. The ψ' to J/ψ cross section ratio was measured in the range 0.55T. Here W denotes the photon-proton centre-of-mass energy, z is the fraction of the incident photon energy carried by the meson and pT is the transverse momentum of the meson with respect to the beam axis. The J/ψ cross sections were measured for 0.1T>1 GeV. Theoretical predictions within the non-relativistic QCD framework including NLO colour-singlet and colour-octet contributions were compared to the data, as were predictions based on the kT-factorisation approach.

  11. Measurement of D* photoproduction at three different centre-of-mass energies at HERA

    International Nuclear Information System (INIS)

    The cross sections for the photoproduction of D*± mesons have been measured with the ZEUS detector at HERA at three different ep centre-of-mass energies, √(s), of 318, 251 and 225 GeV. For each data set, D*± mesons were required to have transverse momentum, pD*T, and pseudorapidity, ηD*, in the ranges 1.9D*TD* vertical stroke 2, of less than 1 GeV2. The dependence on √(s) was studied by normalising to the high-statistics measurement at √(s)=318 GeV. This led to the cancellation of a number of systematic effects both in data and theory. Predictions from next-to-leading-order QCD describe the √(s) dependence of the data well.

  12. Measurement of the t dependence in exclusive photoproduction of Υ(1S) mesons at HERA

    International Nuclear Information System (INIS)

    The exclusive photoproduction reaction γp→Υ(1S)p has been studied with the ZEUS detector in ep collisions at HERA using an integrated luminosity of 468 pb-1. The measurement covers the kinematic range 6022, where W is the photon-proton centre-of-mass energy and Q2 is the photon virtuality. The exponential slope, b, of the t dependence of the cross section, where t is the squared four-momentum transfer at the proton vertex, has been measured, yielding b=4.3+2.0-1.3(stat.)+0.5-0.6(syst.) GeV-2. This constitutes the first measurement of the t dependence of the γp→Υ(1S)p cross section. (orig.)

  13. Small $x$ gluon shadowing from LHC data on coherent $\\mathrm{J/}\\psi$ photoproduction

    CERN Document Server

    Contreras, J G

    2016-01-01

    We present a novel method to extract the coherent $\\mathrm{J/}\\psi$ photoproduction cross section, $\\sigma_{\\gamma \\rm Pb}$, from measurements of peripheral and ultra-peripheral Pb-Pb collisions at the LHC. This method allows to access the contribution from high-energy photons and extract $\\sigma_{\\gamma \\rm Pb}$ up to a photon-lead centre-of-mass energy of 470 GeV, which corresponds to a Bjorken-$x$ of 4.4$\\cdot 10^{-5}$. Using the extracted cross section the nuclear suppression factor is computed and, as an example of the application of these results, it is compared to the predictions of gluon shadowing calculated in the leading-twist approximation approach.

  14. Photoproduction of the omega meson on the proton at large momentum transfer.

    Science.gov (United States)

    Battaglieri, M; Brunoldi, M; De Vita, R; Laget, J M; Osipenko, M; Ripani, M; Taiuti, M; Adams, G; Amaryan, M J; Anciant, E; Anghinolfi, M; Armstrong, D S; Asavapibhop, B; Asryan, G; Audit, G; Auger, T; Avakian, H; Barrow, S; Beard, K; Bektasoglu, M; Berman, B L; Bersani, A; Bianchi, N; Biselli, A S; Boiarinov, S; Bouchigny, S; Bradford, R; Branford, D; Briscoe, W J; Brooks, W K; Burkert, V D; Calarco, J R; Capitani, G P; Carman, D S; Carnahan, B; Cazes, A; Cetina, C; Cole, P L; Coleman, A; Cords, D; Corvisiero, P; Crabb, D; Crannell, H; Cummings, J P; DeSanctis, E; Degtyarenko, P V; Demirchyan, R; Denizli, H; Dennis, L; Dharmawardane, K V; Dhuga, K S; Djalali, C; Dodge, G E; Doughty, D; Dragovitsch, P; Dugger, M; Dytman, S; Eckhause, M; Egiyan, H; Egiyan, K S; Elouadrhiri, L; Farhi, L; Feuerbach, R J; Ficenec, J; Forest, T A; Freyberger, A P; Frolov, V; Funsten, H; Gaff, S J; Gai, M; Garcon, M; Gavalian, G; Gilad, S; Gilfoyle, G P; Giovanetti, K L; Golovach, E; Griffioen, K; Guidal, M; Guillo, M; Guo, L; Gyurjyan, V; Hadjidakis, C; Hancock, D; Hardie, J; Heddle, D; Hersman, F W; Hicks, K; Hicks, R S; Holtrop, M; Hyde-Wright, C E; Ito, M M; Joo, K; Kelley, J H; Khandaker, M; Kim, W; Klein, A; Klein, F J; Klimenko, A V; Klusman, M; Kossov, M; Kramer, L H; Kuang, Y; Kuhn, S E; Lachniet, J; Lawrence, D; Lucas, M; Lukashin, K; Major, R W; Manak, J J; Marchand, C; McAleer, S; McCarthy, J; McNabb, J W C; Mecking, B A; Mestayer, M D; Meyer, C A; Mikhailov, K; Mirazita, M; Miskimen, R; Mokeev, V; Morrow, S; Mozer, M U; Muccifora, V; Mueller, J; Mutchler, G S; Napolitano, J; Nelson, S O; Niccolai, S; Niczyporuk, B B; Niyazov, R A; Nozar, M; O'Brien, J T; Opper, A K; Peterson, G; Philips, S A; Pivnyuk, N; Pocanic, D; Pogorelko, O; Polli, E; Preedom, B M; Price, J W; Protopopescu, D; Qin, L M; Raue, B A; Reolon, A R; Riccardi, G; Ricco, G; Ritchie, B G; Ronchetti, F; Rossi, P; Rowntree, D; Rubin, P D; Sabourov, K; Salgado, C; Sapunenko, V; Schumacher, R A; Serov, V S; Shafi, A; Sharabian, Y G; Shaw, J; Skabelin, A V; Smith, E S; Smith, T; Smith, L C; Sober, D I; Spraker, M; Stavinsky, A; Stepanyan, S; Stoler, P; Taylor, S; Tedeschi, D J; Todor, L; Thoma, U; Thompson, R; Vineyard, M F; Vlassov, A V; Wang, K; Weinstein, L B; Weller, H; Weygand, D P; Whisnant, C S; Wolin, E; Wood, M; Yegneswaran, A; Yun, J; Zhang, B; Zhao, J; Zhou, Z

