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Sample records for hydrogen photoproduction presentation

  1. Algal Systems for Hydrogen Photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Ghirardi, Maria L [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-10-08

    The National Renewable Energy Laboratory (NREL), under the guidance of Drs. Michael Seibert (retired, Fellow Emeritus) and Maria Ghirardi (Fellow), led 15 years of research addressing the issue of algal H2 photoproduction. This project resulted in greatly increased rates and yields of algal hydrogen production; increased understanding of the H2 metabolism in the green alga, Chlamydomonas reinhardtii; expanded our knowledge of other physiological aspects relevant to sustained algal photosynthetic H2 production; led to the genetic identification, cloning and manipulation of algal hydrogenase genes; and contributed to a broader, fundamental understanding of the technical and scientific challenges to improving the conversion efficiencies in order to reach the U.S. Department of Energy’s Fuel Cell Technologies Office’s targets. Some of the tangible results are: (i) 64 publications and 6 patents, (ii) international visibility to NREL, (iii) reinvigoration of national and international biohydrogen research, and (iv) research progress that helped stimulate new funding from other DOE and non-DOE programs, including the AFOSR and the DOE Office of Science.

  2. Hydrogen photoproduction by photoelectrochemical conversion

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    The water-splitting reaction by photoelectrochemical processes has gained much more attention than any of many reactions proposed for solar generation of energy-rich molecules (fuels). The conversion efficiency of the photosystem is the key factor. The higher the efficiency, the more economically feasible will be the conversion scheme. The conversion efficiency is a function of the semiconductor properties, light intensity, spectral quality, properties of the electrolyte, counterelectrode, cell configuration, etc. The semiconductor parameters include band gap, absorption coefficient and diffusion length. The area and material used for a counterelectrode are important when considering polarization losses in a two-electrode system. Besides, the stability problem is also a very important one to meet the requirement for practical applications. This paper reviews some important issues on photoelectrochemical generation of hydrogen by water splitting. It includes energy conversion efficiency, market assessment and cost goal, state of the technology, and future directions for research

  3. ϕ-meson photoproduction on hydrogen in the neutral decay mode

    Science.gov (United States)

    Seraydaryan, H.; Amaryan, M. J.; Gavalian, G.; Baghdasaryan, H.; Weinstein, L.; Adhikari, K. P.; Adikaram, D.; Aghasyan, M.; Anderson, M. D.; Pereira, S. Anefalos; Avakian, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Bennett, R. P.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Brooks, W. K.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Collins, P.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dugger, M.; Dupre, R.; Fassi, L. El; Eugenio, P.; Fedotov, G.; Fegan, S.; Fersch, R.; Fleming, J. A.; Gevorgyan, N.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Heddle, D.; Hicks, K.; Ho, D.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Joo, K.; Keller, D.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Koirala, S.; Kubarovsky, A.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Lewis, S.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Martinez, D.; Mayer, M.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Moutarde, H.; Munevar, E.; Camacho, C. Munoz; Nadel-Turonski, P.; Nasseripour, R.; Niccolai, S.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Park, S.; Pasyuk, E.; Phelps, E.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Protopopescu, D.; Puckett, A. J. R.; Rimal, D.; Ripani, M.; Ritchie, B. G.; Rizzo, A.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Sharabian, Y. G.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S.; Stoler, P.; Strakovsky, I. I.; Strauch, S.; Tang, W.; Taylor, C. E.; Tian, Ye; Tkachenko, S.; Ungaro, M.; Vineyard, M. F.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weinstein, L. B.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; CLAS Collaboration

    2014-05-01

    We report the first measurement of the photoproduction cross section of the ϕ meson in its neutral decay mode in the reaction γp →pϕ(KSKL). The experiment was performed with a tagged photon beam of energy 1.6≤Eγ≤3.6 GeV incident on a liquid hydrogen target of the CLAS spectrometer at the Thomas Jefferson National Accelerator Facility. The pϕ final state is identified via reconstruction of KS in the invariant mass of two oppositely charged pions and by requiring the missing particle in the reaction γp →pKSX to be KL. The presented results significantly enlarge the existing data on ϕ photoproduction. These data, combined with the data from the charged decay mode, will help to constrain different mechanisms of ϕ photoproduction.

  4. Photoproduction of hydrogen - A potential system of solar energy bioconversion

    Energy Technology Data Exchange (ETDEWEB)

    Das, V S.R.

    1979-10-01

    The photoproduction of hydrogen from water utilizing the photosynthetic capacity of green plants is discussed as a possible means of solar energy conversion. Advantages of the biological production of H/sub 2/ over various physical and chemical processes are pointed out, and the system used for the production of hydrogen by biological agents, which comprises the photosynthetic electron transport chain, ferredoxin and hydrogenase, is examined in detail. The various types of biological hydrogen production systems in bacteria, algae, symbiotic systems and isolated chloroplast-ferredoxin-hydrogenase systems are reviewed. The limitations and the scope for further improvement of the promising symbiotic Azolli-Anabena azollae and chloroplast-ferredoxin-hydrogenase are discussed, and it is concluded that future research should concern itself with the identification of the environmental conditions that would maximize solar energy conversion efficiency, the elimination of the oxygen inhibition of biological hydrogen production, and the definition of the metabolic state for the maximal production of hydrogen.

  5. Transverse polarization of Σ+(1189) in photoproduction on a hydrogen target in CLAS

    Science.gov (United States)

    Nepali, C. S.; Amaryan, M.; Adhikari, K. P.; Aghasyan, M.; Anefalos Pereira, S.; Baghdasaryan, H.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A. S.; Bono, J.; Boiarinov, S.; Briscoe, W. J.; Bültmann, S.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Cole, P. L.; Collins, P.; Contalbrigo, M.; Crede, V.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Doughty, D.; Dupre, R.; Alaoui, A. El; Fassi, L. El; Fedotov, G.; Fegan, S.; Fersch, R.; Fleming, J. A.; Gabrielyan, M. Y.; Gevorgyan, N.; Giovanetti, K. L.; Girod, F. X.; Glazier, D. I.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guler, N.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Heddle, D.; Hicks, K.; Ho, D.; Holtrop, M.; Hyde, C. E.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jo, H. S.; Keller, D.; Khandaker, M.; Khetarpal, P.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Koirala, S.; Kubarovsky, V.; Kuhn, S. E.; Kuleshov, S. V.; Kvaltine, N. D.; Lu, H. Y.; MacGregor, I. J. D.; Markov, N.; Mayer, M.; McKinnon, B.; Mineeva, T.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Munevar, E.; Munoz Camacho, C.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Pappalardo, L. L.; Paremuzyan, R.; Park, K.; Park, S.; Pasyuk, E.; Phelps, E.; Phillips, J. J.; Pisano, S.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Puckett, A. J. R.; Raue, B. A.; Rimal, D.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Seraydaryan, H.; Sharabian, Y. G.; Smith, G. D.; Sober, D. I.; Sokhan, D.; Stepanyan, S. S.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tang, W.; Taylor, C. E.; Tian, Ye; Tkachenko, S.; Torayev, B.; Vernarsky, B.; Vlassov, A. V.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Zachariou, N.; Zana, L.; Zhang, J.; Zhao, Z. W.; Zonta, I.

    2013-04-01

    Experimental results on the Σ+(1189) hyperon transverse polarization in photoproduction on a hydrogen target using the CLAS detector at Jefferson Laboratory are presented. The Σ+(1189) was reconstructed in the exclusive reaction γ+p→KS0+Σ+(1189) via the Σ+→pπ0 decay mode. The KS0 was reconstructed in the invariant mass of two oppositely charged pions with the π0 identified in the missing mass of the detected pπ+π- final state. Experimental data were collected in the photon energy range Eγ=1.0-3.5 GeV (s range 1.66-2.73 GeV). We observe a large negative polarization of up to 95%. As the mechanism of transverse polarization of hyperons produced in unpolarized photoproduction experiments is still not well understood, these results will help to distinguish between different theoretical models on hyperon production and provide valuable information for the searches of missing baryon resonances.

  6. Photoproduction of Hydrogen by Decamethylruthenocene Combined with Electrochemical Recycling.

    Science.gov (United States)

    Rivier, Lucie; Peljo, Pekka; Vannay, Laurent A C; Gschwend, Grégoire C; Méndez, Manuel A; Corminboeuf, Clémence; Scanlon, Micheál D; Girault, Hubert H

    2017-02-20

    The photoinduced hydrogen evolution reaction (HER) by decamethylruthenocene, Cp 2 *Ru II (Cp*=C 5 Me 5 ), is reported. The use of a metallocene to photoproduce hydrogen is presented as an alternative strategy to reduce protons without involving an additional photosensitizer. The mechanism was investigated by (spectro)electrochemical and spectroscopic (UV/Vis and 1 H NMR) measurements. The photoactivated hydride involved was characterized spectroscopically and the resulting [Cp 2 *Ru III ] + species was electrochemically regenerated in situ on a fluorinated tin oxide electrode surface. A promising internal quantum yield of 25 % was obtained. Optimal experimental conditions- especially the use of weakly coordinating solvent and counterions-are discussed. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Photoproduction of hydrogen by membranes of green photosynthetic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Bernstein, J D; Olson, J M

    1980-01-01

    Photoproduction of H/sub 2/ from ascorbate by unit-membrane vesicles from Chlorobium limicola f. thiosulfatophilum was achieved with a system containing gramicidin D, tetramethyl-p-phenylenediamine, methyl viologen, dithioerythritol, Clostridium hydrogenase, and an oxygen-scavenging mixture of glucose, glucose oxidase, ethanol, and catalase. Maximum quantum yield was less than one percent. Half maximum rate of H/sub 2/ production occurred at a white-light intensity of approximately 0.15 cm/sup -2/. The reaction was inhibited completely by 0.3% sodium dodecylbenzene sulfonate, 1% Triton X-100, or preheating the vesicles at 100/sup 0/C for 5 minutes. Low concentrations (0.01 and 0.05%) of Triton X-100 about doubled the reaction rate.

  8. Dijet photoproduction

    CERN Document Server

    Butterworth, J M

    2001-01-01

    Recent jet photoproduction measurements are presented, including measurements of jet substructure which are sensitive to parton types. The implications for real and virtual photon structure are discussed. (11 refs).

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

    International Nuclear Information System (INIS)

    Chochois, V.

    2009-09-01

    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)

  10. Strangeness photoproduction

    International Nuclear Information System (INIS)

    Berthot, J.; Saghai, B.

    1989-01-01

    A non exhaustive review, about the strangeness photo-production is presented here in relation with the new electrons machines. Accent is put on the elementary reaction γp → K + Λ. The experiments on electroproduction and the study of hypernuclei with the electromagnetic probe are also discussed [fr

  11. Beauty Photoproduction

    International Nuclear Information System (INIS)

    Turcato, M.

    2002-01-01

    Beauty photoproduction in ep collisions has been studied with the ZEUS detector at HERA, at a center-of-mass energy of 300 GeV. Beauty quarks are tagged via their semi-leptonic decay into a muon or an electron. Events are selected by requiring the presence of two high-transverse energy jets and one high - p T lepton in the final state. The discrimination between beauty and background events is done by a fit to the p rel T variable, the transverse momentum of the lepton with respect to the jet axis. Total and differential cross sections are presented and compared to leading order Monte Carlo simulations and next-to-leading order QCD predictions. (author)

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

    International Nuclear Information System (INIS)

    Clark, Catherine D.; Bruyn, Warren de; Jones, Joshua G.

    2014-01-01

    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 (H 2 O 2 ) 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 H 2 O 2 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 (Θ app ; 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

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

    Science.gov (United States)

    Clark, Catherine D; de Bruyn, Warren; Jones, Joshua G

    2014-02-15

    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 (Θ app; 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. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. 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%

  15. Recent results from Fermilab E-687, charm particle decays, lifetimes and photoproduction dynamics: A compilation results presented at DPF 1994

    International Nuclear Information System (INIS)

    1994-10-01

    This report contains papers on the following topics: Recent results on the semi-leptonic decay Decay D 0 → K - μ + ν μ ; charmed mesons; observation of the Decay Ω c 0 Σ + K - K - φ + ; the physics of charm lifetimes; and photoproduction of charmed hadrons. These papers have been cataloged separately

  16. Photoproduction of π+π-π0 on hydrogen with linearly polarized photons of energy 20-70 GeV

    International Nuclear Information System (INIS)

    Lasalle, J.C.; Patrick, G.N.; Storr, K.M.; Atkinson, M.; Axon, T.J.; Barberis, D.; Brodbeck, T.J.; Brookes, G.R.; Bunn, J.J.; Bussey, P.J.; Clegg, A.B.; Dainton, J.B.; Davenport, M.; Dickinson, B.; Dieckmann, B.; Donnachie, A.; Ellison, R.J.; Flower, P.; Flynn, P.J.; Galbraith, W.; Heinloth, K.; Henderson, R.C.W.; Hughes-Jones, R.E.; Hutton, J.S.; Ibbotson, M.; Jakob, H.P.; Jung, M.; Kemp, M.A.R.; Kumar, B.R.; Laberrigue, J.; Lafferty, G.D.; Lane, J.B.; Levy, J.M.; Liebenau, V.; McClatchey, R.H.; Mercer, D.; Morris, J.A.G.; Morris, J.V.; Newton, D.; Paterson, C.; Paul, E.; Raine, C.; Reidenbach, M.; Rotscheidt, H.; Schloesser, A.; Sharp, P.H.; Skillicorn, I.O.; Smith, K.M.; Thompson, R.J.; Vaissiere, C. de la; Waite, A.P.; Worsell, M.F.; Yiou, T.P.

    1984-01-01

    Results on photoproduction of π + π - π 0 in the photon energy range 20-70 GeV are presented. For the ω meson, the production cross-section is found to be 1010 +- 15 (statistical) +- 290 (systematic) nb and is constant over the incident photon energy range. Spin-density matrix elements are evaluated for ω meson production. The PHI meson is observed with a total photoproduction cross section (corrected for branching ratio to π + π - π 0 ) of 610 +- 35 +- 170 nb. A third resonance, at 1.67 GeV, is seen in the mass spectrum and its interpretation is discussed. The production of a braod π + π - π 0 continuum, mainly via rhoπ, and peaking at 1.2 GeV, contributes with a cross section of about 2.5 μb. The spin-parity content is analysed by the moments of the π + π - π 0 decay angular distribution in the helicity frame and by maximum likelihood fits to the π + π - π 0 Dalitz plot. It is found that production of Jsup(P) = 1 - states accounts for less than half of the total mass spectrum above 900 MeV. There is a broad enhancement in the 1 + wave around 1.15 GeV indicating photoproduction of the H(1190) meson. (orig.)

  17. Biological hydrogen photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    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.

  18. Photoproduction experiments

    International Nuclear Information System (INIS)

    Wattenberg, A.

    1977-01-01

    Results of some experimental collaborations to search for new particles through photoproduction are briefly surveyed. The J/psi photoproduction on protons has been observed to rise slowly till above 12 GeV and then very steeply up to 55 GeV, exhibiting a pseudo-threshold behaviour. The psi production on Be and Ta is obtained to be sigmasub(psiN)=3.5+-0.8 mb at 20 GeV, which is somewhat higher than the vector dominance photoproduction value. A mass spectrum is shown for the γ+Be → μμ reaction at 90-200 GeV exhibiting a psi-like peak. Another mass spectrum for the γ+p → e + e - +p reaction shows very prominent rho/ω and phi peaks on top of Bethe-Heitler background. More data is needed to determine whether these events are due to very improbable statistical fluctuations or due to new narrow resonances

  19. Backward pion photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Sibirtsev, A; Haidenbauer, J; Huang, F; Krewald, S; Meissner, U -G

    2009-04-01

    We present a systematic analysis of backward pion photoproduction for the reactions $ \\gamma$ p $ \\rightarrow$ $ \\pi^{0}_{}$ p and $ \\gamma$ p $ \\rightarrow$ $ \\pi^{+}_{}$ n . Regge phenomenology is applied at invariant collision energies above 3GeV in order to fix the reaction amplitude. A comparision with older data on $ \\pi^{0}_{}$ - and $ \\pi^{+}_{}$ -photoproduction at $ \\vartheta$ = 180° indicates that the high-energy limit as given by the Regge calculation could be reached possibly at energies of around $ \\sqrt{{s}}$ ≃ 3 GeV. In the energy region of $ \\sqrt{{s}}$ $ \\le$2.5 GeV, covered by the new measurements of $ \\gamma$ p $ \\rightarrow$ $ \\pi^{0}_{}$ p differential cross-sections at large angles at ELSA, JLab, and LEPS, we see no clear signal for a convergence towards the Regge results. The baryon trajectories obtained in our analysis are in good agreement with those given by the spectrum of excited baryons.

  20. 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).

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

    International Nuclear Information System (INIS)

    Markou, A.

    1979-12-01

    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 10 6 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

  2. 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.)

  3. Inelastic photoproduction of ω and rho+-mesons

    International Nuclear Information System (INIS)

    Nelson, C.A. Jr.; May, E.N.; Abramson, J.; Andrews, D.E.; Harvey, J.; Lobkowicz, F.; Singer, M.N.; Thorndike, E.H.; Nordberg, M.E. Jr.

    1978-01-01

    We report measurements of inelastic photoproduction of ω and rho +- mesons from hydrogen and deuterium at incident photon energies in the range 7.5-10.5 GeV. For ωΔ and rho - Δ ++ production differential cross sections dsigma/dt' and spin density matrices are presented. For higher missing masses the cross sections dsigma/dM/sub X/ 2 and invariant structure functions F(x) are also given. The data are compared to a one-pion-exchange model. We conclude that pion exchange is dominant for inelastic ω photoproduction, but unimportant for rho +- during annealing, even though the resistively determined transport scattering time increased by a factor of 7.8 during annealing. Orbital depairing was found to follow a relation zeta = zeta 0 + αH 2 and to increase with annealing in a manner expected from the change in mean free path determined from measurements of H/sub cnu/

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

    International Nuclear Information System (INIS)

    Fourmond, V.

    2007-04-01

    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.)

  5. Hadron photoproduction at medium energy

    International Nuclear Information System (INIS)

    Dainton, J.B.

    1985-04-01

    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)

  6. 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 ...

  7. Reaction mechanisms in coherent nuclear photoproduction

    International Nuclear Information System (INIS)

    Lazard, C.

    Nuclear coherent pion photoproduction is studied. Pion rescattering and propagation effects inside nucleus and mesic exchange current effects are discussed. Influence of nuclear wave functions and Fermi motion is presented [fr

  8. Present status of research on hydrogen energy and perspective of HTGR hydrogen production system

    Energy Technology Data Exchange (ETDEWEB)

    Miyamoto, Yoshiaki; Ogawa, Masuro; Akino, Norio [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment] [and others

    2001-03-01

    A study was performed to make a clear positioning of research and development on hydrogen production systems with a High Temperature Gas-cooled Reactor (HTGR) under currently promoting at the Japan Atomic Energy Research Institute through a grasp of the present status of hydrogen energy, focussing on its production and utilization as an energy in future. The study made clear that introduction of safe distance concept for hydrogen fire and explosion was practicable for a HTGR hydrogen production system, including hydrogen properties and need to provide regulations applying to handle hydrogen. And also generalization of hydrogen production processes showed technical issues of the HTGR system. Hydrogen with HTGR was competitive to one with fossil fired system due to evaluation of production cost. Hydrogen is expected to be used as promising fuel of fuel cell cars in future. In addition, the study indicated that there were a large amount of energy demand alternative to high efficiency power generation and fossil fuel with nuclear energy through the structure of energy demand and supply in Japan. Assuming that hydrogen with HTGR meets all demand of fuel cell cars, an estimation would show introduction of the maximum number of about 30 HTGRs with capacity of 100 MWt from 2020 to 2030. (author)

  9. 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.

  10. EDF analysis of hydrogen problem on present NPPs

    International Nuclear Information System (INIS)

    Guieu, S.

    1997-01-01

    By letter dated March 1995, Electricite de France (EDF) has sent to the French Safety Authority (called DSIN, depending jointly from Industry and Environment Ministries) its position, for Present NPPs, regarding three main topics concerning severe accidents pointed by DSIN: hydrogen problem; high pressure core melt risk; and instrumentation. Concerning 'hydrogen problem', EDF answer is not only a state-of-the art analysis but intend to answer the question of the need (or not) for implementation of countermeasures in Present French NPPs. This position is presently under review by DSIN and its Technical Supports. (author)

  11. Photoproduction of the D*+-

    International Nuclear Information System (INIS)

    Avery, P.R.

    1980-01-01

    Using the broad band beam at FNAL, the photoproduction of the D* + (and D* - ) meson was observed, where D* + → D 0 π + and D 0 → K - π + (143 +- 20 events) or D 0 → K/sub s/π + π - (35 +- 11 events). The observation exploited the small D* + - D 0 mass difference to reduce the combinatoric background by 3 orders of magnitude. A variety of analysis techniques are presented to demonstrate that the D* + is created by a diffractive pair production mechanism, with a cross section given by sigma(γ + N → D 0 ) = 160 +- 70 nb/nucleon. Finally the data is discussed in terms of a QCD production mechanism, photon gluon fusion, and certain parameters are fixed in the theory by using the D* P/sub t/ distribution

  12. Heavy quarks photoproduction

    International Nuclear Information System (INIS)

    Cacciari, M.

    1996-08-01

    The state of the art of the theoretical calculations for heavy quarks photoproduction is reviewed. The full next-to-leading order calculation and two possible resummations, the high energy one for total cross sections and the large p T one for differential cross sections, are described. (orig.)

  13. 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.

  14. Pion photoproduction in nucleons at low energies

    International Nuclear Information System (INIS)

    Carvalho, F.A.B.R. de.

    1983-01-01

    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 [pt

  15. Photoproduction of the φ(1020) near threshold in CLAS

    International Nuclear Information System (INIS)

    Tedeschi, D.J.

    2002-01-01

    The differential cross section for the photoproduction of the φ (1020) near threshold (E γ = 1.57GeV) is predicted to be sensitive to production mechanisms other than diffraction. However, the existing low energy data is of limited statistics and kinematical coverage. Complete measurements of φ meson production on the proton have been performed at The Thomas Jefferson National Accelerator Facility using a liquid hydrogen target and the CEBAF Large Acceptance Spectrometer (CLAS). The φ was identified by missing mass using a proton and positive kaon detected by CLAS in coincidence with an electron in the photon tagger. The energy of the tagged, bremsstrahlung photons ranged from φ-threshold to 2.4 GeV. A description of the data set and the differential cross section for (E γ = 2.0 GeV) will be presented and compared with present theoretical calculations. (author)

  16. The FOREST detector for meson photoproduction experiments at ELPH

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, T., E-mail: ishikawa@lns.tohoku.ac.jp [Research Center for Electron Photon Science (ELPH), Tohoku University, Sendai 982–0826 (Japan); Fujimura, H.; Fukasawa, H.; Hashimoto, R.; Ishida, T.; Kaida, S.; Kasagi, J. [Research Center for Electron Photon Science (ELPH), Tohoku University, Sendai 982–0826 (Japan); Kawano, A. [Department of Information Science, Tohoku Gakuin University, Sendai 981–3193 (Japan); Kuwasaki, S. [Research Center for Electron Photon Science (ELPH), Tohoku University, Sendai 982–0826 (Japan); Maeda, K. [Department of Physics, Tohoku University, Sendai 980–8578 (Japan); Miyahara, F.; Mochizuki, K.; Nakabayashi, T.; Nakamura, A.; Nawa, K.; Ogushi, S.; Okada, Y.; Okamura, K.; Onodera, Y.; Saito, Y. [Research Center for Electron Photon Science (ELPH), Tohoku University, Sendai 982–0826 (Japan); and others

    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.

  17. Photon beam asymmetry Σ for η and η′ photoproduction from the proton

    OpenAIRE

    P. Collins; B.G. Ritchie; M. Dugger; A.V. Anisovich; M. Döring; E. Klempt; V.A. Nikonov; D. Rönchen; D. Sadasivan; A. Sarantsev; K.P. Adhikari; Z. Akbar; M.J. Amaryan; S. Anefalos Pereira; H. Avakian

    2017-01-01

    Measurements of the linearly-polarized photon beam asymmetry $\\Sigma$ for photoproduction from the proton of $\\eta$ and $\\eta^\\prime$ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the $\\gamma p \\to \\eta p$ reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the $\\gamma p \\to \\eta^\\pri...

  18. Far-UV-induced dimeric photoproducts in short oligonucleotides: sequence effects

    International Nuclear Information System (INIS)

    Douki, T.; Zalizniak, T.; Cadet, J.

    1997-01-01

    Cyclobutane pyrimidine dimers and pyrimidine (6-4)pyrimidone adducts represent the two major classes of far-UV-induced DNA photoproducts. Because of the lack of appropriate detection methods for each individual photoproduct, little is known about the effect of the sequence on their formaiton. In the present work, the photoproduct distribution obtained upon exposure of a series of dinucleoside monophosphate to 254 nm light was determined. (author)

  19. Solar-hydrogen generation and solar concentration (Conference Presentation)

    NARCIS (Netherlands)

    Sulima, Oleg V.; Chinello, Enrico; Conibeer, Gavin; Modestino, Miquel A.; Schüttauf, Jan-Willem; Lambelet, David; Delfino, Antonio; Domine, Didier; Faes, Antonin; Despeisse, Matthieu; Bailat, Julien; Psaltis, Demetri; Fernandez Rivas, David; Ballif, Christophe; Moser, Christophe

    2016-01-01

    We successfully demonstrated and reported the highest solar-to-hydrogen efficiency with crystalline silicon cells and Earth-abundant electrocatalysts under unconcentrated solar radiation. The combination of hetero-junction silicon cells and a 3D printed Platinum/Iridium-Oxide electrolyzer has been

  20. Photoproduction within the two-component Dual Parton Model: amplitudes and cross sections

    International Nuclear Information System (INIS)

    Engel, R.; Siegen Univ.

    1995-01-01

    In the framework of the Dual Parton Model an approximation scheme to describe high energy photoproduction processes is presented. Based on the distinction between direct, resolved soft, and resolved hard interaction processes we construct effective impact parameter amplitudes. In order to treat low mass diffraction within the eikonal formalism in a consistent way a phenomenological ansatz is proposed. The free parameters of the model are determined by fits to high energy hadro- and photoproduction cross sections. We calculate the partial photoproduction cross sections and discuss predictions of the model at HERA energies. Using hadro- and photoproduction data together, the uncertainties of the model predictions are strongly reduced. (orig.)

  1. Hadronic form factors in kaon photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Syukurilla, L., E-mail: tmart@fisika.ui.ac.id; Mart, T., E-mail: tmart@fisika.ui.ac.id [Department Fisika, FMIPA, Universitas Indonesia, Depok, 164242 (Indonesia)

    2014-09-25

    We have revisited the effect of hadronic form factors in kaon photoproduction process by utilizing an isobaric model developed for kaon photoproduction off the proton. The model is able to reproduce the available experimental data nicely as well as to reveal the origin of the second peak in the total cross section, which was the main source of confusion for decades. Different from our previous study, in the present work we explore the possibility of using different hadronic form factors in each of the KΛN vertices. The use of different hadronic form factors, e.g. dipole, Gaussian, and generalized dipole, has been found to produce a more flexible isobar model, which can provide a significant improvement in the model.

  2. Inelastic J/ψphotoproduction

    International Nuclear Information System (INIS)

    Kraemer, M.; Steegborn, J.; Zerwas, P.M.

    1994-11-01

    Inelastic photoproduction of J/ψ particles at high energies is one of the processes to determine the gluon distribution in the nucleon. We have calculated the QCD radiative corrections to the color-singlet model of this reaction. They are large at moderate photon energies, but decrease with increasing energies. The cross section and the J/ψ energy spectrum are compared with the available fixed-target photoproduction data and predictions are given for the HERA energy range. (orig.)

  3. Jet photoproduction at HERA

    International Nuclear Information System (INIS)

    Frixione, S.

    1997-01-01

    We compute various kinematical distributions for one-jet and two-jet inclusive photoproduction at HERA. Our results are accurate to next-to-leading order in QCD. We use the subtraction method for the cancellation of infrared singularities. We perform a thorough study of the reliability of QCD predictions; in particular, we consider the scale dependence of our results and discuss the cases when the perturbative expansion might break down. We also deal with the problem of the experimental definition of the pointlike and hadronic components of the incident photon, and briefly discuss the sensitivity of QCD predictions upon the input parameters of the calculation, like α S and the parton densities. (orig.)

  4. Photoproduction of charmed baryons

    International Nuclear Information System (INIS)

    Russell, J.J.

    1980-01-01

    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 K 0 . The cross section times branching ratio of γ + C → Λ/sub c/ + + X, γ + C → p + anti K 0 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/c 2 , in good agreement with the Mark II result from SPEAR. Upper limits (90% confidence level) are set on sigma B for the modes Λ 0 π, Λ 0 πππ, pKπ

  5. Present status of the disk pressure tests for hydrogen embrittlement

    International Nuclear Information System (INIS)

    Fidelle, J.P.

    1985-05-01

    The Disk Pressure Tests (DPT) have been developed considerably theoretically and experimentally for Internal Hydrogen Embrittlement (IHE) e.g. Co, Ti, U alloys, for Environment Embrittlement due to H 2 , hydrogenated media such as water vapor, alcohol, machining fluids or liquid NH 3 . The range has been expanded considerably for pressure up to 300 MPa and temperature (-160 0 C to 1000 0 C). Very low strain rate -longer than a month- tests have been able to evidence embrittlement of FFC alloys where H diffusivity is low. Conversely for very oxidation - sensitive metals (e.g. Nb and Ta) effects may appear only at somewhat high rates. The relationship between dynamic (increasing stress) tests, static (delayed failure) and low-cycle fatigue tests has been determined. In a number of instances, including SCC, other techniques and even fracture mechanics have been compared to the DPT and proved at best equivalent and several times, less sensitive than a well conducted DPT. At extreme they could not reproduce the field service phenomenon whereas the DPT did and could also be applied satisfactorily to low yield stress materials. The main rupture aspects have been analyzed mechanically and organized in a rational and comprehensive chart based on 12,000 + tests over 150 + materials in different conditions. From the tests on a large number of metal systems, a theory of HE has been derived which accounts for the behavior of metals and alloys either embrittled and or hydrited. Finally comparison of HGE tests and service behavior of a large variety of materials and industrial equipments has made possible to specify acceptance criteria for industrial service

  6. Present status of the disk pressure tests for hydrogen embrittlements

    International Nuclear Information System (INIS)

    Fidelle, J.P.

    1988-01-01

    The Disk Pressure Tests (DPT) have been developed considerably. Theoretically: a finite elements mechanical analysis shows the build up of a triaxial stress state already at the beginning of the test, which, with other reasons accounts for the very high sensitivity. Experimentally: for Internal Hydrogen Embrittlement (IHE) e.g. Co, Ti, U alloys, for environment embrittlement due to H 2 hydrogenated media such as water vapor, alcohol, machining fluids or liquid NH 3 . The range has been expanded considerably: up to 300 MPa and up to 1000 0 C. Very low strain rate - longer than a month - tests have been able to evidence HGE; of FCC alloys where H diffusivity is low for very oxidation -sensitive metals such as Nb and Ta, effects may appear only at somewhat high rates. The relationship between dynamic tests, static and low-cycle fatigue tests has been determined. In a number of instances, including SCC, other techniques and even fracture mechanics have been compared to the DPT and proved at best equivalent and several times, less sensitive than a well conducted DPT. At extreme they could not reproduce the field service phenomenon whereas the DPT did and could also be applied satisfactorily to low yield stress materials. The main rupture aspects have been analysed mechanically and organized in a rational and comprehensive chart based on 12,000 + tests over 15O + materials in different conditions. Comparison of HGE tests and service behaviour of a large variety of materials and industrial equipments has made possible to specify acceptance criteria for industrial service, which, provided the shape of the stress strain curves is not significantly affected, can be expanded to IHE, HE by other fluids than H 2 , 36 refs

  7. Photoproduction of the K= K0-(1750)

    International Nuclear Information System (INIS)

    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 ρ, ω, and ψ 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 ''p'(1600),'' the ''ωπ 0 (1250),'' the ''ω(1650),'' and the ''K + K - (1750),'' new results from the E831/FOCUS photoproduction experiment at Fermilab are presented which address the interpretation of the K + K - (1750). This enhancement in low-p T K + K - pairs at a mass near 1750 MeV/c 2 has been observed by several previous photoproduction experiments, but, despite several apparent inconsistencies, it has always been interpreted as the J PC = 1 -- ψ(1680) meson. With nearly two orders of magnitude more events than any previous observation of the K + K - (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 + K - (1750) has J PC ≠ 1 -- , and, in fact, the most likely assignment appears to be 2 ++ . It is hoped that this work can help set the stage for future reevaluations and new insights in photoproduction

  8. First time measurements of polarization observables for the charged cascade hyperon in photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Bono, Jason [Florida Intl Univ., Miami, FL (United States)

    2014-08-31

    The parity violating weak decay of hyperons offers a valuable means of measuring their polarization, providing insight into the production of strange quarks and the matter they compose. Jefferson Lab's CLAS collaboration has utilized this property of hyperons, publishing the most precise polarization measurements for the Lambda and Sigma in both photoproduction and electroproduction to date. In contrast, cascades, which contain two strange quarks, can only be produced through indirect processes and as a result, exhibit low cross sections thus remaining experimentally elusive.

    At present, there are two aspects in cascade physics where progress has been minimal: characterizing their production mechanism, which lacks theoretical and experimental developments, and observation of the numerous excited cascade resonances that are required to exist by flavor SU(3)F symmetry. However, CLAS data were collected in 2008 with a luminosity of 68 pb^-1 using a circularly polarized photon beam with energies up to 5.45 GeV, incident on a liquid hydrogen target. This dataset is, at present, the world's largest for meson photoproduction in its energy range and provides a unique opportunity to study cascade physics with polarization measurements.

    The current analysis explores hyperon production through the yp -> K^+ K^+ Xi^- reaction by providing the first ever determination of spin observables P, Cx and Cz for the cascade. Three of our primary goals are to test the only cascade photoproduction model in existence, examine the underlying processes that give rise to hyperon polarization, and to stimulate future theoretical developments while providing constraints for their parameters. Our research is part of a broader program to understand the production of strange quarks and hadrons with strangeness. The remainder of this document discusses the motivation behind such research, the method of data collection, details of their analysis, and the significance of

  9. Quarkonia Photoproduction at Nucleus Colliders

    International Nuclear Information System (INIS)

    D'Enterria, David

    2008-01-01

    Exclusive photoproduction of heavy quarkonia in high-energy ultraperipheral ion-ion interactions (γ A →V A, where V = J/ψ, Y and the nucleus A remains intact) offers a useful means to constrain the small-x nuclear gluon density. We discuss preliminary results on J/ψ photoproduction in Au-Au collisions at RHIC [D. d'Enterria [PHENIX Collaboration], Proceeds. Quark Matter'05, (arXiv:nucl-ex/0601001)], as well as full simulation-reconstruction studies of photo-produced Y in Pb-Pb interactions at the LHC [D. d'Enterria (ed.) et al. [CMS Collaboration], J. Phys. G. 34 2307 (2007)

  10. Inelastic J/ψphotoproduction

    International Nuclear Information System (INIS)

    Kraemer, M.

    1995-04-01

    Inelastic photoproduction of J/ψ particles at high energies is one of the processes to determine the gluon distribution in the nucleon. The QCD radiative corrections to the color-singlet model of this reaction have recently been calculated. They are large at moderate photon energies, but decrease with increasing energies. I compare the cross section and the J/ψ energy spectrum with the available fixed-target photoproduction data. Predictions for the HERA energy range are given which demonstrate the sensitivity of the result to the parametrization of the gluon distribution in the small-x region. (orig.)

  11. 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.

  12. Photon beam asymmetry Σ for η and η′ photoproduction from the proton

    Directory of Open Access Journals (Sweden)

    P. Collins

    2017-08-01

    Full Text Available Measurements of the linearly-polarized photon beam asymmetry Σ for photoproduction from the proton of η and η′ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the γp→ηp reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the γp→η′p reaction. For γp→ηp, the data reported here considerably extend the range of measurements to higher energies, and are consistent with the few previously published measurements for this observable near threshold. For γp→η′p, the results obtained are consistent with the few previously published measurements for this observable near threshold, but also greatly expand the incident photon energy coverage for that reaction. Initial analysis of the data reported here with the Bonn–Gatchina model strengthens the evidence for four nucleon resonances – the N(18951/2−, N(19003/2+, N(21001/2+ and N(21203/2− resonances – which presently lack the “four-star” status in the current Particle Data Group compilation, providing examples of how these new measurements help refine models of the photoproduction process.

  13. Photon beam asymmetry Σ for η and η‧ photoproduction from the proton

    Science.gov (United States)

    Collins, P.; Ritchie, B. G.; Dugger, M.; Anisovich, A. V.; Döring, M.; Klempt, E.; Nikonov, V. A.; Rönchen, D.; Sadasivan, D.; Sarantsev, A.; Adhikari, K. P.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Avakian, H.; Ball, J.; Balossino, I.; Bashkanov, M.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Cao, Frank Thanh; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Colaneri, L.; Cole, P. L.; Compton, N.; 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.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Glazier, D. I.; Gleason, C.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Heddle, D.; Hicks, K.; Holtrop, M.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jenkins, D.; Jo, H. S.; Joosten, S.; Keller, D.; Khachatryan, G.; Khachatryan, M.; Khandaker, M.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Lanza, L.; Lenisa, P.; Livingston, K.; MacGregor, I. J. D.; Markov, N.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Mokeev, V.; Montgomery, R. A.; Movsisyan, A.; Munoz Camacho, C.; Murdoch, G.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Niculescu, I.; Osipenko, M.; Ostrovidov, A. I.; Paolone, M.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ripani, M.; Rizzo, A.; Rosner, G.; Roy, P.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, G. D.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Taiuti, M.; Tian, Ye; Torayev, B.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Wei, X.; Zachariou, N.; Zhang, J.

    2017-08-01

    Measurements of the linearly-polarized photon beam asymmetry Σ for photoproduction from the proton of η and η‧ mesons are reported. A linearly-polarized tagged photon beam produced by coherent bremsstrahlung was incident on a cryogenic hydrogen target within the CEBAF Large Acceptance Spectrometer. Results are presented for the γp → ηp reaction for incident photon energies from 1.070 to 1.876 GeV, and from 1.516 to 1.836 GeV for the γp →η‧ p reaction. For γp → ηp, the data reported here considerably extend the range of measurements to higher energies, and are consistent with the few previously published measurements for this observable near threshold. For γp →η‧ p, the results obtained are consistent with the few previously published measurements for this observable near threshold, but also greatly expand the incident photon energy coverage for that reaction. Initial analysis of the data reported here with the Bonn-Gatchina model strengthens the evidence for four nucleon resonances - the N (1895) 1 /2-, N (1900) 3 /2+, N (2100) 1 /2+ and N (2120) 3 /2- resonances - which presently lack the ;four-star; status in the current Particle Data Group compilation, providing examples of how these new measurements help refine models of the photoproduction process.

  14. The role of screening corrections in high energy photoproduction

    International Nuclear Information System (INIS)

    Gotsman, E.; Maor, U.

    1994-07-01

    The role of screening corrections, calculated using the eikonal model, is discussed in the context of soft photoproduction. A comprehensive calculation is presented considering the total, elastic and diffractive cross sections jointly. The differences between our results and those obtained from the supercritical Pomeron-Reggeon model with no unitary corrections is examined. (author). 16 refs, 2 figs, 1 tab

  15. Measurement of coherent π0 photoproduction on 3He and 3H in the resonance region

    International Nuclear Information System (INIS)

    Bellinghausen, B.; Gassen, H.J.; Reese, E.; Reichelt, T.; Stipp, P.

    1984-01-01

    Neutral pion photoproduction has been measured on 3 He and 3 H nuclei in the Δ(1,232) resonance region. Resonance averaged cross-sections are presented as a function of momentum transfer and compared to theoretical calculations. (orig.)

  16. Photoproduction of charmed D mesons at γ energies of 40-70 GeV

    International Nuclear Information System (INIS)

    Aston, D.; Atkinson, M.; Bailey, R.; Ball, A.H.; Bouquet, B.; Brookes, G.R.; Broering, J.; Bussey, P.J.; Clarke, D.; Clegg, A.B.

    1980-01-01

    Inclusive anti D 0 photoproduction is observed in K + π - and K + π - π 0 . Evidence is presented for an associated (C anti D) production mechanism. Cross section estimates and limits are given for anti D and D mesons. (orig.)

  17. Charm photoproduction and quantum chromodynamics

    International Nuclear Information System (INIS)

    Novikov, V.A.; Shifman, M.A.; Vainshtein, A.I.; Zakharov, V.I.

    1977-01-01

    It is shown that charm photoproduction can be consistently described within asymptotically free field theory. Quantum chromodynamics is used to derive sum rules for the total cross section sigmasub(c)sup(γ) which includes both production of mesons with hidden charm (J/PIS, PIS' and so on) and of charmed particles (pairs DantiD, FantiF and so on). An estimate of sigmasub(c)sup(γ) as a function of energy is given and fast growth is discovered up to energies approximately 1000 GeV. In this energy range sigmasub(c)sup(γ) turns out to be equal to several microbarns. It is argued that measurements of charm photoproduction would give the most direct information on the gluon distribution within a nucleon. All the results are generalized to production of heavier particles containing new quarks. In particular, a simple rescaling law is derived connecting the cross sections for charm and beauty

  18. From meson-baryon scattering to meson photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Mai, Maxim

    2013-09-01

    In the present work we investigate the properties of the lowest baryon resonances. The starting point of our analyses is the low-energy effective theory of quantum chromodynamics, called chiral perturbation theory. As such it describes the long-range observables in terms of the low-energy effects, while the high-energy effects are subsumed in the so-called low-energy constants. In the region of the aforesaid lowest baryon resonances any strict perturbative expansion fails and some resummation scheme is required. For this we employ the Bethe-Salpeter equation (BSE) which guarantees the exact unitarity of the S-matrix and allows to generate resonances dynamically, however, abandoning some other basic principles of quantum field theory as described in chapter 2. Restricting the driving term of this equation to local terms of the second chiral order, we derive an exact solution of the BSE for meson-baryon scattering in chapter 2. Without putting the interaction kernel on shell we preserve the exact correspondence of this solution to an infinite chain of Feynman diagrams. In chapter 4 we apply this ansatz for antikaon-nucleon scattering, trying to get a new insight into the nature of the subthreshold resonance, i.e. {Lambda}(1405). The properties of this resonance have been debated for decades and in recent years it has again attracted a lot of attention by theoreticians since this resonance can be dynamically generated from the so-called chiral unitary approaches. Moreover, the recent measurement of the energy shift and width of kaonic hydrogen in the SIDDHARTA experiment at DA{Phi}NE has provided a very tight constraint on K{sup -}p scattering length. Typically, these approaches predict a two pole structure of {Lambda}(1405), but the question is how precise one can determine the position of these poles relying on data at and above the anti KN threshold. Moreover, we apply our framework for the analysis of pion-nucleon scattering in chapter 3. There we show that the

  19. Present status of r and d on hydrogen production by high temperature electrolysis of steam

    International Nuclear Information System (INIS)

    Hino, Ryutaro; Aita, Hideki; Sekita, Kenji; Haga, Katsuhiro; Miyamoto, Yoshiaki; Iwata, Tomo-o.

    1995-08-01

    In JAERI, design and R and D works on hydrogen production process have been conducted for connecting to the HTTR under construction at the Oarai Establishment of the JAERI as the nuclear heat utilization system. As for a hydrogen production process by high-temperature electrolysis of steam, laboratory-scale experiments have been conducted using a practical electrolysis tube with 12 cells connected in series. Hydrogen was produced at a maximum density of 44 Nml/cm 2 h at 950degC, and know-how of operational procedures and operational experience have been also accumulated. Then, a self-supporting planar electrolysis cell was fabricated in order to improve hydrogen production performance. In the preliminary test with the planar cell, hydrogen has been produced continuously at a maximum density of 36 Nml/cm 2 h at lower electrolysis temperature of 850degC. This report presents typical test results mentioned above, a review of previous studies conducted in the world and R and D items required for connecting to the HTTR. (author)

  20. Aluminum hydride as a hydrogen and energy storage material: Past, present and future

    Energy Technology Data Exchange (ETDEWEB)

    Graetz, J., E-mail: graetz@bnl.gov [Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, NY (United States); Reilly, J.J. [Sustainable Energy Technologies Department, Brookhaven National Laboratory, Upton, NY (United States); Yartys, V.A.; Maehlen, J.P. [Institute for Energy Technology, Kjeller (Norway); Bulychev, B.M. [Department of Chemistry, Lomonosov Moscow State University, Moscow (Russian Federation); Antonov, V.E. [Institute of Solid State Physics, Russian Academy of Sciences, Chernogolovka (Russian Federation); Tarasov, B.P. [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Chernogolovka (Russian Federation); Gabis, I.E. [Department of Physics, Saint-Petersburg State University, St. Petersburg (Russian Federation)

    2011-09-15

    Aluminum hydride (AlH{sub 3}) and its associated compounds make up a fascinating class of materials that have motivated considerable scientific and technological research over the past 50 years. Due primarily to its high energy density, AlH{sub 3} has become a promising hydrogen and energy storage material that has been used (or proposed for use) as a rocket fuel, explosive, reducing agent and as a hydrogen source for portable fuel cells. This review covers the past, present and future research on aluminum hydride and includes the latest research developments on the synthesis of {alpha}-AlH{sub 3} and the other polymorphs (e.g., microcrystallization reaction, batch and continuous methods), crystallographic structures, thermodynamics and kinetics (e.g., as a function of crystallite size, catalysts and surface coatings), high-pressure hydrogenation experiments and possible regeneration routes.