    2003-01-17

    The differential cross section, dsigma/dt, for omega meson exclusive photoproduction on the proton above the resonance region (2.6

  15. Measurement of dijet cross sections for events with a leading neutron in photoproduction at HERA

    International Nuclear Information System (INIS)

    Differential cross sections for dijet photoproduction in association with a leading neutron using the reaction e++p→e++n+jet+jet+Xr have been measured with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb-1. The fraction of dijet events with a leading neutron in the final state was studied as a function of the jet kinematic variables. The cross sections were measured for jet transverse energies ETjet>6 GeV, neutron energy En>400 GeV, and neutron production angle θn<0.8 mrad. The data are broadly consistent with factorization of the lepton and hadron vertices and with a simple one-pion-exchange model

  16. Polarization Transfer in Wide-Angle Compton Scattering and Single-Pion Photoproduction from the Proton

    CERN Document Server

    Fanelli, C; Hamilton, D J; Salme, G; Wojtsekhowski, B; Ahmidouch, A; Annand, J R M; Baghdasaryan, H; Beaufait, J; Bosted, P; Brash, E J; Butuceanu, C; Carter, P; Christy, E; Chudakov, E; Danagoulian, S; Day, D; Degtyarenko, P; Ent, R; Fenker, H; Fowler, M; Frlez, E; Gaskell, D; Gilman, R; Horn, T; Huber, G M; de Jager, C W; Jensen, E; Jones, M K; Kelleher, A; Keppel, C; Khandaker, M; Kohl, M; Kumbartzki, G; Lassiter, S; Li, Y; Lindgren, R; Lovelace, H; Luo, W; Mack, D; Mamyan, V; Margaziotis, D J; Markowitz, P; Maxwell, J; Mbianda, G; Meekins, D; Meziane, M; Miller, J; Mkrtchyan, A; Mkrtchyan, H; Mulholland, J; Nelyubin, V; Pentchev, L; Perdrisat, C F; Piasetzky, E; Prok, Y; Puckett, A J R; Punjabi, V; Shabestari, M; Shahinyan, A; Slifer, K; Smith, G; Solvignon, P; Subedi, R; Wesselmann, F R; Wood, S; Ye, Z; Zheng, X

    2015-01-01

    Wide-angle exclusive Compton scattering and single-pion photoproduction from the proton have been investigated via measurement of the polarization transfer from a circularly polarized photon beam to the recoil proton. The WACS polarization transfer was analyzed at an incident photon energy of 3.7 GeV at a proton scattering angle of \\cma$= 70^\\circ$. The longitudinal transfer \\KLL, measured to be $0.645 \\pm 0.059 \\pm 0.048$, where the first error is statistical and the second is systematic, has the same sign as predicted for the reaction mechanism in which the photon interacts with a single quark carrying the spin of the proton. However, the observed value is $\\sim$3 times larger than predicted by the GPD-based calculations, which indicates a significant unknown contribution to the scattering amplitude.