  1. Photoproduction of scalar mesons at CLAS

    Science.gov (United States)

    Chandavar, Shloka; Hicks, Kenneth; Weygand, Dennis; CLAS Collaboration

    2013-10-01

    A single gluon, which carries color charge, cannot exist independently outside a hadron. Lattice QCD calculations in pure SU(3), however, predict the existence of glueballs which are bound states of two or more gluons. In the real world, the challenge to identify glueballs experimentally is the fact they mix with meson states. The f0 (1500) is one of several candidates for the lightest glueball, with JPC =0++ . We investigate the presence of this particle in photoproduction by analyzing the reaction γp -->fJ p -->KS0KS0 p --> 2 (π+π-) p . This reaction was studied using data from the g12 experiment performed using the CLAS detector at Jefferson Lab. A preliminary partial wave analysis, performed on the KS0KS0 invariant mass spectrum, will be presented. These results update those presented for this reaction channel at previous conferences. This work is supported by grant from NSF.

  2. Results from high energy photoproduction at the CERN SPS

    International Nuclear Information System (INIS)

    Richard, F.

    1979-09-01

    Results from a photoproduction experiment using the CERN spectrometer with a tagged photon beam giving energies between 20 and 70 GeV are presented here. Charm physics and vector meson searches are emphasized. A luminosity of 80 events/nb was obtained on events with a detected charged kaon and of 60 events/nb on events with at least four prongs. Results on an emulsion exposure using the same apparatus are also presented

  3. Exclusive ϒ photoproduction in hadronic collisions at CERN LHC energies

    Energy Technology Data Exchange (ETDEWEB)

    Gonçalves, V.P., E-mail: barros@ufpel.edu.br [High and Medium Energy Group, Instituto de Física e Matemática, Universidade Federal de Pelotas, Caixa Postal 354, CEP 96010-900, Pelotas, RS (Brazil); Moreira, B.D.; Navarra, F.S. [Instituto de Física, Universidade de São Paulo, C.P. 66318, 05315-970 São Paulo, SP (Brazil)

    2015-03-06

    The exclusive ϒ photoproduction in proton–proton and proton–nucleus collisions at LHC energies is investigated using the color dipole formalism and considering different models for the ϒ wave function and forward dipole–target scattering amplitude. Our goal is to update the color dipole predictions and estimate the theoretical uncertainty present in these predictions. We present predictions for the kinematical ranges probed by the ALICE, CMS and LHCb Collaborations.

  4. Strangeness photoproduction and hadronic resonances

    International Nuclear Information System (INIS)

    David, J.C.

    1994-09-01

    The purpose of this thesis is to study the kaon photoproduction off a proton (γp → K + Λ,γp → K + Σ 0 , γp → K 0 Σ + ), with a photon energy between 0.9 and 2.1 GeV. We use an isobaric model where the amplitudes are computed with Feynman diagrams. The insertion of nucleonic resonances with spin 3/2 and 5/2 is necessary to improve the existing models beyond 1.5 GeV. This step is also necessary to extend the elementary process of photoproduction to electroproduction where the data have been taken with photon energies above 2.0 GeV. The parameters of our models are the coupling constants which appear at each Feynman diagram vertex. They are determined by fitting our models to the experimental data (cross sections, polarization asymmetries). Before performing the minimization we drew some informations about coupling constants from mesonic and electromagnetic decays, and from SU(3) and SU(6) symmetries. In conclusion, the models developed here reproduce the experimental data (E γ ≤ 2.0 GeV) and the two main coupling constants are in good agreement with broken SU(3)-symmetry predictions. (author)

  5. psi and excess leptons in photoproduction

    International Nuclear Information System (INIS)

    Ritson, D.M.

    1976-03-01

    The A-dependence of psi photoproduction was measured on beryllium and tantalum. From this it is found sigma/sub psi N/ = 2.75 +- 0.90 mb. A study was made of excess leptons relative to pion production in photoproduction. A μ/π ratio of 1.40 +- 0.25 x 10 -4 was found at 20 GeV incident photon energy. The energy dependence of psi photoproduction was determined and appeared to have a ''pseudo-threshold'' at 12 GeV

  6. Single meson photoproduction and IR renormalons

    International Nuclear Information System (INIS)

    Agaev, S.S.

    1996-10-01

    Single pseudoscalar and vector mesons inclusive photoproduction γh → MX via higher twist mechanism is calculated using the QCD running coupling constant method. It is proved that in the context of this method a higher twist contribution to the photoproduction cross section cannot be normalized in terms of the meson electromagnetic form factor. The structure of infrared renormalon singularities of the higher twist subprocess cross section and the resumed expression (the Borel sum) for it are found. Comparisons are made with earlier results, as well as with leading twist cross section. Phenomenological effects of studied contributions for π, K, ρ-meson photoproduction are discussed. (author). 21 refs, 8 figs

  7. High-energy photoproduction and electroproduction of π+ on nuclei

    International Nuclear Information System (INIS)

    Kuz'menko, V.S.; Mitrofanova, A.V.; Noga, V.I.; Ranyuk, Y.N.; Sorokin, P.V.; Telegin, Y.N.; Blomqvist, I.; Jonsson, G.G.; Freed, N.

    1977-01-01

    Cross sections for photoproduction and electroproduction of π + on 27 Al and 51 V leading to bound states in the daughter nuclei have been measured at Kharkov in the energy range 600--1200 MeV by use of the activation method. Careful comparison is made to other recent results obtained at intermediate and high energies. Agreement is found between the present data and results of earlier work carried out at Lund and DESY. Discrepancies between photoproduction data taken at different laboratories are attributed to differences between methods of background subtraction. Relative bremsstrahlung-induced to electron-induced yield ratios are compared with predictions based on the Dalitz-Yennie formalism for virtual-photon spectra

  8. Pion photoproduction on the nucleon at threshold

    International Nuclear Information System (INIS)

    Cheon, I.T.; Jeong, M.T.

    1989-08-01

    Electric dipole amplitudes of pion photoproduction on the nucleon at threshold have been calculated in the framework of the chiral bag model. Our results are in good agreement with the existing experimental data

  9. 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.)

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

    International Nuclear Information System (INIS)

    Boutle, Sarah

    2010-02-01

    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 Δφ jj =φ j1 -φ j2 =π. Additional soft radiation causes small azimuthal decorrelations, whilst Δφ jj significantly lower than π is evidence of additional hard radiation. In this thesis, the cross section versus Δφ jj for beauty photoproduction and the comparison to NLO QCD predictions and Monte Carlo models are presented. (orig.)

  11. Presentation of a methodology for measuring social acceptance of three hydrogen storage technologies and preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Noirot, I.; Bigay, C. N.

    2005-07-01

    Hydrogen storage is a key technology for the extensive use of H2 as energy carrier. As none of the current technologies satisfies all of the hydrogen storage attributes required by manufacturers and end users, there is intense research works aiming at developing viable solutions. A broad objective of the StorHy European project is to provide technological storage solutions, which are attractive from an economical, environmental and safety point of view. A specific sub-project is dedicated to the comparison of three different potential storage technologies for transport applications (compressed gas, cryogenic liquid, solid media). This evaluation is carried out in a harmonised way, based on common tools and assessment strategies that could be useful for decision makers and stakeholders. The assessment is achieved in a 'sustainable development' spirit, taking into consideration the technical, environmental, economical, safety and social requirements. The latter ones have newly emerged in such evaluations, based on the Quality Function Deployment (QFD) approach, and would require to be further studied. Hydrogen acceptability studies have been conducted in previous projects. They have been reviewed by LBST in the AcceptH2 project Public acceptance of Hydrogen Transport Technologies : Analysis and comparisons of existing studies (www. accepth2. com - August 2003). During these hydrogen acceptance surveys, mainly fuel cell bus passengers from demonstration projects around the world have been questioned. The work presented in this paper goes further in the methodology refinement as it focuses on the evaluation of hydrogen storage solutions. It proposes a methodological tool for efficient social evaluation of new technologies and associated preliminary results concerning France. In a global approach to sustainable development, the CEA has developed a new methodology to evaluate its current research projects : Multicriteria Analysis for Sustainable Industrial

  12. Advanced hydrogen technologies for FC applications and PGM beneficiation in SA: Presentation

    CSIR Research Space (South Africa)

    Langmi, Henrietta W

    2013-03-01

    Full Text Available developing hydrogen storage systems for fuel cell applications, and developing applications and solutions for small- and medium-scale hydrogen production through innovative research and development to promote beneficiation of Platinum-Group Metals (PGMs)....

  13. Quasi-free π0 photoproduction from the bound nucleon

    International Nuclear Information System (INIS)

    Kossert, K.; Camen, M.; Wissmann, F.; Schumacher, M.; Seitz, B.; Ahrens, J.; Arends, H.J.; Beck, R.; Caselotti, G.; Jahn, O.; Jennewein, P.; Leon, V.Olmos de; Annand, J.R.M.; McGeorge, J.C.; Rosner, G.; Grabmayr, P.; Natter, A.; Levchuk, M.I.; L'vov, A.I.; Petrun'kin, V.A.; Smend, F.; Thomas, A.; Weihofen, W.; Zapadtka, F.

    2004-01-01

    Differential cross-sections for quasi-free π 0 photoproduction from the proton and neutron bound in the deuteron have been measured for E γ =200-400 MeV at θγ lab =136.2 using the Glasgow photon tagger at MAMI, the Mainz 48 cm diameter x 64 cm NaI(Tl) photon detector and the Goettingen SENECA recoil detector. For the proton measurements made with both liquid-deuterium and liquid-hydrogen targets allow direct comparison of ''free'' π 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 quasi-free data are significantly smaller than the experimental free cross-sections and theoretical predictions based on multipole analysis. For the first time, ''free'' neutron cross-section have been extracted in the Δ-region. They are also in agreement with the predictions from multipole analysis up to 320 MeV and significantly smaller at higher photon energies. (orig.)

  14. Mechanism of the alkali degradation of (6-4) photoproduct-containing DNA.

    Science.gov (United States)

    Arichi, Norihito; Inase, Aki; Eto, Sachise; Mizukoshi, Toshimi; Yamamoto, Junpei; Iwai, Shigenori

    2012-03-21

    The (6-4) photoproduct is one of the major damaged bases produced by ultraviolet light in DNA. This lesion is known to be alkali-labile, and strand breaks occur at its sites when UV-irradiated DNA is treated with hot alkali. We have analyzed the product obtained by the alkali treatment of a dinucleoside monophosphate containing the (6-4) photoproduct, by HPLC, NMR spectroscopy, and mass spectrometry. We previously found that the N3-C4 bond of the 5' component was hydrolyzed by a mild alkali treatment, and the present study revealed that the following reaction was the hydrolysis of the glycosidic bond at the 3' component. The sugar moiety of this component was lost, even when a 3'-flanking nucleotide was not present. Glycosidic bond hydrolysis was also observed for a dimer and a trimer containing 5-methyl-2-pyrimidinone, which was used as an analog of the 3' component of the (6-4) photoproduct, and its mechanism was elucidated. Finally, the alkali treatment of a tetramer, d(GT(6-4)TC), yielded 2'-deoxycytidine 5'-monophosphate, while 2'-deoxyguanosine 3'-monophosphate was not detected. This result demonstrated the hydrolysis of the glycosidic bond at the 3' component of the (6-4) photoproduct and the subsequent strand break by β-elimination. It was also shown that the glycosidic bond at the 3' component of the Dewar valence isomer was more alkali-labile than that of the (6-4) photoproduct.

  15. 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.)

  16. Prompt photon production in photoproduction at HERA

    International Nuclear Information System (INIS)

    Nowak, Krzysztof

    2010-03-01

    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 -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 2 2 and in the inelasticity range 0.1 T γ γ γ and x 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 T factorisation approach. Neither of calculations is able to describe all the aspects of the measurement. (orig.)

  17. Studies in deep inelastic scattering and vector meson photoproduction

    International Nuclear Information System (INIS)

    Busenitz, J.K.

    1985-01-01

    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 he reports on the observations of elastic omega photoproduction from hydrogen by Fermilab Experiment-401. The omega was detected via its decay into the π + π - π 0 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

  18. NNLO contributions to jet photoproduction and determination of {alpha}{sub s}

    Energy Technology Data Exchange (ETDEWEB)

    Klasen, Michael; Michael, Markus [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Kramer, Gustav [Hamburg Univ. (Germany). 2. Inst. fuer Theoretische Physik

    2013-10-15

    We present the first calculation of inclusive jet photoproduction with next-to-next-to-leading order (NNLO) contributions, obtained from a unified threshold resummation formalism. The leading coefficients for direct photoproduction are computed analytically. Together with the coefficients pertinent to parton-parton scattering, they are shown to agree with those appearing in our full next-to-leading order calculations. For hadron-hadron scattering, numerical agreement is found with a previous calculation of jet production at the Tevatron. We show that the direct and resolved NNLO contributions considerably improve the description of final ZEUS data on jet photoproduction and that the error on the determination of the strong coupling constant is significantly reduced.

  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. Preliminary results for the helicity asymmetry E for eta photoproduction on the proton

    International Nuclear Information System (INIS)

    2012-01-01

    Polarization observables are an important tool for clarifying the nucleon resonance spectrum. No previous measurements for double polarization asymmetries have been published for eta photoproduction. Double polarization measurements have been made at Jefferson Lab using a polarized photon beam and protons in a polarized frozen spin target (FROST). Data were taken during the first running period of FROST using the CLAS detector with photon energies from 0.33 to 2.35 GeV. Preliminary results for the E polarization observable for eta meson photoproduction from the proton at threshold and above, along with comparisons to several theoretical predictions are presented.

  1. CLAS+FROST: new generation of photoproduction experiments at jefferson lab

    International Nuclear Information System (INIS)

    Pasyuk, E.

    2009-01-01

    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. (author)

  2. Transverse polarization of lambda(anti) hyperons from quasireal photoproduction on nuclei at HERMES

    Energy Technology Data Exchange (ETDEWEB)

    Hayrapetyan, Avetik; Brodski, Irina; Etzelmueller, Erik; Dueren, Michael; Zagrebalny, Vitaly [II. Physikalisches Inst., JLU Giessen (Germany)

    2015-07-01

    The transverse polarization of Λ(anti Λ) hyperons was measured in inclusive quasireal photoproduction for various target nuclei ranging from hydrogen to xenon. These data were taken at the HERMES Experiment at HERA/DESY using the 27.6 GeV lepton beam. They are compared to results from previous measurements of the HERMES experiment on hydrogen (H) and deuteron (D) targets. In comparison with earlier measurement a new improved track-fitting algorithm has been used leading to better vertex and momentum resolution. The HERMES data complement extensive transverse polarization studies of hyperons, using hadron beams.

  3. Study ω and φ photoproduction in the nucleon isotopic channels

    International Nuclear Information System (INIS)

    Zhao, Q.

    2002-01-01

    We present results for the photoproduction of ω and φ meson in the nucleon isotopic channels. A recently developed quark model with an effective Lagrangian is employed to account for the non-diffractive s- and u-channel processes; the diffractive feature arising from the natural parity exchange is accounted for by the t-channel pomeron exchange, while the unnatural parity exchange is accounted for by the t-channel pion exchange. In the ω production, the isotopic effects could provide more information concerning the search of 'missing resonances', while in the φ production, the isotopic effects could highlight non-diffractive resonance excitation mechanisms at large angles. (author)

  4. Recent results in photoproduction with real and virtual photons

    International Nuclear Information System (INIS)

    Diekmann, B.

    1984-10-01

    An overview of recent experimental results on soft photon-hadron-interactions is given. It contains results on inclusive photoproduction of rho and ω-mesons, hyperons and the totally inclusive reaction: γp -> Xp. Results on the search for radially excited vectormesons and on the determination of the radiative width of the rho- meson are updated. An improved measurement of the pion form factor and a test of Vector-Meson-Dominance in case of virtual photons (vertical strokeq 2 vertical stroke 2 ) will be presented. (orig.)

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

    International Nuclear Information System (INIS)

    Kusari, Souvik; Prabhakaran, Deivasigamani; Lamshoeft, Marc; Spiteller, Michael

    2009-01-01

    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.

  6. Strangeness photoproduction on the deuterium target

    NARCIS (Netherlands)

    Shende, Sugat Vyankatesh

    2007-01-01

    More information on the nucleon excitation function can be gained by studying the photoproduction experiments. In these experiments, the nucleon inside the nucleous is excited by shooting a high energy photon beam. The excited spectrum of the nucleon is then studied by measuring the energy and

  7. Photoproduction of neutral pions off protons

    NARCIS (Netherlands)

    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.; Suele, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Wendel, Ch

    2011-01-01

    Photoproduction of neutral pions has been studied with the CBELSA/TAPS detector in the reaction gamma p -> p pi(0) for photon energies between 0.85 and 2.50 GeV. The pi(0) mesons are observed in their dominant neutral decay mode: pi(0) -> gamma gamma. For the first time, the differential cross

  8. Constraints on Mars Hydrogen loss from MAVEN: processes and present-day rates

    Science.gov (United States)

    Chaffin, M.; Deighan, J.; Stewart, I. F.; Schneider, N. M.; Chaufray, J. Y.; Jain, S.; Thiemann, E.; Mayyasi, M.; Clarke, J. T.; Crismani, M. M. J.; Stiepen, A.; Montmessin, F.; Epavier, F.; McClintock, B.; Holsclaw, G.; Jakosky, B. M.

    2017-12-01

    The surface of Mars today is dessicated and oxidized, despite a large body of evidence indicating that the planet was wet and redox neutral early in its history. H escape has the potential to explain both conditions, but until recently there was no long-term monitoring of H loss at Mars. The presence of MAVEN at Mars since late 2014 has established a seasonal record of H escape via airglow measurements of coronal hydrogen and the flux of energetic particles whose production is mediated by the H corona. H escape appears from multiple proxies to be more than an order of magnitude larger in Southern summer than Northern summer, potentially as a consequence of enhanced water transport to the middle atmosphere. This newly described escape channel potentially dominates water loss from Mars today and over its history, and may be the most important control on the chemistry of the atmosphere and surface. I will present an overview of MAVEN measurements of H loss, focusing on contributions made by the Imaging Ultraviolet Spectrograph, and discuss how photochemical models of the atmosphere may need to be adjusted to incorporate new mechanisms for H loss.

  9. Hydrogen.

    Science.gov (United States)

    Bockris, John O'M

    2011-11-30

    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.

  10. 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.)

  11. 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.

  12. Photoproduction de Mesons sur le Nucleon aux Energies Intermediaire (in French) [Photoproduction of mesons on the nucleon at intermediate energies

    Energy Technology Data Exchange (ETDEWEB)

    Guidal, Michel [Univ. of Paris, Orsay (France)

    1996-12-13

    One object of this thesis is to propose a model taking account of low transfer reaction mechanisms for a series of photoproduction reactions on nucleons for photon energies ≳4 GeV. If our comprehension of processes with low transfers is correct, then extrapolating our model in the domain of large transfers and the comparison with data supplied will give us information on the domains in energy and transfers from which an interpretation of reactions in terms of the "soft" process ceases to be valid. In the domain of large transfers, only one approach in terms of "hard" process can then explain the data. We are interested in electromagnetic photoproduction reactions because the probe, firstly, interacts with the target via an exact and well known mechanism (described by the QED theory) and also eliminates the interaction phenomena in the initial state. No probe is as well known as the photon. The extraction of reaction mechanisms, amplitudes and coupling constants match is made easier than in the case of hadronic probes. The energy domain Eγ >4 GeV studied is particularly interesting because it is from this energy of incident photons that can be expected to achieve large enough pulse transfers to hope for emergence of hard processes and therefore see the cessation of validity of interpretation of hadron models. Also, resonance effects are minor and do not interfere with our interpretations. Experimentally, this area is widely unexplored and the new generation accelerators of a large duty cycle (CEBAF, MAMI, ESRF, ELF, ...) combined with 4π detectors will allow to precisely measure low cross sections reactions of a large transfer. We first study pion photoproduction reactions on nucleon because they are the most experimentally accessible reactions and many data of high energy and low transfers exist. This will require strong constraints on the model parameters of the numerous analyses performed previously. Then we'll move on to kaon photoproduction

  13. Measurement of elastic ρ0 photoproduction at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-07-01

    Elastic ρ 0 photoproduction has been measured using the ZEUS detector at HERA. Untagged photoproduction events from ep interactions were used to measure the reaction γp→ρ 0 p (ρ 0 →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/dM ππ , where M ππ is the invariant mass of the two pions, and the integrated cross section, σsub(γp→ρ 0 p), 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' t exp(-b' t vertical stroke tvertical stroke +c' t t 2 ) 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→ρ 0 p) and of the t-slope. The ρ 0 is produced predominantly with transverse polarisation, demonstrating that s-channel helicity conservation holds at these energies. (orig.)

  14. F observable in double π{sup 0}-photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Garni, Stefanie [Department of Physics, University of Basel, CH-4056 Basel (Switzerland); Collaboration: A2-Collaboration

    2014-07-01

    The measurement of single and double polarization observables gives information about the different resonance contributions in the cross section and hence leads to a better understanding of the nucleon and its excited states. The double π{sup 0}-photoproduction is one of the most interesting reaction for the measurement of these observables. It allows to search for excited nucleon states which decay preferentially via cascades involving intermediate excited states. Furthermore, the background from non-resonant terms is small since the photon does not couple directly to neutral pions. Double π{sup 0}-photoproduction off a transversally polarized H-Butanol target has been measured using circularly polarized bremsstrahlung photons produced by MAMI-C with incident energies up to 1.5 GeV. The double π{sup 0} reaction was identified using a combined setup of the Crystal Ball colorimeter and a TAPS forward wall which results in an almost 4π acceptance. Preliminary results on the single polarization observable T and double polarization observable F are presented.

  15. Quarkonium momentum distributions in photoproduction and B decay

    CERN Document Server

    Beneke, Martin; Wolf, S

    2000-01-01

    According to our present understanding many $J/\\psi$ production processes proceed through a coloured $c\\bar{c}$ state followed by the emission of soft particles in the quarkonium rest frame. The kinematic effect of soft particle emission is usually a higher-order effect in the non-relativistic expansion, but becomes important near the kinematic endpoint of quarkonium energy (momentum) distributions. In an intermediate region a systematic resummation of the non-relativistic expansion leads to the introduction of so-called `shape functions'. In this paper we provide an implementation of the kinematic effect of soft gluon emission which is consistent with the non-relativistic shape function formalism in the region where it is applicable and which models the extreme endpoint region. We then apply the model to photoproduction of $J/\\psi$ and $J/\\psi$ production in $B$ meson decay. A satisfactory description of $B$ decay data is obtained. For inelastic charmonium photoproduction we conclude that a sensible comparis...

  16. Measurement of elastic ρ0 photoproduction at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-01-01

    Elastic ρ 0 photoproduction has been measured using the ZEUS detector at HERA. Untagged photoproduction events from ep interactions were used to measure the reaction γp→ρ 0 p (ρ 0 →π + π - )at photon-proton centre-of-mass energies between 60 and 80 GeV and vertical stroke t vertical stroke 2 , where t is the square of the four-momentum transferred at the proton vertex. The differential cross section dσ/dM ππ , where M ππ is the invariant mass of the two pions, and the integrated cross section, σ γp →ρ 0 p , 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' t exp(-b' t vertical stroke t vertical stroke +c' t t 2 ) yields a t-slope b' t =9.9±1.2(stat.)±1.4(syst.) GeV -2 . The results, when compared to low energy data, show a weak energy dependence of both σ γp→ρ 0 p and of the t-slope. The ρ 0 is produced predominantly with transverse polarisation, demostrating that s-channel helicity conservation holds at these energies. (orig.)

  17. Diffractive Photoproduction of Psi(2S) Mesons at HERA

    CERN Document Server

    Adloff, C.; Andrieu, B.; Anthonis, T.; Astvatsatourov, A.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Berger, C.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruckner, W.; Bruncko, D.; Busser, 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.; Wolf, E.A.De; Diaconu, C.; Dingfelder, J.; Dixon, P.; Dodonov, V.; Dowell, J.D.; Droutskoi, A.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; 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.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Grab, C.; Grabski, V.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; 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.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hurling, S.; Ibbotson, M.; Issever, C .; Jacquet, M.; Jaffre, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, 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, Christian M.; 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.; Kruger, K.; Kuhr, T.; Kurca, T.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, 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.; Luders, S.; Luke, D.; Lytkin, L.; Malden, N.; Malinovski, E.; Malinovski, I.; Mangano, S.; Maracek, 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.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Nellen, G.; Newman, Paul 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.; Poschl, R.; Potachnikova, I.; Povh, B.; Radel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Samson, J.; Sankey, D.P.C.; Schatzel, S.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, D.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Chekelian, V.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Swart, M.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Uraev, A.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, 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, C.; Wobisch, M.; Woehrling, E.E.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; zur Nedden, M.

    2002-01-01

    Results on diffractive photoproduction of psi(2S) 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 psi(2S) cross section is found to be similar to or possibly somewhat steeper than that for J/psi mesons. The dependences of the elastic and proton dissociative psi(2S) photoproduction cross sections on the squared momentum transfer t at the proton vertex are measured. The t-dependence of the elastic channel, parametrised as e^(bt), yields b_(el)^(psi(2S))=(4.31+-0.57+-0.46) GeV^(-2), compatible with that of the J/psi. For the proton dissociative channel the result b_(pd)^(psi(2S))=(0.59+-0.13+-0.12) GeV^(-2) is 2.3 standard deviations smaller than that measured for the J/psi. With proper account of the individual wavefunctions theoretical predictions based on perturbative QCD are found to describe the measurements well.

  18. THEN: COE-INES international workshop on 'toward hydrogen economy; what nuclear can contribute and how'. Proposal and presentations

    International Nuclear Information System (INIS)

    2005-01-01

    The workshop of the title was held on topics; hydrogen system, nuclear and non-nuclear hydrogen production, hydrogen storage and transportation, fuel-cells, hydrogen energy management, hydrogen economy and all subjects related on hydrogen system, consisted of 4 panels by 15 panelists and a comprehensive discussion session. (J.P.N.)

  19. Measurement of elastic φ photoproduction at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1996-01-01

    The production of φ mesons in the reaction e + p→e + φp(φ→K + K - ) at a median Q 2 of 10 -4 GeV 2 has been studied with the ZEUS detector at HERA. The differential φ photoproduction cross section dσ/dt has an exponential shape and has been determined in the kinematic range 0.1 2 and 60 γp→φp 0.96±0.19 -0.18 +0.21 μb has been obtained by extrapolating to t=0. When compared to lower energy data, the results show a weak energy dependence of both σ γp→φp and the slope of the t distribution. The φ decay angular distributions are consistent with s-channel helicity conservation. From lower energies to HERA energies, the features of φ photoproduction are compatible with those of a soft diffractive process. (orig.)

  20. Drell-Yan lepton pair photoproduction

    International Nuclear Information System (INIS)

    Badalyan, R.G.; Grabskij, V.O.; Matinyan, S.G.

    1989-01-01

    The study of photon structure functions by spectra of massive lepton pairs (M l + l - ≥ 2 GeV) in photon fragmentation region in γp-interactions at high energies is suggested. In calculations of Drell-Yan lepton pair inclusive spectra in γp-interactions for photon structure functions there are used results obtained within QCD, data on γγ-interactions in e + e - → e + e - X on colliders as well as results from the analysis of vector meson non-diffractive photoproduction at high energies. It is shown that there exists a sufficienly wide kinematic region over variables X l + l - and M l + l - , wherein photon structure functions can be studied by spectra of Grell-Yan lepton pairs in the processes of their photoproduction. 31 refs.; 6 figs.; 1 tab

  1. Strangeness photoproduction with the SAPHIR-detector

    International Nuclear Information System (INIS)

    Merkel, H.

    1993-12-01

    At the ELSA facility at Bonn a photon beam with a high duty cycle up to energies of 3.3 GeV is available. In this energy range the large solid angle detector SAPHIR enables us to investigate the strangeness photoproduction starting from threshold. SAPHIR has already achieved results for the reactions γ+p→K + +Λ and γ+p→K + +Σ 0 . This work investigates the possibilities to measure the related reactions γ+n→K 0 +Λ and γ+n→K 0 +Σ 0 at a deuteron target and to measure the reaction γ+p→K 0 +Σ + at a proton target. For the first time the Σ + polarisation has been measured. With an cross section 10 times smaller compared to the kaon hyperon reactions, the photoproduction of the Φ(1020) meson can be investigated with the SAPHIR detector too. First reconstructed events are shown. (orig.)

  2. THEN-2: The 2nd COE-INES international workshop on 'toward hydrogen economy; what nuclear can contribute and how'. Proposal and presentations

    International Nuclear Information System (INIS)

    2006-01-01

    The workshop of the title was held on topics; nuclear hydrogen system in cooperation with other non-nuclear energy systems related with hydrogen production, storage and transportation, and synthesized fuel productions, hydrogen energy management and economy, consisted of 3 keynote lectures and 4 topical sessions by 15 presenters and a panel discussion session. (J.P.N.)

  3. The Λ(1520) photoproduction from proton

    International Nuclear Information System (INIS)

    He, Jun

    2014-01-01

    The Λ(1520) photoproduction from proton target is investigated within the effective Lagrangian method and well compared with the experimental data. The D 13 state N(2120) plays the most important role among the nucleon resonances. Besides N(2120), a nucleon resonance [5/2 - ] 2 (2080) predicted by the constituent quark model is found also important to reproduce the experimental data. Other nucleon resonances give negligible contributions in the channel considered in this work. (author)

  4. Exclusive photoproduction of Υ mesons at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2009-03-01

    The exclusive photoproduction reaction γ p → Υ p has been studied with the ZEUS experiment in ep collisions at HERA using an integrated luminosity of 468 pb -1 . The measurement covers the kinematic range 60 2 2 , where W is the photon-proton centre-of-mass energy and Q 2 is the photon virtuality. These results, which represent the analysis of the full ZEUS data sample for this channel, are compared to predictions based on perturbative QCD. (orig.)

  5. THE ETA-MESON PHOTOPRODUCTION ON PROTON

    Czech Academy of Sciences Publication Activity Database

    Donoval, Jan; Bydžovský, Petr

    2011-01-01

    Roč. 26, 3-4 (2011), s. 645-646 ISSN 0217-751X. [11th International Workshop on Meson Production , Properties and Interaction. Krakow, 10.06.2010-15.06.2010] R&D Projects: GA ČR GA202/08/0984 Institutional research plan: CEZ:AV0Z10480505 Keywords : Eta-meson photoproduction * form factors * nucleon resonances Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.053, year: 2011

  6. NEUTRAL KAON PHOTOPRODUCTION AT LNS, TOHOKU UNIVERSITY

    Czech Academy of Sciences Publication Activity Database

    Kaneta, M.; Chiga, N.; Beckford, B.; Ejima, M.; Fujii, T.; Fujii, Y.; Fujibayashi, T.; Gogami, T.; Futatsukawa, K.; Hashimoto, O.; Hosomi, K.; Hirose, K.; Iguchi, A.; Kameoka, S.; Kanda, H.; Kato, H.; Kawama, D.; Kawasaki, T.; Kimura, C.; Kiyokawa, S.; Koike, T.; Kon, T.; Ma, Y.; Maeda, K.; Maruyama, N.; Matsumura, A.; Miyagi, Y.; Miura, Y.; Miwa, K.; Nakamura, S. N.; Nomura, H.; Okuyama, A.; Ohtani, A.; Otani, T.; Sato, M.; Shichijo, A.; Shirotori, K.; Takahashi, T.; Tamura, H.; Taniya, N.; Tsubota, H.; Tsukada, K.; Terada, N.; Ukai, M.; Uchida, D.; Watanabe, T.; Yamamoto, T.; Yamauchi, H.; Yokota, K.; Ishikawa, T.; Kinoshita, T.; Miyahara, H.; Nakabayashi, T.; Shimizu, H.; Suzuki, K.; Tamae, T.; Terasawa, T.; Yamazaki, H.; Han, Y. C.; Wang, T. S.; Sasaki, A.; Konno, O.; Bydžovský, Petr; Sotona, Miloslav

    2010-01-01

    Roč. 19, č. 12 (2010), s. 2355-2362 ISSN 0218-3013. [Sendai International Conference on Strangeness in Nuclear and Hadronic Systems. Sendai, 15.12.2008-18.12.2008] R&D Projects: GA ČR GA202/05/2142; GA ČR GA202/08/0984 Institutional research plan: CEZ:AV0Z10480505 Keywords : Strangeness * photoproduction Subject RIV: BE - Theoretical Physics Impact factor: 0.695, year: 2010

  7. Beam asymmetry Σ for π0 and η photoproduction on the proton at GlueX

    Science.gov (United States)

    Zhang, Zhenyu; GlueX Collaboration

    2016-09-01

    Measurements of meson photoproduction at high energies began almost 50 years ago with bubble chamber experiments at SLAC, DESY, and Cambridge. These data have been successfully described through Regge theory in terms of t-channel quasi-particle exchange. High statistics measurements of pseudoscalar meson photoproduction at GlueX, using the 9 GeV linearly-polarized, tagged photon beam in Jefferson Lab's Hall D, will provide important new constraints on these Regge models. These measurements will test our understanding of the photoproduction mechanism at high energy, which is a necessary first step toward the broader meson spectroscopy program at GlueX. Through finite energy sum rules, these measurements can also impose new constraints on the extraction of nucleon resonances from low energy photoproduction data. In this talk, preliminary results for the linearly polarized photon beam asymmetry Σ for the exclusive reactions γp -> pπ0 and γp -> pη will be presented. These are the first measurements of the η beam asymmetry at these energies. Supported by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 and the China Scholarship Council No. 201506275156.

  8. Rho0 Photoproduction in Ultra-Peripheral Relativistic Heavy Ion Collisions with STAR

    Energy Technology Data Exchange (ETDEWEB)

    STAR Coll

    2007-12-20

    Photoproduction reactions occur when the electromagnetic field of a relativistic heavy ion interacts with another heavy ion. The STAR collaboration presents a measurement of {rho}{sup 0} and direct {pi}{sup +}{pi}{sup -} photoproduction in ultra-peripheral relativistic heavy ion collisions at {radical}s{sub NN} = 200 GeV. We observe both exclusive photoproduction and photoproduction accompanied by mutual Coulomb excitation. We find a coherent cross-section of {sigma}(AuAu {yields} Au*Au* {rho}{sup 0}) = 530 {+-} 19 (stat.) {+-} 57 (syst.) mb, in accord with theoretical calculations based on a Glauber approach, but considerably below the predictions of a color dipole model. The {rho}{sup 0} transverse momentum spectrum (p{sub T}{sup 2}) is fit by a double exponential curve including both coherent and incoherent coupling to the target nucleus; we find {sigma}{sub inc}/{sigma}{sub coh} = 0.29 {+-} 0.03 (stat.) {+-} 0.08 (syst.). The ratio of direct {pi}{sup +}{pi}{sup -} production is comparable to that observed in {gamma}p collisions at HERA, and appears to be independent of photon energy. Finally, the measured {rho}{sup 0} spin helicity matrix elements agree within errors with the expected s-channel helicity conservation.

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

    International Nuclear Information System (INIS)

    Wolfreys, A.; Henderson, L.; Clingen, P.

    1997-01-01

    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. Photoproduction of Neutral Kaons on Deuterons

    Science.gov (United States)

    Beckford, Brian

    2006-11-01

    Experimentation to greater understand the strangeness production mechanism can be performed by observing the electromagnetic interaction that leads to Kaon photoproduction. The n (γ, K^0) λ reaction may assist in answering questions about the strangeness photo-production process. An experiment into the elementary Kaon photoproduction process was investigated in an experiment conducted at the Laboratory of Nuclear Science of Tohoku University (LNS) using the Neutral Kaon Spectrometer. (NKS). The experiment was conducted by the d (γ, K^0) reaction. K^0 will be measured in the K^0->π^+π^- decay chain by the NKS. The NKS implements many detectors working in coincidence: These ranging from the Tagged Photon Beam generated by the 1.2 GeV Electron beam via bremsstrahlung, an Inner Plastic Scintillator Hodoscope (IH), a Straw Drift Chamber (SDC), a Cylindrical Drift Chamber (CDC), and an Outer Plastic Scintillator Hodoscope. Due to the background produced through the γ-> e+e- process, electron veto counters (EV) were placed in the middle of the OH to reject charged particles in the horizontal plane of the beam line. Preliminary analysis of the data indicates the need for pulse height correction. This was achieved by analysis of the Inner and Outer hodoscopes, and determining the energy deposit in the scintillators.

  11. Measurement of elastic ω photoproduction at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1996-08-01

    The reaction γp→ωp (ω→π + π - π 0 and π 0 →γγ) has been studied in ep interactions using the ZEUS detector at photon-proton centre-of-mass energies between 70 and 90 GeV and vertical stroke t vertical stroke 2 , where t is the squared four momentum transferred at the proton vertex. The elastic ω photoproduction cross section has been measured to be σ γp→ωp =1.21±0.12±0.23 μb. The differential cross section dσ γp→ωp /d vertical stroke t vertical stroke has an exponential shape e -b vertical stroke t vertical stroke with a slope b=10.0±1.2±1.3 GeV -2 . The angular distributions of the decay pions are consistent with s-channel helicity conservation. When compared to low energy data, the features of ω photoproduction as measured at HERA energies are in agreement with those of a soft diffractive process. Previous measurements of the ρ 0 and φ photoproduction cross sections at HERA show a similar behaviour. (orig.)

  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. Spin Observables in h Meson Photoproduction on the Proton

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, Ross [Arizona State Univ., Tempe, AZ (United States)

    2016-05-01

    A series of experiments using a polarized beam incident on a polarized frozen spin target (FROST) was conducted at Jefferson Lab in 2010. Results presented here were taken during the second running period with the FROST target using the CEBAF Large Acceptance Spectrometer (CLAS) detector at Jefferson Lab, which used transversely-polarized protons in a butanol target and a circularly-polarized incident tagged photon beam with energies between 0:62 and 2:93 GeV. Data are presented for the F and T polarization observables for n meson photoproduction on the proton from W = 1:55 GeV to 1:80 GeV. The data presented here will improve the world database and refine theoretical approaches of nucleon structure.

  14. 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.)

  15. Relating inclusive and exclusive meson photoproduction at large transverse momentum

    International Nuclear Information System (INIS)

    Scott, D.M.

    1975-01-01

    Inclusive and exclusive meson photoproduction at large transverse momentum are related by a local application of the correspondence principle of Bjorken and Kogut. The recent predictions for the inclusive process by Escobar are thus compared with wide angle exclusive data. The inclusive photoproduction of (rho 0 +ω) at large transverse momentum is discussed. (Auth.)

  16. Coupled-channel analysis for phi photoproduction with Lambda

    NARCIS (Netherlands)

    Ozaki, S.; Hosaka, A.; Nagahiro, H.; Scholten, O.

    We investigate photoproduction of phi mesons off protons within a coupled-channel effective-Lagrangian method which is based on the K-matrix approach. Since the threshold energy of the K Lambda(1520) channel is close to that of phi N, the contribution of this channel to f photoproduction near the

  17. Measurement of the helium-3 Panofsky ratio and of π+ photoproduction near the threshold for deuterium and helium-3

    International Nuclear Information System (INIS)

    Botton, Nico de.

    1979-01-01

    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 [fr

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

    CERN Document Server

    Aktas, A.; Anthonis, T.; Asmone, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brisson, V.; Broker, H.-B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Chekelian, V.; Collard, C.; 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, K.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dodonov, V.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; 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.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garutti, E.; Garvey, J.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Grassler, H.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Heremans, R.; Herrera, G.; Herynek, I.; Heuer, R.-D.; Hildebrandt, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; 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.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lueders, H.; Luke, 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-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morozov, I.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul 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.; Perez, E.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Poschl, 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.; 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.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; 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, Ch.; Woehrling, E.-E.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zohrabyan, H.; 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.

  19. Learning about nucleon resonances with pion photoproduction

    International Nuclear Information System (INIS)

    Walker, R.L.

    1989-01-01

    This chapter charts the discovery of nucleon resonances from pion-nucleon interactions. It was not until after the Albuquerque meeting in 1953 the experimentalists were able to persuade physicists about the existence of this phenomenon with the discovery of the P 33 resonance. The second and third resonances to be discovered, D 13 and F 15 , were seen as peaks in the total cross section for pion plus photoproduction, from 1956 onwards. Knowledge of pion-nucleon scattering has played an important role in the development of quark models. (UK)

  20. High pT charm photoproduction

    International Nuclear Information System (INIS)

    Abbiendi, G.; Butterworth, J.M.

    1996-09-01

    The expected rates for charm-tagged jet photoproduction are evaluated for a number of tagging procedures, and some of the physics potential is discussed. Charm in jets is tagged using D * 's, μ's, or tracks from secondary vertices which might be identified in a microvertex detector. We find high expected event rates, leading to the possibility of placing strong constraints on the kinematics of charm production and on the gluon content of the proton and the charm content of the photon. (orig.)

  1. 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.

  2. 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

  3. Prompt photons in photoproduction at HERA

    International Nuclear Information System (INIS)

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

    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 T γ γ γ 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 factorization approaches. (orig.) 7

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

    International Nuclear Information System (INIS)

    Manley, D. Mark

    2016-01-01

    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.

  5. 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.

  6. Photoproduction of Inelastic and Elastic $J/\\psi$ Vector Mesons

    Energy Technology Data Exchange (ETDEWEB)

    Stundzia, Audrius Bronius [Toronto U.

    1992-06-01

    Results and analysis on the inelastic and elastic photoproduction of $J /\\psi$ vector mesons by Fermilab experiment E691 are presented. The inelastic, deep inelastic, coherent elastic and incoherent elastic cross sections were measured at ($E_{\\gamma}$) = 145 GeV. The $d\\sigma / dzdp^2_{\\tau}$} distribution and the photon energy dependence of the cross sections for these production processes were also measured. The deep inelastic $J /\\psi$ was analyzed in the colour-singlet photon-gluon-fusion model. It was found that the $d\\sigma / dzdp^2_{\\tau}$ distribution and the the rise of the cross section with $E\\gamma$ are both well described by a relatively soft gluon distribution [xG( x) $\\alpha$ ($1 - x )^{ng}$, where $n_g$ = 6.5 ± 1.1 (stat.)$^{+1.0}_{-0.6}$(syst.)].

  7. Correlations between D and D-bar mesons in high energy photoproduction

    International Nuclear Information System (INIS)

    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.

    2003-01-01

    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 Ψ(3770)

  8. Photoproduction of scalar mesons using CLAS at JLab

    Science.gov (United States)

    Chandavar, Shloka; Hicks, Kenneth; Weygand, Dennis; CLAS Collaboration

    2014-09-01

    The search for glueballs has been ongoing for decades. The lightest glueball has been predicted by quenched lattice QCD to have a mass in the range of 1.0-1.7 GeV and JPC =0++ . The mixing of glueball states with neighbouring meson states complicates their identification. The f0 (1500) is one of several candidates for the lightest glueball, whose presence in the Ks0 Ks0 channel is investigated in photoproduction using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. This is done by studying the reaction, γp -->fJ p -->Ks0> Ks0p --> 2 (π+π-) p using data from the g12 experiment. A brief description of this analysis, along with a preliminary partial wave analysis results will be presented. The search for glueballs has been ongoing for decades. The lightest glueball has been predicted by quenched lattice QCD to have a mass in the range of 1.0-1.7 GeV and JPC =0++ . The mixing of glueball states with neighbouring meson states complicates their identification. The f0 (1500) is one of several candidates for the lightest glueball, whose presence in the Ks0Ks0 channel is investigated in photoproduction using the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab. This is done by studying the reaction, γp -->fJ p -->Ks0 Ks0p --> 2 (π+π-) p using data from the g12 experiment. A brief description of this analysis, along with a preliminary partial wave analysis results will be presented. NSF.

  9. Measurement of charm and beauty dijet cross sections in photoproduction at HERA using the H1 vertex detector

    International Nuclear Information System (INIS)

    Finke, L.

    2007-01-01

    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)

  10. Photoproduction of mesons on the nucleon at intermediate energies; Photoproduction de mesons sur le nucleon aux energies intermediaires

    Energy Technology Data Exchange (ETDEWEB)

    Guidal, M

    1997-01-01

    In this work a model is proposed to simulate the photoproduction of pseudoscalar mesons ('PI' and K) on the nucleon at high energy. This model is based on the exchange of mesonic or baryonic Regge trajectories, it is gauge invariant and it uses a Feynman diagram formalism inspired from isobaric models. The measurements concerning the following reactions {gamma}p {yields} n{pi}{sup +}, {gamma}n {yields} p{pi}{sup -}, {gamma}p {yields} p{pi}{sup 0} and {gamma}n {yields} n{pi}{sup 0} are reviewed and the new model is confronted to the experimental results. The model gives a reasonable and coherent description of these 4 reactions. The model has also been applied to the photoproduction of strange mesons and of {lambda} and {sigma} baryons and has been extrapolated at low energy to the threshold of the reaction, the model matches the results even up to E{sub {gamma}} = 2 GeV for differential cross-sections and recoil polarization. An attempt has been made to associate a Regge based description, which is valid with low transfers, with perturbative quantum chromodynamics which is valid with high transfers. The model relies on the saturation of trajectories in the high transfer region and on the counting laws that give the right variation of the cross-section. It seems that a model based on linear trajectories can be reliable up to 4 GeV. The domain of high transfer has been too little investigated to provide enough experimental data to validate the model. An experiment whose purpose is to study the photoproduction of {phi} at high transfer, is proposed. This experiment requires an accelerator with high useful cycle because of the smallness of the expected cross-section. The CEBAF (continuous electron beam accelerator facility) as well as the CLAS 4{pi} detector is presented. The study of {gamma}p {yields} p{phi} and {gamma}p {yields} K{lambda}{sup *} (1520) requires the discrimination of kaons from pions so the measurement of 180 ps as time resolution allows the

  11. Photoproduction of Mesons off Light Nuclei

    International Nuclear Information System (INIS)

    Keshelashvili, Irakli

    2011-01-01

    During the last few years, a series of experiments has been done at the ELSA accelerator in Bonn with the Crystal Barrel/TAPS setup and at the MAMI accelerator in Mainz with the Crystal Ball/TAPS setup. Photoproduction of light mesons off the deuteron and 3 He-nuclei has been studied in detail. We will report some of the most interesting results.A completely unexpected finding, is the pronounced structure in the excitation function of the γn → nη reaction around 1 GeV, which has no counterpart for the proton. Recent measurements at GRAAL, Sendai, ELSA [1] and MAMI estimate it's width below 50 MeV, which would be extremely narrow for a nucleon resonance at this excitation energy. In the experiment with the 3 He target, special attention was given to the threshold behavior of the γHe 3 reactions in view of possible indications for the formation of (quasi-)bound η-nucleus states, so-called η-mesic nuclei. A very strong threshold enhancement of coherent η-photoproduction off 3 He was found. In a new experiment, this reaction was measured with much better statistical accuracy compared to an earlier experiment at MAMI-B using the TAPS detector [2].

  12. Photoproduction at collider energies: from RHIC and HERA to the LHC

    CERN Document Server

    Baltz, A; Brodsky, S J; D'Enterria, D G; Dreyer, U; Engel, R; Frankfurt, L; Gorbunov, Y; Guzey, V; Hamilton, A; Klasen, M; Klein, S R; Kowalski, H; Levonian, S; Lourenço, C; Machado, M V T; Nachtmann, O; Nagy, Z; Nystrand, J; Piotrzkowski, K; Ramalhete, P; Savin, A; Scapparone, E; Schicker, R; Silvermyr, D; Strikman, M I; Valkárová, A; Vogt, R; Yilmaz, M; Enterria, David d'

    2007-01-01

    We present the mini-proceedings of the workshop on "Photoproduction at collider energies: from RHIC and HERA to the LHC" held at the European Centre for Theoretical Studies in Nuclear Physics and Related Areas (ECT*, Trento) from January 15 to 19, 2007. The workshop gathered both theorists and experimentalists to discuss the current status of investigations of high-energy photon-induced processes at different colliders (HERA, RHIC, and Tevatron) as well as preparations for extension of these studies at the LHC. The main physics topics covered were: (i) small-$x$ QCD in photoproduction studies with protons and in electromagnetic (aka. ultraperipheral) nucleus-nucleus collisions, (ii) hard diffraction physics at hadron colliders, and (iii) photon-photon collisions at very high energies: electroweak and beyond the Standard Model processes. These mini-proceedings consist of an introduction and short summaries of the talks presented at the meeting.

  13. 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...

  14. Structure function of carbon nucleus in cumulative π-meson photoproduction processes

    International Nuclear Information System (INIS)

    Egiyan, K.Sh.; Ohandjanyan, M.S.

    1992-01-01

    The results of data analysis (10,11) on π meson photoproduction on nucleus 1 2C at E γ m ax = 4,5 GeV from the point of obtaining information about factorization of invariant cross section f π (α,P l 2 ) are presented. It is shown that in the representation f π (α,P l 2 ) ∼ f 1π (α )

  15. Coupled channel analysis of s-wave ππ and K anti-K photoproduction

    International Nuclear Information System (INIS)

    Chueng-Ryong Ji; Szczepaniak, A.; Kaminski, R.; Lesniak, L.; Williams, R.

    1997-10-01

    We present a coupled channel partial wave analysis of non-diffractive S-wave π + π - and K + K - photoproduction focusing on the K anti-K threshold. Final state interactions are included. We calculate total cross sections, angular and effective mass distributions in both ππ and K anti-K channels. Our results indicate that these processes are experimentally measurable and valuable information on the f 0 (980) resonance structure can be obtained. (author)

  16. Photoproduction of the f1(1285)/η(1295) Mesons using CLAS at Jefferson Lab

    Energy Technology Data Exchange (ETDEWEB)

    Dickson, Ryan [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2011-07-18

    This work presents the results of analysis of a meson mass mx =1281.0 ± 0.8 MeV/ c2 and a FWHM of Γx = 18.4 ± 1.4 MeV/ c2 seen in CLAS at Jefferson Lab in photoproduction off the proton, γp → xp.

  17. 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.)

  18. Measurement of J/ψ photoproduction at large momentum transfer at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2009-09-01

    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.)

  19. Pion photoproduction in the Skyrme model and low-energy theorem

    International Nuclear Information System (INIS)

    Saito, Sakae; Takeuchi, Fuminaka; Uehara, Masayuki

    1993-01-01

    We investigate pion photoproduction on the nucleon in the Skyrme model. We employ the formulation, which was recently developed by Hayashi et al., that the full pion field is treated as an interpolating field between asymptotic in and out fields. It is shown that the amplitude of the pion photoproduction is correctly given by the direct and the crossed baryon-pole terms, and the equal-time commutator terms between the axial-vector current and the electromagnetic current and between the pion field and the latter. We show that the lowest-order Kroll-Ruderman and the pion pole terms are reproduced, and that the seagull terms inherent to the Skyrme model are present. Further, the threshold behavior of the amplitude is discussed. (orig.)

  20. A reagentless non-enzymatic hydrogen peroxide sensor presented using electrochemically reduced graphene oxide modified glassy carbon electrode

    International Nuclear Information System (INIS)

    Mutyala, Sankararao; Mathiyarasu, Jayaraman

    2016-01-01

    Herein, we report a simple, facile and reproducible non-enzymatic hydrogen peroxide (H 2 O 2 ) sensor using electrochemically reduced graphene oxide (ERGO) modified glassy carbon electrode (GCE). The modified electrode was characterized by Fourier transform infrared (FT-IR), UV–Visible, scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. Cyclic voltammetric (CV) analysis revealed that ERGO/GCE exhibited virtuous charge transfer properties for a standard redox systems and showed excellent performance towards electroreduction of H 2 O 2 . Amperometric study using ERGO/GCE showed high sensitivity (0.3 μA/μM) and faster response upon the addition of H 2 O 2 at an applied potential of − 0.25 V vs. Ag/AgCl. The detection limit is assessed to be 0.7 μM (S/N = 3) and the time to reach a stable study state current is < 3 s for a linear range of H 2 O 2 concentration (1–16 μM). In addition, the modified electrode exhibited good reproducibility and long-term stability. - Graphical abstract: We presented a reagentless non-enzymatic hydrogen peroxide sensor using electrochemically reduced graphene oxide material. - Highlights: • A facile green procedure proposed for high quality graphene synthesis using electrochemical reduction of graphene oxide • A simple, facile and reagentless non-enzymatic hydrogen peroxide sensor developed using ERGO/GCE. • ERGO/GCE exhibited high sensitivity, selectivity and finite limit of detection for H 2 O 2 sensing at low overpotential. • ERGO/GCE exhibited long term stability and good reproducibility.

  1. A reagentless non-enzymatic hydrogen peroxide sensor presented using electrochemically reduced graphene oxide modified glassy carbon electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mutyala, Sankararao; Mathiyarasu, Jayaraman, E-mail: al_mathi@yahoo.com

    2016-12-01

    Herein, we report a simple, facile and reproducible non-enzymatic hydrogen peroxide (H{sub 2}O{sub 2}) sensor using electrochemically reduced graphene oxide (ERGO) modified glassy carbon electrode (GCE). The modified electrode was characterized by Fourier transform infrared (FT-IR), UV–Visible, scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. Cyclic voltammetric (CV) analysis revealed that ERGO/GCE exhibited virtuous charge transfer properties for a standard redox systems and showed excellent performance towards electroreduction of H{sub 2}O{sub 2}. Amperometric study using ERGO/GCE showed high sensitivity (0.3 μA/μM) and faster response upon the addition of H{sub 2}O{sub 2} at an applied potential of − 0.25 V vs. Ag/AgCl. The detection limit is assessed to be 0.7 μM (S/N = 3) and the time to reach a stable study state current is < 3 s for a linear range of H{sub 2}O{sub 2} concentration (1–16 μM). In addition, the modified electrode exhibited good reproducibility and long-term stability. - Graphical abstract: We presented a reagentless non-enzymatic hydrogen peroxide sensor using electrochemically reduced graphene oxide material. - Highlights: • A facile green procedure proposed for high quality graphene synthesis using electrochemical reduction of graphene oxide • A simple, facile and reagentless non-enzymatic hydrogen peroxide sensor developed using ERGO/GCE. • ERGO/GCE exhibited high sensitivity, selectivity and finite limit of detection for H{sub 2}O{sub 2} sensing at low overpotential. • ERGO/GCE exhibited long term stability and good reproducibility.

  2. Vector meson photoproduction with a linearly polarized beam

    Science.gov (United States)

    Mathieu, V.; Nys, J.; Fernández-Ramírez, C.; Jackura, A.; Pilloni, A.; Sherrill, N.; Szczepaniak, A. P.; Fox, G.; Joint Physics Analysis Center

    2018-05-01

    We propose a model based on Regge theory to describe photoproduction of light vector mesons. We fit the SLAC data and make predictions for the energy and momentum-transfer dependence of the spin-density matrix elements in photoproduction of ω , ρ0 and ϕ mesons at Eγ˜8.5 GeV , which are soon to be measured at Jefferson Lab.

  3. RAYPHOTON version 2. 0 - an interface for HERA photoproduction physics

    Energy Technology Data Exchange (ETDEWEB)

    Brook, N.H.; Doyle, A.T. (Glasgow Univ. (United Kingdom). Dept. of Physics and Astronomy); DeRoeck, A. (Max-Planck-Institut fuer Physik, Muenchen (Germany). Werner-Heisenberg Inst.)

    1992-04-01

    RAYPHOTON allows photoproduction of both light and heavy quarks for the direct and resolved photon. It is a convolution of the Weiszaecker-Williams approximation with the cross section for the hard interaction. The hard interaction cross sections and colour flows are set up using the generators for real photoproduction LUCIFER, for the direct photon, and TWISTER, for the resolved photon. It includes QCD cascades in the colour dipole formalism, via an interface, RADIATE, to the ARIADNE package. (orig.).

  4. Presentations

    International Nuclear Information System (INIS)

    2007-01-01

    The presented materials consist of presentations of international workshop which held in Warsaw from 4 to 5 October 2007. Main subject of the meeting was progress in manufacturing as well as research program development for neutron detector which is planned to be placed at GANIL laboratory and will be used in nuclear spectroscopy research

  5. Exclusive Meson Photoproduction off Bound Nucleons

    Science.gov (United States)

    Strakovsky, Igor; Briscoe, William

    2017-09-01

    An overview of the GW SAID group effort to analyze pion photoproduction on the neutron-target will be given. The disentangling of the isoscalar and isovector EM couplings of N * and Δ * resonances does require compatible data on both proton and neutron targets. The final-state interactions play a critical role in the state-of-the-art analysis in extraction of the γn -> π N data from the deuteron target experiments. Then resonance couplings determined by the SAID PWA technique are compared to previous findings. The neutron program is an important component of the current JLab, MAMI-C, SPring-8, ELSA, and ELPH studies. DOE Research Grant DE``SC0016583.

  6. Putative Enzymes of UV Photoproduct Repair

    Directory of Open Access Journals (Sweden)

    Cynthia J. Sakofsky

    2011-01-01

    Full Text Available In order to determine the biological relevance of two S. acidocaldarius proteins to the repair of UV photoproducts, the corresponding genes (Saci_1227 and Saci_1096 were disrupted, and the phenotypes of the resulting mutants were examined by various genetic assays. The disruption used integration by homologous recombination of a functional but heterologous pyrE gene, promoted by short sequences attached to both ends via PCR. The phenotypic analyses of the disruptants confirmed that ORF Saci_1227 encodes a DNA photolyase which functions in vivo, but they could not implicate ORF Saci_1096 in repair of UV- or other externally induced DNA damage despite its similarity to genes encoding UV damage endonucleases. The success of the gene-disruption strategy, which used 5′ extensions of PCR primers to target cassette integration, suggests potential advantages for routine construction of Sulfolobus strains.

  7. Deuteron Compton scattering below pion photoproduction threshold

    Science.gov (United States)

    Levchuk, M. I.; L'vov, A. I.

    2000-07-01

    Deuteron Compton scattering below pion photoproduction threshold is considered in the framework of the nonrelativistic diagrammatic approach with the Bonn OBE potential. A complete gauge-invariant set of diagrams is taken into account which includes resonance diagrams without and with NN-rescattering and diagrams with one- and two-body seagulls. The seagull operators are analyzed in detail, and their relations with free- and bound-nucleon polarizabilities are discussed. It is found that both dipole and higher-order polarizabilities of the nucleon are required for a quantitative description of recent experimental data. An estimate of the isospin-averaged dipole electromagnetic polarizabilities of the nucleon and the polarizabilities of the neutron is obtained from the data.

  8. Deuteron Compton scattering below pion photoproduction threshold

    International Nuclear Information System (INIS)

    Levchuk, M.I.; L'vov, A.I.

    2000-01-01

    Deuteron Compton scattering below pion photoproduction threshold is considered in the framework of the nonrelativistic diagrammatic approach with the Bonn OBE potential. A complete gauge-invariant set of diagrams is taken into account which includes resonance diagrams without and with NN-rescattering and diagrams with one- and two-body seagulls. The seagull operators are analyzed in detail, and their relations with free- and bound-nucleon polarizabilities are discussed. It is found that both dipole and higher-order polarizabilities of the nucleon are required for a quantitative description of recent experimental data. An estimate of the isospin-averaged dipole electromagnetic polarizabilities of the nucleon and the polarizabilities of the neutron is obtained from the data

  9. Deuteron Compton scattering below pion photoproduction threshold

    Energy Technology Data Exchange (ETDEWEB)

    Levchuk, M.I. E-mail: levchuk@dragon.bas-net.by; L' vov, A.I. E-mail: lvov@x4u.lebedev.ru

    2000-07-17

    Deuteron Compton scattering below pion photoproduction threshold is considered in the framework of the nonrelativistic diagrammatic approach with the Bonn OBE potential. A complete gauge-invariant set of diagrams is taken into account which includes resonance diagrams without and with NN-rescattering and diagrams with one- and two-body seagulls. The seagull operators are analyzed in detail, and their relations with free- and bound-nucleon polarizabilities are discussed. It is found that both dipole and higher-order polarizabilities of the nucleon are required for a quantitative description of recent experimental data. An estimate of the isospin-averaged dipole electromagnetic polarizabilities of the nucleon and the polarizabilities of the neutron is obtained from the data.

  10. Photoproduction of rhorho and rhof systems

    International Nuclear Information System (INIS)

    Atkinson, M.; Axon, T.J.; Barberis, D.; Brodbeck, T.J.; Brookes, G.R.; Bunn, J.J.; Bussey, P.J.; Clegg, A.B.; Dainton, J.B.; Davenport, M.; Dickinson, B.; Diekmann, B.; Donnachie, A.; Ellison, R.L.; Flower, P.; Flynn, P.J.; Galbraith, W.; Heinloth, K.; Henderson, R.C.W.; Hughes-Jones, R.E.; Hutton, J.S.; Ibbotson, M.; Jakob, H.P.; Jung, M.; Kemp, M.A.R.; Kumar, B.R.; Laberrigue, J.; Lafferty, G.D.; Lane, J.B.; Levy, J.M.; Liebenau, V.; McClatchey, R.; Mercer, D.; Morris, J.A.G.; Morris, J.V.; Newton, D.; Paterson, C.; Paul, E.; Raine, C.; Reidenbach, M.; Rotscheidt, H.; Schloesser, A.; Sharp, P.H.; Skillicorn, I.O.; Smith, K.M.; Thompson, R.J.; La Vaissiere, D. de; Waite, A.P.; Worsell, M.F.; Yiou, T.P.

    1984-01-01

    A study is made of photoproduction of rhorho, rhof, rhoω and ωω systems, produced with masses > 1.8 GeV at high Feynman chisub(F) by photons of energy 20-70 GeV. There is evidence for a peak at a mass of approx.= 2.3 GeV with a width of approx.= 0.25 GeV in rho 0 f 0 and rhosup(+-)f 0 combinations. Angular distributions, in the 4π CM system, are found to be isotropic for these states, in sharp contrast to the strongly peaked angular distribution found for rho 0 rho 0 combinations at the same mass. (orig.)

  11. Suppression factors in diffractive photoproduction of dijets

    International Nuclear Information System (INIS)

    Klasen, Michael; Kramer, Gustav

    2010-06-01

    After new publications of H1 data for the diffractive photoproduction of dijets, which overlap with the earlier published H1 data and the recently published data of the ZEUS collaboration, have appeared, we have recalculated the cross sections for this process in next-to-leading order (NLO) of perturbative QCD to see whether they can be interpreted consistently. The results of these calculations are compared to the data of both collaborations. We find that the NLO cross sections disagree with the data, showing that factorization breaking occurs at that order. If direct and resolved contributions are both suppressed by the same amount, the global suppression factor depends on the transverse-energy cut. However, by suppressing only the resolved contribution, also reasonably good agreement with all the data is found with a suppression factor independent of the transverse-energy cut. (orig.)

  12. 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.

  13. High-ET dijet photoproduction at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2007-06-01

    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 pho- ton, Q 2 , of less than 1 GeV 2 and a photon-proton centre-of-mass energy in the range 142 γp T jet1 >20 GeV and E T jet2 >15 GeV and pseudorapidity requirements of -1 jet1,2 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. (orig.)

  14. 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.

  15. Hard photoproduction of multiparticle hadronic final states

    International Nuclear Information System (INIS)

    Paul, E.

    1992-02-01

    Recent results from fixed-target experiments on the photoproduction of hadrons have shown that pointlike photon interaction processes of lowest order in QCD can be studied. These are the flavour-dependent γg-fusion process which is the keyprocess to explore the gluon structure function of the nucleon at small x g and the QCD-Compton process which is a tool to study gluon fragmentation. The status of experimental results and comparison to QCD prediction is reviewed. The γg-fusion process will be measured in ep scatterings with almost real photons at HERA photon energies (equivalent to up to 50 TeV in the rest frame of the proton) down to x g > or approx. 10 -4 . Resolved (partonlike) photon interactions are predicted to be measurable at these high energies, too. (orig.)

  16. Photoproduction of scalar mesons at medium energies

    Energy Technology Data Exchange (ETDEWEB)

    Da Silva, M. L. [Instituto de Fisica e Matematica, Universidade Federal de Pelotas, Caixa Postal 354, CEP 96010-090, Pelotas, RS (Brazil); Machado, M. V. [High Energy Physics Phenomenology Group, GFPAE IF-UFRGS, Caixa Postal 15051, CEP 91501-970, Porto Alegre, RS (Brazil)

    2013-03-25

    In this work we will focus on photoproduction of mesons states a{sub 0}(980), f{sub 0}(1500) and f{sub 0}(1710). The f{sub 0}(1500) and f{sub 0}(1710) mesons will be considered in distinct mixing possibilities and assuming that a{sub 0}(980) is member of the ground-state nonet. The theoretical formalism is the Regge approach with reggeized {rho} and {omega} exchange. The differential and integrated total cross section are computed for the cases of the mesons a{sub 0}(980), f{sub 0}(1500) and f{sub 0}(1710) focusing the GlueX energy regime with photon energy E = 9 GeV.

  17. 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.

  18. Effects of exogenous lactase administration on hydrogen breath excretion and intestinal symptoms in patients presenting lactose malabsorption and intolerance.

    Science.gov (United States)

    Ibba, Ivan; Gilli, Agnese; Boi, Maria Francesca; Usai, Paolo

    2014-01-01

    To establish whether supplementation with a standard oral dose of Beta-Galactosidase affects hydrogen breath excretion in patients presenting with lactose malabsorption. Ninety-six consecutive patients positive to H2 Lactose Breath Test were enrolled. Mean peak H2 levels, the time to reach the peak H2, the time to reach the cut-off value of 20 ppm, the cumulative breath H2 excretion, the areas under the curve, and a Visual Analogical 10-point Scale for symptoms were calculated. Genotyping of the C/T-13910 variant was carried out. Following the oral administration of Beta-Galactosidase, in 21.88% of the cases, H2 Lactose Breath Test became negative (Group A), while mean peak H2 levels (74.95 ppm versus 7.85), P lactose malabsorption presents a significant variability.

  19. Near-threshold charged pion photoproduction from 13C

    International Nuclear Information System (INIS)

    LeRose, J.J.

    1981-01-01

    Differential cross sections to discrete final states have been measured for both positive and negative pion photo-production on 13 C at 90 0 in the lab at pion energies of 18, 29, and 41 MeV. Measurements were made using a fixed angle magnetic spectrometer located in the 14 0 area of the MIT Bates linear accelerator. Pions were detected using a 90 channel multi-wire proportional counter in the focal plane along with a backup array consisting of three 1/16'' thick plastic scintillator detectors and a 1/2'' thick Cerenkov detector. Positive pion photo-production cross sections were obtained for the excitation of the 3/2 - ground state and for the 3.45 MeV first excited state of 13 B. Negative pion photo-production cross sections were obtained for the excitation of the 1/2 - ground state, and the 3/2 to 3.51 MeV and 5/2 to 7.39 MeV excited states of 13 N. The measured positive pion photo-production ground state cross sections are in reasonable agreement wth theoretical calculations. However, there is a large discrepancy between the measured negative pion photoproduction ground state cross sections and the theoretical values. There are no theoretical calculations available for comparison with the excited state measurements in either positive or negative pion photoproduction on 13 C

  20. Polarisation observables F and T in double π{sup 0} photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Garni, Stefanie [Departement of Physics, University of Basel, CH-4056 Basel (Switzerland); Collaboration: A2-Collaboration

    2013-07-01

    The measurement of single and double polarization observables gives information about the different resonance contributions to the cross section and hence leads to a better understanding of the nucleon and it's excited states. Double π{sup 0} photo-production is a very interesting reaction for the investigation of nuclear resonances. Photo-production of pion pairs allows to study states which decay preferentially via intermediate resonances. The double neutral channel has the additional advantage of only small non-resonant background contributions. Double π{sup 0}-photo-production off a transversally polarized H-butanol target has been measured using circularly polarized bremsstrahlung photons produced by MAMI-C with incident energies up to 1.5 GeV. The double π{sup 0} reaction was identified using a combined setup of the Crystal Ball colorimeter and a TAPS forward wall which results in an almost 4π acceptance. Preliminary results on the single polarization observable T and double polarization observable F are presented.

  1. Presentations

    International Nuclear Information System (INIS)

    2007-01-01

    The PARIS meeting held in Cracow, Poland from 14 to 15 May 2007. The main subjects discussed during this meeting were the status of international project dedicated to gamma spectroscopy research. The scientific research program includes investigations of giant dipole resonance, probe of hot nuclei induced in heavy reactions, Jacobi shape transitions, isospin mixing and nuclear multifragmentation. The mentioned programme needs Rand D development such as new scintillations materials as lanthanum chlorides and bromides as well as new photo detection sensors as avalanche photodiodes - such subjects are also subjects of discussion. Additionally results of computerized simulations of scintillation detectors properties by means of GEANT- 4 code are presented

  2. Tests of QCD factorisation in the diffractive production of dijets in deep-inelastic scattering and photoproduction at HERA

    Science.gov (United States)

    Aktas, A.; Andreev, V.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Büsser, F. W.; 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.; 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.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B. R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Jacquet, M.; Janssen, X.; Jemanov, V.; Jönsson, L.; 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.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; 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.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, 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.; Pandurovic, M.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Plačakytė, R.; 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.; Schätzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smiljanic, I.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Steder, M.; Stella, B.; Stiewe, J.; Stoilov, A.; Straumann, U.; Sunar, D.; Sykora, T.; 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.; Usik, A.; Utkin, D.; Valkárová, A.; Vallée, C.; van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, C.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2007-08-01

    Measurements are presented of differential dijet cross sections in diffractive photoproduction (Q2<0.01 GeV2) and deep-inelastic scattering processes (DIS, 4photoproduction, the predicted dijet cross section has to be multiplied by a factor of approximately 0.5 for both direct and resolved photon interactions to describe the measurements. The ratio of measured dijet cross section to NLO prediction in photoproduction is a factor 0.5±0.1 smaller than the same ratio in DIS. This suppression is the first clear observation of QCD hard scattering factorisation breaking at HERA. The measurements are also compared to the two soft colour neutralisation models SCI and GAL. The SCI model describes diffractive dijet production in DIS but not in photoproduction. The GAL model fails in both kinematic regions.

  3. Photoproduction and Radiative Decay of eta' Meson in CLAS at Jlab

    Energy Technology Data Exchange (ETDEWEB)

    Mbianda Njencheu, Georgie [Old Dominion Univ., Norfolk, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2017-05-01

    In this work the η' meson photoproduction cross sections as well as the distribution of the di-pion invariant mass, m(π+π-), in the radiative decay mode n' -> π+π-γ have been measured using the CLAS detector at the Thomas Jefferson National Accelerator Facility using tagged incident photons in the center-of-mass energy range 1.96 GeV - 2.72 GeV. The measurements are performed on a liquid hydrogen target in the reaction γ π -> π η'(η'-> π+π-γ). The analysis is based on the highest statistics collected in this decay channel in comparison to other experiments reported so far. The n' photoproduction cross sections measured with radiative decay are in a good agreement with results of previous publication from the same data set in CLAS obtained through η' -> π+π-γ decay mode. Two free parameters, α and Β, are extracted from a model-independent fit to the m(π+π-) distribution and their values are found to agree well with recent theoretical expectations. The results of both parameters confirm the existence of the box anomaly, ρ-ω mixing and effects of the a2(1320) tensor meson in the radiative decay of η'.

  4. Presentation

    Directory of Open Access Journals (Sweden)

    Eduardo Vicente

    2013-06-01

    Full Text Available In the present edition of Significação – Scientific Journal for Audiovisual Culture and in the others to follow something new is brought: the presence of thematic dossiers which are to be organized by invited scholars. The appointed subject for the very first one of them was Radio and the invited scholar, Eduardo Vicente, professor at the Graduate Course in Audiovisual and at the Postgraduate Program in Audiovisual Media and Processes of the School of Communication and Arts of the University of São Paulo (ECA-USP. Entitled Radio Beyond Borders the dossier gathers six articles and the intention of reuniting works on the perspectives of usage of such media as much as on the new possibilities of aesthetical experimenting being build up for it, especially considering the new digital technologies and technological convergences. It also intends to present works with original theoretical approach and original reflections able to reset the way we look at what is today already a centennial media. Having broadened the meaning of “beyond borders”, four foreign authors were invited to join the dossier. This is the first time they are being published in this country and so, in all cases, the articles where either written or translated into Portuguese.The dossier begins with “Radio is dead…Long live to the sound”, which is the transcription of a thought provoking lecture given by Armand Balsebre (Autonomous University of Barcelona – one of the most influential authors in the world on the Radio study field. It addresses the challenges such media is to face so that it can become “a new sound media, in the context of a new soundscape or sound-sphere, for the new listeners”. Andrew Dubber (Birmingham City University regarding the challenges posed by a Digital Era argues for a theoretical approach in radio studies which can consider a Media Ecology. The author understands the form and discourse of radio as a negotiation of affordances and

  5. Inelastic Photoproduction of J/Psi Mesons at HERA

    CERN Document Server

    Adloff, C.; Andrieu, B.; Anthonis, T.; Astvatsatourov, A.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Berger, C.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruckner, W.; Bruncko, D.; Busser, 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, Guenter; 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.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Grab, C.; Grabski, V.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; 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.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hurling, S.; Ibbotson, M.; Issever, C.; Jacquet, M.; Jaffre, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, 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, Christian M.; 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.; Kruger, K.; Kuhr, T.; Kurca, T.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, 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.; Luders, S.; Luke, D.; Lytkin, L.; Malden, N.; Malinovski, E.; Malinovski, I.; Mangano, S.; Maracek, 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.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Nellen, G.; Newman, Paul R.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Nozicka, M.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Petrukhin, A.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Potachnikova, I.; Povh, B.; Radel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Samson, J.; Sankey, D.P.C.; Schatzel, S.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, D.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Chekelian, V.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Swart, M.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Uraev, A.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, 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, C.; Wobisch, M.; Woehrling, E.E.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; zur Nedden, M.

    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: 60presented for the first time. Theoretical calculations within the Colour Singlet Model at NLO for direct photon processes are shown to give a good description of the data in the medium z region (0.3

  6. Photoproduction with a Leading Proton at HERA

    CERN Document Server

    Adloff, C.; Andrieu, B.; Anthonis, T.; Arkadov, V.; Astvatsatourov, A.; Ayyaz, I.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bate, P.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Benisch, T.; Berger, Christoph; Berndt, T.; Bizot, J.C.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruckner, W.; Bruel, P.; Bruncko, D.; Burger, J.; Busser, F.W.; Bunyatyan, A.; Burkhardt, H.; Burrage, A.; Buschhorn, G.; Campbell, A.J.; Cao, Jun; Carli, T.; Caron, S.; Chabert, E.; Clarke, D.; Clerbaux, B.; 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.; Dixon, P.; Dodonov, V.; Dowell, J.D.; Droutskoi, A.; Duprel, C.; Eckerlin, Guenter; 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.; Fleming, Y.H.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Foster, J.M.; Franke, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goodwin, C.; Grab, C.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Hadig, T.; Haidt, D.; Hajduk, L.; 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.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hurling, S.; Ibbotson, M.; Issever, C .; Jacquet, M.; Jaffre, M.; Janauschek, L.; Jansen, D.M.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jones, M.A.S.; Jung, H.; Kastli, H.K.; Kant, D.; Kapichine, M.; Karlsson, M.; Karschnick, O.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kermiche, S.; Kiesling, Christian M.; Kjellberg, P.; Klein, M.; Kleinwort, C.; Knies, G.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Kotelnikov, S.K.; Koutouev, R.; Koutov, A.; Krasny, M.W.; Krehbiel, H.; Kroseberg, J.; Kruger, K.; Kupper, A.; Kuhr, T.; Kurca, T.; Lahmann, R.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, 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.; Luders, S.; Luke, D.; Lytkin, L.; Magnussen, N.; Mahlke-Kruger, H.; Malden, N.; Malinovski, E.; Malinovski, I.; Maracek, R.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.U.; Martyniak, J.; Maxfield, S.J.; Mehta, A.; Meier, K.; Merkel, P.; Meyer, A.B.; Meyer, H.; Meyer, J.; Meyer, P.O.; Mikocki, S.; Milstead, D.; Mkrtchyan, T.; Mohr, R.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Nellen, G.; Newman, Paul R.; Nicholls, T.C.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Nunnemann, T.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Perez, E.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Potachnikova, I.; Povh, B.; Rabbertz, K.; Radel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Riess, S.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Royon, C.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, D.; Schmitt, S.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Chekelian, V.; Sheviakov, I.; Shtarkov, L.N.; Sievers, P.; Sirois, Y.; Sloan, T.; Smirnov, P.; Solochenko, V.; Soloviev, Y.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Steinhart, J.; Stella, B.; Stellberger, A.; Stiewe, J.; Straumann, U.; Struczinski, W.; Swart, M.; Tasevsky, M.; Tchernyshov, V.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tobien, N.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vassiliev, S.; Vazdik, Y.; Vichnevski, A.; Wacker, K.; Wallny, R.; Walter, T.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; Werner, M.; White, G.; Wiesand, S.; Wilksen, T.; Winde, M.; Winter, G.G.; Wissing, C.; Wobisch, M.; Wollatz, H.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; Zsembery, J.; Zur Nedden, M.

    2001-01-01

    The total cross section for the photoproduction process with a leading proton in the final state has been measured at gamma p centre-of-mass energies W of 91, 181 and 231 GeV. The measured cross sections apply to the kinematic range with the transverse momentum of the scattered proton restricted to p_Tproton Xp'}(W,z)/dz is observed to be independent of W and z within the measurement errors and amounts to (8.05 +- 0.06 stat +- 0.89 syst) mub on average. The data are well described by a Triple Regge model in which the process is mediated by a mixture of exchanges with an effective Regge trajectory of intercept alpha_i(0)=0.33 +- 0.04 stat +- 0.04 syst. The total cross section for the interaction of the photon with this mixture (gamma alpha_i -> X) can be described by an effective trajectory of intercept alpha_k(0)=0.99 +- 0.01 stat +- 0.05 syst. The measured cross sections are compared with deep inelastic scattering leading proton data in the same region of z and p_Tproton for photon virtuality Q^2 > 2.5 GeV^...

  7. Strangeness photoproduction and hadronic resonances; Photoproduction d`etrangete et resonances hadroniques

    Energy Technology Data Exchange (ETDEWEB)

    David, J C

    1994-09-01

    The purpose of this thesis is to study the kaon photoproduction off a proton ({gamma}p {yields} K{sup +}{Lambda},{gamma}p {yields} K{sup +}{Sigma}{sup 0}, {gamma}p {yields} K{sup 0}{Sigma}{sup +}), with a photon energy between 0.9 and 2.1 GeV. We use an isobaric model where the amplitudes are computed with Feynman diagrams. The insertion of nucleonic resonances with spin 3/2 and 5/2 is necessary to improve the existing models beyond 1.5 GeV. This step is also necessary to extend the elementary process of photoproduction to electroproduction where the data have been taken with photon energies above 2.0 GeV. The parameters of our models are the coupling constants which appear at each Feynman diagram vertex. They are determined by fitting our models to the experimental data (cross sections, polarization asymmetries). Before performing the minimization we drew some informations about coupling constants from mesonic and electromagnetic decays, and from SU(3) and SU(6) symmetries. In conclusion, the models developed here reproduce the experimental data (E{sub {gamma}} {<=} 2.0 GeV) and the two main coupling constants are in good agreement with broken SU(3)-symmetry predictions. (author). 47 refs.

  8. Strangeness photoproduction at the BGO-OD experiment

    Energy Technology Data Exchange (ETDEWEB)

    Jude, Thomas [Physikalisches Institut, Universitaet Bonn, Nussallee 12, Bonn (Germany); Collaboration: BGO-OD-Collaboration

    2015-07-01

    The BGO-OD experiment at the ELSA accelerator facility uses an energy tagged bremstrahlung photon beam to investigate the internal structure of the nucleon. The setup consists of a highly segmented BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. The BGO-OD is ideal for investigating the photoproduction of hadrons of non-zero strangeness. The high momentum resolution at forward angles covers a kinematic region where t-channel exchange mechanisms play a dominant role. This is complemented by the neutral and charged particle identification in the BGO calorimeter for the identification of hyperon decays. The first part of an extensive physics programme includes measurements of the differential cross section at forward angles for γp → K{sup +}Λ and, using linearly polarised photons, the beam asymmetry, Σ, for γp → K{sup 0}Σ{sup +}. This latter measurement is focussed on the K* threshold region where a cusp-like structure was recently observed in the total cross section. Analysis of these reaction channels for both real and simulated data is presented.

  9. 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.)

  10. Diffractive Dijet Photoproduction in ep Collisions at HERA

    CERN Document Server

    Aaron, F.D.; Andreev, V.; 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.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cerny, K.; Cerny, V.; Chekelian, V.; Cholewa, A.; Contreras, J.G.; Coughlan, J.A.; Cvach, J.; Dainton, J.B.; Daum, K.; Deak, M.; Delcourt, B.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dobre, M.; 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, Samvel; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; 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.; Huber, F.; 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.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kutak, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lendermann, V.; Levonian, S.; Lipka, K.; 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, J.; Mikocki, S.; Milcewicz-Mika, I.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, M.U.; Mudrinic, M.; Muller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nowak, K.; Olsson, J.E.; Osman, S.; Ozerov, D.; Pahl, P.; Palichik, V.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Piec, S.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Raicevic, N.; Raspiareza, A.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Tabasco, J.E.Ruiz; 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, Ivan; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Staykova, Z.; Steder, M.; Stella, B.; Stoicea, G.; Straumann, U.; Sunar, D.; Sykora, T.; Thompson, G.; Thompson, P.D.; Toll, T.; Tran, T.H.; Traynor, D.; Truol, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Urban, K.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Trevino, A.Vargas; Vazdik, Y.; von den Driesch, M.; Wegener, D.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zohrabyan, H.; Zomer, F.

    2010-01-01

    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^-1. The events are of the type ep -> 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_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.

  11. Diffractive dijet photoproduction in ep collisions at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G. [National Inst. for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y. [Lebedev Physical Inst., Moscow (Russian Federation); Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N. [Univ. of Montenegro, Faculty of Science, Podgorica (ME); Baghdasaryan, A.; Zohrabyan, H. [Yerevan Physics Inst. (Armenia); Barrelet, E. [CNRS/IN2P3, LPNHE, Univ. Pierre et Marie Curie Paris 6, Univ. Denis Diderot Paris 7, Paris (France); Bartel, W.; Brandt, G.; Campbell, A.J.; Cholewa, A.; Deak, M.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Grell, B.R.; Habib, S.; Haidt, D.; Helebrant, C.; Katzy, J.; Kleinwort, C.; Knutsson, A.; Kraemer, M.; Kutak, K.; Levonian, S.; Lipka, K.; List, J.; Marti, Ll.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Nikiforov, A.; Olsson, J.E.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Piec, S.; Pitzl, D.; Placakyte, R.; Schmitt, S.; Sefkow, F.; Staykova, Z.; Steder, M.; Toll, T.; Vargas Trevino, A.; Driesch, M. von den; Wuensch, E. [DESY, Hamburg (Germany); Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B. [Inst. of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F. [CNRS/IN2P3, LAL, Univ. Paris-Sud, Orsay (France); Boudry, V.; Moreau, F.; Specka, A. [CNRS/IN2P3, LLR, Ecole Polytechnique, Palaiseau (France); Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I. [Vinca Inst. of Nuclear Sciences, Belgrade (RS); Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Shaw-West, R.N.; Thompson, P.D. [Univ. of Birmingham (United Kingdom). School of Physics and Astronomy] (and others)

    2010-11-15

    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.)

  12. 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.)

  13. Diffractive dijet photoproduction in ep collisions at HERA

    International Nuclear Information System (INIS)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Loktionova, N.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y.; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Zohrabyan, H.; Barrelet, E.; Bartel, W.; Brandt, G.; Campbell, A.J.; Cholewa, A.; Deak, M.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Grell, B.R.; Habib, S.; Haidt, D.; Helebrant, C.; Katzy, J.; Kleinwort, C.; Knutsson, A.; Kraemer, M.; Kutak, K.; Levonian, S.; Lipka, K.; List, J.; Marti, Ll.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Nikiforov, A.; Olsson, J.E.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Piec, S.; Pitzl, D.; Placakyte, R.; Schmitt, S.; Sefkow, F.; Staykova, Z.; Steder, M.; Toll, T.; Vargas Trevino, A.; Driesch, M. von den; Wuensch, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Mudrinic, M.; Pandurovic, M.; Smiljanic, I.; Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Shaw-West, R.N.; Thompson, P.D.; Brinkmann, M.; Dobre, M.; List, B.; Bruncko, D.; Cerny, V.; Ferencei, J.; Bunyatyan, A.; Buschhorn, G.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Kogler, R.; Raspiareza, A.; Shushkevich, S.; Bystritskaya, L.; Efremenko, V.; Fedotov, A.; Kropivnitskaya, A.; Lubimov, V.; Ozerov, D.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Cerny, K.; Pokorny, B.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cvach, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Daum, K.; Meyer, H.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Marage, P.; Mozer, M.U.; Roosen, R.; Sunar, D.; Sykora, T.; Mechelen, P. van; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Vallee, C.; Dodonov, V.; Povh, B.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Falkiewicz, A.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Feltesse, J.; Perez, E.; Schoeffel, L.; Grab, C.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Jung, A.W.; Krueger, K.; Lendermann, V.; Schultz-Coulon, H.C.; Urban, K.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Herrera, G.; Lopez-Fernandez, R.; Huber, F.; Pirumov, H.; Radescu, V.; Sauter, M.; Schoening, A.; Joensson, L.; Osman, S.; Jung, H.; DESY, Hamburg; Landon, M.P.J.; Rizvi, E.; Thompson, G.; Traynor, D.; Martyn, H.U.; Mueller, K.; Nowak, K.; Robmann, P.; Straumann, U.; Truoel, P.; South, D.; Wegener, D.; Stella, B.; INFN Roma 3, Rome

    2010-01-01

    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 -1 . The events are of the type ep→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 γ 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.)

  14. Double KS0 photoproduction off the proton at CLAS

    Science.gov (United States)

    Chandavar, S.; Goetz, J. T.; Hicks, K.; Keller, D.; Kunkel, M. C.; Paolone, M.; Weygand, D. P.; Adhikari, K. P.; Adhikari, S.; Akbar, Z.; Ball, J.; Balossino, I.; Barion, L.; Bashkanov, M.; Battaglieri, M.; Bedlinskiy, I.; Biselli, A. S.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Cao, F.; Carman, D. S.; Celentano, A.; Charles, G.; Chetry, T.; Ciullo, G.; Clark, L.; Cole, P. L.; Contalbrigo, M.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Defurne, M.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fedotov, G.; Filippi, A.; Fradi, A.; Gavalian, G.; Ghandilyan, Y.; Gilfoyle, G. P.; Girod, F. X.; Glazier, D. I.; Gohn, W.; Golovatch, E.; Gothe, R. W.; Griffioen, K. A.; Guidal, M.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Heddle, D.; Holtrop, M.; Ilieva, Y.; Ireland, D. G.; Isupov, E. L.; Jenkins, D.; Johnston, S.; Joo, K.; Joosten, S.; Kabir, M. L.; Khachatryan, G.; Khachatryan, M.; Khandaker, M.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Lanza, L.; Lenisa, P.; Livingston, K.; MacGregor, I. J. D.; Markov, N.; McCracken, M. E.; McKinnon, B.; Meyer, C. A.; Mineeva, T.; Mokeev, V.; Movsisyan, A.; Munoz Camacho, C.; Nadel-Turonski, P.; Niccolai, S.; Niculescu, G.; Osipenko, M.; Ostrovidov, A. I.; Paremuzyan, R.; Park, K.; Pasyuk, E.; Phelps, W.; Pogorelko, O.; Price, J. W.; Prok, Y.; Protopopescu, D.; Raue, B. A.; Ripani, M.; Riser, D.; Ritchie, B. G.; Rizzo, A.; Rosner, G.; Sabatié, F.; Salgado, C.; Schumacher, R. A.; Sharabian, Y. G.; Simonyan, A.; Skorodumina, Iu.; Sokhan, D.; Smith, G. D.; Sparveris, N.; Stepanyan, S.; Strakovsky, I. I.; Strauch, S.; Ungaro, M.; Voutier, E.; Wei, X.; Zachariou, N.; Zhang, J.; Zhao, Z. W.; CLAS Collaboration

    2018-02-01

    The f0(1500 ) meson resonance is one of several contenders to have significant mixing with the lightest glueball. This resonance is well established from several previous experiments. Here we present the first photoproduction data for the f0(1500 ) via decay into the KS0KS0 channel using the CLAS detector. The reaction γ p →fJp →KS0KS0p , where J =0 ,2 , was measured with photon energies from 2.7-5.1 GeV. A clear peak is seen at 1500 MeV in the background subtracted invariant mass spectra of the two kaons. This is enhanced if the measured four-momentum transfer to the proton target is restricted to be less than 1.0 GeV2. By comparing data with simulations, it can be concluded that the peak at 1500 MeV is produced primarily at low t , which is consistent with a t -channel production mechanism.