  17. Differential Photoproduction Cross Sections of the Sigma0(1385), Lambda(1405), and Lambda(1520)

    Energy Technology Data Exchange (ETDEWEB)

    Moriya, Kei [Indiana U.; Schumacher, Reinhard A. [Carnegie Mellon U.

    2013-10-01

    We report the exclusive photoproduction cross sections for the Sigma(1385), Lambda(1405), and Lambda(1520) in the reactions gamma + p -> K+ + Y* using the CLAS detector for energies from near the respective production thresholds up to a center-of-mass energy W of 2.85 GeV. The differential cross sections are integrated to give the total exclusive cross sections for each hyperon. Comparisons are made to current theoretical models based on the effective Lagrangian approach and fitted to previous data. The accuracy of these models is seen to vary widely. The cross sections for the Lambda(1405) region are strikingly different for the Sigma+pi-, Sigma0 pi0, and Sigma- pi+ decay channels, indicating the effect of isospin interference, especially at W values close to the threshold.

  18. Measurement of dijet cross sections for events with a leading neutron in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Breitweg, J.; Chekanov, S.; Derrick, M.; Krakauer, D.; Magill, S.; Musgrave, B.; Pellegrino, A.; Repond, J.; Stanek, R.; Yoshida, R.; Mattingly, M.C.K.; Antonioli, P.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cara Romeo, G.; Cifarelli, L.; Cindolo, F.; Contin, A.; Corradi, M.; De Pasquale, S.; Giusti, P.; Iacobucci, G.; Levi, G.; Margotti, A.; Massam, T.; Nania, R.; Palmonari, F.; Pesci, A.; Sartorelli, G.; Zichichi, A.; Amelung, C.; Bornheim, A.; Brock, I.; Coboeken, K.; Crittenden, J.; Deffner, R.; Hartmann, H.; Heinloth, K.; Hilger, E.; Irrgang, P.; Jakob, H.-P.; Kappes, A.; Katz, U.F.; Kerger, R.; Paul, E.; Rautenberg, J.; Schnurbusch, H.; Stifutkin, A.; Tandler, J.; Voss, K.C.; Weber, A.; Wieber, H.; Bailey, D.S.; Barret, O.; Brook, N.H.; Foster, B. E-mail: b.foster@bristol.ac.uk; Heath, G.P.; Heath, H.F.; Rodrigues, E.; Scott, J.; Tapper, R.J.; Capua, M.; Schioppa, M.; Susinno, G.; Jeoung, H.Y.; Kim, J.Y.; Lee, J.H.; Lim, I.T.; Ma, K.J.; Pac, M.Y.; Caldwell, A.; Liu, W.; Liu, X.; Mellado, B.; Paganis, S.; Sampson, S.; Schmidke, W.B.; Sciulli, F.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Klimek, K.; Olkiewicz, K.; Piotrzkowski, K.; Przybycien, M.B.; Stopa, P.; Zawiejski, L.; Bednarek, B.; Jelen, K.; Kisielewska, D.; Kowal, A.M.; Kowalski, T.; Przybycien, M.; Rulikowska-Zarebska, E.; Suszycki, L.; Szuba, D.; Kotanski, A.; Bauerdick, L.A.T.; Behrens, U.; Bienlein, J.K.; Borras, K.; Chiochia, V.; Dannheim, D.; Desler, K.; Drews, G.; Fox-Murphy, A.; Fricke, U.; Goebel, F.; Goers, S.; Goettlicher, P.; Graciani, R.; Haas, T.; Hain, W.; Hartner, G.F.; Hebbel, K.; Hillert, S.; Koch, W.; Koetz, U.; Kowalski, H.; Labes, H.; Loehr, B.; Mankel, R.; Martens, J.; Martinez, M.; Milite, M.; Moritz, M.; Notz, D.; Petrucci, M.C.; Polini, A.; Rohde, M.; Savin, A.A.; Schneekloth, U.; Selonke, F.; Sievers, M.; Stonjek, S.; Wolf, G.; Wollmer, U.; Youngman, C.; Zeuner, W.; Coldewey, C.; Lopez-Duran Viani, A.; Meyer, A.; Schlenstedt, S.[and others

    2001-02-26

    Differential cross sections for dijet photoproduction in association with a leading neutron using the reaction e{sup +}+p{yields}e{sup +}+n+jet+jet+X{sub r} have been measured with the ZEUS detector at HERA using an integrated luminosity of 6.4 pb{sup -1}. The fraction of dijet events with a leading neutron in the final state was studied as a function of the jet kinematic variables. The cross sections were measured for jet transverse energies E{sub T}{sup jet}>6 GeV, neutron energy E{sub n}>400 GeV, and neutron production angle {theta}{sub n}<0.8 mrad. The data are broadly consistent with factorization of the lepton and hadron vertices and with a simple one-pion-exchange model.