  15. Separation of minimum and higher twist in the photoproduction of mesons with large transverse momenta

    International Nuclear Information System (INIS)

    Hoeger, K.C.

    1990-10-01

    Higher-twist effects in point-like photon interactions on hydrogen have been studied in xF-distributions of charged particles for -0.2 2.0 GeV/c. Data were taken with a tagged photon beam with energies between 70 and 170 GeV and a pion/kaon beam at fixed energies of 80 and 140 GeV using the same setup of detectors at the CERN-Ω-spectrometer (WA69 experiment). The pion and kaon interactions were used to obtain an estimate of the hadron-like photon component. A first estimation of Higher-Twist cross sections in photoproduction of mesons at high pT has been obtained that is consistent with QCD-expectations. (orig.) [de

  16. Effects of Exogenous Lactase Administration on Hydrogen Breath Excretion and Intestinal Symptoms in Patients Presenting Lactose Malabsorption and Intolerance

    Directory of Open Access Journals (Sweden)

    Ivan Ibba

    2014-01-01

    Full Text Available Objective. To establish whether supplementation with a standard oral dose of Beta-Galactosidase affects hydrogen breath excretion in patients presenting with lactose malabsorption. Methods. Ninety-six consecutive patients positive to H2 Lactose Breath Test were enrolled. Mean peak H2 levels, the time to reach the peak H2, the time to reach the cut-off value of 20 ppm, the cumulative breath H2 excretion, the areas under the curve, and a Visual Analogical 10-point Scale for symptoms were calculated. Genotyping of the C/T-13910 variant was carried out. Results. Following the oral administration of Beta-Galactosidase, in 21.88% of the cases, H2 Lactose Breath Test became negative (Group A, while mean peak H2 levels (74.95 ppm versus 7.85, P<0.0000, in 17.71% (Group B were still positive, with the H2 level 20 ppm above the baseline, but the peak H2 levels were significantly lower than those observed at the baseline test (186.7 ppm versus 66.64, P<0.0000, while in 60.41% (Group C they were still positive with the peak H2 levels similar to those observed at the baseline test (94.43 versus 81.60 ppm. All 96 individuals tested presented the C/C-13910 genotype nonpersistence. Conclusions. The response to oral administration of Beta-Galactosidase in patients with symptoms of lactose malabsorption presents a significant variability.

  17. Photoproduction of isolated photons, inclusively and with a jet, at HERA

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.

    2013-12-01

    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 6 T γ γ T jet jet 2 2 . 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.

  18. Photoproduction of isolated photons, inclusively and with a jet, at HERA

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Antonelli, S.; Arslan, O.; Aushev, V.; Aushev, Y.; Bachynska, O.; Barakbaev, A.N.; Bartosik, N.; Behnke, O.; Behr, J.; Behrens, U.; Bertolin, A.; Bhadra, S.; Bloch, I.; Bokhonov, V.; Boos, E.G.

    2014-01-01

    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 6 T γ γ T jet jet 2 2 . 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. Quantum effects and colour transparency in charmonium photoproduction on nuclei

    International Nuclear Information System (INIS)

    Kopeliovich, B.Z.; Zakharov, B.G.

    1991-01-01

    A rigorous quantum-mechanical treatment of colour transparency effects in diffractive photoproduction of c-barc-pairs on nuclei was developed. The evolution of the c-barc wave function during propagating through a nucleus is rather a considerable distortion of its form, than a trivial attenuation. One of the manifestations of the quantum effects is a nuclear antishadowing of Ψ' yield, i.e. transparency above one. On the contrary, a considerable nuclear shadowing is predicted for the photoproduction of J/Ψ, which has a much smaller absorption cross section than Ψ'. 26 refs.; 5 figs.; 1 tab

  20. Features of πΔ photoproduction at high energies

    Science.gov (United States)

    Nys, J.; Mathieu, V.; Fernández-Ramírez, C.; Jackura, A.; Mikhasenko, M.; Pilloni, A.; Sherrill, N.; Ryckebusch, J.; Szczepaniak, A. P.; Fox, G.; Joint Physics Analysis Center

    2018-04-01

    Hybrid/exotic meson spectroscopy searches at Jefferson Lab require the accurate theoretical description of the production mechanism in peripheral photoproduction. We develop a model for πΔ photoproduction at high energies (5 ≤Elab ≤ 16 GeV) that incorporates both the absorbed pion and natural-parity cut contributions. We fit the available observables, providing a good description of the energy and angular dependencies of the experimental data. We also provide predictions for the photon beam asymmetry of charged pions at Elab = 9 GeV which is expected to be measured by GlueX and CLAS12 experiments in the near future.

  1. Quasi-free K+ photo-production in 12C

    International Nuclear Information System (INIS)

    Maeda, K.; Yamazaki, H.; Asano, S.; Emura, T.; Endo, I.; Endo, S.; Ito, S.; Itoh, H.; Ifuku, K.; Konno, O.; Koike, M.; Maruyama, K.; Niki, K.; Niwa, K.; Okuno, H.; Sakaguchi, A.; Sasaki, T.; Suda, T.; Sumi, Y.; Takeya, M.; Terasawa, T.; Uchida, H.; Yamashita, H.; Yoshida, K.

    1994-01-01

    Quasi-free K + photo-production in the 12 C(γ,K + ) reaction has been investigated in a photon energy range of 0.7-1.1GeV. Differential cross sections for the quasi-free process of the 12 C(γ,K + ) reaction have been obtained and they are compared with a calculation of a quasi-free K + photo-production. The effective proton number Z eff =4.2±0.6 obtained from the experiment was in good agreement with a calculation of a semi-classical attenuation model. ((orig.))

  2. Photoproduction with a leading proton at HERA

    International Nuclear Information System (INIS)

    Adloff, C.; Andreev, V.; Andrieu, B.; Anthonis, T.; Arkadov, V.; Astvatsatourov, A.; Ayyaz, I.; Babaev, A.; Baehr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bate, P.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Benisch, T.; Berger, Ch.; Berndt, T.; Bizot, J.C.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broeker, H.-B.; Brown, D.P.; Brueckner, W.; Bruel, P.; Bruncko, D.; Buerger, J.; Buesser, F.W.; Bunyatyan, A.; Burkhardt, H.; Burrage, A.; Buschhorn, G.; Campbell, A.J.; Cao, J.; Carli, T.; Caron, S.; Chabert, E.; Clarke, D.; Clerbaux, B.; 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.; Dixon, P.; Dodonov, V.; Dowell, J.D.; Droutskoi, 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.; Fleming, Y.H.; Fluegge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Foster, J.M.; Franke, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, J.; Gerhards, R.; Ghazaryan, S.; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goodwin, C.; Grab, C.; Graessler, H.; Greenshaw, T.; Grindhammer, G.; Hadig, T.; Haidt, D.; Hajduk, L.; 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.; Hladky, J.; Hoeting, P.; Hoffmann, D.; Horisberger, R.; Hurling, S.; Ibbotson, M.; Issever, C.; Jacquet, M.; Jaffre, M.; Janauschek, L.; Jansen, D.M.; Janssen, X.; Jemanov, V.; Joensson, L.; Johnson, D.P.; Jones, M.A.S.; Jung, H.; Kaestli, H.K.; 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.; Knies, G.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Kotelnikov, S.K.; Koutouev, R.; Koutov, A.; Krasny, M.W.; Krehbiel, H.; Kroseberg, J.; Krueger, K.; Kuepper, A.; Kuhr, T.; Kurca, T.; Lahmann, R.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, 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.; Lueders, S.; Lueke, D.; Lytkin, L.; Magnussen, N.; Mahlke-Krueger, H.; Malden, N.; Malinovski, E.; Malinovski, I.; Maracek, R.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.-U.; Martyniak, J.; Maxfield, S.J.; Mehta, A.; Meier, K.; Merkel, P.; Meyer, A.B.; Meyer, H.; Meyer, J.; Meyer, P.-O.; Mikocki, S.; Milstead, D.; Mkrtchyan, T.; Mohr, R.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Mueller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, Th.; Nellen, G.; Newman, P.R.; Nicholls, T.C.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Nunnemann, T.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Perez, E.; Phillips, J.P.; Pitzl, D.; Poeschl, R.; Potachnikova, I.; Povh, B.; Rabbertz, K.; Raedel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Riess, S.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Royon, C.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Scheins, J.; Schilling, F.-P.; Schleper, P.; Schmidt, D.; Schmidt, D.; Schmitt, S.; Schoeffel, L.; Schoening, A.; Schoerner, T.; Schroeder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Shekelyan, V.; Sheviakov, I.; Shtarkov, L.N.; Sievers, P.; Sirois, Y.; Sloan, T.; Smirnov, P.; Solochenko, V.; Soloviev, Y.; Spaskov, V.; Specka, A.; Spitzer, H.; Stamen, R.; Steinhart, J.; Stella, B.; Stellberger, A.; Stiewe, J.; Straumann, U.; Struczinski, W.; Swart, M.; Tasevsky, M.; Tchernyshov, V.; Tchetchelnitski, S.; Thompson, G.; Thompson, P.D.; Tobien, N.; Traynor, D.; Truoel, P.; Tsipolitis, G.; Tsuri n, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vassiliev, S.; Vazdik, Y.; Vichnevski, A.; Wacker, K.; Wallny, R.; Walter, T.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; Werner, M.; White, G.; Wiesand, S.; Wilksen, T.; Winde, M.; Winter, G.-G.; Wissing, Ch.; Wobisch, M.; Wollatz, H.; Wuensch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; Zsembery, J.; Nedden, M. zur

    2001-01-01

    The total cross section for the photoproduction process with a leading proton in the final state has been measured at γp centre-of-mass energies W of 91, 181 and 231 GeV. The measured cross sections apply to the kinematic range with the transverse momentum of the scattered proton restricted to p T ≤0.2 GeV and 0.68≤z≤0.88, where z=E p '/E p is the scattered proton energy normalised to the beam energy. The cross section dσ γp→Xp' (W,z)/dz is observed to be independent of W and z within the measurement errors and amounts to (8.05±0.06 (stat)±0.89 (syst)) μb on average. The data are well described by a Triple Regge model in which the process is mediated by a mixture of exchanges with an effective Regge trajectory of intercept α i (0)=0.33±0.04 (stat)±0.04 (syst). The total cross section for the interaction of the photon with this mixture (γα i →X) can be described by an effective trajectory of intercept α k (0)=0.99±0.01 (stat)±0.05 (syst). Predictions based on previous triple Regge analyses of pp→pX data assuming vertex factorisation are broadly consistent with the γp data. The measured cross sections are compared with deep inelastic scattering leading proton data in the same region of z and p T for photon virtuality Q 2 >2.5 GeV 2 . The ratio of the cross section for leading proton production to the total cross section is found to rise with Q 2

  3. Hydrogen detector

    International Nuclear Information System (INIS)

    Kumagaya, Hiromichi; Yoshida, Kazuo; Sanada, Kazuo; Chigira, Sadao.

    1994-01-01

    The present invention concerns a hydrogen detector for detecting water-sodium reaction. The hydrogen detector comprises a sensor portion having coiled optical fibers and detects hydrogen on the basis of the increase of light transmission loss upon hydrogen absorption. In the hydrogen detector, optical fibers are wound around and welded to the outer circumference of a quartz rod, as well as the thickness of the clad layer of the optical fiber is reduced by etching. With such procedures, size of the hydrogen detecting sensor portion can be decreased easily. Further, since it can be used at high temperature, diffusion rate is improved to shorten the detection time. (N.H.)

  4. Inclusive photoproduction of {rho}{sup 0}, K{sup *0} and {phi} mesons at HERA

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-12-15

    Inclusive non-diffractive photoproduction of {rho}(770){sup 0}, K{sup *}(892){sup 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 0.5presented as a function of transverse momentum and rapidity, and are compared to the predictions of hadroproduction models. (orig.)

  5. π minus Photoproduction on neutrons via the inverse reaction or Cebaf at LAMPF

    International Nuclear Information System (INIS)

    Nefkens, B.M.K.

    1989-01-01

    The investigation of π minus photoproduction on neutrons is presented. The double experimental handicap of the lack of a free neutron target and a monochromatic photon beam was overcome in the π minus-proton channel by measuring the inverse process, or radiative exchange π minus + p → γ+n. The detector configuration is shown and the experimental results are discussed. The energy regions included the δ (1232), the P 11 (1440) and the S 11 (1535). Comparison between data concerning the radiative exchange cross sections is shown

  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.; Deak, 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, Samvel; 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.; Jonsson, L.; Jung, Andreas Werner; 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.; 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.; 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, Matthias Ulrich; Mudrinic, M.; Muller, K.; Murin, 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.; Salek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; Smiljanic, Ivan; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, Arnd E.; 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.

    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 0.5presented as a function of transverse momentum and rapidity, and are compared to the predictions of hadroproduction models.

  7. 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.

  8. 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.

  9. Measurement of Charm and Beauty Photoproduction at HERA using D* mu Correlations

    CERN Document Server

    Aktas, A.; Anthonis, T.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bahr, 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.; Busser, 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, Guenter; 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.; Formanek, J.; Franke, G.; Frising, G.; Frisson, T.; Gabathuler, E.; Garutti, E.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; 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.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Koutouev, R.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, 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.; Luke, 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, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul 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.; Placakyte, 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.; Schatzel, S.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, 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.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zimmermann, J.; Zohrabyan, H.; 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.

  10. High-performance liquid chromatography method for the determination of hydrogen peroxide present or released in teeth bleaching kits and hair cosmetic products.

    Science.gov (United States)

    Gimeno, Pascal; Bousquet, Claudine; Lassu, Nelly; Maggio, Annie-Françoise; Civade, Corinne; Brenier, Charlotte; Lempereur, Laurent

    2015-03-25

    This manuscript presents an HPLC/UV method for the determination of hydrogen peroxide present or released in teeth bleaching products and hair products. The method is based on an oxidation of triphenylphosphine into triphenylphosphine oxide by hydrogen peroxide. Triphenylphosphine oxide formed is quantified by HPLC/UV. Validation data were obtained using the ISO 12787 standard approach, particularly adapted when it is not possible to make reconstituted sample matrices. For comparative purpose, hydrogen peroxide was also determined using ceric sulfate titrimetry for both types of products. For hair products, a cross validation of both ceric titrimetric method and HPLC/UV method using the cosmetic 82/434/EEC directive (official iodometric titration method) was performed. Results obtained for 6 commercialized teeth whitening products and 5 hair products point out similar hydrogen peroxide contain using either the HPLC/UV method or ceric sulfate titrimetric method. For hair products, results were similar to the hydrogen peroxide content using the cosmetic 82/434/EEC directive method and for the HPLC/UV method, mean recoveries obtained on spiked samples, using the ISO 12787 standard, ranges from 100% to 110% with a RSDhydrogen peroxide contents higher than the regulated limit. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. radiation-accompanied π0 photoproduction on the proton

    International Nuclear Information System (INIS)

    Schumann, S.

    2007-01-01

    This thesis describes an experiment for the radiation-accompanied π 0 photoproduction on the proton int the energy range of the Δ resonance. With the detector system from Crystal Ball (672 NaI(Tl) crystals) and the TAPS forward wall (510 BaF 2 modules) and the space-angle covering of this arrangement of nearly 4π the reaction γp→pπ 0 γ' could be studied with high statistics; furthermore the use of a both linearly and circularly polarized photon beam allowed beside the study of unpolarized cross sections also the consideration of polarization observables like the photon asymmetry of the π 0 meson or the single-spin asymmetry of the photon γ'. The experiment described hera was performed with a real photon beam, which was produced via the bremsstrahlung of the MAMI electron beam with energies of E 0 =883 MeV respectively E 0 =570 MeV on a diamond respectively iron radiator. By the momentum determination in a magnetic spectrometer (Glasgow-Mainz-Tagger) and a coincidence analysis with the product detectors Crystal Ball and TAPS this photon beam was energy-marked and allowed by this together with the liquid-hydrogen target a precise knowledge of the incident side of the photoinduced reactions. For the study of the reaction γp→pπ 0 γ' all final-state particle were detected in the detector systems with their complete energy and momentum informations. With the data analysis described in this thesis about 27,000 events of the radiation-accompanied π 0 production could be reconstructed, from which in connection with a simulation of the detector and analysis efficiency energy and angular differential cross sections of the photon γ', the π 0 meson, as well as the proton were determined in each three intervals of the beam energy (ω=325..375 MeV, ω=375..425 MeV, and ω=425..475 MeV). In the energy range between 325 MeV and 475 MeV for the total cross section values of about 60 nb to 80 nb result. Additionally the photon asymmetry (linearly polarized photons

  12. 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.

  13. Phi Photoproduction in a Coupled-Channel Approach

    NARCIS (Netherlands)

    Ozaki, S.; Nagahiro, H.; Hosaka, A.; Scholten, O.

    2010-01-01

    We investigate photoproduction of phi-mesons off protons within a coupled-channel effective-Lagrangian method which is based on the K-matrix approach. We take into account pi N, rho N, eta N, K Lambda, K Sigma, K Lambda (1520) and phi N channels. Especially we focus on K Lambda(1520) channel. We

  14. Search for Evidence of Photoproduction of Higher Twist QCD Events at Experiment 683 at Fermi National Accelerator Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Traynor, Michael M. [Rice Univ., Houston, TX (United States)

    1996-01-01

    Experiment 683 at Fermilab Wide Band Photon Laboratory observed events via $\\gamma P \\to jets$ during the 1991-1992 fixed target run. The present analysis attempted to observe the higher-twist subprocess in QCD using that data to measure the $p_\\perp$ spectrum via a clustering algorithm tuned to optimize the distinctive topology of higher-twist events. Results indicate a substantial $k_\\perp$ promotion effect at lower $p_\\perp$ and a significant NLO contribution to the photoproduction.

  15. Measurement of $J/\\psi$ photoproduction in UPC of PbPb at 5 TeV

    CERN Document Server

    Dobishuk, Vasyl

    2017-01-01

    A first look at $J/\\psi$ photoproduction in ultra-peripheral PbPb collisions at center-of-mass energy $\\sqrt{s_{NN}} = 5\\, \\mathrm{TeV}$ with the LHCb experiment is presented. The measurement is based on a low multiplicity data sample of $J/\\psi$ mesons, decaying through the dimuon channel. An analysis of signal contamination as well as a method of two stage fit to obtain yield of coherent $J/\\psi$ is described.

  16. Gluon polarization in the nucleon from quasi-real photoproduction of high-pT hadron pairs

    CERN Document Server

    Ageev, E S; Alexandrov, Yu A; Alexeev, G D; Amoroso, A; Badelek, B; Balestra, F; Ball, J; Baum, G; Bedfer, Y; Berglund, P; Bernet, C; Bertini, R; Birsa, R; Bisplinghoff, J; Bordalo, P; Bradamante, Franco; Bravar, A; Bressan, A; Brona, G; Burtin, E; Bussa, M P; Bychkov, V N; Cerini, L; Chapiro, A; Cicuttin, A; Colantoni, M L; Colavita, A A; Costa, S; Crespo, M L; Dalla Torre, S; Das-Gupta, S S; Dedek, N; De Masi, R; Denisov, O Yu; Dhara, L; Díaz, V; Dinkelbach, A M; Dolgopolov, A V; Donskov, S V; Dorofeev, V A; Doshita, N; Duic, V; Dünnweber, W; Ehlers, J; Eversheim, P D; Eyrich, W; Fabro, M; Faessler, Martin A; Falaleev, V; Fauland, P; Ferrero, A; Ferrero, L; Finger, Miroslav H; Finger, M Jr; Fischer, H; Franz, J; Friedrich, J M; Frolov, V; Garfagnini, R; Gautheron, F; Gavrichtchouk, O P; Gerassimov, S G; Geyer, R; Giorgi, M; Gobbo, B; Görtz, S; Gorin, A M; Grajek, O A; Grasso, A; Grube, B; Grünemaier, A; Hannappel, J; Von Harrach, D; Hasegawa, T; Hedicke, S; Heinsius, F H; Hermann, R; Hess, C; Hinterberger, F; Von Hodenberg, M; Horikawa, N; Horikawa, S; D'Hose, N; Ijaduola, R B; Ilgner, C; Ioukaev, A I; Ishimoto, S; Ivanov, O; Iwata, T; Jahn, R; Janata, A; Joosten, R; Jouravlev, N I; Kabuss, E M; Kalinnikov, V; Kang, D; Karstens, F; Kastaun, W; Ketzer, B; Khaustov, G V; Khokhlov, Yu A; Khomutov, N V; Kisselev, Yu V; Klein, F; Koblitz, S; Koivuniemi, J H; Kolosov, V N; Komissarov, E V; Kondo, K; Königsmann, K C; Konoplyannikov, A K; Konorov, I; Konstantinov, V F; Korentchenko, A S; Korzenev, A; Kotzinian, A M; Koutchinski, N A; Kowalik, K L; Kravchuk, N P; Krivokhizhin, V G; Krumshtein, Z; Kühn, R; Kunne, Fabienne; Kurek, K; Ladygin, M E; Lamanna, M; Leberig, M; Le Goff, J M; Lichtenstadt, J; Liska, T; Ludwig, I; Maggiora, A; Maggiora, M; Magnon, A; Mallot, G K; Manuilov, I V; Marchand, C; Marroncle, J; Martin, A; Marzec, J; Matsuda, T; Maksimov, A N; Medved, K S; Meyer, W; Mielech, A; Mikhailov, Yu V; Moinester, M A; Nahle, O; Nassalski, J P; Neliba, S; Neyret, D P; Nikolaenko, V I; Nozdrin, A A; Obraztsov, V F; Olshevskii, A G; Ostrick, M; Padee, A; Pagano, P; Panebianco, S; Panzieri, D; Paul, S; Pereira, H D; Peshekhonov, V D; Piragino, G; Platchkov, S; Platzer, K; Pochodzalla, J; Polyakov, V A; Popov, A A; Pretz, J; Procureur, S; Quintans, C; Ramos, S; Rebourgeard, P C; Reicherz, G; Reymann, J; Rith, K; Rondio, Ewa; Rozhdestvensky, A M; Sadovski, A B; Saller, E; Samoylenko, V D; Sandacz, A; Sans, M; Sapozhnikov, M G; Savin, I A; Schiavon, Paolo; Schill, C; Schmidt, T; Schmitt, H; Schmitt, L; Shevchenko, O Yu; Shishkin, A A; Siebert, H W; Sinha, L; Sissakian, A N; Skachkova, A N; Slunecka, M; Smirnov, G I; Sozzi, F; Srnka, A; Stinzing, F; Stolarski, M; Sugonyaev, V P; Sulc, M; Sulej, R; Takabayashi, N; Tchalishev, V V; Tessarotto, F; Teufel, A; Thers, D; Tkatchev, L G; Toeda, T; Tretyak, V I; Trousov, S; Varanda, M; Virius, M; Vlassov, N V; Wagner, M; Webb, R; Weise, E; Weitzel, Q; Wiedner, U; Wiesmann, M; Windmolders, R; Wirth, S; Wislicki, W; Zanetti, A M; Zaremba, K; Zhao, J; Ziegler, R; Zvyagin, A

    2006-01-01

    We present a determination of the gluon polarization Delta G/G in the nucleon, based on the helicity asymmetry of quasi-real photoproduction events, Q^2 = 0.002 +- 0.019(stat.) +- 0.003(syst.). From this value, we obtain in a leading-order QCD analysis Delta G/G=0.024 +- 0.089(stat.) +- 0.057(syst.) at x_g = 0.095 and mu^2 =~ 3 (GeV}/c)^2.

  17. Study of the Two Pion Photoproduction on Deuterium

    Science.gov (United States)

    Gauss, Lewis P. Graham, Jr.

    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 inter-action 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 γN 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 Δ 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 Acceptance

  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. Tests of QCD Factorisation in the Diffractive Production of Dijets in Deep-Inelastic Scattering and 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, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Busser, F.W.; 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.; de Boer, Y.; Delcourt, B.; Del Degan, M.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; 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.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B.R.; Grindhammer, G.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Jacquet, M.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Lytkin, L.; Makankine, A.; Malinovski, E.; Marage, P.; Marti, Ll.; 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.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul 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.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; 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.; Schatzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smiljanic, Ivan; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Steder, M.; Stella, B.; Stiewe, J.; Stoilov, A.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Traynor, D.; Trinh, T.N.; Truol, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Usik, A.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmerman, J.; Zimmerman, T.; Zohrabyan, H.; Zomer, F.

    2007-01-01

    Measurements are presented of differential dijet cross sections in diffractive photoproduction (Q^2 e X Y, in which the system X, containing at least two jets, is separated from a leading low-mass proton remnant system Y by a large rapidity gap. The dijet cross sections are compared with NLO QCD predictions based on diffractive parton densities previously obtained from a QCD analysis of inclusive diffractive DIS cross sections by H1. In DIS, the dijet data are well described, supporting the validity of QCD factorisation. The diffractive DIS dijet data are more sensitive to the diffractive gluon density at high fractional parton momentum than the measurements of inclusive diffractive DIS. In photoproduction, the predicted dijet cross section has to be multiplied by a factor of approximately 0.5 for both direct and resolved photon interactions to describe the measurements. The ratio of measured dijet cross section to NLO prediction in photoproduction is a factor 0.5+-0.1 smaller than the same ratio in DIS. This...

  20. Dynamic Time-Resolved Chirped-Pulse Rotational Spectroscopy of Vinyl Cyanide Photoproducts in a Room Temperature Flow Reactor

    Science.gov (United States)

    Zaleski, Daniel P.; Prozument, Kirill

    2017-06-01

    Chirped-pulsed (CP) Fourier transform rotational spectroscopy invented by Brooks Pate and coworkers a decade ago is an attractive tool for gas phase chemical dynamics and kinetics studies. A good reactor for such a purpose would have well-defined (and variable) temperature and pressure conditions to be amenable to accurate kinetic modeling. Furthermore, in low pressure samples with large enough number of molecular emitters, reaction dynamics can be observable directly, rather than mediated by supersonic expansion. In the present work, we are evaluating feasibility of in situ time-resolved CP spectroscopy in a room temperature flow tube reactor. Vinyl cyanide (CH_2CHCN), neat or mixed with inert gasses, flows through the reactor at pressures 1-50 μbar (0.76-38 mTorr) where it is photodissociated by a 193 nm laser. Millimeter-wave beam of the CP spectrometer co-propagates with the laser beam along the reactor tube and interacts with nascent photoproducts. Rotational transitions of HCN, HNC, and HCCCN are detected, with ≥10 μs time-steps for 500 ms following photolysis of CH_2CHCN. The post-photolysis evolution of the photoproducts' rotational line intensities is investigated for the effects of rotational and vibrational thermalization of energized photoproducts. Possible contributions from bimolecular and wall-mediated chemistry are evaluated as well.

  1. Ultraviolet degradation of procymidone -structuralcharacterization by gas chromatography coupled with masss spectrometry and potential toxicity of photoproducts using in silico tests

    International Nuclear Information System (INIS)

    Rifai, A.; Jaber, F.; Souissi, Y.; Genty, Ch.; Bourcier, S.; Bouchonnet, S.; Clavaguera, C.

    2013-01-01

    RATIONALE: Procymidone is a dicarboximide fungicide mainly used for vineyard protection but also for different crops. The structural elucidation of by-products arising from the UV-visible photodegradation of procymidone has been investigated by gas chromatography coupled with mass spectrometry. The potential toxicities of photoproducts were estimated by in silico tests. METHODS: Aqueous solutions of procymidone were irradiated for up to 90 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out on a gas chromatograph coupled with an ion trap mass spectrometer operated in electron ionization and methanol positive chemical ionization. Multistage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. Toxicities of byproducts were estimated using the QSAR T.E.S.T. program. RESULTS: Sixteen photoproducts were investigated. Chemical structures were proposed mainly based on the interpretation of multistage CID experiments, but also on their relative retention times and kinetics data. These structures enabled photodegradation pathways to be suggested. Only three photoproducts remain present after 90 min of irradiation. Among them, 3,5-dichloroaniline presents a predicted rat LD50 toxicity about ten times greater than that of procymidone. CONCLUSIONS: 3,5-Dichloroaniline is the only photoproduct reported in previous articles. Eight by-products among the sixteen characterized might be as toxic, if not more, than procymidone itself considering the QSAR-predicted rat LD 50. (author)

  2. Data compilation of single pion photoproduction below 2 GeV

    International Nuclear Information System (INIS)

    Ukai, K.; Nakamura, T.

    1984-09-01

    An updated data compilation on single pion photoproduction experiment below 2 GeV is presented. This data bank includes not only the data of single pion photoproduction processes but also those of the proton Compton scattering (γp → γp) and the inverse process of the γn → π - p (π - p → γn). The number of total data points are 6240 for γp → π + n, 5715 for γp → π 0 p, 2835 for γn → π - p, 177 for γn → π 0 n, 669 for γp → γp, and 112 for π - p → γn processes. The compiled data are stored in the central computer (FACOM M-380R) of the Institute of Nuclear Study, University of Tokyo, for direct use of this data bank and on magnetic tapes with the standard label for other laboratories. The FACOM computer is compatible with an IBM 370 series or IBM 303X or 308X series machines. The data on the magnetic tapes are available on request. (Kato, T.)

  3. 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)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-08-15

    Three- and four-jet final states have been measured in photoproduction at HERA using the ZEUS detector with an integrated luminosity of 121 pb{sup -1}. The results are presented for jets with transverse energy E{sup jet}{sub T}>6 GeV and pseudorapidity vertical stroke {eta}{sup jet} vertical stroke <2.4, in the kinematic region given by the virtuality of the photon Q{sup 2}<1 GeV{sup 2} and the inelasticity 0.2{<=}y{<=}0.85 and in two mass regions defined as 25{<=}M{sub nj}<50 GeV and M{sub nj}{>=}50 GeV, where M{sub 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 O({alpha}{alpha}{sup 2}{sub s}) perturbative QCD calculation. (orig.)

  5. Measurement of dijet photoproduction for events with a leading neutron at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, B.

    2009-09-01

    Differential cross sections for dijet photoproduction and this process in association with a leading neutron, e + +p→e + +jet+jet+X(+n), have been measured with the ZEUS detector at HERA using an integrated luminosity of 40 pb -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 L , and of its transverse momentum squared, p T 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 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)

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

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2007-08-01

    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 jet T >6 GeV and pseudorapidity vertical stroke η jet vertical stroke 2 2 and the inelasticity 0.2≤y≤0.85 and in two mass regions defined as 25≤M nj nj ≥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 O(αα 2 s ) perturbative QCD calculation. (orig.)

  7. Exclusive $\\rho^0$ Meson Photoproduction with a Leading Neutron at HERA

    CERN Document Server

    Andreev, V.; Begzsuren, K.; Belousov, A.; Bolz, A.; Boudry, V.; Brandt, G.; Brisson, V.; Britzger, D.; Buniatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Cerny, K.; Chekelian, V.; Contreras, J.G.; Cvach, J.; Dainton, J.B.; Daum, K.; Diaconu, C.; Dobre, M.; Dodonov, V.; Eckerlin, G.; Egli, S.; Elsen, E.; Favart, L.; Fedotov, A.; Feltesse, J.; Ferencei, J.; Fleischer, M.; Fomenko, A.; Gabathuler, E.; Gayler, J.; Ghazaryan, S.; Goerlich, L.; Gogitidze, N.; Gouzevitch, M.; Grab, C.; Grebenyuk, A.; Greenshaw, T.; Grindhammer, G.; Haidt, D.; Henderson, R.C.W.; Hladký, J.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jung, H.; Kapichine, M.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kogler, R.; Kostka, P.; Kretzschmar, J.; Krüger, K.; Landon, M.P.J.; Lange, W.; Laycock, P.; Lebedev, A.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Malinovski, E.; Martyn, H.-U.; Maxfield, S.J.; Mehta, A.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Morozov, A.; Müller, K.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nowak, G.; Olsson, J.E.; Ozerov, D.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Plačakytė, R.; Pokorny, B.; Polifka, R.; Povh, B.; Radescu, V.; Raicevic, N.; Ravdandorj, T.; Reimer, P.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Rusakov, S.; Šálek, D.; Sankey, D.P.C.; Sauter, M.; Sauvan, E.; Schmitt, S.; Schoeffel, L.; Schöning, A.; Sefkow, F.; Shushkevich, S.; Soloviev, Y.; Sopicki, P.; South, D.; Spaskov, V.; Specka, A.; Steder, M.; Stella, B.; Straumann, U.; Sykora, T.; Thompson, P.D.; Traynor, D.; Truöl, P.; Tsakov, I.; Tseepeldorj, B.; Turnau, J.; Valkárová, A.; Vallée, C.; Van Mechelen, P.; Vazdik, Y.; Wegener, D.; Wünsch, E.; Žáček, J.; Zhang, Z.; Žlebčík, R.; Zohrabyan, H.; Zomer, F.

    2016-01-23

    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 $\\sqrt{s}=319$ GeV and correspond to an integrated luminosity of $1.16$ pb$^{-1}$. The $\\rho^0$ mesons with transverse momenta $p_T0.35$, are detected in the Forward Neutron Calorimeter. The phase space of the measurement is defined by the photon virtuality $Q^2 < 2$ GeV$^2$, the total energy of the photon-proton system $20 < W_{\\gamma p} < 100$ GeV and the polar angle of the leading neutron $\\theta_n < 0.75$ mrad. The cross section of the reaction $\\gamma p \\to \\rho^0 n \\pi^+$ is 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 se...

  8. Diffractive photoproduction of D*±(2010) at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2007-03-01

    Diffractive photoproduction of D *± (2010) mesons was measured with the ZEUS detector at the ep collider HERA, using an integrated luminosity of 78.6 pb -1 . The D * mesons were reconstructed in the kinematic range: transverse momentum p T (D * )>1.9 GeV and pseudorapidity vertical stroke η(D * ) vertical stroke *+ → D 0 π + s followed by D 0 → K - π + (+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 130 2 2 , in two ranges of the Pomeron fractional momentum x P P *± (2010) photoproduction 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.)

  9. Role of nucleon resonance excitation in φ meson photoproduction

    International Nuclear Information System (INIS)

    Zhao, Q.; Didelez, J.P.; Guidal, M.; Saghai, B.

    2000-01-01

    The resonance effects are investigated in the φ meson photoproduction near threshold through a quark model approach with an effective Lagrangian. The diffractive contribution is consistently estimated by the t-channel Pomeron exchange. Another non-diffractive process, t-channel π 0 exchange is also included. The numerical result shows that the Pomeron exchange plays dominant role in the φ meson photoproduction, while the cross sections of the non-diffractive processes, i.e., s- and u-channel excitations, and t-channel π 0 exchange, are quite small. In the polarization observables, we find that large asymmetries are produced in the backward direction by the interferences from the s- and u-channel resonances, while in the forward direction, only very small asymmetries are generated. Meanwhile, we find that the effects from the π 0 exchange are generally negligible. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-12-15

    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{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{sub T}{sup C}UT. 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. (orig.)

  11. Pion photoproduction cross section at large momentum transfer

    Energy Technology Data Exchange (ETDEWEB)

    Sjoegren, Johan [Univ. of Glasgow, Scotland, United Kingdom

    2015-02-27

    The Real Compton Scattering experiment was performed in Hall A at the Thomas Jefferson National Accelerator Facility. It was designed to measure, for Compton scattering and π0-photoproduction, the differential cross section over a range of kinematic points and the polarisation transfer to the proton at a single kinematic point. The full range of the experiment in Mandelstam variables t and s was 1.6-6.46 GeV2 and 4.82-10.92 GeV2 respectively with beam energies of 2-6 GeV. The motivation for the experiment is to test the cross section and polarisation transfer predictions of perturbative QCD versus that of predictions from Generalised Parton Distribution models. This thesis will give an overview of the pertinent theory, experimental setup in Hall A and the extracting of the π0-photoproduction cross section.

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

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2006-12-01

    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 T C UT. 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. (orig.)

  13. Near-threshold photoproduction of {phi} mesons from deuterium

    Energy Technology Data Exchange (ETDEWEB)

    Qian, X., E-mail: xqian@caltech.ed [Duke University, Durham, NC 27708 (United States); Kellogg Radiation Laboratory, California Institute of Technology, CA 91125 (United States); Chen, W.; Gao, H. [Duke University, Durham, NC 27708 (United States); Hicks, K. [Ohio University, Athens, OH 45701 (United States); Kramer, K. [Duke University, Durham, NC 27708 (United States); Laget, J.M. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Mibe, T. [Ohio University, Athens, OH 45701 (United States); Qiang, Y. [Duke University, Durham, NC 27708 (United States); Stepanyan, S. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Tedeschi, D.J. [University of South Carolina, Columbia, SC 29208 (United States); Xu, W. [Massachusetts Institute of Technology, Cambridge, MA 02139-4307 (United States); Adhikari, K.P.; Amaryan, M. [Old Dominion University, Norfolk, VA 23529 (United States); Anghinolfi, M. [INFN, Sezione di Genova, 16146 Genova (Italy); Ball, J. [CEA, Centre de Saclay, Irfu/Service de Physique Nucleaire, 91191 Gif-sur-Yvette (France); Battaglieri, M. [INFN, Sezione di Genova, 16146 Genova (Italy); Batourine, V. [Thomas Jefferson National Accelerator Facility, Newport News, VA 23606 (United States); Bedlinskiy, I. [Institute of Theoretical and Experimental Physics, Moscow 117259 (Russian Federation); Bellis, M. [Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Biselli, A.S. [Fairfield University, Fairfield, CT 06824 (United States); Carnegie Mellon University, Pittsburgh, PA 15213 (United States)

    2011-02-07

    We report the first, kinematically-complete measurement of the differential cross section of {phi}-meson photoproduction from deuterium near the production threshold for a proton using the CLAS detector and a tagged-photon beam in Hall B at Jefferson Lab. The measurement was carried out by a triple coincidence detection of a proton, K{sup +} and K{sup -} near the theoretical production threshold of 1.57 GeV. The extracted differential cross sections (d{sigma})/(dt) for the initial photon energy range of 1.65-1.75 GeV are consistent with predictions based on a quasifree mechanism. Our finding is different from recent LEPS results on {phi}-meson photoproduction from deuterium in a similar incident photon energy range, but in a different momentum transfer region.

  14. 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 $\\simeq$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 $\\simeq$ 40 msr and consists of four bending magnets interspaced by sets of drift chambers, counter hodoscopes and photon detectors. The momentum resolution...

  15. Dijet angular distributions in direct and resolved photoproduction at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1996-05-01

    Jet photoproduction, where the two highest transverse energy (E T jet ) jets have E T jet 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. They agree with the predictions of QCD calculations, where the different angular distributions reflect the different spins of the quark and gluon exchanged in the hard subprocess. (orig.)

  16. Pseudoscalar meson photoproduction: from known to undiscovered resonances

    Energy Technology Data Exchange (ETDEWEB)

    Saghai, B. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee; Tabakin, F.

    1996-12-31

    The role of dynamics in spin observables for pseudoscalar meson photoproduction is investigated using a density matrix approach in a multipole truncated framework. Extraction of novel rules for {gamma}p {yields} {pi}{sup +}n, K{sup +}{Lambda} and {eta}p reactions based on resonance dominance, and on other broad and reasonable dynamical assumptions, are discussed. Observables that are particularly sensitive to missing nucleonic resonances predicted by quark-based approaches, are singled out. (authors). 25 refs.

  17. Autumn photoproduction of carbon monoxide in Jiaozhou Bay, China

    Science.gov (United States)

    Ren, Chunyan; Yang, Guipeng; Lu, Xiaolan

    2014-06-01

    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 dissolved 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 31.98 μmol 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.

  18. On rescattering in meson coherent photoproduction on nuclei

    International Nuclear Information System (INIS)

    Starkov, N.I.; Tsarev, V.A.

    1978-01-01

    Screening corrections for cross section of π deg-meson photoproduction on He nuclei were calculated: γ + 4 He → π 0 + 4 He. On the basis of the Glauber theory the effect of meson rescattering in the range of small transferred pulses (t) 2 and ''mean'' photon energies 2 2 ), determined by interference of members of one-and twofold interactions. The results are compared with those obtained by other authors

  19. Coherent pion photoproduction from deuterium at intermediate energies

    International Nuclear Information System (INIS)

    Osland, P.; Rej, A.K.

    1975-12-01

    The coherent photoproduction of neutral pions on deuterons is studied at energies around the (3,3) resonance and discuss the effects of the Fermi motion, rescattering and kinematical approximations. The results are very dependent upon what kinematical approximations one adopts for the impulse approximation term, which dominates up to very large angles. Allowing for this uncertainty in the kinematics, our results are in good agreement with the most recent experimental data

  20. Neutral pion photoproduction off nucleons and nuclei near threshold

    International Nuclear Information System (INIS)

    Kamalov, S.S.; Chumbalov, A.A.

    1989-01-01

    The modern experimental data on the coherent photoproduction off 4 He, 6 Li, 12 C, 16 O, 40 Ca and 208 Pb 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

  1. Nondiffraction photoproduction of vector mesons and the photon structure function

    International Nuclear Information System (INIS)

    Badalyan, R.G.; Gulkanyan, H.R.

    1988-01-01

    In the framework of the recombination model of hadron production a self-consistent description of the available data on the inclusive spectra of the nondiffraction photoproduction of vector mesons in the fragmentation region of photons at high energies is obtained. The parameters of parton distribution in the hadron component of a photon are estimated and its structure is compared with the measurements of the photon structure function in γγ-interactions at low Q 2 . 15 refs.; 2 figs.; 1 tab

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

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-01-01

    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-p T jets (p T >6 GeV, η T 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.)

  3. Pseudoscalar meson photoproduction: from known to undiscovered resonances

    International Nuclear Information System (INIS)

    Saghai, B.; Tabakin, F.

    1996-01-01

    The role of dynamics in spin observables for pseudoscalar meson photoproduction is investigated using a density matrix approach in a multipole truncated framework. Extraction of novel rules for γp → π + n, K + Λ and ηp reactions based on resonance dominance, and on other broad and reasonable dynamical assumptions, are discussed. Observables that are particularly sensitive to missing nucleonic resonances predicted by quark-based approaches, are singled out. (authors)

  4. Strangeness photoproduction at the BGO-OD experiment

    Energy Technology Data Exchange (ETDEWEB)

    Jude, Thomas [Physikalisches Institut, Bonn University (Germany); Collaboration: BGO-OD-Collaboration

    2016-07-01

    The BGO-OD experiment at the ELSA accelerator facility uses an energy tagged bremstrahlung photon beam to investigate the internal structure of the nucleon. The setup consists of a highly segmented BGO calorimeter surrounding the target, with a particle tracking magnetic spectrometer at forward angles. Compared to constituent quark models (CQMs), models including psuedoscalar meson-baryon interactions have had improved success in describing baryon excitation spectra. For example, the Λ(1405) appears to be dynamically generated from meson-baryon interactions at least to some extent. Vector-meson baryon interactions have also been predicted to dynamically generate states, which may have been observed in photoproduction reactions. BGO-OD is ideal for investigating low momentum transfer processes due to the acceptance and high momentum resolution at forward angles. This enables the investigation of degrees of freedom not derived from CQMs, and in particular, strangeness photoproduction where t-channel exchange mechanisms play a dominant role. With the first major data taking periods for BGO-OD complete, an extensive programme for the investigation of associated strangeness photoproduction has begun.

  5. 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.

  6. {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.

  7. Dijets in photoproduction and soft multiparton interactions at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Naumann, S.

    2007-07-15

    Dijet events in photoproduction at HERA have been studied using data collected with the ZEUS detector in the period 1998-2000 that correspond to an integrated luminosity of 81.7 pb{sup -1}. The events have been selected in a kinematic region defined by restricting the virtuality of the incoming photon, Q{sup 2}, to Q{sup 2}<1 GeV{sup 2} and its inelasticity, y, to 0.214 GeV and E{sub T,2}>11 GeV in each event. Cross sections measured for this inclusive dijet sample have been compared to results obtained in data from the 1996-1997 period. Another sample of dijet events has been obtained using the transverse-energy requirements E{sub T,1}>10 GeV and E{sub T,2}>8 GeV, demanding additionally that the two jets are roughly back-to-back in the azimuthal plane and have almost equal transverse energies and that no third hard jet is found in the event. All results have been compared to leading-order Monte Carlo predictions. The transverse energy in the region between the jets shows a large sensitivity to multiparton interactions, allowing parameters of the corresponding models to be tested. The measurement suggests that multiparton interactions are needed to describe the data. The analysis presented here contains the most comprehensive study of soft multiparton interactions at ZEUS to date. (orig.)

  8. 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.

  9. Energy-independent multipole analysis of single-pion photoproduction from protons

    Energy Technology Data Exchange (ETDEWEB)

    Get' man, V.A.; Sanin, V.M.; Telegin, Y.N.; Shalatskii, S.V.

    1983-08-01

    For the first time photoproduction multipole amplitudes are evaluated unambiguously on the basis of new experimental data on pion photoproduction from protons and the latest ..pi..N scattering phase shifts. The multipole amplitudes obtained are compared with the results of previous multipole analyses and dispersion-relation predictions.

  10. Energy-independent multipole analysis of single-pion photoproduction from protons

    International Nuclear Information System (INIS)

    Get'man, V.A.; Sanin, V.M.; Telegin, Y.N.; Shalatskii, S.V.

    1983-01-01

    For the first time photoproduction multipole amplitudes are evaluated unambiguously on the basis of new experimental data on pion photoproduction from protons and the latest πN scattering phase shifts. The multipole amplitudes obtained are compared with the results of previous multipole analyses and dispersion-relation predictions

  11. Photoproduction of isolated photons, inclusively and with a jet, at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Abramowicz, H. [Raymond and Beverly Sackler Faculty of Exact Sciences, School of Physics, Tel Aviv University, Tel Aviv (Israel); Abt, I. [Max-Planck-Institut für Physik, München (Germany); Adamczyk, L. [AGH—University of Science and Technology, Faculty of Physics and Applied Computer Science, Krakow (Poland); Adamus, M. [National Centre for Nuclear Research, Warsaw (Poland); Aggarwal, R. [Panjab University, Department of Physics, Chandigarh (India); Antonelli, S. [University and INFN Bologna, Bologna (Italy); Arslan, O. [Physikalisches Institut der Universität Bonn, Bonn (Germany); Aushev, V. [Institute for Nuclear Research, National Academy of Sciences, Kyiv (Ukraine); Department of Nuclear Physics, National Taras Shevchenko University of Kyiv, Kyiv (Ukraine); Aushev, Y. [Department of Nuclear Physics, National Taras Shevchenko University of Kyiv, Kyiv (Ukraine); Bachynska, O. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Barakbaev, A.N. [Institute of Physics and Technology of Ministry of Education and Science of Kazakhstan, Almaty (Kazakhstan); Bartosik, N.; Behnke, O.; Behr, J.; Behrens, U. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Bertolin, A. [INFN Padova, Padova (Italy); Bhadra, S. [Department of Physics, York University, Ontario, M3J 1P3 (Canada); Bloch, I. [Deutsches Elektronen-Synchrotron DESY, Zeuthen (Germany); Bokhonov, V. [Institute for Nuclear Research, National Academy of Sciences, Kyiv (Ukraine); Boos, E.G. [Institute of Physics and Technology of Ministry of Education and Science of Kazakhstan, Almaty (Kazakhstan); and others

    2014-03-07

    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{sup −1}. Differential cross sections are presented in the isolated-photon transverse-energy and pseudorapidity ranges 6presented 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.

  12. Photoproduction of isolated photons, inclusively and with a jet, 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, Krakow (Poland). Faculty of Physics and Applied Computer Science; Collaboration: ZEUS Collaboration; and others

    2013-12-15

    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{sup -1}. Differential cross sections are presented in the isolated-photon transverse-energy and pseudorapidity ranges 6presented 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.

  13. Hydrogen Embrittlement

    Science.gov (United States)

    Woods, Stephen; Lee, Jonathan A.

    2016-01-01

    Hydrogen embrittlement (HE) is a process resulting in a decrease in the fracture toughness or ductility of a metal due to the presence of atomic hydrogen. In addition to pure hydrogen gas as a direct source for the absorption of atomic hydrogen, the damaging effect can manifest itself from other hydrogen-containing gas species such as hydrogen sulfide (H2S), hydrogen chloride (HCl), and hydrogen bromide (HBr) environments. It has been known that H2S environment may result in a much more severe condition of embrittlement than pure hydrogen gas (H2) for certain types of alloys at similar conditions of stress and gas pressure. The reduction of fracture loads can occur at levels well below the yield strength of the material. Hydrogen embrittlement is usually manifest in terms of singular sharp cracks, in contrast to the extensive branching observed for stress corrosion cracking. The initial crack openings and the local deformation associated with crack propagation may be so small that they are difficult to detect except in special nondestructive examinations. Cracks due to HE can grow rapidly with little macroscopic evidence of mechanical deformation in materials that are normally quite ductile. This Technical Memorandum presents a comprehensive review of experimental data for the effects of gaseous Hydrogen Environment Embrittlement (HEE) for several types of metallic materials. Common material screening methods are used to rate the hydrogen degradation of mechanical properties that occur while the material is under an applied stress and exposed to gaseous hydrogen as compared to air or helium, under slow strain rates (SSR) testing. Due to the simplicity and accelerated nature of these tests, the results expressed in terms of HEE index are not intended to necessarily represent true hydrogen service environment for long-term exposure, but rather to provide a practical approach for material screening, which is a useful concept to qualitatively evaluate the severity of

  14. Ultraviolet-induced mutations in Cockayne syndrome cells are primarily caused by cyclobutane dimer photoproducts while repair of other photoproducts is normal

    International Nuclear Information System (INIS)

    Parris, C.N.; Kraemer, K.H.

    1993-01-01

    The authors compared the contribution to mutagenesis on Cockayne syndrome (CS) cells of the major class of UV photoproducts, the cyclobutane pyrimidine dimer, to that of other DNA photoproducts by using the mutagenesis shuttle vector pZ189. Lymphoblastoid cell lines from the DNA repair-deficient disorders CS and xeroderma pigmentosum (XP) and a normal line were transfected with UV-treated pZ189. Cyclobutane dimers were selectively removed before transfection by photoreactivation (PR), leaving nondimer photoproducts intact. After UV exposure and replication in CS and XP cells, plasmid survival was abnormally elevated. After PR, plasmid survival increased and mutation frequency in CS cells decreased to normal levels but remained abnormal in XP cells. Sequence analysis of >200 mutant plasmids showed that with CS cells a major mutational hot spot was caused by unrepaired cyclobutane dimers. These data indicate that with both CS and XP cyclobutane dimers are major photoproducts generating reduced plasmid survival and increased mutation frequency. However, unlike XP, CS cells are proficient in repair of nondimer photoproducts. Since XP but not CS patients have a high frequency of UV-induced skin cancers, the data suggest that prevention of UV-induced skin cancers is associated with proficient repair of nondimer photoproducts. 38 refs., 3 figs., 2 tabs

  15. Carbon monoxide apparent quantum yields and photoproduction in the Tyne estuary

    Directory of Open Access Journals (Sweden)

    A. Stubbins

    2011-03-01

    Full Text Available Carbon monoxide (CO apparent quantum yields (AQYs are reported for a suite of riverine, estuarine and sea water samples, spanning a range of coloured dissolved organic matter (CDOM sources, diagenetic histories, and concentrations (absorption coefficients. CO AQYs were highest for high CDOM riverine samples and almost an order of magnitude lower for low CDOM coastal seawater samples. CO AQYs were between 47 and 80% lower at the mouth of the estuary than at its head. Whereas, a conservative mixing model predicted only 8 to 14% decreases in CO AQYs between the head and mouth of the estuary, indicating that a highly photoreactive pool of terrestrial CDOM is lost during estuarine transit. The CDOM absorption coefficient (a at 412 nm was identified as a good proxy for CO AQYs (linear regression r2 > 0.8; n = 12 at all CO AQY wavelengths studied (285, 295, 305, 325, 345, 365, and 423 nm and across environments (high CDOM river, low CDOM river, estuary and coastal sea. These regressions are presented as empirical proxies suitable for the remote sensing of CO AQYs in natural waters, including open ocean water, and were used to estimate CO AQY spectra and CO photoproduction in the Tyne estuary based upon annually averaged estuarine CDOM absorption data. A minimum estimate of annual CO production was determined assuming that only light absorbed by CDOM leads to the formation of CO and a maximum limit was estimated assuming that all light entering the water column is absorbed by CO producing photoreactants (i.e. that particles are also photoreactive. In this way, annual CO photoproduction in the Tyne was estimated to be between 0.99 and 3.57 metric tons of carbon per year, or 0.004 to 0.014% of riverine dissolved organic carbon (DOC inputs to the estuary. Extrapolation of CO photoproduction rates to estimate total DOC photomineralisation indicate that less than 1% of DOC inputs are removed via photochemical processes during

  16. Photoproduction of vector mesons off nucleons near threshold

    International Nuclear Information System (INIS)

    Friman, B.; Soyeur, M.

    1995-11-01

    We propose a simple meson-exchange model of the photoproduction of ρ-and ω-mesons off protons near threshold (E γ < or∼2 GeV). We show that this model provides a good description of the available data and implies a large ρ-nucleon interaction in the scalar channel (σ-exchange). We use this phenomenological interaction to estimate the leading contribution to the self-energy of ρ-mesons in matter. We discuss the implications of our calculation for experimental studies of the ρ-meson mass in nuclei. (orig.)

  17. Latest results from meson photoproduction at ELSA and MAMI

    Science.gov (United States)

    Krusche, B.

    2014-06-01

    Photoproduction of mesons plays a key role for the investigation of the excitation spectrum of the nucleon and thus for our understanding of the strong interaction in the non-perturbative regime. In this contribution we discuss recent results from the experiments at the tagged photon beams of the electron accelerators ELSA in Bonn and MAMI in Mainz. They include the measurement of cross sections and (double) polarization observables for single meson production and production of meson pairs off free protons as well as of quasi-free nucleons bound in light nuclei (in particular the deuteron).

  18. Photoproduction of {omega} mesons on nuclei near the production threshold

    Energy Technology Data Exchange (ETDEWEB)

    Nanova, M.; Friedrich, S.; Metag, V.; Thiel, M.; Gregor, R.; Kotulla, M.; Lugert, S.; Novotny, R.; Pant, L.M.; Pfeiffer, M.; Roy, A.; Schadmand, S.; Trnka, D.; Varma, R. [Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Weil, J.; Mosel, U. [Universitaet Giessen, Institut fuer Theoretische Physik I, Giessen (Germany); Anton, G.; Bogendoerfer, R.; Hoessl, J.; Suft, G. [Universitaet Erlangen, Physikalisches Institut, Erlangen (Germany); Bacelar, J.C.S.; Castelijns, R.; Loehner, H.; Messchendorp, J.G.; Shende, S. [Kernfysisch Versneller Institut, Groningen (Netherlands); Bartholomy, O.; Crede, V.; Ehmanns, A.; Essig, K.; Fabry, I.; Fuchs, M.; Funke, C.; Gutz, E.; Hoeffgen, S.; Hoffmeister, P.; Horn, I.; Junkersfeld, J.; Kalinowsky, H.; Klempt, E.; Lotz, J.; Pee, H. van; Schmidt, C.; Szczepanek, T.; Thoma, U.; Walther, D.; Weinheimer, C.; Wendel, C. [Helmholtz-Institut fuer Strahlen- und Kernphysik Universitaet Bonn, Bonn (Germany); Bayadilov, D. [Helmholtz-Institut fuer Strahlen- und Kernphysik Universitaet Bonn, Bonn (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Beloglazov, Y.A.; Gridnev, A.B.; Lopatin, I.V.; Radkov, A.; Sumachev, V.V. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Dutz, H.; Elsner, D.; Ewald, R.; Gothe, R.; Klein, Frank; Klein, Friedrich; Konrad, M.; Menze, D.; Morales, C.; Ostrick, M.; Schmieden, H.; Schoch, B.; Suele, A. [Universitaet Bonn, Physikalisches Institut, Bonn (Germany); Jaegle, I.; Krusche, B.; Mertens, T. [Universitaet Basel, Physikalisches Institut, Basel (Switzerland); Kopf, B. [Institut fuer Kern- und Teilchenphysik, TU Dresden, Dresden (Germany); Universitaet Bochum, Physikalisches Institut, Bochum (Germany); Langheinrich, J. [Universitaet Bonn, Physikalisches Institut, Bonn (Germany); Universitaet Bochum, Physikalisches Institut, Bochum (Germany)

    2011-02-15

    The photoproduction of {omega} mesons on LH{sub 2}, C and Nb has been measured for incident photon energies from 900 to 1300MeV using the CB/TAPS detector at ELSA. The {omega} lineshape does not show any significant difference between the LH{sub 2} and the Nb targets. The experiment was motivated by transport calculations that predicted a sensitivity of the {omega} lineshape to in-medium modifications near the production threshold on a free nucleon of E{sub {gamma}}{sup lab}=1109 MeV. A comparison with recent calculations is given. (orig.)

  19. Beauty photoproduction using decays into electrons at HERA

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-05-15

    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{sup -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.)

  20. Measurement of heavy-quark jet photoproduction at HERA

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.

    2011-04-01

    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, p jet T , and pseudorapidity, η jet , were measured. The data are compared with previous measurements and are well described by next-to-leading-order QCD predictions. (orig.)

  1. Photoproduction of vector mesons off nucleons near threshold

    International Nuclear Information System (INIS)

    Friman, B.

    1995-01-01

    A simple meson-exchange model is proposed for the photoproduction of ρ- and ω-mesons off protons near threshold. This model provides a good description of the available data and implies a large ρ-nucleon interaction in the scalar channel (σ-exchange). This phenomenological interaction is applied to estimate the leading contribution to the self-energy of ρ-mesons in matter. The implications of our calculation for experimental studies of the ρ-meson mass in nuclei are discussed. (author)

  2. Threshold pion photoproduction in A light-cone quark model

    International Nuclear Information System (INIS)

    Konen, W.; Drechsel, D.

    1991-01-01

    The instantaneous and seagull graphs are calculated for pion photoproduction in a relativistic light-cone model of the nucleon. In both pseudoscalar and pseudovector coupling we find the ratios A (-) :A (0) :A (+) =1:(-1/2μ):(-9/5 1/2μ) in the nonrelativistic limit. These results correspond to the sum of seagull and Z-graph in the nonrelativistic quark model. In pseudovector coupling also the numerical results for realistic-model parameters are close to those values. (orig.)

  3. Hard photoproduction: An analysis of the first ZEUS data

    International Nuclear Information System (INIS)

    Feld, L.W.

    1993-10-01

    The electron-proton storage ring HERA gives the unique opportunity to study photon-proton collisions at center of mass energies around 200 GeV. This analysis covers the extraction of hard photoproduction events from the data taken by the ZEUS-detector in its first year of operation. It is shown, that these events are well described by the Monte Carlo generators PYTHIA and HERWIG. A jet analysis allows to measure the kinematics of the hard subprocess. Clear evidence for both direct and resolved photon processes is seen in the data. In detailed Monte Carlo studies different photon structure functions are compared to the data. (orig.)

  4. Color-octet contributions to J/ψ photoproduction

    International Nuclear Information System (INIS)

    Cacciari, M.; Kraemer, M.

    1996-01-01

    We have calculated the leading color-octet contributions to the production of J/ψ particles in photon-proton collisions. Using the values for the color-octet matrix elements extracted from fits to prompt J/ψ data at the Tevatron, we demonstrate that distinctive color-octet signatures should be visible in J/ψ photoproduction. However, these predictions appear at variance with recent experimental data obtained at HERA, indicating that the phenomenological importance of the color-octet contributions is smaller than expected from theoretical considerations and suggested by the Tevatron fits. (orig.)

  5. Meson Spectroscopy in Photo-production at CLAS

    OpenAIRE

    Nozar, Mina

    2003-01-01

    Photo-production of excited mesons in the 1-2 GeV mass range decaying via multi-pion or multi-kaon emission has been investigated at the TJNAF\\thanks{This work was supported by the U.S. Department of Energy and The U.S. National Science Foundation.} experiment E01-017 (g6c) in the $4.8-5.4$ GeV photon beam energy range. The main objective of the experiment is to extract resonance parameters of the produced states by way of a Partial Wave Analysis (PWA) technique. In this paper, we will focus ...

  6. Soft and hard contributions to hard pion photoproduction

    International Nuclear Information System (INIS)

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

    2000-01-01

    Pion photoproduction at high transverse momentum supplements what can be learned in the standard probes of deep inelastic scattering and Drell-Yan processes. With polarized initial states there is sensitivity to the polarized gluon distribution, Δg, in leading order. This contrasts to other processes mentioned, which have no leading order gluon contribution. Additionally, in some kinematic regions the process occurs mainly due to pion production at short distances ('direct pion production', resulting in kinematically isolated pions), which gives sensitivity to the high-x valence quark distribution

  7. Beauty photoproduction using decays into electrons at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2008-05-01

    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.)

  8. Isotensor electromagnetic current in low energy pion photoproduction

    International Nuclear Information System (INIS)

    Aznauryan, I.G.; Nagorskaya, I.A.; Zaslavskij, A.N.

    1974-01-01

    Recent experimental data on single pion photoproduction in the Δ (1236) resonance region are discussed. The role of the high energy contributions into the dispersion integrals are analyzed. Estimates for the magnitude of the isotensor contributions are obtained in the dispersion approach using the experimental data of various groups. In spite of the great number of the experiments the estimate is ambiguous yet since there are direct discrepancies between the data of various groups, besides, certain available data are incomplete. The data of some groups are compatible with 10% isotensor contribution

  9. Observation of hard scattering in photoproduction at HERA

    Science.gov (United States)

    Derrick, M.; Krakauer, D.; Magill, S.; Musgrave, B.; Repond, J.; Sugano, K.; Stanek, R.; Talaga, R. L.; Thron, J.; Arzarello, F.; Ayed, R.; Barbagli, G.; Bari, G.; Basile, M.; Bellagamba, L.; Boscherini, D.; Bruni, G.; Bruni, P.; Cara Romeo, G.; Castellini, G.; Chiarini, M.; Cifarelli, L.; Cindolo, F.; Ciralli, F.; Contin, A.; D'Auria, S.; Del Papa, C.; Frasconi, F.; Giusti, P.; Iacobucci, G.; Laurenti, G.; Levi, G.; Lin, Q.; Lisowski, B.; Maccarrone, G.; Margotti, A.; Massam, T.; Nania, R.; Nemoz, C.; Palmonari, F.; Sartorelli, G.; Timellini, R.; Zamora Garcia, Y.; Zichichi, A.; Bargende, A.; Barreiro, F.; Crittenden, J.; Dabbous, H.; Desch, K.; Diekmann, B.; Geerts, M.; Geitz, G.; Gutjahr, B.; Hartmann, H.; Hartmann, J.; Haun, D.; Heinloth, K.; Hilger, E.; Jakob, H.-P.; Kramarczyk, S.; Kückes, M.; Mass, A.; Mengel, S.; Mollen, J.; Müsch, H.; Paul, E.; Schattevoy, R.; Schneider, B.; Schneider, J.-L.; Wedemeyer, R.; Cassidy, A.; Cussans, D. G.; Dyce, N.; Fawcett, H. F.; Foster, B.; Gilmore, R.; Heath, G. P.; Lancaster, M.; Llewellyn, T. J.; Malos, J.; Morgado, C. J. S.; Tapper, R. J.; Wilson, S. S.; Rau, R. R.; Bernstein, A.; Caldwell, A.; Gialas, I.; Parsons, J. A.; Ritz, S.; Sciulli, F.; Straub, P. B.; Wai, L.; Yang, S.; Barillari, T.; Schioppa, M.; Susinno, G.; Burkot, W.; Chwastowski, J.; Dwuraźny, A.; Eskreys, A.; Nizioł, B.; Jakubowski, Z.; Piotrzkowski, K.; Zachara, M.; Zawiejski, L.; Borzemski, P.; Eskreys, K.; Jeleń, K.; Kisielewska, D.; Kowalski, T.; Kulka, J.; Rulikowska-Zarȩbska, E.; Suszycki, L.; Zajaç, J.; Kȩdzierski, T.; Kotański, A.; Przybycień, M.; Bauerdick, L. A. T.; Behrens, U.; Bienlein, J. K.; Coldewey, C.; Dannemann, A.; Dierks, K.; Dorth, W.; Drews, G.; Erhard, P.; Flasiński, M.; Fleck, I.; Fürtjes, A.; Gläser, R.; Göttlicher, P.; Haas, T.; Hagge, L.; Hain, W.; Hasell, D.; Hultschig, H.; Jahnen, G.; Joos, P.; Kasemann, M.; Klanner, R.; Koch, W.; Kötz, U.; Kowalski, H.; Labs, J.; Ladage, A.; Löhr, B.; Löwe, M.; Lüke, D.; Mainusch, J.; Manczak, O.; Momayezi, M.; Nickel, S.; Notz, D.; Park, I.; Pösnecker, K.-U.; Rohde, M.; Ros, E.; Schneekloth, U.; Schroeder, J.; Schulz, W.; Selonke, F.; Tscheslog, E.; Tsurugai, T.; Turkot, F.; Vogel, W.; Woeniger, T.; Wolf, G.; Youngman, C.; Grabosch, H. J.; Leich, A.; Meyer, A.; Rethfeldt, C.; Schlenstedt, S.; Casalbuoni, R.; De Curtis, S.; Dominici, D.; Francescato, A.; Nuti, M.; Pelfer, P.; Anzivino, G.; Casaccia, R.; Laakso, I.; De Pasquale, S.; Qian, S.; Votano, L.; Bamberger, A.; Freidhof, A.; Poser, T.; Söldner-Rembold, S.; Theisen, G.; Trefzger, T.; Brook, N. H.; Bussey, P. J.; Doyle, A. T.; Forbes, J. R.; Jamieson, V. A.; Raine, C.; Saxon, D. H.; Gloth, G.; Holm, U.; Kammerlocher, H.; Krebs, B.; Neumann, T.; Wick, K.; Hofmann, A.; Kröger, W.; Krüger, J.; Lohrmann, E.; Milewski, J.; Nakahata, M.; Pavel, N.; Poelz, G.; Salomon, R.; Seidman, A.; Schott, W.; Wiik, B. H.; Zetsche, F.; Bacon, T. C.; Butterworth, I.; Markou, C.; McQuillan, D.; Miller, D. B.; Mobayyen, M. M.; Prinias, A.; Vorvolakos, A.; Bienz, T.; Kreutzmann, H.; Mallik, U.; McCliment, E.; Roco, M.; Wang, M. Z.; Cloth, P.; Filges, D.; Chen, L.; Imlay, R.; Kartik, S.; Kim, H.-J.; McNeil, R. R.; Metcalf, W.; Cases, G.; Hervás, L.; Labarga, L.; del Peso, J.; Roldán, J.; Terrón, J.; de Trocóniz, J. F.; Ikraiam, F.; Mayer, J. K.; Smith, G. R.; Corriveau, F.; Gilkinson, D. J.; Hanna, D. S.; Hung, L. W.; Mitchell, J. W.; Patel, P. M.; Sinclair, L. E.; Stairs, D. G.; Ullmann, R.; Bashindzhagyan, G. L.; Ermolov, P. F.; Golubkov, Y. A.; Kuzmin, V. A.; Kuznetsov, E. N.; Savin, A. A.; Voronin, A. G.; Zotov, N. P.; Bentvelsen, S.; Dake, A.; Engelen, J.; de Jong, P.; de Jong, S.; de Kamps, M.; Kooijman, P.; Kruse, A.; van der Lugt, H.; O'Dell, V.; Straver, J.; Tenner, A.; Tiecke, H.; Uijterwaal, H.; Vermeulen, J.; Wiggers, L.; de Wolf, E.; van Woudenberg, R.; Yoshida, R.; Bylsma, B.; Durkin, L. S.; Li, C.; Ling, T. Y.; McLean, K. W.; Murray, W. N.; Park, S. K.; Romanowski, T. A.; Seidlein, R.; Blair, G. A.; Butterworth, J. M.; Byrne, A.; Cashmore, R. J.; Cooper-Sarkar, A. M.; Devenish, R. C. E.; Gingrich, D. M.; Hallam-Baker, P. M.; Harnew, N.; Khatri, T.; Long, K. R.; Luffman, P.; McArthur, I.; Morawitz, P.; Nash, J.; Smith, S. J. P.; Roocroft, N. C.; Wilson, F. F.; Abbiendi, G.; Brugnera, R.; Carlin, R.; Dal Corso, F.; De Giorgi, M.; Dosselli, U.; Fanin, C.; Gasparini, F.; Limentani, S.; Morandin, M.; Posocco, M.; Stanco, L.; Stroili, R.; Voci, C.; Lim, J. N.; Oh, B. Y.; Whitmore, J.; Bonori, M.; Contino, U.; D'Agostini, G.; Guida, M.; Iori, M.; Mari, S.; Marini, G.; Mattioli, M.; Monaldi, D.; Nigro, A.; Hart, J. C.; McCubbin, N. A.; Shah, T. P.; Short, T. L.; Barberis, E.; Cartiglia, N.; Heusch, C.; Hubbard, B.; Leslie, J.; Ng, J. S. T.; O'Shaughnessy, K.; Sadrozinski, H. F.; Seiden, A.; Badura, E.; Biltzinger, J.; Chaves, H.; Rost, M.; Seifert, R. J.; Walenta, A. H.; Weihs, W.; Zech, G.; Dagan, S.; Heifetz, R.; Levy, A.; Zer-Zion, D.; Hasegawa, T.; Hazumi, M.; Ishii, T.; Kasai, S.; Kuze, M.; Nagasawa, Y.; Nakao, M.; Okuno, H.; Tokushuku, K.; Watanabe, T.; Yamada, S.; Chiba, M.; Hamatsu, R.; Hirose, T.; Kitamura, S.; Nagayama, S.; Nakamitsu, Y.; Arneodo, M.; Costa, M.; Ferrero, M. I.; Lamberti, L.; Maselli, S.; Peroni, C.; Solano, A.; Staiano, A.; Dardo, M.; Bailey, D. C.; Bandyopadhyay, D.; Benard, F.; Bhadra, S.; Brkic, M.; Burow, B. D.; Chlebana, F. S.; Crombie, M. B.; Hartner, G. F.; Levman, G. M.; Martin, J. F.; Orr, R. S.; Prentice, J. D.; Sampson, C. R.; Stairs, G. G.; Teuscher, R. J.; Yoon, T.-S.; Bullock, F. W.; Catterall, C. D.; Giddings, J. C.; Jones, T. W.; Khan, A. M.; Lane, J. B.; Makkar, P. L.; Shaw, D.; Shulman, J.; Blankenship, K.; Kochocki, J.; Lu, B.; Mo, L. W.; Charchuła, K.; Ciborowski, J.; Gajewski, J.; Grzelak, G.; Kasprzak, M.; Krzyżanowski, M.; Muchorowski, K.; Nowak, R. J.; Pawlak, J. M.; Stojda, K.; Stopczyński, A.; Szwed, R.; Tymieniecka, T.; Walczak, R.; Wróblewski, A. K.; Zakrzewski, J. A.; Żarnecki, A. F.; Adamus, M.; Abramowicz, H.; Eisenberg, Y.; Glasman, C.; Karshon, U.; Montag, A.; Revel, D.; Shapira, A.; Ali, I.; Behrens, B.; Camerini, U.; Dasu, S.; Fordham, C.; Foudas, C.; Goussiou, A.; Lomperski, M.; Loveless, R. J.; Nylander, P.; Ptacek, M.; Reeder, D. D.; Smith, W. H.; Silverstein, S.; Frisken, W. R.; Furutani, K. M.; Iga, Y.; ZEUS Collaboration

    1992-12-01

    We report a study of electron proton collisions at very low Q2, corresponding to virtual photoproduction at centre of mass energies in the range 100-295 GeV. The distribution in transverse energy of the observed hadrons is much harder than can be explained by soft processes. Some of the events show back-to-back two-jet production at the rate and with the characteristics expected from hard two-body scattering. A subset of the two-jet events have energy in the electron direction consistent with that expected from the photon remnant in resolved photon processes.

  10. 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.)

  11. Beauty photoproduction at HERA. k{sub T}-factorization versus experimental data

    Energy Technology Data Exchange (ETDEWEB)

    Lipatov, A.V.; Zotov, N.P. [M.V. Lomonosov Moscow State Univ., Moscow (Russian Federation). D.V. Skobeltsyn Institute of Nuclear Physics

    2006-05-15

    We present calculations of the beauty photoproduction at HERA collider in the framework of the k{sub T}-factorization approach. Both direct and resolved photon contributions are taken into account. The unintegrated gluon densities in a proton and in a photon are obtained from the full CCFM, from unified BFKL-DGLAP evolution equations as well as from the Kimber-Martin-Ryskin prescription. We investigate different production rates (both inclusive and associated with hadronic jets) and compare our theoretical predictions with the recent experimental data taken by the H1 and ZEUS collaborations. Special attention is put on the x{sup obs}{sub {gamma}} variable which is sensitive to the relative contributions to the beauty production cross section. (Orig.)

  12. Measurement of Beauty and Charm Photoproduction using Semi-muonic Decays in Dijet Events at HERA

    CERN Document Server

    Aaron, F.D.; Andreev, V.; Backovic, S.; Baghdasaryan, A.; Baghdasaryan, S.; Barrelet, E.; Bartel, W.; Begzsuren, K.; Belousov, A.; Belov, P.; Bizot, J.C.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Bruncko, D.; Bunyatyan, A.; Bylinkin, A.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; Ceccopieri, F.; Cerny, K.; Cerny, V.; Chekelian, V.; Contreras, J.G.; Coughlan, J.A.; Cvach, J.; Dainton, J.B.; Daum, K.; Delcourt, B.; Delvax, J.; De Wolf, E.A.; Diaconu, C.; Dobre, M.; Dodonov, V.; Dossanov, A.; Dubak, A.; Eckerlin, G.; Egli, S.; Eliseev, A.; 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.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hreus, T.; Huber, F.; Jacquet, M.; Janssen, X.; Jonsson, L.; Jung, H.; Kapichine, M.; Kenyon, I.R.; Kiesling, C.; Klein, M.; Kleinwort, C.; Kluge, T.; Kogler, R.; Kostka, P.; Kramer, M.; Kretzschmar, J.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lendermann, V.; 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.; Moreau, F.; 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.; Panagoulias, I.; Pandurovic, M.; Papadopoulou, Th.; Pascaud, C.; Patel, G.D.; Perez, E.; Petrukhin, A.; Picuric, I.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Pokorny, B.; Polifka, R.; Povh, B.; 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.; Shtarkov, L.N.; Shushkevich, S.; Sloan, T.; 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.; Tran, T.H.; 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.; Zhokin, A.; Zlebcik, R.; Zohrabyan, H.; Zomer, F.

    2012-07-13

    Measurements of cross sections for beauty and charm events with dijets and a muon in the photoproduction regime at HERA are presented. The data were collected with the H1 detector and correspond to an integrated luminosity of 179 pb^{-1}. Events with dijets of transverse momentum P_T^{jet1} > 7 GeV and P_T^{jet2} > 6 GeV in the pseudorapidity range -1.5 2.5 GeV in the pseudorapidity range -1.3 < \\eta^{\\mu} < 1.5. The fractions of beauty and charm events are determined using the impact parameters of the muon tracks with respect to the primary vertex and their transverse momentum relative to the axis of the associated jet. Both variables are reconstructed using the H1 vertex detector. The measurements are in agreement with QCD predictions at leading and next-to-leading order.

  13. Regge-plus-resonance predictions for charged-kaon photoproduction from the deuteron

    Directory of Open Access Journals (Sweden)

    Van Cauteren T.

    2010-04-01

    Full Text Available We present a Regge-inspired effective-Lagrangian framework for charged-kaon photoproduction from the deuteron. Quasi-free kaon production is investigated using the Regge-plus-resonance elementary operator within the non-relativistic plane-wave impulse approximation. The Regge-plus-resonance model was developed to describe photoinduced and electroinduced kaon production off protons and can be extended to strangeness production off neutrons. The non-resonant contributions to the amplitude are modelled in terms of K+ (494 and K*+ (892 Regge-trajectory exchange in the t-channel. This amplitude is supplemented with a selection of s-channel resonance-exchange diagrams. We investigate several sources of theoretical uncertainties on the semi-inclusive charged-kaon production cross section. The experimental error bars on the photocoupling helicity amplitudes turn out to put severe limits on the predictive power when considering quasi-free kaon production on a bound neutron.

  14. Measurement of Di-jet Cross-Sections in Photoproduction and Photon Structure

    CERN Document Server

    Adloff, C.; Andrieu, B.; Arkadov, V.; Astvatsatourov, A.; Ayyaz, I.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bassler, U.; Bate, P.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Benisch, T.; Berger, Christoph; Bernardi, G.; Berndt, T.; Bertrand-Coremans, G.; Bizot, J.C.; Borras, K.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruckner, W.; Bruel, P.; Bruncko, D.; Burger, J.; Busser, F.W.; Bunyatyan, A.; Burke, Stephen; Burkhardt, H.; Burrage, A.; Buschhorn, G.; Campbell, A.J.; Cao, Jun; Carli, T.; Caron, S.; Chabert, E.; Clarke, D.; Clerbaux, B.; Collard, C.; 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.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dixon, P.; Dodonov, V.; Donovan, K.T.; Dowell, J.D.; Droutskoi, A.; Duprel, C.; Ebert, J.; Eckerlin, Guenter; Eckstein, D.; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Eisenhandler, E.; Ellerbrock, M.; Elsen, E.; Erdmann, M.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Ferrarotto, F.; Ferron, S.; Fleischer, M.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Foster, J.M.; Franke, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Ghazaryan, Samvel; Glazov, A.; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goodwin, C.; Gorelov, I.; Grab, C.; Grassler, H.; Greenshaw, T.; Griffiths, R.K.; Grindhammer, Guenter; Hadig, T.; Haidt, D.; Hajduk, L.; Haustein, V.; Haynes, W.J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Heremans, R.; Herrera, G.; Herynek, I.; Hilgers, M.; Hiller, K.H.; Hilton, C.D.; Hladky, J.; Hoting, P.; Hoffmann, D.; Hoprich, W.; Horisberger, R.; Hurling, S.; Ibbotson, M.; Issever, C.; Jacquet, M.; Jaffre, M.; Janauschek, L.; Jansen, D.M.; Janssen, X.; Jemanov, V.; Jonsson, L.; 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, I.R.; Kermiche, S.; Kiesling, Christian M.; 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.; Krucker, D.; Kruger, K.; Kupper, A.; Kuhr, T.; Kurca, T.; Kutuev, R.; Lachnit, W.; Lahmann, R.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Lebedev, A.; Leissner, B.; Lemaitre, V.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstrom, M.; Lobo, G.; Lobodzinska, E.; Lobodzinski, B.; Loktionova, N.; Lubimov, V.; Luders, S.; Luke, D.; Lytkin, L.; Magnussen, N.; Mahlke-Kruger, H.; Malden, N.; Malinovski, E.; Malinovski, 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.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, D.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Negri, I.; Newman, Paul R.; Nguyen, H.K.; Nicholls, T.C.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Nunnemann, T.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Passaggio, S.; Patel, G.D.; Perez, E.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Potachnikova, I.; Povh, B.; Rabbertz, K.; Radel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Riess, S.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Royon, C.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Scheins, J.; Schilling, F.P.; Schleif, S.; Schleper, P.; Schmidt, D.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Sedlak, K.; Sefkow, F.; Chekelian, V.I.; Sheviakov, I.; Shtarkov, L.N.; Siegmon, G.; Sievers, P.; Sirois, Y.; Sloan, T.; Smirnov, P.; Smith, M.; Solochenko, V.; Solovev, Y.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Steinhart, J.; Stella, B.; Stellberger, A.; Stiewe, J.; Straumann, U.; Struczinski, W.; Sutton, J.P.; Swart, M.; Tasevsky, M.; Tchernyshov, V.; Tchetchelnitsky, S.; Thompson, Graham; Thompson, P.D.; Tobien, N.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; 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.; Wunsch, E.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; 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.

  15. Elastic Photoproduction of $J/\\psi$ and $\\Upsilon$ Mesons at HERA

    CERN Document Server

    Adloff, C.; Andrieu, B.; Arkadov, V.; Astvatsatourov, A.; Ayyaz, I.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Bassler, U.; Bate, P.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Benisch, T.; Berger, Christoph; Bernardi, G.; Berndt, T.; Bizot, J.C.; Borras, K.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruckner, W.; Bruel, P.; Bruncko, D.; Burger, J.; Busser, F.W.; Bunyatyan, A.; Burkhardt, H.; Burrage, A.; Buschhorn, G.; Campbell, A.J.; Cao, Jun; Carli, T.; Caron, S.; Chabert, E.; Clarke, D.; Clerbaux, B.; Collard, C.; 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.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dixon, P.; Dodonov, V.; Dowell, J.D.; Droutskoi, A.; Duprel, C.; Eckerlin, Guenter; 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.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Foster, J.M.; Franke, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Ghazarian, S.; Goerlich, L.; Gogitidze, N.; Goldberg, M.; Goodwin, C.; Grab, C.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Hadig, T.; Haidt, D.; Hajduk, L.; Hauschildt, T.; Haynes, W.J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Heremans, R.; Herrera, G.; Herynek, I.; Hilgers, M.; Hiller, K.H.; Hilton, C.D.; Hladky, J.; Hoting, P.; Hoffmann, D.; Hoprich, W.; Horisberger, R.; Hurling, S.; Ibbotson, M.; Issever, C .; Jacquet, M.; Jaffre, M.; Janauschek, L.; Jansen, D.M.; Janssen, X.; Jemanov, V.; Jonsson, L.; 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, I.R.; Kermiche, S.; Kiesling, Christian M.; 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.; Krucker, D.; Kruger, K.; Kupper, A.; Kuhr, T.; Kurca, T.; Kutuev, R.; Lachnit, W.; Lahmann, R.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Lebedev, A.; Leissner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindstrom, M.; List, B.; Lobodzinska, E.; Lobodzinski, B.; Loktionova, N.; Lubimov, V.; Luders, S.; Luke, D.; Lytkin, L.; Magnussen, N.; Mahlke-Kruger, H.; Malden, N.; Malinovski, E.; Malinovski, I.; Maracek, R.; Marage, P.; Marks, J.; Marshall, R.; Martyn, H.U.; Martyniak, J.; Maxfield, S.J.; 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.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, D.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Negri, I.; Nellen, G.; Newman, Paul R.; Nicholls, T.C.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Nunnemann, T.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Perez, E.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Potachnikova, I.; Povh, B.; Rabbertz, K.; Radel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Riess, S.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Royon, C.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Scheins, J.; Schilling, F.P.; Schleif, S.; Schleper, P.; Schmidt, D.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Sedlak, K.; Sefkow, F.; Chekelian, V.I.; Sheviakov, I.; Shtarkov, L.N.; Siegmon, G.; Sievers, P.; Sirois, Y.; Sloan, T.; Smirnov, P.; Solochenko, V.; Solovev, Y.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Steinhart, J.; Stella, B.; Stellberger, A.; Stiewe, J.; Straumann, U.; Struczinski, W.; Swart, M.; Tasevsky, M.; Tchernyshov, V.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tobien, N.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; von Dombrowski, S.; Wacker, K.; Wallny, R.; Walter, T.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; Wegner, A.; Wengler, T.; Werner, M.; White, G.; Wiesand, S.; Wilksen, T.; Winde, M.; Winter, G.G.; Wissing, C.; Wobisch, M.; Wollatz, H.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; Zsembery, J.; zur Nedden, M.

    2000-01-01

    Cross sections for elastic photoproduction of J/Psi and Upsilon mesons are presented. For J/Psi mesons the dependence on the photon-proton centre-of-mass energy W_gammap is analysed in an extended range with respect to previous measurements of 26<=W_gammap<= 285 GeV. The measured energy dependence is parameterized as sigma_gammap proportional W_gammap^delta with delta=0.83+-0.07. The differential cross section dsigma/dt for J/Psi mesons is derived, its dependence on W_gammap and on t is analysed and the effective trajectory (in terms of Regge theory) is determined to be alpha(t)=(1.27+-0.05)+(0.08+-0.17)*t/GeV^2. Models based on perturbative QCD and on pomeron exchange are compared to the data.

  16. First measurement of the helicity asymmetry E in η photoproduction on the proton

    Science.gov (United States)

    Senderovich, I.; Morrison, B. T.; Dugger, M.; Ritchie, B. G.; Pasyuk, E.; Tucker, R.; Brock, J.; Carlin, C.; Keith, C. D.; Meekins, D. G.; Seely, M. L.; Rönchen, D.; Döring, M.; Collins, P.; Adhikari, K. P.; Adikaram, D.; Akbar, Z.; Anderson, M. D.; Anefalos Pereira, S.; 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.; Credé, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Filippi, A.; Fleming, J. A.; Fradi, 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.; Munoz Camacho, C.; 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.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Simonyan, A.; Skorodumina, Iu.; Smith, G. D.; Sober, D. I.; 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.

    2016-04-01

    Results are presented for the first measurement of the double-polarization helicity asymmetry E for the η photoproduction reaction γp → ηp. 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 Jülich-Bonn 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 from that model. Further comparison with several theoretical approaches indicates these data will significantly enhance our understanding of nucleon resonances.

  17. First measurement of the helicity asymmetry E in η photoproduction on the proton

    Energy Technology Data Exchange (ETDEWEB)

    Senderovich, I.; Morrison, B. T.; Dugger, M.; Ritchie, B. G.; Pasyuk, E.; Tucker, R.; Brock, J.; Carlin, C.; Keith, C. D.; Meekins, D. G.; Seely, M. L.; Rönchen, D.; Döring, M.; Collins, P.; Adhikari, K. P.; Adikaram, D.; Akbar, Z.; Anderson, M. D.; Anefalos Pereira, S.; 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.; Credé, V.; D' Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dupre, R.; Egiyan, H.; El Alaoui, A.; El Fassi, L.; Elouadrhiri, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Filippi, A.; Fleming, J. A.; Fradi, 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.; Munoz Camacho, C.; 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.; Sabatié, F.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Simonyan, A.; Skorodumina, Iu.; Smith, G. D.; Sober, D. I.; 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.

    2016-01-26

    Results are presented for the first measurement of the double-polarization helicity asymmetry E for the η photoproduction reaction γ p → ηp. 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 Jülich–Bonn 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 from that model. Further comparison with several theoretical approaches indicates these data will significantly enhance our understanding of nucleon resonances.

  18. The hydrogen; L'hydrogene

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    The hydrogen as an energy system represents nowadays a main challenge (in a scientific, economical and environmental point of view). The physical and chemical characteristics of hydrogen are at first given. Then, the challenges of an hydrogen economy are explained. The different possibilities of hydrogen production are described as well as the distribution systems and the different possibilities of hydrogen storage. Several fuel cells are at last presented: PEMFC, DMFC and SOFC. (O.M.)

  19. Photoproduction of hydroxyl radicals in aqueous solution with algae under high-pressure mercury lamp.

    Science.gov (United States)

    Liu, Xianli; Wu, Feng; Deng, Nansheng

    2004-01-01

    Photoproduction of hydroxyl radicals (*OH) could be induced in aqueous solution with algae (Nitzschia hantzschiana, etc.) and (or not) Fe3+ under high-pressure mercury lamp with an exposure time of 4 h. *OH was determined by HPLC using benzene as a probe. The photoproduction of *OH increased with increasing algae concentration. Fe3+ could enhance the photoproduction of *OH in aqueous solution with algae. The results showed that the photoproduction of *OH in algal solution with Fe3+ was greater than that in algal solution without Fe3+. The light intensity and pH affected the photoproduction of *OH in aqueous solution with algae with/without Fe3+. The photoproduction of *OH in aqueous solution with algae and Fe3+ under 250 W was greater than that under 125 W HPML. The photoproduction of *OH in algal solution (pH ranged from 4.0 to 7.0) with (or not) Fe3+ at pH 4 was the greatest.