  19. First measurement of the helicity asymmetry E in $\\eta$ photoproduction on the proton

    CERN Document Server

    Senderovich, I; Dugger, M; Ritchie, B G; Pasyuk, E; Tucker, R; Brock, J; Carlin, C; Keith, C D; Meekins, D G; Seely, M L; R, D; D, M; Collins, P; Adhikari, K P; Adikaram, D; Akbar, Z; Anderson, M D; Pereira, S Anefalos; Badui, R A; Ball, J; Baltzell, N A; Battaglieri, M; Batourine, V; Bedlinskiy, I; Biselli, A S; Boiarinov, S; Briscoe, W J; Brooks, W K; Burkert, V D; Carman, D S; Celentano, A; Chandavar, S; Charles, G; Colaneri, L; Cole, P L; Contalbrigo, M; Cortes, O; Crede, V; D'Angelo, A; Dashyan, N; De Vita, R; De Sanctis, E; Deur, A; Djalali, C; Dupre, R; Egiyan, H; Alaoui, A El; Fassi, L El; Fradi, A; Elouadrhiri, L; Eugenio, P; Fedotov, G; Fegan, S; Filippi, A; Fleming, J A; Garillon, B; Ghandilyan, Y; Gilfoyle, G P; Giovanetti, K L; Girod, F -X; Glazier, D I; Goetz, J T; Gohn, W; Golovatch, E; Gothe, R W; Griffioen, K A; Guidal, M; Guo, L; Hafidi, K; Hakobyan, H; Hanretty, C; Hattawy, M; Hicks, K; Ho, D; Holtrop, M; Hughes, S M; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Jenkins, D; Jiang, H; Jo, H S; Joo, K; Joosten, S; Keller, D; Khachatryan, G; Khandaker, M; Kim, A; Klein, F J; Kubarovsky, V; Kunkel, M C; Lenisa, P; Livingston, K; Lu, H Y; MacGregor, I J D; Mattione, P; McKinnon, B; Meyer, C A; Mineeva, T; Mokeev, V; Montgomery, R A; Movsisyan, A; Camacho, C Munoz; Nadel-Turonski, P; Net, L A; Niccolai, S; Niculescu, G; Niculescu, I; Osipenko, M; Park, K; Park, S; Peng, P; Phelps, W; Pisano, S; Pogorelko, O; Price, J W; Prok, Y; Puckett, A J R; Ripani, M; Rizzo, A; Rosner, G; Roy, P; Sabatie, F; Salgado, C; Schott, D; Schumacher, R A; Seder, E; Simonyan, A; Skorodumina, Iu; Smith, G D; Sober, D I; Sokhan, D; Sparveris, N; Stepanyan, S; Stoler, P; Strakovsky, I I; Strauch, S; Sytnik, V; Tian, Ye; Ungaro, M; Voskanyan, H; Voutier, E; Walford, N K; Wei, X; Wood, M H; Zachariou, N; Zana, L; Zhang, J; Zhao, Z W; Zonta, I

    2015-01-01

    Results are presented for the first measurement of the double-polarization helicity asymmetry E for the $\\eta$ photoproduction reaction $\\gamma p \\rightarrow \\eta p$. Data were obtained using the FROzen Spin Target (FROST) with the CLAS spectrometer in Hall B at Jefferson Lab, covering a range of center-of-mass energy W from threshold to 2.15 GeV and a large range in center-of-mass polar angle. As an initial application of these data, the results have been incorporated into the J\\"ulich model to examine the case for the existence of a narrow $N^*$ resonance between 1.66 and 1.70 GeV. The addition of these data to the world database results in marked changes in the predictions for the E observable using that model. Further comparison with several theoretical approaches indicates these data will significantly enhance our understanding of nucleon resonances.

  20. BFKL evolution and the growth with energy of exclusive J /Ψ and ϒ photoproduction cross sections

    Science.gov (United States)

    Bautista, I.; Fernandez Tellez, A.; Hentschinski, M.

    2016-09-01

    We investigate whether the Balitsky-Fadin-Kuraev-Lipatov (BFKL) low x evolution equation is capable to describe the energy dependence of the exclusive photo-production cross-section of vector mesons J /Ψ and ϒ on protons. Such cross-sections have been measured by both HERA experiments H1 and ZEUS in electron-proton collisions and by LHC experiments ALICE, CMS and LHCb in ultra-peripheral proton-proton and ultra-peripheral proton-lead collisions. Our approach provides a perturbative description of the rise with energy and relies only on a fit of the initial transverse momentum profile of the proton impact factor, which can be extracted from BFKL fits to inclusive HERA data. We find that BFKL evolution is capable to provide a very good description of the energy dependence of the current data set, while the available fits of the proton impact factor require an adjustment in the overall normalization.