  20. Carbon/hydrogen clusters [CnHx+] formation from laser irradiation of coronene

    International Nuclear Information System (INIS)

    Betancourt, F; Alvarez, I; Guerrero, A; Cisneros, C; Poveda, J C

    2015-01-01

    This article presents the photo induced dehydrogenation of a cooled molecular jet of coronene, exposed to 266 nm laser radiation. Using unfocused laser radiation of 1064 nm, synchronously coupled with the ionization laser pulses, a system recently developed. Molecular beams were produced by laser desorption of coronene. Analysis of the photoproducts made by time-of flight mass spectrometer showed that a wide variety of ionic species were formed; more than 300 different species were observed. The results showed carbon clusters C + n with n up to 24 as well as carbon/hydrogen clusters C + n H + x with masses higher than 300 m/z. The effect on the laser irradiance on the formation of different ions, in the rage from 10 9 W/cm2 to 10 10 W/cm2, is discussed as it is reflected on the evolution from the big ions to the smaller ones. (paper)

  1. Measurement of charm and beauty dijet cross sections in photoproduction at HERA using the H1 vertex detector

    International Nuclear Information System (INIS)

    Aktas, A.; Andreev, V.; Anthonis, T.

    2006-04-01

    A measurement of charm and beauty dijet photoproduction cross sections at the ep collider HERA is presented. Events are selected with two or more jets of transverse momentum p jet 1(2)t >11(8) GeV in the central range of pseudo-rapidity -0.9 jet 1(2) obs γ . Taking into account the theoretical uncertainties, the charm cross sections are consistent with a QCD calculation in next-to-leading order, while the predicted cross sections for beauty production are somewhat lower than the measurement. (Orig.)

  2. Elastic photoproduction of ρ0 mesons at HERA

    International Nuclear Information System (INIS)

    Aid, S.; Andreev, V.; Andrieu, B.

    1995-12-01

    The cross section for the elastic photoproduction of ρ 0 mesons (γp→ρ 0 p) has been measured with the H1 detector at HERA for two average photon-proton centre-of-mass energies of 55 and 187 GeV. The lower energy point was measured by observing directly the ρ 0 decay giving a cross section of 9.1±0.9 (stat.)±2.5 (syst.) μb. The logarithmic slope parameter of the differential cross section, dσ/dt, is found to be 10.9±2.4 (stat.)±1.1 (syst.) GeV -2 . The ρ 0 decay polar angular distribution is found to be consistent with s-channel helicity conservation. The higher energy cross section was determined from analysis of the lower part of the hadronic invariant mass spectrum of diffractive photoproduction and found to be 13.6±0.8 (stat.)±2.4 (syst.) μb. (orig.)

  3. Photoproduction of pions on low-energy protons

    International Nuclear Information System (INIS)

    Grushin, V.F.

    1989-01-01

    This paper reports that a study is made of the complete experiment problem and photoproduction of pions on protons. The problem of the volume and content of a complete experiment is solved in the area of photon energies up to 500 MeV for the channels γp-π + n and γp-π → π 0 p. Experimental data assuring a complete experiment are used for multipole analysis of the channels γp → π + n, π 0 p and the real and imaginary parts of s- and p-wave multipole amplitudes are obtained. Estimates are produced for the pole parameters (mass and width) of the Δ + 33 isobar. An electrical quadrupole amplitude of the transition γp → Δ + 33 was found which is significantly different form zero, indicating the existence of a tensor interaction between quarks in hadrons. Data on photoproduction on mesons are used to extract quantitative estimates of the vector and tensor constants of interaction of an ω meson with nucleons

  4. High energy photoproduction of the rho and rho' vector mesons

    International Nuclear Information System (INIS)

    Bronstein, J.M.

    1977-01-01

    In an experiment in the broad band photon beam at Fermilab diffractive production of 2π + and 4π +- states from Be, Al, Cu, and Pb targets was observed. The 2π + data are dominated by the rho(770) and the 4π +- is dominated by the rho'(1500). The energy dependence of rho photoproduction from Be was measured, and no evidence was seen for energy variation of the forward cross section in the range 30 to 160 GeV. The forward cross section is consistent with its average value d sigma/dtlt. slash 0 = 3.42 +- 0.28 μb/GeV 2 over the entire range. For the /sub rho'// a mass of 1487 +- 20 MeV and a width of 675 +- 60 MeV are obtained. All quoted errors are statistical. A standard optical model analysis of the A dependence of the rho and rho'/ photoproduction yields the following results. f/sub rho'/ 2 /f/sub rho/ 2 = 3.7 +- 0.7, sigma /sub rho'//sigma /sub rho/ = 1.05 +- 0.18. Results for the photon coupling constants are in good agreement with GVMD and with the e + e - storage ring results. The approximate equality of the rho-nucleon and rho'-nucleon total cross sections is inconsistent with the diagonal version of GVMD and provides strong motivation for including transitions between different vector mesons in GVMD

  5. 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.)

  6. 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

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

    International Nuclear Information System (INIS)

    Toll, Tobias

    2010-02-01

    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.)

  8. Antibacterial activity of oxytetracycline photoproducts in marine aquaculture's water.

    Science.gov (United States)

    Leal, J F; Henriques, I S; Correia, A; Santos, E B H; Esteves, V I

    2017-01-01

    Oxytetracycline (OTC) is one of the most used antibiotics in aquaculture. The main concern related to its use is the bacterial resistance, when ineffective treatments are applied for its removal or inactivation. OTC photo-degradation has been suggested as an efficient complementary process to conventional methods used in intensive fish production (e.g.: ozonation). Despite this, and knowing that the complete mineralization of OTC is difficult, few studies have examined the antibacterial activity of OTC photoproducts. Thus, the main aim of this work is to assess whether the OTC photoproducts retain the antibacterial activity of its parent compound (OTC) after its irradiation, using simulated sunlight. For that, three Gram-negative bacteria (Escherichia coli, Vibrio sp. and Aeromonas sp.) and different synthetic and natural aqueous matrices (phosphate buffered solutions at different salinities, 0 and 21‰, and three different samples from marine aquaculture industries) were tested. The microbiological assays were made using the well-diffusion method before and after OTC has been exposed to sunlight. The results revealed a clear effect of simulated sunlight, resulting on the decrease or elimination of the antibacterial activity for all strains and in all aqueous matrices due to OTC photo-degradation. For E. coli, it was also observed that the antibacterial activity of OTC is lower in the presence of sea-salts, as demonstrated by comparison of halos in aqueous matrices containing or not sea-salts. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Exclusive ρ{sup 0} meson photoproduction with a leading neutron at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Andreev, V.; Belousov, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Vazdik, Y. [Lebedev Physical Institute, Moscow (Russian Federation); Baghdasaryan, A.; Zohrabyan, H. [Yerevan Physics Institute, Yerevan (Armenia); Begzsuren, K.; Ravdandorj, T. [Institute of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Bolz, A.; Huber, F.; Radescu, V.; Sauter, M.; Schoening, A. [Universitaet Heidelberg, Physikalisches Institut, Heidelberg (Germany); Boudry, V.; Specka, A. [LLR, Ecole Polytechnique, CNRS/IN2P3, Palaiseau (France); Brandt, G. [Universitaet Goettingen, II. Physikalisches Institut, Goettingen (Germany); Brisson, V.; Jacquet, M.; Pascaud, C.; Zhang, Z.; Zomer, F. [LAL, Universite Paris-Sud, CNRS/IN2P3, Orsay (France); Britzger, D.; Campbell, A.J.; Dodonov, V.; Eckerlin, G.; Elsen, E.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Haidt, D.; Kleinwort, C.; Krueger, K.; Levonian, S.; Lipka, K.; List, B.; List, J.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Ozerov, D.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E. [DESY, Hamburg (Germany); Buniatyan, A.; Newman, P.R.; Thompson, P.D. [University of Birmingham, School of Physics and Astronomy, Birmingham (United Kingdom); Bylinkin, A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Moscow Institute of Physics and Technology, Moscow (Russian Federation); Bystritskaya, L.; Fedotov, A. [Institute for Theoretical and Experimental Physics, Moscow (Russian Federation); Cantun Avila, K.B.; Contreras, J.G. [CINVESTAV, Departamento de Fisica Aplicada, Merida, Yucatan (Mexico); Cerny, K.; Pokorny, B.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R. [Charles University, Faculty of Mathematics and Physics, Prague (Czech Republic); Chekelian, V.; Grindhammer, G.; Kiesling, C.; Lobodzinski, B. [Max-Planck-Institut fuer Physik, Munich (Germany); Cvach, J.; Hladka, J.; Reimer, P. [Academy of Sciences of the Czech Republic, Institute of Physics, Prague (Czech Republic); Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kostka, P.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D. [University of Liverpool, Department of Physics, Liverpool (United Kingdom); Daum, K. [Fachbereich C, Universitaet Wuppertal, Wuppertal (Germany); Universitaet Wuppertal, Rechenzentrum, Wuppertal (Germany); Diaconu, C.; Hoffmann, D.; Vallee, C. [Aix Marseille Universite, CNRS/IN2P3, CPPM UMR 7346, Marseille (France); Dobre, M.; Rotaru, M. [Horia Hulubei National Institute for R and D in Physics and Nuclear Engineering (IFIN-HH), Bucharest (Romania); Egli, S.; Horisberger, R. [Paul Scherrer Institut, Villigen (Switzerland); Favart, L.; Grebenyuk, A.; Hreus, T.; Janssen, X.; Roosen, R.; Van Mechelen, P. [Inter-University Institute for High Energies ULB-VUB, Brussels and Universiteit Antwerpen, Antwerp (Belgium); Feltesse, J.; Schoeffel, L. [Irfu/SPP, CE Saclay, Gif-sur-Yvette Cedex (France); Ferencei, J. [Slovak Academy of Sciences, Institute of Experimental Physics, Kosice (Slovakia); Goerlich, L.; Mikocki, S.; Nowak, G.; Sopicki, P.; Turnau, J. [Institute of Nuclear Physics Polish Academy of Sciences, Krakow (Poland); Gouzevitch, M.; Petrukhin, A. [IPNL, Universite Claude Bernard Lyon 1, CNRS/IN2P3, Villeurbanne (France); Grab, C. [Institut fuer Teilchenphysik, ETH, Zurich (Switzerland); Henderson, R.C.W. [University of Lancaster, Department of Physics, Lancaster (United Kingdom); Jung, H. [Inter-University Institute for High Energies ULB-VUB, Brussels and Universiteit Antwerpen, Antwerp (Belgium); DESY, Hamburg (Germany); Kapichine, M.; Morozov, A.; Spaskov, V. [Joint Institute for Nuclear Research, Dubna (RU); Kogler, R. [Universitaet Hamburg, Institut fuer Experimentalphysik, Hamburg (DE); Landon, M.P.J.; Rizvi, E.; Traynor, D. [Queen Mary, University of London, School of Physics and Astronomy, London (GB); Lange, W.; Naumann, T. [DESY, Zeuthen (DE); Martyn, H.U. [I. Physikalisches Institut der RWTH, Aachen (DE); Meyer, H. [Fachbereich C, Universitaet Wuppertal, Wuppertal (DE); Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P. [Physik-Institut der Universitaet Zuerich, Zurich (CH); Perez, E. [CERN, Geneva (CH); Picuric, I.; Raicevic, N. [University of Montenegro, Faculty of Science, Podgorica (ME); Polifka, R. [Charles University, Faculty of Mathematics and Physics, Prague (CZ); University of Toronto, Department of Physics, Toronto, ON (CA); Povh, B. [Max-Planck-Institut fuer Kernphysik, Heidelberg (DE); Rostovtsev, A. [Institute for Information Transmission Problems RAS, Moscow (RU); Sankey, D.P.C. [STFC, Rutherford Appleton Laboratory, Didcot, Oxfordshire (GB); Sauvan, E. [Aix Marseille Universite, CNRS/IN2P3, CPPM UMR 7346, Marseille (FR); Universite de Savoie, CNRS/IN2P3, LAPP, Annecy-le-Vieux (FR); Soloviev, Y. [DESY, Hamburg (DE); Lebedev Physical Institute, Moscow (RU); Stella, B. [Universita di Roma Tre, Dipartimento di Fisica, Rome (IT); INFN Roma 3 (IT); Sykora, T. [Inter-University Institute for High Energies ULB-VUB, Brussels and Universiteit Antwerpen, Antwerp (BE); Charles University, Faculty of Mathematics and Physics, Prague (CZ); Tsakov, I. [Institute for Nuclear Research and Nuclear Energy, Sofia (BG); Tseepeldorj, B. [Institute of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (MN); Ulaanbaatar University, Ulaanbaatar (MN); Wegener, D. [TU Dortmund, Institut fuer Physik, Dortmund (DE); Collaboration: H1 Collaboration

    2016-01-15

    A first measurement is presented of exclusive photoproduction of ρ{sup 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 √(s) = 319 GeV and correspond to an integrated luminosity of 1.16 pb{sup -1}. The ρ{sup 0} mesons with transverse momenta p{sub T} < 1 GeV are reconstructed from their decays to charged pions, while leading neutrons carrying a large fraction of the incoming proton momentum, x{sub L} > 0.35, are detected in the Forward Neutron Calorimeter. The phase space of the measurement is defined by the photon virtuality Q{sup 2} < 2 GeV{sup 2}, the total energy of the photon.proton system 20 < W{sub γp} < 100 GeV and the polar angle of the leading neutron θ{sub n} < 0.75 mrad. The cross section of the reaction γp → ρ{sup 0}nπ{sup +} is 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 ρ{sup 0} meson on the virtual pion. In the framework of one-pion-exchange dominance the elastic cross section of photon-pion scattering, σ{sup el}(γπ{sup +} → ρ{sup 0}π{sup +}), is extracted. The value of this cross section indicates significant absorptive corrections for the exclusive reaction γp → ρ{sup 0}nπ{sup +}. (orig.)

  10. Photoproduction of Scalar Mesons Using the CEBAF Large Acceptance Spectrometer (CLAS)

    Science.gov (United States)

    Chandavar, Shloka K.

    The search for glueballs has been ongoing for several decades. The lightest glueball has been predicted by quenched lattice QCD to have mass in the range of 1.0--1.7 GeV and JPC = 0++ . The mixing of glueball states with neighbouring meson states complicates their identification and hence several experiments have been carried out over the years to study the glueball candidates. By analyzing the decay channels and production mechanisms of these candidates, their glueball content can theoretically be determined. In reality, a lot of confusion still exists about the status of these glueball candidates. The f0(1500) is one of several contenders for the lightest glueball, which has been extensively studied in several different kinds of experiments. However, there exists no photoproduction data on this particle. In the analysis presented in this dissertation, the presence of the f0(1500) in the KS 0KS0 channel is investigated in photoproduction using the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Accelerator Facility, also called Jefferson Lab (JLab). This is done by studying the reaction, gammap → fJp → KS0 KS0p → 2(pi +pi-)p using data from the g12 experiment. A clear peak is seen at 1500 MeV in the background subtracted data. This is enhanced if the momentum transfer is restricted to be less than 1 GeV2. Comparing with simulations, it is seen that this peak is associated with t channel production mechanism. The f 2'(1525) has a mass of 1525 MeV and a width of 73 MeV, and hence there is a possibility of it contributing to the peak observed in our data. A moments analysis seems to suggest some presence of a D wave, however, the low acceptance at forward and backward angles prohibits a definitive conclusion.

  11. The thymine-thymine pyrimidine-pyrimidone(6-4) ultraviolet light photoproduct is highly mutagenic and specifically induces 3' thymine-to-cytosine transitions in Escherichia coli

    International Nuclear Information System (INIS)

    LeClerc, J.E.; Borden, A.; Lawrence, C.W.

    1991-01-01

    The authors have constructed single-stranded, M13-based vectors that contain a specifically located thymine-thymine pyrimidine-pyrimidone(6-4) UV photoproduct and have used these to estimate the frequency and accuracy of DNA replication past this adduct in uvrA6 cells of Escherichia coli. Both the normal and the Dewar valence photoisomer of the (6-4) adduct were studied. In the absence of SOS induction, vectors carrying the photoproducts were rarely replicated; relative to the lesion-free control, 1.9% of vectors carrying the normal (6-4) isomer produced plaques, and with the Dewar valence isomer the proportion was 0.4%. In SOS-induced cells, these frequencies rose to 22.1% and 12.3%, respectively. The error frequency of replication past the normal isomer in SOS-induced cells was high. They speculate that the high error frequency and specificity arise from the formation of a stable T·G base pair, involving hydrogen bonds at O-2 and N-3 in the pyrimidone ring. Potential hydrogen bonds at these sites are coplanar in the normal but not in the Dewar isomer, perhaps explaining the reduced specificity of mutagenesis with the latter adduct

  12. Search for Odderon induced contributions to exclusive Meson Photoproduction at HERA

    International Nuclear Information System (INIS)

    Olsson, J.

    2001-01-01

    A search for exclusive photoproduction of π 0 , f 2 (1270) and a 2 (1320), induced by Odderon exchange, was performed using multi-photon final states. No signal was found. Upper limits for the cross sections are below the predictions of a model based on non-perturbative QCD. Exclusive ω and ωπ 0 photoproduction is observed in three and five photon final states, at levels consistent with the expectations from Pomeron exchange and consistent with other observations of exclusive vector and axial vector meson photoproduction

  13. Exclusive J /ψ photoproduction off protons in ultraperipheral p -Pb collisions at sNN =5.02TeV

    NARCIS (Netherlands)

    Abelev, B.; Adam, J.; Adamová, D.; Aggarwal, M. M.; Aglieri Rinella, G.; Agnello, M.; Agostinelli, A.; Agrawal, N.; Ahammed, Z.; Ahmad, N.; Ahmed, I.; Ahn, S. U.; Ahn, S. A.; Aimo, I.; Aiola, S.; Ajaz, M.; Akindinov, A.; Alam, S. N.; Aleksandrov, D.; Alessandro, B.; Alexandre, D.; Alici, A.; Alkin, A.; Alme, J.; Alt, T.; Altinpinar, S.; Altsybeev, I.; Alves Garcia Prado, C.; Andrei, C.; Andronic, A.; Anguelov, V.; Anielski, J.; Antičić, T.; Antinori, F.; Antonioli, P.; Aphecetche, L.; Appelshäuser, H.; Arcelli, S.; Armesto, N.; Arnaldi, R.; Aronsson, T.; Arsene, I. C.; Arslandok, M.; Augustinus, A.; Averbeck, R.; Awes, T. C.; Azmi, M. D.; Bach, M.; Badalà, A.; Baek, Y. W.; Bagnasco, S.; Bailhache, R.; Bala, R.; Baldisseri, A.; Baltasar Dos Santos Pedrosa, F.; Baral, R. C.; Barbera, R.; Barile, F.; Barnaföldi, G. G.; Barnby, L. S.; Barret, V.; Bartke, J.; Basile, M.; Bastid, N.; Basu, S.; Bathen, B.; Batigne, G.; Batista Camejo, A.; Batyunya, B.; Batzing, P. C.; Baumann, C.; Bearden, I. G.; Beck, H.; Bedda, C.; Behera, N. K.; Belikov, I.; Bellini, F.; Bellwied, R.; Belmont-Moreno, E.; Belmont, R.; Belyaev, V.; Bencedi, G.; Beole, S.; Berceanu, I.; Bercuci, A.; Berdnikov, Y.; Berenyi, D.; Berger, M. E.; Bertens, R. A.; Berzano, D.; Betev, L.; Bhasin, A.; Bhat, I. R.; Bhati, A. K.; Bhattacharjee, B.; Bhom, J.; Bianchi, L.; Bianchi, N.; Bianchin, C.; Bielčík, J.; Bielčíková, J.; Bilandzic, A.; Bjelogrlic, S.; Blanco, F.; Blau, D.; Blume, C.; Bock, F.; Bogdanov, A.; Bøggild, H.; Bogolyubsky, M.; Böhmer, F. V.; Boldizsár, L.; Bombara, M.; Book, J.; Borel, H.; Borissov, A.; Bossú, F.; Botje, M.; Botta, E.; Böttger, S.; Braun-Munzinger, P.; Bregant, M.; Breitner, T.; Broker, T. A.; Browning, T. A.; Broz, M.; Bruna, E.; Bruno, G. E.; Budnikov, D.; Buesching, H.; Bufalino, S.; Buncic, P.; Busch, O.; Buthelezi, Z.; Caffarri, D.; Cai, X.; Caines, H.; Calero Diaz, L.; Caliva, A.; Calvo Villar, E.; Camerini, P.; Carena, F.; Carena, W.; Castillo Castellanos, J.; Casula, E. A R; Catanescu, V.; Cavicchioli, C.; Ceballos Sanchez, C.; Cepila, J.; Cerello, P.; Chang, B.; Chapeland, S.; Charvet, J. L.; Chattopadhyay, S.; Chattopadhyay, S.; Chelnokov, V.; Cherney, M.; Cheshkov, C.; Cheynis, B.; Chibante Barroso, V.; Chinellato, D. D.; Chochula, P.; Chojnacki, M.; Choudhury, S.; Christakoglou, P.; Christensen, C. H.; Christiansen, P.; Chujo, T.; Chung, S. U.; Cicalo, C.; Cifarelli, L.; Cindolo, F.; Cleymans, J.; Colamaria, F.; Colella, D.; Collu, A.; Colocci, M.; Conesa Balbastre, G.; Conesa Del Valle, Z.; Connors, M. E.; Contreras, J. G.; Cormier, T. M.; Corrales Morales, Y.; Cortese, P.; Cortés Maldonado, I.; Cosentino, M. R.; Costa, F.; Crochet, P.; Cruz Albino, R.; Cuautle, E.; Cunqueiro, L.; Dainese, A.; Dang, R.; Danu, A.; Das, D.; Das, I.; Das, K.; Das, S.; Dash, A.; Dash, S.; De, S.; Delagrange, H.; Deloff, A.; Dénes, E.; D'erasmo, G.; De Caro, A.; De Cataldo, G.; De Cuveland, J.; De Falco, A.; De Gruttola, D.; De Marco, N.; De Pasquale, S.; De Rooij, R.; Diaz Corchero, M. A.; Dietel, T.; Dillenseger, P.; Divià, R.; Di Bari, D.; Di Liberto, S.; Di Mauro, A.; Di Nezza, P.; Djuvsland, O.; Dobrin, A.; Dobrowolski, T.; Domenicis Gimenez, D.; Dönigus, B.; Dordic, O.; Dørheim, S.; Dubey, A. K.; Dubla, A.; Ducroux, L.; Dupieux, P.; Dutta Majumdar, A. K.; Hilden, T. E.; Ehlers, R. J.; Elia, D.; Engel, H.; Erazmus, B.; Erdal, H. A.; Eschweiler, D.; Espagnon, B.; Esposito, M.; Estienne, M.; Esumi, S.; Evans, D.; Evdokimov, S.; Fabris, D.; Faivre, J.; Falchieri, D.; Fantoni, A.; Fasel, M.; Fehlker, D.; Feldkamp, L.; Felea, D.; Feliciello, A.; Feofilov, G.; Ferencei, J.; Fernández Téllez, A.; Ferreiro, E. G.; Ferretti, A.; Festanti, A.; Figiel, J.; Figueredo, M. A S; Filchagin, S.; Finogeev, D.; Fionda, F. M.; Fiore, E. M.; Floratos, E.; Floris, M.; Foertsch, S.; Foka, P.; Fokin, S.; Fragiacomo, E.; Francescon, A.; Frankenfeld, U.; Fuchs, U.; Furget, C.; Furs, A.; Fusco Girard, M.; Gaardhøje, J. J.; Gagliardi, M.; Gago, A. M.; Gallio, M.; Gangadharan, D. R.; Ganoti, P.; Gao, C.; Garabatos, C.; Garcia-Solis, E.; Gargiulo, C.; Garishvili, I.; Gerhard, J.; Germain, M.; Gheata, A.; Gheata, M.; Ghidini, B.; Ghosh, P.; Ghosh, S. K.; Gianotti, P.; Giubellino, P.; Gladysz-Dziadus, E.; Glässel, P.; Gomez Ramirez, A.; González-Zamora, P.; Gorbunov, S.; Görlich, L.; Gotovac, S.; Graczykowski, L. K.; Grelli, A.; Grigoras, A.; Grigoras, C.; Grigoriev, V.; Grigoryan, A.; Grigoryan, S.; Grinyov, B.; Grion, N.; Grosse-Oetringhaus, J. F.; Grossiord, J. Y.; Grosso, R.; Guber, F.; Guernane, R.; Guerzoni, B.; Guilbaud, M.; Gulbrandsen, K.; Gulkanyan, H.; Gumbo, M.; Gunji, T.; Gupta, A.; Gupta, R.; Khan, K. H.; Haake, R.; Haaland, O.; Hadjidakis, C.; Haiduc, M.; Hamagaki, H.; Hamar, G.; Hanratty, L. D.; Hansen, A.; Harris, J. W.; Hartmann, H.; Harton, A.; Hatzifotiadou, D.; Hayashi, S.; Heckel, S. T.; Heide, M.; Helstrup, H.; Herghelegiu, A.; Herrera Corral, G.; Hess, B. A.; Hetland, K. F.; Hippolyte, B.; Hladky, J.; Hristov, P.; Huang, M.; Humanic, T. J.; Hussain, N.; Hutter, D.; Hwang, D. S.; Ilkaev, R.; Ilkiv, I.; Inaba, M.; Innocenti, G. M.; Ionita, C.; Ippolitov, M.; Irfan, M.; Ivanov, M.; Ivanov, V.; Jachołkowski, A.; Jacobs, P. M.; Jahnke, C.; Jang, H. J.; Janik, M. A.; Jayarathna, P. H S Y; Jena, C.; Jena, S.; Jimenez Bustamante, R. T.; Jones, P. G.; Jung, H.; Jusko, A.; Kadyshevskiy, V.; Kalcher, S.; Kalinak, P.; Kalweit, A.; Kamin, J.; Kang, J. H.; Kaplin, V.; Kar, S.; Karasu Uysal, A.; Karavichev, O.; Karavicheva, T.; Karpechev, E.; Kebschull, U.; Keidel, R.; Keijdener, D. L D; Keil Svn, M.; Khan, M. M.; Khan, P.; Khan, S. A.; Khanzadeev, A.; Kharlov, Y.; Kileng, B.; Kim, B.; Kim, D. W.; Kim, D. J.; Kim, J. S.; Kim, M.; Kim, M.; Kim, S.; Kim, T.; Kirsch, S.; Kisel, I.; Kiselev, S.; Kisiel, A.; Kiss, G.; Klay, J. L.; Klein, J.; Klein-Bösing, C.; Kluge, A.; Knichel, M. L.; Knospe, A. G.; Kobdaj, C.; Kofarago, M.; Köhler, M. K.; Kollegger, T.; Kolojvari, A.; Kondratiev, V.; Kondratyeva, N.; Konevskikh, A.; Kovalenko, V.; Kowalski, M.; Kox, S.; Koyithatta Meethaleveedu, G.; Kral, J.; Králik, I.; Kravčáková, A.; Krelina, M.; Kretz, M.; Krivda, M.; Krizek, F.; Kryshen, E.; Krzewicki, M.; Kučera, V.; Kucheriaev, Y.; Kugathasan, T.; Kuhn, C.; Kuijer, P. G.; Kulakov, I.; Kumar, J.; Kurashvili, P.; Kurepin, A.; Kurepin, A. B.; Kuryakin, A.; Kushpil, S.; Kweon, M. J.; Kwon, Y.; Ladron De Guevara, P.; Lagana Fernandes, C.; Lakomov, I.; Langoy, R.; Lara, C.; Lardeux, A.; Lattuca, A.; La Pointe, S. L.; La Rocca, P.; Lea, R.; Leardini, L.; Lee, G. R.; Legrand, I.; Lehnert, J.; Lemmon, R. C.; Lenti, V.; Leogrande, E.; Leoncino, M.; León Monzón, I.; Lévai, P.; Li, S.; Lien, J.; Lietava, R.; Lindal, S.; Lindenstruth, V.; Lippmann, C.; Lisa, M. A.; Ljunggren, H. M.; Lodato, D. F.; Loenne, P. I.; Loggins, V. R.; Loginov, V.; Lohner, D.; Loizides, C.; Lopez, X.; López Torres, E.; Lu, X. G.; Luettig, P.; Lunardon, M.; Luparello, G.; Ma, R.; Maevskaya, A.; Mager, M.; Mahapatra, D. P.; Mahmood, S. M.; Maire, A.; Majka, R. D.; Malaev, M.; Maldonado Cervantes, I.; Malinina, L.; Mal'kevich, D.; Malzacher, P.; Mamonov, A.; Manceau, L.; Manko, V.; Manso, F.; Manzari, V.; Marchisone, M.; Mareš, J.; Margagliotti, G. V.; Margotti, A.; Marín, A.; Markert, C.; Marquard, M.; Martashvili, I.; Martin, N. A.; Martinengo, P.; Martínez, M. I.; Martínez García, G.; Martin Blanco, J.; Martynov, Y.; Mas, A.; Masciocchi, S.; Masera, M.; Masoni, A.; Massacrier, L.; Mastroserio, A.; Matyja, A.; Mayer, C.; Mazer, J.; Mazzoni, M. A.; Meddi, F.; Menchaca-Rocha, A.; Meninno, E.; Mercado Pérez, J.; Meres, M.; Miake, Y.; Mikhaylov, K.; Milano, L.; Milosevic, J.; Mischke, A.; Mishra, A. N.; Mis̈kowiec, D.; Mitra, J.; Mitu, C. M.; Mlynarz, J.; Mohammadi, N.; Mohanty, B.; Molnar, L.; Montaño Zetina, L.; Montes, E.; Morando, M.; Moreira De Godoy, D. A.; Moretto, S.; Morreale, A.; Morsch, A.; Muccifora, V.; Mudnic, E.; Mühlheim, D.; Muhuri, S.; Mukherjee, M.; Müller, H.; Munhoz, M. G.; Murray, S.; Musa, L.; Musinsky, J.; Nandi, B. K.; Nania, R.; Nappi, E.; Nattrass, C.; Nayak, K.; Nayak, T. K.; Nazarenko, S.; Nedosekin, A.; Nicassio, M.; Niculescu, M.; Nielsen, B. S.; Nikolaev, S.; Nikulin, S.; Nikulin, V.; Nilsen, B. S.; Noferini, F.; Nomokonov, P.; Nooren, G.; Norman, J.; Nyanin, A.; Nystrand, J.; Oeschler, H.; Oh, S.; Oh, S. K.; Okatan, A.; Olah, L.; Oleniacz, J.; Oliveira Da Silva, A. C.; Onderwaater, J.; Oppedisano, C.; Ortiz Velasquez, A.; Oskarsson, A.; Otwinowski, J.; Oyama, K.; Ozdemir, M.; Sahoo, P.; Pachmayer, Y.; Pachr, M.; Pagano, P.; Paić, G.; Painke, F.; Pajares, C.; Pal, S. K.; Palmeri, A.; Pant, D.; Papikyan, V.; Pappalardo, G. S.; Pareek, P.; Park, W. J.; Parmar, S.; Passfeld, A.; Patalakha, D. I.; Paticchio, V.; Paul, B.; Pawlak, T.; Peitzmann, T.; Pereira Da Costa, H.; Pereira De Oliveira Filho, E.; Peresunko, D.; Pérez Lara, C. E.; Pesci, A.; Peskov, V.; Pestov, Y.; Petráček, V.; Petran, M.; Petris, M.; Petrovici, M.; Petta, C.; Piano, S.; Pikna, M.; Pillot, P.; Pinazza, O.; Pinsky, L.; Piyarathna, D. B.; Płoskoń, M.; Planinic, M.; Pluta, J.; Pochybova, S.; Podesta-Lerma, P. L M; Poghosyan, M. G.; Pohjoisaho, E. H O; Polichtchouk, B.; Poljak, N.; Pop, A.; Porteboeuf-Houssais, S.; Porter, J.; Potukuchi, B.; Prasad, S. K.; Preghenella, R.; Prino, F.; Pruneau, C. A.; Pshenichnov, I.; Puddu, G.; Pujahari, P.; Punin, V.; Putschke, J.; Qvigstad, H.; Rachevski, A.; Raha, S.; Rak, J.; Rakotozafindrabe, A.; Ramello, L.; Raniwala, R.; Raniwala, S.; Räsänen, S. S.; Rascanu, B. T.; Rathee, D.; Rauf, A. W.; Razazi, V.; Read, K. F.; Real, J. S.; Redlich, K.; Reed, R. J.; Rehman, A.; Reichelt, P.; Reicher, M.; Reidt, F.; Renfordt, R.; Reolon, A. R.; Reshetin, A.; Rettig, F.; Revol, J. P.; Reygers, K.; Riabov, V.; Ricci, R. A.; Richert, T.; Richter, M.; Riedler, P.; Riegler, W.; Riggi, F.; Rivetti, A.; Rocco, E.; Rodríguez Cahuantzi, M.; Rodriguez Manso, A.; Røed, K.; Rogochaya, E.; Rohni, S.; Rohr, D.; Röhrich, D.; Romita, R.; Ronchetti, F.; Ronflette, L.; Rosnet, P.; Rossi, A.; Roukoutakis, F.; Roy, A.; Roy, C.; Roy, P.; Rubio Montero, A. J.; Rui, R.; Russo, R.; Ryabinkin, E.; Ryabov, Y.; Rybicki, A.; Sadovsky, S.; Šafařík, K.; Sahlmuller, B.; Sahoo, R.; Sahu, P. K.; Saini, J.; Sakai, S.; Salgado, C. A.; Salzwedel, J.; Sambyal, S.; Samsonov, V.; Sanchez Castro, X.; Sánchez Rodríguez, F. J.; Šándor, L.; Sandoval, A.; Sano, M.; Santagati, G.; Sarkar, D.; Scapparone, E.; Scarlassara, F.; Scharenberg, R. P.; Schiaua, C.; Schicker, R.; Schmidt, C.; Schmidt, H. R.; Schuchmann, S.; Schukraft, J.; Schulc, M.; Schuster, T.; Schutz, Y.; Schwarz, K.; Schweda, K.; Scioli, G.; Scomparin, E.; Scott, R.; Segato, G.; Seger, J. E.; Sekiguchi, Y.; Selyuzhenkov, I.; Seo, J.; Serradilla, E.; Sevcenco, A.; Shabetai, A.; Shabratova, G.; Shahoyan, R.; Shangaraev, A.; Sharma, N.; Sharma, S.; Shigaki, K.; Shtejer, K.; Sibiriak, Y.; Siddhanta, S.; Siemiarczuk, T.; Silvermyr, D.; Silvestre, C.; Simatovic, G.; Singaraju, R.; Singh, R.; Singha, S.; Singhal, V.; Sinha, B. C.; Sinha, T.; Sitar, B.; Sitta, M.; Skaali, T. B.; Skjerdal, K.; Slupecki, M.; Smirnov, N.; Snellings, R. J M; Søgaard, C.; Soltz, R.; Song, J.; Song, M.; Soramel, F.; Sorensen, S.; Spacek, M.; Spiriti, E.; Sputowska, I.; Spyropoulou-Stassinaki, M.; Srivastava, B. K.; Stachel, J.; Stan, I.; Stefanek, G.; Steinpreis, M.; Stenlund, E.; Steyn, G.; Stiller, J. H.; Stocco, D.; Stolpovskiy, M.; Strmen, P.; Suaide, A. A P; Sugitate, T.; Suire, C.; Suleymanov, M.; Sultanov, R.; Šumbera, M.; Susa, T.; Symons, T. J M; Szabo, A.; Szanto De Toledo, A.; Szarka, I.; Szczepankiewicz, A.; Szymanski, M.; Takahashi, J.; Tangaro, M. A.; Tapia Takaki, J. D.; Tarantola Peloni, A.; Tarazona Martinez, A.; Tarzila, M. G.; Tauro, A.; Tejeda Muñoz, G.; Telesca, A.; Terrevoli, C.; Thäder, J.; Thomas, D.; Tieulent, R.; Timmins, A. R.; Toia, A.; Trubnikov, V.; Trzaska, W. H.; Tsuji, T.; Tumkin, A.; Turrisi, R.; Tveter, T. S.; Ullaland, K.; Uras, A.; Usai, G. L.; Vajzer, M.; Vala, M.; Valencia Palomo, L.; Vallero, S.; Vande Vyvre, P.; Van Der Maarel, J.; Van Hoorne, J. W.; Van Leeuwen, M.; Vargas, A.; Vargyas, M.; Varma, R.; Vasileiou, M.; Vasiliev, A.; Vechernin, V.; Veldhoen, M.; Velure, A.; Venaruzzo, M.; Vercellin, E.; Vergara Limón, S.; Vernet, R.; Verweij, M.; Vickovic, L.; Viesti, G.; Viinikainen, J.; Vilakazi, Z.; Villalobos Baillie, O.; Vinogradov, A.; Vinogradov, L.; Vinogradov, Y.; Virgili, T.; Viyogi, Y. P.; Vodopyanov, A.; Völkl, M. A.; Voloshin, K.; Voloshin, S. A.; Volpe, G.; Von Haller, B.; Vorobyev, I.; Vranic, D.; Vrláková, J.; Vulpescu, B.; Vyushin, A.; Wagner, B.; Wagner, J.; Wagner, V.; Wang, M.; Wang, Y.; Watanabe, D.; Weber, M.; Wessels, J. P.; Westerhoff, U.; Wiechula, J.; Wikne, J.; Wilde, M.; Wilk, G.; Wilkinson, J.; Williams, M. C S; Windelband, B.; Winn, M.; Yaldo, C. G.; Yamaguchi, Y.; Yang, H.; Yang, P.; Yang, S.; Yano, S.; Yasnopolskiy, S.; Yi, J.; Yin, Z.; Yoo, I. K.; Yushmanov, I.; Zaccolo, V.; Zach, C.; Zaman, A.; Zampolli, C.; Zaporozhets, S.; Zarochentsev, A.; Závada, P.; Zaviyalov, N.; Zbroszczyk, H.; Zgura, I. S.; Zhalov, M.; Zhang, H.; Zhang, X.; Zhang, Y.; Zhao, C.; Zhigareva, N.; Zhou, D.; Zhou, F.; Zhou, Y.; Zhou, Zhuo; Zhu, H.; Zhu, J.; Zhu, X.; Zichichi, A.; Zimmermann, A.; Zimmermann, M. B.; Zinovjev, G.; Zoccarato, Y.; Zyzak, M.

    2014-01-01

    We present the first measurement at the LHC of exclusive J/ψ photoproduction off protons, in ultraperipheral proton-lead collisions at sNN=5.02TeV. Events are selected with a dimuon pair produced either in the rapidity interval, in the laboratory frame, 2.5

  14. Λc photoproduction and lifetime measurement

    International Nuclear Information System (INIS)

    Amendolia, S.R.; Bagliesi, G.; Batignani, G.; Bertolucci, E.; Bettoni, D.; Bizetti, A.; Bosisio, L.; Bottigli, U.; Bradaschia, C.; Dell'Orso, M.; Fidecaro, F.; Foa, L.; Focardi, E.; Giannetti, P.; Giorgi, M.A.; Marrocchesi, P.S.; Menzione, A.; Raso, G.; Ristori, L.; Scribano, A.; Stefanini, A.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Beck, G.A.; Bologna, G.; D'Ettorre Piazzoli, B.; Picchi, P.; Budinich, M.; Liello, F.; Milotti, E.; Rolandi, L.; Carter, J.; Green, M.G.; Landon, M.P.J.; March, P.V.; Sacks, L.; Sanjari, A.H.; Strong, J.A.; Ciocci, M.A.; Enorini, M.; Fabbri, F.L.; Laurelli, P.; Mannocchi, G.; Simonelli, L.; Spillantini, P.; Zallo, A.

    1987-01-01

    A measurement of the lifetime of the Λ c baryon photoproduced coherently of a germanium-silicon target is presented. A signal of Λ c → ΔΚ * → pKππ 0 has been observed and the two different decay diagrams for this process are compared. A sample of 9 Λ c decays give a lifetime of 1.1(+0.8-0.4)10 13 s. (orig.)

  15. Investigating the impact of the gluon saturation effects on the momentum transfer distributions for the exclusive vector meson photoproduction in hadronic collisions

    Directory of Open Access Journals (Sweden)

    V.P. Gonçalves

    2017-05-01

    Full Text Available The exclusive vector meson production cross section is one of the most promising observables to probe the high energy regime of the QCD dynamics. In particular, the squared momentum transfer (t distributions are an important source of information about the spatial distribution of the gluons in the hadron and about fluctuations of the color fields. In this paper we complement previous studies on exclusive vector meson photoproduction in hadronic collisions presenting a comprehensive analysis of the t-spectrum measured in exclusive ρ, ϕ and J/Ψ photoproduction in pp and PbPb collisions at the LHC. We compute the differential cross sections taking into account gluon saturation effects and compare the predictions with those obtained in the linear regime of the QCD dynamics. Our results show that gluon saturation suppresses the magnitude of the cross sections and shifts the position of the dips towards smaller values of t.

  16. Polarization Measurements in Neutral Pion Photoproduction

    International Nuclear Information System (INIS)

    C. Jones; Krishni Wijesooriya; B. Fox; Andrei Afanasev; Moscov Amaryan; Konrad Aniol; Stephen Becher; Kamal Benslama; Louis Bimbot; Peter Bosted; Edward Brash; John Calarco; Zhengwei Chai; C. Chang; Ting Chang; Jian-Ping Chen; Seonho Choi; Eugene Chudakov; Steve Churchwell; Domenick Crovelli; Sonja Dieterich; Scott Dumalski; Dipangkar Dutta; Martin Epstein; Kevin Fissum; Salvatore Frullani; Haiyan Gao; Juncai Gao; Franco Garibaldi; Olivier Gayou; Ronald Gilman; Oleksandr Glamazdin; Charles Glashausser; Javier Gomez; Viktor Gorbenko; Ole Hansen; Roy Holt; Jordan Hovdebo; Garth Huber; Kees de Jager; Xiaodong Jiang; Mark Jones; Jim Kelly; Edward Kinney; Edgar Kooijman; Gerfried Kumbartzki; Michael Kuss; John LeRose; Meme Liang; Richard Lindgren; Nilanga Liyanage; Sergey Malov; Demetrius Margaziotis; Pete Markowitz; Kathy McCormick; Dave Meekins; Zein-Eddine Meziani; Robert Michaels; Joe Mitchell; Ludyvine Morand; Charles Perdrisat

    2002-01-01

    We present measurements of the recoil proton polarization for the 1 H(gamma-vector,p-vector)pi 0 reaction for theta c.m. pi = 60 o -135 o and for photon energies up to 4.1 GeV. These are the first data in this reaction for polarization transfer with circularly polarized photons. Various theoretical models are compared with the results. No evidence for hadron helicity conservation is observed. Models that employ factorization are not favored. It appears from the strong angular dependence of the induced polarization at photon energies of 2.5 and 3.1 GeV that a relatively high spin resonance or background amplitude might exist in this energy region

  17. Color-singlet and color-octet contributions to J/ψ photoproduction

    International Nuclear Information System (INIS)

    Kraemer, M.

    1996-09-01

    I discuss the impact of color-octet contributions and higher-order QCD corrections on the cross section for inelastic J/ψ photoproduction. The theoretical predictions are compared with recent experimental data obtained at HERA. (orig.)

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

    International Nuclear Information System (INIS)

    Mariotto, C. Brenner; Ducati, M.B. Gay; Machado, M.V.T.

    2002-01-01

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

  19. The relative cytotoxicity and mutagenicity of cyclobutane pyrimidine dimers and photoproducts in Escherichia coli cells

    International Nuclear Information System (INIS)

    Tang, Moon-shong; Hrncir, J.; Mitchell, D.; Ross, J.; Clarkson, J.

    1986-01-01

    In order to calculate the relative cytotoxicity and mutagenicity of cyclobutane pyrimidine dimers and photoproducts, the authors have measured survival and mutation induction in UV-irradiated excision-deficient E. coli uvrA cells, with or without complete photoreactivation of the dimers. Radioimmunoassays with specificity for dimers or photoproducts have shown that maximum photoreactivation eliminates all of the dimers produce up to 10 Jm -2 254-nm light, while it has no effect on photoproducts. These results were confirmed by measuring the frequency of T4 endonuclease V-sensitive sites. Based on the best fit equations for survival and mutation induction, the authors have found that the calculated cytotoxicity of photoproducts is similar to that of dimers; however, the former is much more mutagenic than the latter. (Auth.)

  20. Study of the strangeness photoproduction on deuteron

    International Nuclear Information System (INIS)

    Rouvier, F.

    1997-01-01

    Hypernuclear physics has been getting more and more attention in the last fifteen years with the realization that it is important to study hyperon - nucleon interactions in addition to nucleon - nucleon interactions in order to have a comprehensive understanding of strong interactions. One is to study final-state interactions in processes initiated with electromagnetic probes. In this thesis we focus our attention on a particular case of hyperon-nucleon interaction, namely the Λn interaction in the continuum. The reaction γd → K +Λn is ideal for this purpose. A covariant formalism developed from an effective Lagrangian and based upon an isobaric approach is used to perform a thorough study of the electromagnetic strangeness process γd → K +Λn , for 0.8 ≤ E γ ≤ 1.7 GeV. The present model using a diagrammatic technique consists of the loop Feynman's diagram evaluation by means of the relativistic impulse approximation (the neutron is considered as spectator on its mass-shell during the process). First, we have therefore to calculate the three diagram which dominates the dynamics by its pole terms and does not include the final-state interaction. A Watson-Migdal approximation is first used to incorporate the final-state interaction Λn without Λ ↔ Σ conversion. Secondly, we have calculated the full loop diagram with many potentials models in a slow-variation approximation. It consists of extracting the tree diagram amplitude T fi t from the integral which calculates the full loop diagram T fi l . In conclusion, we have examined the changes caused by (Λ - Σ)n final-state interaction on d 3σ , d 2σ and Λ polarization for various kinematical choices. (author)

  1. 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.

  2. Off-shell form factors in the soft photon limit for pion photoproduction

    International Nuclear Information System (INIS)

    Chumbalov, A.A.; Kamalov, S.S.

    1991-01-01

    The low energy theorems for the pion photoproduction are considered on the basis of the Adler-Dothan procedure. It is shown that the soft photon limit necessarily leads to the Born approximation for the π 0 -photoproduction amplitude at the threshold. All additional terms, according to the Adler-Dothan recipe, are to be neglected in the derivation of the LET. 5 refs.; 2 figs

  3. Energy-independent multiple analysis of one-pion photoproduction processes on protons

    Energy Technology Data Exchange (ETDEWEB)

    Get' man, V.A.; Sanin, V.M.; Telegin, Yu.N.; Shalatskij, S.V. (AN Ukrainskoj SSR, Kharkov. Fiziko-Tekhnicheskij Inst.)

    1983-08-01

    For the first time unambiguous estimates are obtained for the multipole photoproduction amplitudes which are based upon the new experimental data on the pion photoproduction on protons combined with the new estiamtes of the ..pi..N-scattering phase shifts. The obtained estimates of the multipole amplitudes are compared with the results of the previous multipole analyses and with the predictions based uoon the dispersion relations.

  4. 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.)

  5. Lambda Polarization in Exclusive Electro- and Photoproduction at CLAS

    International Nuclear Information System (INIS)

    Mestayer, M.D.

    2003-01-01

    The CLAS collaboration at JLab has recent results on Λ polarization for both electroproduction and photoproduction of K + Λ exclusive states. I note the striking phenomenological trends in the data and discuss the underlying physics which might give rise to these phenomena; both in the context of an e.ective Lagrangian formalism, where the degrees of freedom are intermediate mesons and baryons, and also in the context of a simple quark picture. The quark model argument leads to the conclusion that the s and (bar s) quarks are produced with spins anti-aligned, in apparent contradiction to the popular 3 P 0 model of quark pair creation in which the pair is created with vacuum quantum numbers (J=0 and positive parity), i.e. in an S=1, L=1, J=0 angular momentum state

  6. Application of the Lorentz-transform technique to meson photoproduction

    International Nuclear Information System (INIS)

    Reiss, C.; Leidemann, W.; Orlandini, G.; Tomusiak, E.L.

    2003-01-01

    We show that the Lorentz integral transform (LIT) technique which has been successfully applied to photoreactions in light nuclei can also be applied to photoreactions involving particle production. A simple model where results are easily calculable in the traditional fashion is used to test the technique. Specifically, we compute inclusive π + photoproduction from deuterium for photon energies less than 200 MeV using a Yamaguchi model for the NN interaction. It is demonstrated that, although the response functions for inclusive meson production do not have favourable asymptotic behavior, one can nonetheless extract them by inversion of the transform. The implication is that one can treat realistic problems of photo-meson production, including all final-state interactions, by means of the LIT technique. (orig.)

  7. Studies of the diffractive photoproduction of isolated photons at HERA

    International Nuclear Information System (INIS)

    Abramowicz, H.; Abt, I.; Adamczyk, L.

    2017-01-01

    The photoproduction of isolated photons has been measured in diffractive events recorded by the ZEUS detector at HERA. Cross sections are evaluated in the photon transverse-energy and pseudorapidity ranges 50.9, where z meas P is the fraction of the longitudinal momentum of the colourless ''Pomeron'' exchange that is transferred to the photon-jet final state, giving evidence for direct Pomeron interactions.

  8. Dijets in diffractive photoproduction measured with the ZEUS experiment

    International Nuclear Information System (INIS)

    Renner, R.

    2006-10-01

    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 0.2 P P is the fraction of the proton momentum taken by the diffractive exchange. The jets have been reconstructed using the k T algorithm. The two jets with the highest transversal energy have been required to satisfy E T >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.)

  9. Photoproduction of ρ mesons with a final state proton

    International Nuclear Information System (INIS)

    Karschnick, O.

    2001-06-01

    The elastic photoproduction of ρ mesons is studied with the H1 detector for the first time by measuring the final state proton using the forward proton spectrometer. In these reactions the proton is scattered under small angles θ p -1 . The photon-proton center-of-mass energy in this analysis is in the range 25 GeV 2 2 at the proton vertex. The distribution of the π + π - invariant mass is found to be skewed. In the Soeding Model this is attributed to an interference between resonant and non-resonant production of π + π - pairs. The amount of skewing increases with decreasing vertical stroke t vertical stroke as expected. A variation with W is not observed. (orig.)

  10. Diffractive photoproduction of dijets in ep collisions at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2007-09-01

    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 2 , 0.20 P 2 is the photon virtuality, y is the inelasticity and x P is the fraction of the proton momentum taken by the diffractive exchange. The two jets with the highest transverse energy, E jet T , were required to satisfy E jet T >7.5 and 6.5 GeV, respectively, and to lie in the pseudorapidity range -1.5 jet <1.5. Differential cross sections were compared to perturbative QCD calculations using available parameterisations of diffractive parton distributions of the proton. (orig.)

  11. Measurement of Dijet Cross Sections in Photoproduction at HERA

    CERN Document Server

    Adloff, C.; Andrieu, B.; Anthonis, T.; Arkadov, V.; Astvatsatourov, A.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Becker, J.; Beglarian, A.; Behnke, O.; Beier, C.; Belousov, A.; Berger, C.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruckner, W.; Bruncko, D.; Burger, J.; Busser, 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, Guenter; 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.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Grab, C.; Grabski, V.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; 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.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hurling, S.; Ibbotson, M.; Issever, C .; Jacquet, M.; Jaffre, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, 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, Christian M.; 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.; Krehbiel, H.; Kroseberg, J.; Kruger, K.; Kuhr, T.; Kurca, T.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, 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.; Luders, S.; Luke, D.; Lytkin, L.; Mahlke-Kruger, H.; Malden, N.; Malinovski, E.; Malinovski, I.; Mangano, S.; Maracek, 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.; Mkrtchyan, T.; Mohrdieck, S.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Nellen, G.; Newman, Paul 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.; Poschl, R.; Potachnikova, I.; Povh, B.; Radel, G.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Reyna, D.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; Rybicki, K.; Sankey, D.P.C.; Schatzel, S.; Scheins, J.; Schilling, F.P.; Schleper, P.; Schmidt, D.; Schmidt, S.; Schmitt, S.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schorner, T.; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Chekelian, V.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Straumann, U.; Swart, M.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tobien, N.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Udluft, S.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vassiliev, S.; Vazdik, Y.; Vichnevski, A.; Wacker, K.; Wagner, J.; Wallny, R.; Waugh, B.; Weber, G.; Weber, M.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; White, G.; Wiesand, S.; Wilksen, T.; Winde, M.; Winter, G.G.; Wissing, C.; Wobisch, M.; Woehrling, E.E.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; zur Nedden, M.

    2002-01-01

    Dijet cross sections as functions of several jet observables are measured in photoproduction using the H1 detector at HERA. The data sample comprises e^+p data with an integrated luminosity of 34.9 pb^(-1). Jets are selected using the inclusive k_T algorithm with a minimum transverse energy of 25 GeV for the leading jet. The phase space covers longitudinal proton momentum fraction x_p and photon longitudinal momentum fraction x_gamma in the ranges 0.05

  12. Lambda-neutron interaction in kaon photoproduction from the deuteron

    International Nuclear Information System (INIS)

    Adelseck, R.A.; Wright, L.E.

    1989-01-01

    The importance of hyperon-nucleon final-state interaction in kaon photoproduction from the deuteron is examined. By calculating the deuteron wave function using the Reid, Paris, or Bonn NN potentials, the uncertainty of this process due to the nucleonic wave function is found to be negligible. The insignificance of off-shell and relativistic effects is demonstrated by employing a completely relativistic wave function and comparing various approximations. We find the influence of the kaon production operator to be the most critical ingredient in this calculation. Final-state effects, which are included via a distorted-wave formalism, involve partial waves up to l = 3. They produce a sharp rise of the cross section near threshold resulting in an enhancement by about a factor of 3, but diminish rapidly as the energy increases. Different ΛN potential models show variations of the effect by up to 10%

  13. Recent Results from Photoproduction of Mesons in A2

    Directory of Open Access Journals (Sweden)

    Walford Natalie

    2016-01-01

    Full Text Available Recent experiments using the Crystal Ball/TAPS setup at the MAMI accelerator in Mainz, Germany continue to study the properties and the excitation spectrum of the nucleon with meson photoproduction. Electromagnetic excitations of the proton and neutron are essential for understanding their isospin decomposition. The electromagnetic coupling of photons to protons is different than that of neutrons in certain states. Hence, a complete partial wave analysis (PWA can assist in yielding more information about any reaction, but gains from polarization observables constraining the fits. Polarization observables play a crucial role as they are essential in disentangling the contributing resonant and non-resonant amplitudes, whereas cross-section data alone is not sufficient for separating resonances. Preliminary results of polarization observables (E, T, and F of η and double π production off a polarized neutron (dButanol target are shown with comparison to predictions of recent multipole analyses. These results will allow for developing the world database.

  14. A-dependence of inclusive πsup(+-) meson photoproduction

    International Nuclear Information System (INIS)

    Alanakyan, K.V.; Amaryan, M.D.; Demirchyan, R.A.; Egiyan, K.Sh.; Kocharova, Zh.L.; Ogandjanyan, M.S.; Sharabyan, Yu.G.; Stepanyan, S.G.

    1981-01-01

    The experimental data on A-dependence of photopions in wide energy and angular intervals of secondary PI +- -mesons are discussed. It is shown that if the invariant cross section of photopion production on 12 C, 27 Al, 63 Cu, 118 Sn and 208 Pb nuclei in the γ+A→PI +- +X reaction is represented in the form of f approximately equal to BAsup(n), then in the energy dependence of exponent n one can observe the same singularities as in the analogous hadron processes. The expansion of the angular interval up to 20-160 deg in the laboratory system made it possible to study in detail the nature of these singularities. The attempts are made to explain the observed singularities in the energy dependence n=n(TPI) by taking into account additional (to tne direct process of photoproduction on nuclear nucleons) sources of the inclusive PI-meson production [ru

  15. Photoproduction of Dijets with High Transverse Momenta at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bahr, 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.; Bruncko, D.; Busser, 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, K.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; 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, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, 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, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Lastovicka-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.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, 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.; Michels, V.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul 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.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, 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.; Schoning, A.; Schultz-Coulon, H.-C.; Sedlak, K.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Steder, M.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Sunar, D.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truol, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Urban, Marcel; Usik, A.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; 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, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, 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.

  16. Photoproduction of dijets with high transverse momenta at HERA

    Science.gov (United States)

    H1 Collaboration; Aktas, A.; Andreev, V.; Anthonis, T.; Antunovic, B.; 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.; Bruncko, D.; 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, K.; 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.; Goerlich, 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, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jönsson, L.; 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.; Kückens, J.; Landon, M. P. J.; Lange, W.; Laštovička, T.; Laštovička-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.; 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.; 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.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; 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.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Plačakytė, 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.; Schätzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sedlák, K.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; 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, Y.; 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, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-07-01

    Differential dijet cross sections are measured in photoproduction in the region of photon virtualities Q<1 GeV 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 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.

  17. Theoretical study of incoherent φ photoproduction on a deuteron target

    International Nuclear Information System (INIS)

    Sekihara, T.; Martinez Torres, A.; Jido, D.; Oset, E.

    2012-01-01

    We study the photoproduction of φ mesons in deuteron, paying attention to the modification of the cross-section from bound protons to the free ones. For this purpose we take into account Fermi motion in single scattering and rescattering of φ to account for φ absorption on a second nucleon as well as the rescattering of the proton on the neutron. We find that the contribution of the double scattering for φ is much smaller than the typical cross-section of γp→φp in free space, which implies a very small screening of the φ production in deuteron. The contribution from the proton rescattering, on the other hand, is found to be not negligible compared to the cross-section of γp→φp in free space, and leads to a moderate reduction of the φ photoproduction cross-section on a deuteron at forward angles if the LEPS set-up is taken into account. The Fermi motion allows contribution of the single scattering in regions forbidden by phase-space in the free case. In particular, we find that for momentum transfer squared close to the maximum value, the Fermi motion changes drastically the shape of dσ/dt, to the point that the ratio of this cross-section to the free one becomes very sensitive to the precise value of t chosen, or the size of the bin used in an experimental analysis. Hence, this particular region of t does not seem to be the most indicated to find effects of a possible φ absorption in the deuteron. This reaction is studied theoretically as a function of t and the results are contrasted with recent experiments at LEPS and Jefferson Lab. The effect of the experimental angular cuts at LEPS is also discussed, providing guidelines for future experimental analyses of the reaction. (orig.)

  18. Electric arc hydrogen heaters

    International Nuclear Information System (INIS)

    Zasypin, I.M.

    2000-01-01

    The experimental data on the electric arc burning in hydrogen are presented. Empirical and semiempirical dependences for calculating the arc characteristics are derived. An engineering method of calculating plasma torches for hydrogen heating is proposed. A model of interaction of a hydrogen arc with a gas flow is outlined. The characteristics of plasma torches for heating hydrogen and hydrogen-bearing gases are described. (author)

  19. Measurement of charm and beauty dijet cross sections in photoproduction at HERA using the H1 vertex detector

    Science.gov (United States)

    Aktas, A.; Andreev, V.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; 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.; 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.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; 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, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jönsson, L.; 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.; Laštovička-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.; 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.; 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.; Murín, P.; Nankov, K.; Naroska, B.; Naumann, Th.; 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.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Plačakytė, 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.; Schätzel, S.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schoeffel, L.; Schöning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R. N.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; 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.; 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, Y.; Veelken, C.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wissing, Ch.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-09-01

    A measurement of charm and beauty dijet photoproduction cross sections at the ep collider HERA is presented. Events are selected with two or more jets of transverse momentum pt jet1(2)>11(8) GeV in the central range of pseudo-rapidity -0.9<ηjet1(2)<1.3. The fractions of events containing charm and beauty quarks are determined using a method based on the impact parameter, in the transverse plane, of tracks to the primary vertex, as measured by the H1 central vertex detector. Differential dijet cross sections for charm and beauty, and their relative contributions to the flavour inclusive dijet photoproduction cross section, are measured as a function of the transverse momentum of the leading jet, the average pseudo-rapidity of the two jets and the observable xγ obs. Taking into account the theoretical uncertainties, the charm cross sections are consistent with a QCD calculation in next-to-leading order, while the predicted cross sections for beauty production are somewhat lower than the measurement.

  20. Measurement of Charm and Beauty Dijet Cross Sections in Photoproduction at HERA using the H1 Vertex Detector

    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, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; 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.; Busser, 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.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; 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, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; 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, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-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.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; 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, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, Th.; Newman, Paul 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.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, 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.; Schoning, A.; Schultz-Coulon, H.-C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; 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.; Truol, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Urban, Marcel; Usik, A.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wessling, B.; Wissing, Ch.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2006-01-01

    A measurement of charm and beauty dijet photoproduction cross sections at the ep collider HERA is presented. Events are selected with two or more jets of transverse momentum $p_t^{jet}_{1(2)}>11(8)$ GeV in the central range of pseudo-rapidity $-0.9<\\eta^{jet}_{1(2)}<1.3$. The fractions of events containing charm and beauty quarks are determined using a method based on the impact parameter, in the transverse plane, of tracks to the primary vertex, as measured by the H1 central vertex detector. Differential dijet cross sections for charm and beauty, and their relative contributions to the flavour inclusive dijet photoproduction cross section, are measured as a function of the transverse momentum of the leading jet, the average pseudo-rapidity of the two jets and the observable $x_{\\gamma}^{obs}$. Taking into account the theoretical uncertainties, the charm cross sections are consistent with a QCD calculation in next-to-leading order, while the predicted cross sections for beauty production are somewhat lo...

  1. A LIBS method for simultaneous monitoring of the impurities and the hydrogenic composition present in the wall of the TJ-II stellarator

    Energy Technology Data Exchange (ETDEWEB)

    López-Miranda, B., E-mail: belen.lopez@ciemat.es; Zurro, B.; Baciero, A. [Laboratorio Nacional de Fusión, CIEMAT, Av. Complutense, 40, 28040 Madrid (Spain); Martínez, M. [Universidad Carlos III de Madrid, Av de la Universidad, 30, 28911 Leganés, Madrid (Spain)

    2016-11-15

    The study of plasma-wall interactions and impurity transport in the plasma fusion devices is critical for the development of future fusion reactors. An experiment to perform laser induced breakdown spectroscopy, using minor modifications of our existing laser blow-off impurity injection system, has been set up thus making both experiments compatible. The radiation produced by the laser pulse focused at the TJ-II wall evaporates a surface layer of deposited impurities and the subsequent radiation produced by the laser-produced plasma is collected by two separate lens and fiber combinations into two spectrometers. The first spectrometer, with low spectral resolution, records a spectrum from 200 to 900 nm to give a survey of impurities present in the wall. The second one, with high resolution, is tuned to the wavelengths of the Hα and Dα lines in order to resolve them and quantify the hydrogen isotopic ratio present on the surface of the wall. The alignment, calibration, and spectral analysis method will be described in detail. First experimental results obtained with this setup will be shown and its relevance for the TJ-II experimental program discussed.

  2. 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'.

  3. Study of beauty photoproduction with the ZEUS experiment at the electron-proton collider HERA

    Energy Technology Data Exchange (ETDEWEB)

    Yaguees Molina, Ana Gloria

    2008-02-22

    This thesis presents a measurement of beauty photoproduction in ep interactions at the HERA collider working at a center of mass energy of {radical}(s)=318 GeV. Two goals are followed in this thesis: first the development of a reliable algorithm (secondary vertex b-tagging) to identify jets originating from b quarks by exploiting exclusively the full micro-vertex-detector potential and the properties of the b quark, and second the determination of its performance by obtaining first measurements of inclusive beauty dijet photoproduction. The main result presented here is based on a data set collected in 2004 corresponding to an integrated luminosity of 35 pb{sup -1}. Events containing at least two jets, each having an identified secondary vertex, are selected. The fraction of events containing b-quarks is extracted using the characteristic distributions of reconstructed decay length and invariant mass of the secondary vertex. The jets are required to be within the pseudorapidity region vertical stroke {eta} vertical stroke <1.5 with transverse momenta p{sub T}>7(6) GeV/c respectively. No requirements are imposed on the b decay final state so that the measurement is kept inclusive. Total and differential cross sections as a function of transverse momentum d{sigma}/dp{sub T} and pseudorapidity d{sigma}/d{eta} of the b-jet are measured. Furthermore, the results on d{sigma}/dp{sub T} were extrapolated to obtain a measurement at the b-quark level. Motivated by the results of this exploratory analysis of beauty quark production using secondary vertex b-tagging and profiting from improvements of the ZEUS tracking software since this first analysis, a more precise measurement became possible. The new analysis, still ongoing, is based on the data set collected in 2005 by the ZEUS detector and profits of higher statistics (L=132.6 pb{sup -1}) as well as of an improved detector alignment and calibration and a better understanding of the tracking/vertexing procedures which

  4. Study of beauty photoproduction with the ZEUS experiment at the electron-proton collider HERA

    International Nuclear Information System (INIS)

    Yaguees Molina, Ana Gloria

    2008-01-01

    This thesis presents a measurement of beauty photoproduction in ep interactions at the HERA collider working at a center of mass energy of √(s)=318 GeV. Two goals are followed in this thesis: first the development of a reliable algorithm (secondary vertex b-tagging) to identify jets originating from b quarks by exploiting exclusively the full micro-vertex-detector potential and the properties of the b quark, and second the determination of its performance by obtaining first measurements of inclusive beauty dijet photoproduction. The main result presented here is based on a data set collected in 2004 corresponding to an integrated luminosity of 35 pb -1 . Events containing at least two jets, each having an identified secondary vertex, are selected. The fraction of events containing b-quarks is extracted using the characteristic distributions of reconstructed decay length and invariant mass of the secondary vertex. The jets are required to be within the pseudorapidity region vertical stroke η vertical stroke T >7(6) GeV/c respectively. No requirements are imposed on the b decay final state so that the measurement is kept inclusive. Total and differential cross sections as a function of transverse momentum dσ/dp T and pseudorapidity dσ/dη of the b-jet are measured. Furthermore, the results on dσ/dp T were extrapolated to obtain a measurement at the b-quark level. Motivated by the results of this exploratory analysis of beauty quark production using secondary vertex b-tagging and profiting from improvements of the ZEUS tracking software since this first analysis, a more precise measurement became possible. The new analysis, still ongoing, is based on the data set collected in 2005 by the ZEUS detector and profits of higher statistics (L=132.6 pb -1 ) as well as of an improved detector alignment and calibration and a better understanding of the tracking/vertexing procedures which contribute significantly to the reduction of the uncertainties of the measurements

  5. A 2-deoxyribonolactone-containing nucleotide: Isolation and characterization of the alkali-sensitive photoproduct of the trideoxyribonucleotide d(ApCpA)

    International Nuclear Information System (INIS)

    Urata, H.; Yamamoto, K.; Akagi, M.; Hiroaki, H.; Uesugi, S.

    1989-01-01

    It has been reported that ACA sequences in DNA are mutagenic hot spots in UV-induced mutagenesis and are sites of an alkali-sensitive lesion produced by UV irradiation. In order to characterize the UV-induced lesion of an ACA site, chemically synthesized trideoxyribonucleotide d(ApCpA) was irradiated with UV light and the alkali-sensitive photoproduct was isolated. The structure of this photoproduct was characterized as the trinucleotide containing 2-deoxyribonolactone at the internal residue by 2D DQF-COSY, FT-IR, FAB-MS, and chemical properties. It is known that this lesion is also produced by gamma-irradiation, neocarzinostatin, the 1,10-phenanthroline-copper complex, and hydrogen peroxide and is highly mutagenic because of its resistance to cleavage by certain apurinic/apyrimidinic (AP) endonucleases. Thus, 2-deoxyribonolactone may be one of the lethal DNA lesions induced by UV irradiation to organisms and one of the intermediates of UV-induced DNA strand breaks because the DNA strand is cleaved at this site with beta- and subsequent delta-elimination mechanisms

  6. Economic feasibility of hydrogen enrichment for reducing NOx emissions from landfill gas power generation alternatives: A comparison of the levelized cost of electricity with present strategies

    International Nuclear Information System (INIS)

    Kornbluth, Kurt; Greenwood, Jason; Jordan, Eddie; McCaffrey, Zach; Erickson, Paul A.

    2012-01-01

    Based on recent research showing that hydrogen enrichment can lower NO x emissions from landfill gas combustion below future NO x emission control standards imposed by both federal and California state regulations, an investigation was performed to compare the levelized cost of electricity of this technology with other options. In this cost study, a lean-burn reciprocating engine with no after-treatment was the baseline case to compare six other landfill gas-to-energy projects. These cases include a lean burn engine with selective catalytic reduction after treatment, a lean-burn microturbine, and four variations on an ultra-lean-burn engine utilizing hydrogen enrichment with each case using a different method of hydrogen production. Only hydrogen enrichment with an in-stream autothermal fuel reformer was shown to be potentially cost-competitive with current strategies for reaching the NO x reduction target in IC engines. - Highlights: ► Levelized cost of electricity for hydrogen enriched combustion was compared. ► Various ultra-lean-burn engines and microturbines with hydrogen were analyzed. ► Combustion with an autothermal fuel reformer was potentially cost-competitive.

  7. Handbook of hydrogen energy

    CERN Document Server

    Sherif, SA; Stefanakos, EK; Steinfeld, Aldo

    2014-01-01

    ""This book provides an excellent overview of the hydrogen economy and a thorough and comprehensive presentation of hydrogen production and storage methods.""-Scott E. Grasman, Rochester Institute of Technology, New York, USA

  8. Hydrogen energy

    International Nuclear Information System (INIS)

    2005-03-01

    This book consists of seven chapters, which deals with hydrogen energy with discover and using of hydrogen, Korean plan for hydrogen economy and background, manufacturing technique on hydrogen like classification and hydrogen manufacture by water splitting, hydrogen storage technique with need and method, hydrogen using technique like fuel cell, hydrogen engine, international trend on involving hydrogen economy, technical current for infrastructure such as hydrogen station and price, regulation, standard, prospect and education for hydrogen safety and system. It has an appendix on related organization with hydrogen and fuel cell.

  9. Carbon Monoxide Photoproduction from Particles and Solutes in the Delaware Estuary under Contrasting Hydrological Conditions.

    Science.gov (United States)

    Song, Guisheng; Richardson, John D; Werner, James P; Xie, Huixiang; Kieber, David J

    2015-12-15

    Full-spectrum, ultraviolet (UV), and visible broadband apparent quantum yields (AQYs) for carbon monoxide (CO) photoproduction from chromophoric dissolved organic matter (CDOM) and particulate organic matter (POM) were determined in the Delaware Estuary in two hydrologically contrasting seasons in 2012: an unusually low flow in August and a storm-driven high flow in November. Average AQYs for CDOM and POM in November were 10 and 16 times the corresponding AQYs in August. Maximum AQYs in November occurred in a midestuary particle absorption maximum zone. Although POM AQYs were generally smaller than CDOM AQYs, the ratio of the former to the latter increased substantially from the UV to the visible. In both seasons, UV solar radiation was the primary driver for CO photoproduction from CDOM whereas visible light was the principal contributor to POM-based CO photoproduction. CDOM dominated CO photoproduction in the uppermost water layer while POM prevailed at deeper depths. On a depth-integrated basis, the Delaware Estuary shifted from a CDOM-dominated system in August to a POM-dominated system in November with respect to CO photoproduction. This study reveals that flood events may enhance photochemical cycling of terrigenous organic matter and switch the primary photochemical driver from CDOM to POM.

  10. Calibrations for charged particle tracking and measurements of w photoproduction with the GlueX detector

    Energy Technology Data Exchange (ETDEWEB)

    Staib, Michael [Carnegie Mellon Univ., Pittsburgh, PA (United States)

    2017-09-21

    The GlueX experiment is a new experimental facility at Jefferson Lab in Newport News, VA. The experiment aims to map out the spectrum of hybrid mesons in the light quark sector. Measurements of the spin-density matrix elements in omega photoproduction are performed with a linear polarized photon beam on an unpolarized proton target, and presented in bins of Mandelstam t for beam energies of 8.4-9.0 GeV. The spin-density matrix elements are exclusively measured through two decays of the omega meson: omega -> pi^+ pi^- pi^0 and omega ->pi^0 gamma. A description of the experimental apparatus is presented. Several methods used in the calibration of the charged particle tracking system are described. These measurements greatly improve the world statistics in this energy range. These are the first results measured through the omega ->pi^0 gamma decay at this energy. Results are generally consistent with a theoretical model based on diffractive production with Pomeron and pseudoscalar exchange in the t-channel.

  11. Double longitudinal spin asymmetries in single hadron photoproduction at high p_T at COMPASS

    CERN Document Server

    Levillain, Maxime

    This thesis presents a new study aiming at constraining the gluon contribution {\\Delta G} to the 1/2 nucleon spin. The collinear pQCD theoretical framework, on which it is based, deals with asymmetries calculated from cross-sections for single inclusive hadron in the regime of quasi-real photoproduction {Q^2 1 GeV/c). These calculations are done up to Next-to-Leading order with a foreseen inclusion of Next-to-Leading logarithm threshold gluon resummation, only performed for the unpolarised cross-sections yet. This makes the asymmetries sensitive to the gluon polarisation not only through Photon Gluon Fusion {\\gamma* g} but also through resolved {\\gamma*}g processes such as qg or gg. The measurement of the asymmetries is performed for all the COMPASS data available from 2002 to 2011 with a polarised muon beam at 160-200 GeV scattered off a longitudinally polarised target of deuteron ( {_6LiD} for 2002-2006) or proton ({NH_3} for 2007 and 2011). The asymmetries are presented in bins of pT and of pseudorapidity...

  12. Data compilation of single pion photoproduction below 2 GeV

    International Nuclear Information System (INIS)

    Inagaki, Y.; Nakamura, T.; Ukai, K.

    1976-01-01

    The compilation of data of single pion photoproduction experiment below 2 GeV is presented with the keywords which specify the experiment. These data are written on a magnetic tape. Data format and the indices for the keywords are given. Various programs of using this tape are also presented. The results of the compilation are divided into two types. The one is the reference card on which the information of the experiment is given. The other is the data card. These reference and data cards are written using all A-type format on an original tape. The copy tapes are available, which are written by various types on request. There are two kinds of the copy tapes. The one is same as the original tape, and the other is the one different in the data card. Namely, this card is written by F-type following the data type. One experiment on this tape is represented by 3 kinds of the cards. One reference card with A-type format, many data cards with F-type format and one identifying card. Various programs which are written by FORTRAN are ready for these original and copy tapes. (Kato, T.)

  13. Melanin offers protection against induction of cyclobutane pyrimidine dimers and 6-4 photoproducts by UVB in cultured human melanocytes

    NARCIS (Netherlands)

    Smit, N.P.M.; Vink, A.A.; Kolb, R.M.; Steenwinkel, M.J.S.T.; Berg, P.T.M. van den; Nieuwpoort, F. van; Roza, L.; Pavel, S.

    2001-01-01

    The goal of this investigation was to correlate the melanin content in human pigmentary cells with the generation of UVB-induced photoproducts and to examine the relationship between the melanin content and the removal of the photoproducts. Cultured melanocytes from light-skinned individuals

  14. Soft gluon approach for diffractive photoproduction of J/ψ

    International Nuclear Information System (INIS)

    Ma, J.P.; Xu Jiasheng

    2002-01-01

    We study diffractive photoproduction of J/ψ by taking the charm quark as a heavy quark. A description of nonperturbative effect related to J/ψ can be made by using NRQCD. In the forward region of the kinematics, the interaction between the cc-bar-pair and the initial hadron is due to exchange of soft gluons. The effect of the exchange can be studied by using the expansion in the inverse of the quark mass m c . At the leading order we find that the nonperturbative effect related to the initial hadron is represented by a matrix element of field strength operators, which are separated in the moving direction of J/ψ in the spacetime. The S-matrix element is then obtained without using perturbative QCD and the results are not based on any model. Corrections to the results can be systematically added. Keeping the dominant contribution of the S-matrix element in the large energy limit we find that the imaginary part of the S-matrix element is related to the gluon distribution for x→0 with a reasonable assumption, the real part can be obtained with another approximation or with dispersion relation. Our approach is different than previous approaches and also our results are different than those in these approaches. The differences are discussed in detail. A comparison with experiment is also made and a qualitative agreement is found. (author)

  15. Spin information from vector-meson decay in photoproduction

    International Nuclear Information System (INIS)

    Kloet, W.M.; Chiang, W.; Tabakin, F.

    1998-01-01

    For the photoproduction of vector mesons, all single and double spin observables involving vector-meson two-body decays are defined consistently in the γN center-of-mass frame. These definitions yield a procedure for extracting physically meaningful single and double spin observables that are subject to known rules concerning their angle and energy evolution. As part of this analysis, we show that measuring the two-meson decay of a photo produced ρ or φ does not determine the vector meson's vector polarization, but only its tensor polarization. The vector meson decay into lepton pairs is also insensitive to the vector meson's vector polarization, unless one measures the spin of one of the leptons. Similar results are found for all double spin observables which involve observation of vector-meson decay. To access the vector meson's vector polarization, one therefore needs to either measure the spin of the decay leptons, make an analysis of the background interference effects, or relate the vector meson's vector polarization to other accessible spin observables. copyright 1998 The American Physical Society

  16. 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.)

  17. Rapidity gaps between jets in Photoproduction at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-10-01

    Photoproduction events which have two or more jets have been studied in the W γp range 135 GeV γp <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.)

  18. Beauty photoproduction using decays into muons at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Samson, U.

    2008-05-15

    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, Q{sup 2}{approx}0. Two jets with transverse momentum p{sub T}>7(6) GeV and pseudo-rapidities vertical stroke {eta} 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. Studies of the diffractive photoproduction of isolated photons 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 Institut fuer Physik, Muenchen (Germany); Adamczyk, L. [AGH Univ. of Science and Technology, Krakow (Poland). Faculty of Physics and Applied Computer Science; Collaboration: ZEUS Collaboration; and others

    2017-07-20

    The photoproduction of isolated photons has been measured in diffractive events recorded by the ZEUS detector at HERA. Cross sections are evaluated in the photon transverse-energy and pseudorapidity ranges 50.9, where z{sup meas}{sub P} is the fraction of the longitudinal momentum of the colourless ''Pomeron'' exchange that is transferred to the photon-jet final state, giving evidence for direct Pomeron interactions.

  20. 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.)

  1. Quasifree η photoproduction from nuclei and medium modifications of resonances

    International Nuclear Information System (INIS)

    Ventel, B.I.S. van der; Abu-Raddad, L.J.; Hillhouse, G.C.

    2003-01-01

    This paper establishes the case that the process of quasifree η photoproduction from nuclei is an important tool to study medium modifications and changes to the elementary process γN→ηN in the nuclear medium. We investigate the sensitivity of the differential cross section, recoil nucleon polarization, and the photon asymmetry to changes in the elementary amplitude, medium modifications of the resonance (S 11 ,D 13 ) masses, as well as nuclear target effects. All calculations are performed within a relativistic plane-wave impulse approximation formalism resulting in analytical expressions for all observables. Our results indicate that polarization observables are largely insensitive to nuclear target effects. Depending on the type of coupling, the spin observables do display a sensitivity to the magnitude of the ηNN coupling constant. The polarization observables are identified to be the prime candidates to investigate the background processes and their medium modifications in the elementary process such as the D 13 resonance. Moreover, as a consequence of the large dominance in the differential cross section of the S 11 resonance, the quasifree differential cross section provides an exceptional instrument to study medium modifications to the S 11 resonance in such a manner that helps to distinguish between various models that attempt to understand the S 11 resonance and its distinctive position as the lowest lying negative parity state in the baryon spectrum

  2. Beauty photoproduction using decays into muons at HERA

    International Nuclear Information System (INIS)

    Samson, U.

    2008-05-01

    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, Q 2 ∼0. Two jets with transverse momentum p T >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.)

  3. High-E{sub T} dijet photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

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

    2007-06-15

    The cross section for high-E{sub T} dijet production in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 81.8 pb{sup -1}. The events were required to have a virtuality of the incoming pho- ton, Q{sup 2}, of less than 1 GeV{sup 2} and a photon-proton centre-of-mass energy in the range 14220 GeV and E{sub T}{sup jet2}>15 GeV and pseudorapidity requirements of -1<{eta}{sup jet1,2}<3, with at least one of the jets satisfying -1<{eta}{sup 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. (orig.)

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

    CERN Document Server

    Adloff, C.; Andrieu, B.; Anthonis, T.; Astvatsatourov, A.; Babaev, A.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Beglarian, A.; Behnke, O.; Belousov, A.; Berger, C.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boudry, V.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Burrage, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Chekelian, V.; 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.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; 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.; Flucke, G.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Grab, C.; Grabski, V.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Haidt, D.; Hajduk, L.; Haller, J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Hengstmann, S.; Henschel, H.; Henshaw, O.; Heremans, R.; Herrera, G.; Herynek, I.; Hildebrandt, M.; Hilgers, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Issever, C .; Jacquet, M.; Jaffre, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; 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, I.R.; Kiesling, Christian M.; 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.; Kruger, K.; Kuhr, T.; Lamb, D.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebailly, E.; Lebedev, A.; Leissner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; List, B.; Lobodzinska, E.; Lobodzinski, B.; Loginov, A.; Loktionova, N.; Lubimov, V.; Luders, S.; Luke, D.; Lytkin, L.; Malden, N.; Malinovski, E.; 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.; Mondragon, M.N.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Newman, Paul R.; Niebergall, F.; Niebuhr, C.; Nix, O.; Nowak, G.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Petrukhin, A.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Potachnikova, I.; Povh, B.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; 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.; Schoning, A.; Schoerner-Sadenius, Thomas; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchetchelnitski, S.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vassiliev, S.; Vazdik, Y.; 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.; Woehrling, E.E.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, 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.

  5. 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.

  6. Hydrogen in metals

    CSIR Research Space (South Africa)

    Carter, TJ

    2001-04-01

    Full Text Available .J. Cartera,*, L.A. Cornishb aAdvanced Engineering & Testing Services, MATTEK, CSIR, Private Bag X28, Auckland Park 2006, South Africa bSchool of Process and Materials Engineering, University of the Witwatersrand, Private Bag 3, P.O. WITS 2050, South Africa... are contrasted, and an unusual case study of hydrogen embrittlement of an alloy steel is presented. 7 2001 Published by Elsevier Science Ltd. Keywords: Hydrogen; Hydrogen-assisted cracking; Hydrogen damage; Hydrogen embrittlement 1. Introduction Hydrogen suC128...

  7. Large-pT photoproduction of D*± mesons in ep collisions

    International Nuclear Information System (INIS)

    Kniehl, B.A.; Kramer, G.; Spira, M.

    1996-10-01

    The cross section for the inclusive photoproduction of large-p T D *± mesons is calculated at next-to-leading order, adopting different approaches to describe the fragmentation of charm quarks into D *± mesons. We treat the charm quark according to the massless factorization scheme, where it is assumed to be one of the active flavours inside the proton and the photon. We present inclusive single-particle distributions in transverse momentum and rapidity, including the contributions due to both direct and resolved photons. We compare and assess the various implementations of fragmentation. We argue that, in the high-p T regime, a particularly realistic description can be obtained by convoluting the Altarelli-Parisi-evolved fragmentation functions of Peterson et al. with the hard-scattering cross sections of massless partons where the factorization of the collinear singularities associated with final-state charm quarks is converted to the massive-charm scheme. The predictions thus obtained agree well with recent experimental data by the H1 and ZEUS Collaborations at DESY HERA, better than the all-massive calculation. (orig.)

  8. Photoproduction of neutral mesons with the crystal-barrel detector at ELSA

    International Nuclear Information System (INIS)

    Crede, V.

    2004-01-01

    The general success of quark models led to the problem of missing resonances. Many states predicted by constituent quark model calculations have not been observed experimentally or are only weakly established. This open question is discussed on the basis of experimental results of the CB-ELSA experiment at the e - accelerator ELSA in Bonn. Differential cross sections of γp → pπ 0 and γp → pη are presented for incident photon energies up to E γ =3 GeV. At low energies, results of experiments such as GRAAL and CLAS are reproduced to a good accuracy. New data points have been added for forward angles of the meson and at energies above 2 GeV. In the differential cross sections of both π 0 and η photoproduction, a transition from dominant resonance production to a strong peaking in the forward direction can be observed around E γ =2 GeV. Moreover, total cross sections of γp → pπ 0 π 0 (π 0 η) are discussed. Resonance production and even cascades of the type N**(Δ**) → N* (Δ*) → pπ 0 π 0 (pπ 0 η) are observed. Indications for at least one Δ resonance around 1900 MeV are seen. The latter would be particularly interesting if it had negative parity because this state would be in contradiction with constituent quark models. (author)

  9. Diffractive open charm production in deep-inelastic scattering and photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aktas, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Andreev, V. [Lebedev Physical Institute, Moscow (Russian Federation); Anthonis, T. [Inter-Univ. Institute for High Energies ULB-VUB, Brussels (Belgium)]|[Antwerp Univ. (BE)] (and others)

    2006-10-15

    Measurements are presented of diffractive open charm production at HERA. The event topology is given by ep{yields}eXY where the system X contains at least one charmed hadron and is well separated by a large rapidity gap from a leading low-mass proton remnant system Y. Two analysis techniques are used for the cross section measurements. In the first, the charm quark is tagged by the reconstruction of a D{sup *{+-}}(2010) meson. This technique is used in deep-inelastic scattering (DIS) and photoproduction ({gamma}p). In the second, a method based on the displacement of tracks from the primary vertex is used to measure the open charm contribution to the inclusive diffractive cross section in DIS. The measurements are compared with next-to-leading order QCD predictions based on diffractive parton density functions previously obtained from a QCD analysis of the inclusive diffractive cross section at H1. A good agreement is observed in the full kinematic regime, which supports the validity of QCD factorization for open charm production in diffractive DIS and {gamma}p. (orig.)

  10. Measurement of beauty and charm photoproduction using semi-muonic decays in dijet events 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)

    2012-04-15

    Measurements of cross sections for beauty and charm events with dijets and a muon in the photoproduction regime at HERA are presented. The data were collected with the H1 detector and correspond to an integrated luminosity of 179 pb{sup -1}. Events with dijets of transverse momentum P{sup jet1}{sub T}>7 GeV and P{sup jet2}{sub T}>6 GeV in the pseudorapidity range -1.5<{eta}{sup jet}<2.5 in the laboratory frame are selected in the kinematic region of photon virtuality Q{sup 2}<2.5 GeV{sup 2} and inelasticity 0.22.5 GeV in the pseudorapidity range -1.3<{eta}{sup {mu}}<1.5. The fractions of beauty and charm events are determined using the impact parameters of the muon tracks with respect to the primary vertex and their transverse momentum relative to the axis of the associated jet. Both variables are reconstructed using the H1 vertex detector. The measurements are in agreement with QCD predictions at leading and next-to-leading order.

  11. Polarization observables for strangeness photoproduction on a frozen spin target with CLAS at Jefferson Lab

    International Nuclear Information System (INIS)

    Fegan, Stuart

    2012-01-01

    The FROST experiment at Jefferson Lab used the CLAS detector in Hall B with the intention of performing a complete measurement of polarization observables associated with strangeness photoproduction, in combination with data from previous JLab experiments. This was achieved by utilizing the FROST polarized target in conjunction with polarized photon beams, allowing direct measurement of beam-target double polarization observables. By studying strangeness reactions, such as γp → K + Λ 0 , it may be possible to find 'missing' baryon resonances, predicted by symmetric quark models but not observed in previous experiments, whose results are consistent with the di-quark model. It is thought these 'missing' resonances remain undiscovered because they have different coupling strengths for different reaction channels, such as the strangeness reactions, whereas the current data is dominated by studies of pN reactions. Observing these resonances therefore has important implications for our knowledge of the excited states of nucleons, and the models predicting the quark interactions within them. The G polarization observable is one of the beam-target double polarization observables, associated with a longitudinally polarized target and a linearly polarized photon beam, and its measurement for the strangeness reaction γp → K + Λ 0 is the focus of the work presented.

  12. Coupling constants deduced for the resonances in kaon photo-production

    International Nuclear Information System (INIS)

    Cheoun, M. K.; Kim, K. S.; Choi, T. K.

    2004-01-01

    We deduced the coupling constants of nucleon and hyperon resonances, which participate in kaon productions as intermediate states that are formed by electro-magnetic probes and that finally decay into hadronic final states. We used an isobaric model based on an effective Lagrangian approach to describe the processes, in which relevant coupling constants regarding related resonances are effectively determined by fitting available experimental data. Our scheme to deduce the coupling constants was as follows: First, we calculated the lower and the upper limits on the coupling constants by using the experimental decay data available until now and/or theoretical predictions, such as those from quark models and SU(3) symmetry. Second, we exploited those limits as physical constraints on our fitting scheme for the kaon photo-production data. Finally, the deduced values and regions of the coupling constants, which satisfy not only the reaction data but also the decay data, are presented as figures with respect to the strong and the electro-magnetic coupling constants, and their multiplicative values. Our results for the coupling constants give physical values that are more restricted than those allowed by the experimental data nowadays.

  13. Diffractive Photoproduction of J/psi Mesons with Large Momentum Transfer at HERA

    CERN Document Server

    Aktas, A.; Anthonis, T.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Beglarian, A.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, C.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boenig, M.O.; Boudry, V.; Bracinik, J.; Braunschweig, W.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Burrage, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Chekelian, V.; 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.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; 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.; Ferron, S.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garvey, J.; Gassner, J.; Gayler, Joerg; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Grabski, V.; Grassler, H.; Greenshaw, T.; Grindhammer, Guenter; Haidt, D.; Hajduk, L.; Haller, J.; Heinemann, B.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Heremans, R.; Herrera, G.; Herynek, I.; Hildebrandt, M.; Hilgers, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, C.; Johnson, D.P.; Jones, M.A.S.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keil, F.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Kluge, T.; Knies, G.; Koblitz, B.; Kolya, S.D.; Korbel, V.; Kostka, P.; Koutouev, R.; Koutov, A.; Kroseberg, J.; Kruger, K.; Kueckens, J.; Kuhr, T.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leissner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lueders, H.; Luders, S.; Luke, D.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; 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.; Moreau, F.; Morozov, A.; Morris, J.V.; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, T.; Newman, Paul R.; Niebergall, F.; Niebuhr, C.; Nikitin, D.; Nowak, G.; Nozicka, M.; Olivier, B.; Olsson, J.E.; Ozerov, D.; Panassik, V.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Petrukhin, A.; Phillips, J.P.; Pitzl, D.; Poschl, R.; Povh, B.; Raicevic, N.; Rauschenberger, J.; Reimer, P.; Reisert, B.; Risler, C.; Rizvi, E.; Robmann, P.; Roosen, R.; Rostovtsev, A.; Rusakov, S.; 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.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Turney, J.E.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vassiliev, S.; Vazdik, Y.; 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.; Wessling, B.; Winde, M.; Winter, G.G.; Wissing, C.; Woehrling, E.E.; Wunsch, E.; Wyatt, A.C.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zomer, F.; zur Nedden, M.

    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 rise of the cross section with W is observed for each t range and the slope for the effective linear Pomeron trajectory is measured to be alpha^\\prime= -0.0135 \\pm 0.0074 (stat.) \\pm 0.0051 (syst.) GeV^-2. The measurements are compared with perturbative QCD models based on BFKL and DGLAP evolution. The data are found to be compatible with s-channel helicity conservation.

  14. Measurement of beauty and charm photoproduction using semi-muonic decays in dijet events at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G. [National Inst. for Physics and Nuclear Engineering, Bucharest (Romania); Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Vazdik, Y. [Lebedev Physical Inst., Moscow (Russian Federation); Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N. [Univ. of Montenegro, Faculty of Science, Podgorica (ME); Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H. [Yerevan Physics Inst., Yerevan (Armenia); Barrelet, E. [CNRS/IN2P3, LPNHE, Univ. Pierre et Marie Curie Paris 6, Univ. Denis Diderot Paris 7, Paris (France); Bartel, W.; Belov, P.; Brandt, G.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Habib, S.; Haidt, D.; Kleinwort, C.; Kraemer, M.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Olsson, J.E.; Ozerov, D.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Radescu, V.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E. [DESY, Hamburg (Germany); Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B. [Inst. of Physics and Technology of the Mongolian Academy of Sciences, Ulaanbaatar (Mongolia); Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F. [CNRS/IN2P3, LAL, Univ. Paris-Sud, Orsay (France); Boudry, V.; Moreau, F.; Specka, A. [CNRS/IN2P3, LLR, Ecole Polytechnique, Palaiseau (France); Bozovic-Jelisavcic, I.; Pandurovic, M. [Univ. of Belgrade, Vinca Inst. of Nuclear Sciences, Belgrade (RS); Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Thompson, P.D. [Univ. of Birmingham, School of Physics and Astronomy, Birmingham (United Kingdom); Bruncko, D.; Cerny, V.; Ferencei, J. [Slovak Academy of Sciences, Kosice (Slovakia)] [and others

    2012-06-15

    Measurements of cross sections for beauty and charm events with dijets and a muon in the photoproduction regime at HERA are presented. The data were collected with the H1 detector and correspond to an integrated luminosity of 179 pb{sup -1}. Events with dijets of transverse momentum P{sub T}{sup jet1}> 7 GeV and P{sub T}{sup jet2}> 6 GeV in the pseudorapidity range -1.5<{eta}{sup jet}<2.5 in the laboratory frame are selected in the kinematic region of photon virtuality Q{sup 2}<2.5 GeV{sup 2} and inelasticity 0.2 2.5 GeV in the pseudorapidity range -1.3<{eta}{sup {mu}}<1.5. The fractions of beauty and charm events are determined using the impact parameters of the muon tracks with respect to the primary vertex and their transverse momentum relative to the axis of the associated jet. Both variables are reconstructed using the H1 vertex detector. The measurements are in agreement with QCD predictions at leading and next-to-leading order. (orig.)

  15. Diffractive open charm production in deep-inelastic scattering and photoproduction at HERA

    Science.gov (United States)

    Aktas, A.; Andreev, V.; Anthonis, T.; Antunovic, B.; Aplin, S.; Asmone, A.; Astvatsatourov, A.; Babaev, A.; Backovic, S.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J. C.; Boenig, M.-O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Büsser, F. W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A. J.; Cantun Avila, K. B.; 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.; 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.; Ghazaryan, S.; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B. R.; Grindhammer, G.; Gwilliam, C.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R. C. W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K. H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Jacquet, M.; Janssen, X.; Jemanov, V.; Jönsson, L.; 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.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Krüger, K.; Landon, M. P. J.; Lange, W.; Laštovička-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.-I.; Lueders, H.; Lytkin, L.; Makankine, A.; Malinovski, E.; 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.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J. V.; Mozer, M. U.; Müller, K.; Murín, 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.; Pandurovic, M.; Papadopoulou, T.; Pascaud, C.; Patel, G. D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Plačakytė, R.; 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.; Sheviakov, I.; Shtarkov, L. N.; Sloan, T.; Smiljanic, I.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, A.; Steder, M.; Stella, B.; Stiewe, J.; Stoilov, A.; Straumann, U.; Sunar, D.; Sykora, T.; 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 Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, C.; Wolf, R.; Wünsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Žáček, J.; Zálešák, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y. C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2007-03-01

    Measurements are presented of diffractive open charm production at HERA. The event topology is given by ep→eXY where the system X contains at least one charmed hadron and is well separated by a large rapidity gap from a leading low-mass proton remnant system Y. Two analysis techniques are used for the cross section measurements. In the first, the charm quark is tagged by the reconstruction of a D*±(2010) meson. This technique is used in deep-inelastic scattering (DIS) and photoproduction (γp). In the second, a method based on the displacement of tracks from the primary vertex is used to measure the open charm contribution to the inclusive diffractive cross section in DIS. The measurements are compared with next-to-leading order QCD predictions based on diffractive parton density functions previously obtained from a QCD analysis of the inclusive diffractive cross section at H1. A good agreement is observed in the full kinematic regime, which supports the validity of QCD factorization for open charm production in diffractive DIS and γp.

  16. Diffractive Open Charm Production in Deep-Inelastic Scattering and 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, W.; Baudrand, S.; Beckingham, M.; Begzsuren, K.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, N.; Bizot, J.C.; Boenig, M.O.; Boudry, V.; Bozovic-Jelisavcic, I.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Cantun Avila, K.B.; 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.; Daum, K.; de Boer, Y.; Delcourt, B.; Del Degan, M.; De Roeck, A.; De Wolf, E.A.; Diaconu, C.; Dodonov, V.; Dubak, A.; Eckerlin, Guenter; 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.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Gouzevitch, M.; Grab, C.; Greenshaw, T.; Gregori, M.; Grell, B.R.; Grindhammer, G.; Gwilliam, C.; Habib, S.; Haidt, D.; Hansson, M.; Heinzelmann, G.; Helebrant, C.; Henderson, R.C.W.; Henschel, H.; Herrera, G.; Hildebrandt, M.; Hiller, K.H.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Hreus, T.; Hussain, S.; Ibbotson, M.; Jacquet, M.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, Andreas Werner; Jung, H.; Kapichine, M.; Katzy, J.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Kraemer, M.; Krastev, K.; Kretzschmar, J.; Kropivnitskaya, A.; Kruger, K.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Leibenguth, G.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; Liptaj, A.; List, B.; List, J.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lucaci-Timoce, A.I.; Lueders, H.; Lytkin, L.; Makankine, A.; Malinovski, E.; 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.; Mladenov, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nankov, K.; Naroska, B.; Naumann, T.; Newman, Paul 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.; Pandurovic, M.; Papadopoulou, T.; Pascaud, C.; Patel, G.D.; Peng, H.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Picuric, I.; Piec, S.; Pitzl, D.; Placakyte, R.; 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.; Schoning, A.; Schultz-Coulon, H.C.; Sefkow, F.; Shaw-West, R.N.; Sheviakov, I.; Shtarkov, L.N.; Sloan, T.; Smiljanic, Ivan; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Steder, M.; Stella, B.; Stiewe, J.; Stoilov, A.; Straumann, U.; Sunar, D.; Sykora, T.; Tchoulakov, V.; Thompson, G.; Thompson, P.D.; Toll, T.; Tomasz, F.; Traynor, D.; Trinh, T.N.; Truoel, P.; Tsakov, I.; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Urban, K.; Urban, Marcel; Usik, A.; Utkin, D.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vazdik, Y.; Vinokurova, S.; Volchinski, V.; Wacker, K.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Wessels, M.; Wissing, C.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zhu, Y.C.; Zimmermann, J.; Zimmermann, T.; Zohrabyan, H.; Zomer, F.

    2007-01-01

    Measurements are presented of diffractive open charm production at HERA. The event topology is given by ep -> eX Y where the system X contains at least one charmed hadron and is well separated by a large rapidity gap from a leading low-mass proton remnant system Y. Two analysis techniques are used for the cross section measurements. In the first, the charm quark is tagged by the reconstruction of a D*(2010) meson. This technique is used in deep-inelastic scattering (DIS) and photoproduction. In the second, a method based on the displacement of tracks from the primary vertex is used to measure the open charm contribution to the inclusive diffractive cross section in DIS. The measurements are compared with next-to-leading order QCD predictions based on diffractive parton density functions previously obtained from a QCD analysis of the inclusive diffractive cross section at H1. A good agreement is observed in the full kinematic regime, which supports the validity of QCD factorization for open charm production in...

  17. J/Psi and Gamma Photoproduction in Pb-Pb Collisions at LHC

    CERN Document Server

    Li Yun De; CERN. Geneva

    1996-01-01

    abstractINT-96-01 Hard photoproduction of J/psi and upsilon at LHC Pb-Pb collisions with cms energy 6300 AGeV, is discussed in the process Pb+Pb--Pb + J/psi (upsilon) + X with three types of equivalent photon spectrum function. It turns out that in hard photoproduction the J/psi cross section is dominated by the gluon and heavy quark fragmentation, especially the gluon fragmentation is very important at large pt; while the Upsilon cross section is dominated by the leading order process. It may be concluded from the result that the hard photoproduction processes can be used to test several important problems such as the gluon distribution in nucleus, gluon and heavy quark fragmentation of J/psi , etc. In addition, these processes also provide a new way of testing the EMC effects.

  18. Evidence for a ωrhosup(+-)πsup(+-) state in diffractive photoproduction

    International Nuclear Information System (INIS)

    Atkinson, M.; Davenport, M.; Flower, P.; Hutton, J.S.; Kumar, B.R.; Morris, J.A.G.; Morris, J.V.; Sharp, P.H.; Brodbeck, T.J.; Clegg, A.B.; Flynn, P.J.; Henderson, R.C.W.; Newton, D.; Brookes, G.R.; Bunn, J.J.; Galbraith, W.; McClatchey, R.H.; Bussey, P.J.; Dainton, J.B.; Paterson, C.; Raine, C.; Skillicorn, I.O.; Smith, K.M.; Diekmann, B.; Heinloth, K.; Jakob, H.P.; Jung, M.; Liebenau, V.; Paul, E.; Reidenbach, M.; Rotscheidt, H.; Schloesser, A.; Laberrigue, J.; La Vaissilere, C. de; Yiou, T.P.

    1985-01-01

    The photoproduction of the final state ωπ + π - π 0 has been studied as part of a survey of photoproduction in the energy range 20-70 GeV in the Omega spectrometer at CERN. The π + π - π 0 system produced with the ω meson has a strong rhosup(+-)πsup(+-) component which is predominantly I=1 and Jsup(π)=1+. For the ωrhosup(+-)π + state a spin-parity analysis favours Jsup(π)=1-, and the mass spectrum peaks at 2.28+-0.05 GeV. The fitted width is GAMMA=0.44+-0.11 GeV. The photoproduction cross-section of the ωrhosup(+-)rhosup(+-) state, averaged over the energy range 25-60 GeV, is 150+-50 nb. (orig.)

  19. 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.

  20. Probing hydrogen bonding interactions and proton transfer in proteins

    Science.gov (United States)

    Nie, Beining

    intermediate states of proteins. Our MD simulations on the structures of photoactive yellow protein (PYP) and its photoproducts provide deep insight into the much-debated structural nature of chromophore photo-isomerization. Our simulation data of three plausible photoproducts provide a specific guide on how to use time-resolved infrared spectroscopy to identify which photoproduct is formed after photo-isomerization. Our data also indicate that hydrogen bond with Tyr42 may be crucial to increase the proton affinity of the chromophore and trigger the intra-protein proton transfer during PYP photoreceptor activation.

  1. Evidences of oxidative stress during hydrogen photoproduction in sulfur-deprived cultures of Chlamydomonas reinhardtii

    Czech Academy of Sciences Publication Activity Database

    Sáens, M. E.; Bišová, Kateřina; Touloupakis, E.; Faraloni, C.; Dario Di Marzio, W.; Torzillo, G.

    2015-01-01

    Roč. 40, č. 30 (2015), s. 10410-10417 ISSN 0360-3199 Institutional support: RVO:61388971 Keywords : Oxidative stress * Chlamydomonas reinhardtii * H-2 production Subject RIV: EE - Microbiology, Virology Impact factor: 3.205, year: 2015

  2. Phi photoproduction near threshold with Okubo-Zweig-Iizuka evading phi NN interactions

    CERN Document Server

    William, R A

    1998-01-01

    Existing intermediate and high energy phi-photoproduction data is consistent with purely diffractive production (i.e., Pomeron exchange). However, near threshold (1.574 GeV K sup + K sup - decay angular distribution. We stress the importance of measurements with linearly polarized photons near the phi threshold to separate natural and unnatural parity exchange mechanisms. Approved and planned phi photoproduction and electroproduction experiments at Jefferson Lab will help establish the relative dynamical contributions near threshold and clarify outstanding theoretical issues related to apparent Okubo-Zweig-Iizuka violations.

  3. 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.)

  4. Detailed comparison of next-to-leading order predictions for jet photoproduction at HERA.

    Energy Technology Data Exchange (ETDEWEB)

    Harris, B. W.; Klassen, M.; Vossebeld, J.

    1999-06-02

    The precision of new HERA data on jet photoproduction opens up the possibility to discriminate between different models of the photon structure. This requires equally precise theoretical predictions from perturbative QCD calculations. In the past years, next-to-leading order calculations for the photoproduction of jets at HERA have become available. Using the kinematic cuts of recent ZEUS analyses, we compare the predictions of three calculations for different dijet and three-jet distributions. We find that in general all three calculations agree within the statistical accuracy of the Monte Carlo integration yielding reliable theoretical predictions. In certain restricted regions of phase space, the calculations differ by up to 5%.

  5. Exclusive photoproduction of Upsilon in pPb collisions at LHC energies

    International Nuclear Information System (INIS)

    Dutta, Dipanwita; Chudasama, Ruchi; Mohanty, A.K.

    2014-01-01

    Recent results of exclusive photoproduction of heavy vector mesons at LHC energies by ALICE and LHCb in pp, pPb and PbPb Ultraperipheral collisions (UPC) confirmed the expectations that UPCs are a very promising probe to study the gluon distributions in nucleons and in nuclei at small x. In this work, we have estimated the photoproduction of γ in pPb collisions at √s NN = 5.02 TeV in the framework of perturbative two-gluon exchange formalism employing various parametrization of gluon distributions functions

  6. Electro- and Photoproduction of Omega(783) Mesons using CLAS at Jefferson Lab

    International Nuclear Information System (INIS)

    Manak, J.J.; Volker Burkert; Franz Klein; Bernhard Mecking; Alan Coleman; Herb Funsten

    2000-01-01

    Electro- and photoproduction of w(783) from a proton target have been measured in the CLAS detector at the Thomas Jefferson National Accelerator Facility in Newport News VA. The photoproduction data were taken over a photon energy range from 0.5 to 2.3 GeV, while the electroproduction data was obtained over a W range of 1.8-2.5 GeV/c2. Preliminary acceptance corrected center-of-mass angular distributions have been examined for both data sets

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

    International Nuclear Information System (INIS)

    Ryan, P.D.

    2006-11-01

    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 -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 CUT 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.)

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

    Science.gov (United States)

    Egiyan, H.; Langheinrich, J.; Gothe, R. W.; Graham, L.; Holtrop, M.; Lu, H.; Mattione, P.; Mutchler, G.; Park, K.; Smith, E. S.; Stepanyan, S.; Zhao, Z. W.; Adhikari, K. P.; Aghasyan, M.; Anghinolfi, M.; Baghdasaryan, H.; Ball, J.; Baltzell, N. A.; Battaglieri, M.; Bedlinskiy, I.; Bennett, R. P.; Biselli, A. S.; Bookwalter, C.; Branford, D.; Briscoe, W. J.; Brooks, W. K.; Burkert, V. D.; Carman, D. S.; Celentano, A.; Chandavar, S.; Contalbrigo, M.; D'Angelo, A.; Daniel, A.; Dashyan, N.; de Vita, R.; de Sanctis, E.; Deur, A.; Dey, B.; Dickson, R.; Djalali, C.; Doughty, D.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fedotov, G.; Fegan, S.; Fradi, A.; Gabrielyan, M. Y.; Gevorgyan, N.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Goetz, J. T.; Gohn, W.; Golovatch, E.; Griffioen, K. A.; Guidal, M.; Guler, N.; Guo, L.; Gyurjyan, V.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Heddle, D.; Hicks, K.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Jo, H. S.; Joo, K.; Khetarpal, P.; Kim, A.; Kim, W.; Klein, A.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Livingston, K.; MacGregor, I. J. D.; Mao, Y.; Mayer, M.; McKinnon, B.; Mokeev, V.; Munevar, E.; Nadel-Turonski, P.; Ni, A.; Niculescu, G.; Ostrovidov, A. I.; Paolone, M.; Pappalardo, L.; Paremuzyan, R.; Park, S.; Pasyuk, E.; Anefalos Pereira, S.; Phelps, E.; Pogorelko, O.; Pozdniakov, S.; Price, J. W.; Procureur, S.; Protopopescu, D.; Raue, B. A.; Ricco, G.; Rimal, D.; Ripani, M.; Ritchie, B. G.; Rosner, G.; Rossi, P.; Sabatié, F.; Saini, M. S.; Salgado, C.; Schott, D.; Schumacher, R. A.; Seder, E.; Seraydaryan, H.; Sharabian, Y. G.; Smith, G. D.; Sober, D. I.; Stepanyan, S. S.; Strauch, S.; Taiuti, M.; Tang, W.; Taylor, C. E.; Tedeschi, D. J.; Ungaro, M.; Voutier, E.; Watts, D. P.; Weinstein, L. B.; Weygand, D. P.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhao, B.

    2012-01-01

    We searched for the Φ--(1860) pentaquark in the photoproduction process off the deuteron in the Ξ-π--decay channel using CLAS. The invariant-mass spectrum of the Ξ-π- 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 Φ--(1860) with a consecutive decay into Ξ-π- in the photon-energy range 4.5GeV

  9. Measurement of inclusive and DiJet D{sup *}-meson photoproduction at the H1-experiment at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Urban, K.

    2009-03-15

    In the present analysis the production mechanism of charm quarks in electron proton scattering at the HERA collider is investigated using 30.68 pb{sup -1}, 68.23 pb{sup -1} and 93.39 pb{sup -1} of data collected with the H1 experiment. Events containing charm quarks are detected by the reconstruction of D{sup *} mesons in the kinematic domain of photoproduction. For the first time D{sup *} mesons are selected on the basis of the third level of the H1 Fast Track Trigger. Compared to the previous analysis the phase space studied was extended significantly and the data statistics increased by a factor of eight. The investigated kinematic region covers photons of virtuality of Q{sup 2}<2 GeV{sup 2} and photon-proton center-of-mass energies in the range of 100photoproduction and low p{sub t}(D{sup *}) is of particular interest since it allows the test of different theoretical models at the limit of applicability of pertubative QCD. In a further measurement, which is based on the events with D{sup *} mesons, at least two jets are selected. Jets with p{sub t}>4 GeV and p{sub t}>3 GeV, are studied in the pseudorapidity range of vertical stroke {eta} vertical stroke <1.5, where one of the selected jets is associated with the D{sup *} meson. The investigation of two hard partons, by means of the jets, results in an improved understanding of the production mechanism of charm quarks. This measurement demonstrates that resolved photon processes play an important role in the photoproduction of charm quarks. Single and double differential cross sections of both event samples are compared to predictions of perturbative QCD in leading and next to leading order. (orig.)

  10. Measurement of the Asymmetry of Photoproduction of π- Mesons on Linearly Polarized Deuterons by Linearly Polarized Photons

    Science.gov (United States)

    Gauzshtein, V. V.; Zevakov, S. A.; Levchuk, M. I.; Loginov, A. Yu.; Nikolenko, D. M.; Rachek, I. A.; Sadykov, R. Sh.; Toporkov, D. K.; Shestakov, Yu. V.

    2018-05-01

    The first results of a double polarization experiment to extract the asymmetry of the reaction of photoproduction of a π- meson by a linearly polarized photon on a tensor-polarized deuteron in the energy range of the virtual photon (300-700 MeV) are presented. The measurements were performed on an internal tensor-polarized deuterium target in the VEPP-3 electron-positron storage ring for the electron beam energy equal to 2 GeV. The experiment employed the method of recording two protons and the scattered electron in coincidence. The obtained measurement results are compared with the theoretical predictions obtained in the momentum approximation with allowance for πN and NN rescattering in the final state.

  11. Measurement of charm and beauty cross sections in photoproduction using events with muons and dijets at HERA

    International Nuclear Information System (INIS)

    Kraemer, M.

    2009-09-01

    A measurement of open charm and beauty cross sections in photoproduction using dijet events containing a muon at the ep collider HERA is presented. The analysed data are collected with the H1 detector in the years 2006 and 2007, corresponding to an integrated luminosity of 179 pb -1 . Events are selected, which contain at least two jets with transverse momenta of p t jet1(2) >7(6) GeV in the pseudorapidity region -2.5 jet1(2) t μ >2.5 GeV in the pseudorapidity range -1.3 μ γ obs . Double differential cross sections for charm and beauty are measured in the region of direct and resolved processes. (orig.)

  12. Spin-dependent hadro- and photoproduction of heavy quarks at next-to-leading order of QCD

    International Nuclear Information System (INIS)

    Riedl, Johann

    2014-01-01

    In this thesis, we have studied heavy quark hadro- and photoproduction in detail and examined the possibilities of using heavy quark production for the extraction of the polarised parton distribution functions. All calculations are performed at O(α s 3 ) and O(αα s 2 ) accuracy, respectively, and theoretical uncertainties due to the choice of scales μ f,r and the heavy quark mass m Q have been discussed in detail. Based on our theoretical results we have presented detailed phenomenological studies for the existing PHENIX and STAR experiments at BNL-RHIC and the COMPASS experiment at CERN. Predictions have been made for possible future experiments at a low-energy antiproton-proton collider at GSI-FAIR, a proton-proton collider at J-PARC and an upcoming high-energy electron-ion collider (EIC).

  13. Photoproduction of the f1(1285 ) meson

    Science.gov (United States)

    Dickson, R.; Schumacher, R. A.; Adhikari, K. P.; Akbar, Z.; Amaryan, M. J.; Anefalos Pereira, S.; Badui, R. A.; Ball, J.; Battaglieri, M.; Batourine, V.; Bedlinskiy, I.; Biselli, A.; Boiarinov, S.; Briscoe, W. J.; Burkert, V. D.; Cao, T.; Carman, D. S.; Celentano, A.; Chandavar, S.; Charles, G.; Chetry, T.; Ciullo, G.; Colaneri, L.; Cole, P. L.; Compton, N.; Contalbrigo, M.; Cortes, O.; Crede, V.; D'Angelo, A.; Dashyan, N.; De Vita, R.; De Sanctis, E.; Deur, A.; Djalali, C.; Dugger, M.; Dupre, R.; El Alaoui, A.; El Fassi, L.; Eugenio, P.; Fanchini, E.; Fedotov, G.; Filippi, A.; Fleming, J. A.; Gevorgyan, N.; Ghandilyan, Y.; Gilfoyle, G. P.; Giovanetti, K. L.; Girod, F. X.; Gothe, R. W.; Griffioen, K. A.; Guo, L.; Hafidi, K.; Hakobyan, H.; Hanretty, C.; Harrison, N.; Hattawy, M.; Holtrop, M.; Hicks, K.; Hughes, S. M.; Ilieva, Y.; Ireland, D. G.; Ishkhanov, B. S.; Isupov, E. L.; Jiang, H.; Jo, H. S.; Joosten, S.; Keller, D.; Khachatryan, G.; Khandaker, M.; Kim, A.; Kim, W.; Klein, F. J.; Kubarovsky, V.; Kuleshov, S. V.; Lanza, L.; Lenisa, P.; Livingston, K.; Lu, H. Y.; MacGregor, I. J. D.; Mattione, P.; McKinnon, B.; Meyer, C. A.; Mirazita, M.; Markov, N.; Mokeev, V.; Moriya, K.; Munevar, E.; Murdoch, G.; Nadel-Turonski, P.; Net, L. A.; Ni, A.; Osipenko, M.; Ostrovidov, A. I.; Park, K.; Pasyuk, E.; Phelps, W.; Pisano, S.; Pogorelko, O.; Price, J. W.; Prok, Y.; Puckett, A. J. R.; Raue, B. A.; Ripani, M.; Rizzo, A.; Rosner, G.; Roy, P.; Salgado, C.; Seder, E.; Sharabian, Y. G.; Skorodumina, Iu.; Smith, E. S.; Smith, G. D.; Sober, D.; Sokhan, D.; Sparveris, N.; Stepanyan, S.; Strakovsky, I. I.; Stankovic, I.; Strauch, S.; Sytnik, V.; Taiuti, M.; Ungaro, M.; Voskanyan, H.; Voutier, E.; Walford, N. K.; Watts, D. P.; Weygand, D.; Wood, M. H.; Zachariou, N.; Zana, L.; Zhang, J.; Zonta, I.; CLAS Collaboration

    2016-06-01

    The f1(1285 ) meson with mass 1281.0 ±0.8 MeV/c2 and width 18.4 ±1.4 MeV (full width at half maximum) was measured for the first time in photoproduction from a proton target using CLAS at Jefferson Lab. Differential cross sections were obtained via the η π+π-,K+K¯0π- , and K-K0π+ decay channels from threshold up to a center-of-mass energy of 2.8 GeV. The mass, width, and an amplitude analysis of the η π+π- final-state Dalitz distribution are consistent with the axial-vector JP=1+ f1(1285 ) identity, rather than the pseudoscalar 0- η (1295 ) . The production mechanism is more consistent with s -channel decay of a high-mass N* state and not with t -channel meson exchange. Decays to η π π go dominantly via the intermediate a0±(980 ) π∓ states, with the branching ratio Γ [a0π (noK ¯K )] /Γ [η π π (all)] =0.74 ±0.09 . The branching ratios Γ (K K ¯π ) /Γ (η π π ) =0.216 ±0.033 and Γ (γ ρ0) /Γ (η π π ) =0.047 ±0.018 were also obtained. The first is in agreement with previous data for the f1(1285 ) , while the latter is lower than the world average.

  14. Photoproduction of ηπ pairs off nucleons and deuterons

    Energy Technology Data Exchange (ETDEWEB)

    Kaeser, A.; Mueller, F.; Dieterle, M.; Garni, S.; Jaegle, I.; Keshelashvili, I.; Krusche, B.; Maghrbi, Y.; Oberle, M.; Pheron, F.; Rostomyan, T.; Strub, T.; Walford, N.K.; Witthauer, L. [University of Basel, Department of Physics, Basel (Switzerland); Ahrens, J.; Arends, H.J.; Bartolome, P.A.; Ostrick, M.; Otte, P.; Thomas, A. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); Annand, J.R.M.; Hamilton, D.; Howdle, D.; Livingston, K.; MacGregor, I.J.D.; Mancell, J.; McGeorge, J.C.; McNicoll, E.; Robinson, J. [University of Glasgow, SUPA School of Physics and Astronomy, Glasgow (United Kingdom); Bantawa, K.; Manley, D.M. [Kent State University, Kent, OH (United States); Beck, R.; Nikolaev, A.; Schumann, S.; Unverzagt, M. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); University Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Braghieri, A.; Costanza, S.; Mushkarenkov, A.; Pedroni, P. [INFN Sezione di Pavia, Pavia (Italy); Briscoe, W.J.; Marinides, Z. [The George Washington University, Center for Nuclear Studies, Washington (United States); Cherepnya, S.; Fil' kov, L.V. [Lebedev Physical Institute, Moscow (Russian Federation); Downie, E.J. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); University of Glasgow, SUPA School of Physics and Astronomy, Glasgow (United Kingdom); The George Washington University, Center for Nuclear Studies, Washington (United States); Drexler, P.; Metag, V.; Novotny, R.; Thiel, M. [University of Giessen, II. Physikalisches Institut, Giessen (Germany); Fix, A. [Tomsk Polytechnic University, Laboratory of Mathematical Physics, Tomsk (Russian Federation); Glazier, D.I. [University of Glasgow, SUPA School of Physics and Astronomy, Glasgow (United Kingdom); University of Edinburgh, SUPA School of Physics, Edinburgh (United Kingdom); Hornidge, D.; Middleton, D.G. [Mount Allison University, Sackville, New Brunswick (Canada); Huber, G.M. [University of Regina, Regina (Canada); Jude, T.C.; Sikora, M.H.; Watts, D.P. [University of Edinburgh, SUPA School of Physics, Edinburgh (United Kingdom); Kashevarov, V.L. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); Lebedev Physical Institute, Moscow (Russian Federation); Kondratiev, R.; Lisin, V.; Polonski, A. [Institute for Nuclear Research, Moscow (Russian Federation); Korolija, M.; Mekterovic, D.; Micanovic, S.; Supek, I. [Rudjer Boskovic Institute, Zagreb (Croatia); Oussena, B. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); The George Washington University, Center for Nuclear Studies, Washington (United States); Prakhov, S.; Starostin, A. [University of California Los Angeles, Los Angeles, California (United States); Sober, D. [The Catholic University of America, Washington (United States); Werthmueller, D. [University of Basel, Department of Physics, Basel (Switzerland); University of Glasgow, SUPA School of Physics and Astronomy, Glasgow (United Kingdom); Collaboration: The A2 Collaboration

    2016-09-15

    Quasi-free photoproduction of πη-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 πη and meson-nucleon pairs, and beam-helicity asymmetries have been measured for the reactions γp → pπ{sup 0}η, γn → nπ{sup 0}η, γp → nπ{sup +}η, and γn → pπ{sup -}η from nucleons bound inside the deuteron. For the γp initial-state data for free protons have also been analyzed. Finally, the total cross sections for quasi-free production of π{sup 0}η pairs from nucleons bound in {sup 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 4π covering electromagnetic calorimeter composed of the Crystal Ball and TAPS detectors. The shapes of all differential cross section data and the asymmetries are very similar for protons and neutrons and agree with the conjecture that the reactions are dominated by the sequential Δ*3/2{sup -} → ηΔ(1232) → πηN decay chain, mainly with Δ(1700)3/2{sup -} and Δ(1940)3/2{sup -}. The ratios of the magnitude of the total cross sections also agree with this assumption. However, the absolute magnitudes of the cross sections are reduced by FSI effects with respect to free proton data. (orig.)

  15. Why hydrogen; Pourquoi l'hydrogene?

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-02-01

    The energy consumption increase and the associated environmental risks, led to develop new energy sources. The authors present the potentialities of the hydrogen in this context of energy supply safety. They detail the today market and the perspectives, the energy sources for the hydrogen production (fossils, nuclear and renewable), the hydrogen transport, storage, distribution and conversion, the application domains, the associated risks. (A.L.B.)

  16. Determination of amplitudes in neutral pion photoproduction and comparison with partial waves analysis in the energy range of 1.3 to 2.1 GeV

    International Nuclear Information System (INIS)

    Forozani, G.

    2004-01-01

    The magnitude of four independent amplitudes are obtained pion photoproduction in the energy range of 1300 to 2100 MeV incident photon. Different cross section and three polarization parameters are required for such amplitudes reconstruction at different pion scattering angles. Results of the direct amplitudes reconstruction have been compared with the solution of partial wave analysis SM95 and SM00K at all energies. This analysis indicates that we have a fair agreement between the present work and the results of partial wave analysis at many angles

  17. Determination of amplitudes in neutral pion photoproduction and comparison with partial waves analysis in the energy range of 1.3 to 2.1 GeV

    International Nuclear Information System (INIS)

    Forozani, G.

    2004-01-01

    The magnitude of four independent amplitudes are obtained in neutral pion photoproduction in the energy range of 1300 to 2100 MeV incident photon. Differential gross section and three polarization parameters are required for such amplitudes reconstruction at different pion scattering angles. Results of the direct amplitudes reconstruction have been compared with the solution of partial wave analysis SM95 and SM00K at all energies. This analysis indicates that we have a fair agreement between the present work and the results of partial wave analysis at meny angles (Author)

  18. New results from HERA on photoproduction and diffraction, the proton structure function, deep inelastic scattering at low x, heavy flavour production, jets and searches for leptoquarks

    International Nuclear Information System (INIS)

    Barreiro, F.; Bhadra, S.; Lancaster, M.; Lim, J.N.; Soeldner-Rembold, S.; Straub, B.

    1994-11-01

    This report contains some of the papers presented by the ZEUS Collaboration at the 27th international conference on high energy physics in Glasgow (20-27 July 1994). These concern deep inelastic ep scattering at low x, photoproduction and diffraction in ep scattering, a measurement of the proton structure function and determination of the low-x gluon distribution, D * and J/Ψ production in ep scattering, multi-jet production and determination of α s in ep scattering, and the search for leptoquarks in ep collisions. (HSI)

  19. Exclusive J/ψ photoproduction off protons in ultra-peripheral p-Pb collisions at √sNN=5.02 TeV

    DEFF Research Database (Denmark)

    Abelev, B.; Adam, J.; Adamová, D.

    2014-01-01

    We present the first measurement at the LHC of exclusive J/ψ photoproduction off protons, in ultraperipheral proton-lead collisions at sNN−−−√=5.02  TeV. Events are selected with a dimuon pair produced either in the rapidity interval, in the laboratory frame, 2.5

  20. Inclusive photoproduction of bottom quarks for low and medium pT in the general-mass variable-flavour-number scheme

    International Nuclear Information System (INIS)

    Kramer, G.; Spiesberger, H.; Cape Town Univ., Rondebosch

    2015-09-01

    We present predictions for b-quark production in photoproduction and compare with experimental data from HERA. Our theoretical predictions are obtained at next-to-leading-order in the general-mass variable-flavor-number scheme, an approach which takes into account the finite mass of the b quarks. We use realistic evolved nonperturbative fragmentation functions obtained from fits to e + e - data. We find in general good agreement of data with both the GM-VFNS and the FFNS calculations, while the more precise ZEUS data seem to prefer the GM-VFNS predictions.

  1. Connections between Compton scattering and pion photoproduction in the delta region

    International Nuclear Information System (INIS)

    Mukhopadhyay, N.C.; Benmerrouche, M.

    1992-01-01

    Using textbook tools like analyticity, unitarity and optical theorem, the authors discuss the relationship between pion-nucleon scattering, pion photoproduction and Compton scattering in the Δ(1232) resonance region. They review the relevant data and draw conclusions pertinent to the QCD-inspired models. 27 refs

  2. Search for exclusive photoproduction of Z(c)(+/-) (3900) at COMPASS

    Czech Academy of Sciences Publication Activity Database

    Adolph, C.; Akhunzyanov, R.; Alekseev, M.; Alexakhin, V. Yu.; Alexandrov, Yu.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anosov, V. A.; Austregisilio, A.; Badelek, B.; Balestra, F.; Barth, J.; Baum, G.; Beck, R.; Bedfer, Y.; Berlin, A.; Bernhard, J.; Bertini, R.; Bicker, K.; Bieling, J.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bravar, A.; Bressan, A.; Büchele, M.; Burtin, E.; Capozza, L.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Crespo, M.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O.; Donskov, S.; Doshita, N.; Duic, V.; Dünnweber, W.; Dziewiecki, M.; Efremov, A.V.; Elia, C.; Eversheim, P.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; Finger jr., M.; Fischer, H.; Franco, C.; Fresne von Hohenesche, N.; Friedrich, J.; Frolov, V.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gnesi, I.; Gobbo, B.; Goertz, S.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grube, B.; Gushterski, R.; Guskov, A.; Guthörl, T.; Haas, F.; von Harrach, D.; Hahne, D.; Hashimoto, R.; Heinsius, F.; Herrmann, F.; Hess, C.; Hinterberger, F.; Höppner, Ch.; Horikawa, N.; d'Hose, N.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jasinski, P.; Joerg, P.; Joosten, R.; Kabuss, E.; Kang, D.; Ketzer, B.; Khaustov, G.; Khokhlov, Y.; Kisselev, Y.; Klein, F.; Klimaszewski, K.; Koivuniemi, J.; Kolosov, V.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V.; Kotzinian, A.; Kouznetsov, O.; Král, Z.; Krämer, M.; Kroumchtein, Z.; Kuchinski, N.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A.; Lehmann, A.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makke, N.; Mallot, G.; Marchand, C.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Y.; Miyachi, Y.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V.; Nový, J.; Nowak, W. D.; Nunes, A.S.; Orlov, I.; Olshevsky, A.; Ostrick, M.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Pešek, M.; Peshekhonov, D.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Reicherz, G.; Rocco, E.; Rodionov, V. K.; Rondio, E.; Rossiyskaya, N. S.; Ryabchikov, D.; Samoylenko, V.; Sandacz, A.; Sapozhnikov, M.; Sarkar, S.; Savin, I.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schlütter, T.; Schmidt, A.; Schmidt, K.; Schmiden, H.; Schmitt, L.; Schönning, K.; Schopferer, S.; Schott, M.; Shevchenko, O.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sosio, S.; Sozzi, F.; Srnka, Aleš; Steiger, L.; Stolarski, M.; Sulc, M.; Sulej, R.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Ter Wolbeek, J.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Uhl, S.; Uman, I.; Vandenbroucke, M.; Virius, M.; Vondra, J.; Wang, L.; Weisrock, T.; Wilfert, M.; Windmolders, R.; Wislicki, W.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Zhuravlev, N.; Ziembicki, M.

    2015-01-01

    Roč. 742, MAR 6 (2015), s. 330-334 ISSN 0370-2693 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : COMPASS * Z(c)(3900) * Photoproduction * Tetraquark Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 4.787, year: 2015

  3. Helicity Asymmetry Measurement for π0 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.

  4. ω(→ π+π−π0) meson photoproduction on proton

    Indian Academy of Sciences (India)

    PRAMANA c Indian Academy of Sciences. Vol. 75, No. 4. — journal of. October 2010 physics pp. 665–674 ω(→ π+π−π0) meson photoproduction on proton ... The vector meson can probe the low-lying nucleonic resonances [7] because it ... reaction amplitudes from the latest measurement of the four-momentum transfer.

  5. 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.

  6. Measurement of the t dependence in exclusive photoproduction of Upsilon(1S) mesons at HERA

    CERN Document Server

    Abramowicz, H.

    2012-02-14

    The exclusive photoproduction reaction gamma p -> Upsilon(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 60 Upsilon(1S) p cross section.

  7. Search for a PHI' vector meson in diffractive photoproduction of K+K-π+π-

    International Nuclear Information System (INIS)

    Atkinson, M.; Davenport, M.; Flower, P.; Hutton, J.S.; Kumar, B.R.; Morris, J.A.G.; Morris, J.V.; Patrick, G.N.; Sharp, P.H.; Bussey, P.J.; Dainton, J.B.; Paterson, C.; Raine, C.; Skillicorn, I.O.; Smith, K.M.; Brodbeck, T.J.; Clegg, A.B.; Flynn, P.J.; Henderson, R.C.W.; Newton, D.; Axon, T.J.; Barberis, D.; Dickinson, B.; Donnachie, A.; Ellison, R.J.; Hughes-Jones, R.E.; Ibbotson, M.; Lafferty, G.D.; Lane, J.B.; Mercer, D.; Thompson, R.J.; Waite, A.P.; Worsell, M.F.; Levy, J.M.; Laberrigue, J.; La Vaissiere, C. de; Yiou, T.P.; Brookes, G.R.; Bunn, J.J.; Galbraith, W.; McClatchey, R.H.

    1986-01-01

    A study of photoproduction of K + K - π + π - shows a broad threshold enhancement, about 30% of which is due to Ksup(*)Kπ production. This Ksup(*)Kπ component shows no dynamical features indicative of the existence of a PHI' vector meson in this channel. (orig.)

  8. Neutrino photoproduction on an electron in the QED two-dimensional approximation

    International Nuclear Information System (INIS)

    Loskutov, Yu.M.; Skobelev, V.V.

    1980-01-01

    Characteristic reactions of electron and muon neutrino photoproduction on an electron in a strong magnetic field are considered in the Weinberg model. The ratio of the corresponding cross sections depending on the charged boson mass permits to cherish hopes on the possibility of evaluating its mass on the basis of the experiment according to neutrino luminosity of neutron stars [ru

  9. Exclusive ρ.sup.0./sup. meson photoproduction with a leading neutron at HERA

    Czech Academy of Sciences Publication Activity Database

    Andreev, V.; Baghdasaryan, A.; Begzsuren, K.; Cvach, Jaroslav; Hladký, Jan; Reimer, Petr

    2016-01-01

    Roč. 76, č. 1 (2016), 1-21, č. článku 41. ISSN 1434-6044 R&D Projects: GA MŠk LG14033 Institutional support: RVO:68378271 Keywords : deep-inelastic scattering * vector meson production * pion exchange model * elastic photoproduction Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 5.331, year: 2016

  10. Electroproduction and photoproduction of vector mesons and generalized vector meson dominance

    International Nuclear Information System (INIS)

    Fraas, H.; Kuroda, M.

    1977-05-01

    Using generalized vector meson dominance, electro- and photoproduction of vector mesons is studied. The unnatural parity exchange part of ω(1.2) production is estimated to be about one fourth of that of ω-production. The off diagonal transition model suggests the suppression of diffractive rho(1.2) and ω(1.2) production. (orig.) [de

  11. Photoproduction of eta-mesons off nuclei for E(gamma)

    NARCIS (Netherlands)

    Mertens, T.; Jaegle, I.; Muehlich, P.; Bacelar, J. C. S.; Bantes, B.; Bartholomy, O.; Bayadilov, D. E.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Crede, V.; Dutz, H.; Ehmanns, A.; Elsner, D.; Essig, K.; Ewald, R.; Fabry, I.; Fornet-Ponse, K.; Fuchs, M.; Funke, C.; Gothe, R.; Gregor, R.; Gridnev, A. B.; Gutz, E.; Hoeffgen, S.; Hoffmeister, P.; Horn, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Kleber, V.; Klein, Frank; Klein, Friedrich; Klempt, E.; Konrad, M.; Kotulla, M.; Krusche, B.; Lang, M.; Langheinrich, J.; Loehner, H.; Lopatin, I. V.; Lotz, J.; Lugert, S.; Menze, D.; Messchendorp, J. G.; Metag, V.; Morales, C.; Mosel, U.; Nanova, M.; Novinski, D. V.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Radkov, A. K.; Roy, A.; 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.; Weinheimer, C.; Wendel, C.

    2008-01-01

    The photoproduction of eta-mesons off (12)C, (40)Ca, (93)Nb, and (nat)Pb nuclei has been measured with a tagged photon beam with energies between 0.6 and 2.2 GeV. The experiment was performed at the Bonn ELSA accelerator with the combined setup of the Crystal Barrel and TAPS calorimeters. It aimed

  12. Inelastic J/Ψ photoproduction off nuclei: Gluon enhancement or double color exchange?

    International Nuclear Information System (INIS)

    Huefner, J.; Zamolodchikov, A.

    1996-01-01

    The nuclear enhancement observed in inelastic photoproduction of J/Ψ should not be interpreted as evidence for an increased gluon density in nuclei. The nuclear suppression of the production rate due to initial and final state interactions is calculated and a novel two-step color exchange process is proposed, which is able to explain the data. (orig.)

  13. Photo-production of neutral kaons on C-12 in the threshold region

    Czech Academy of Sciences Publication Activity Database

    Watanabe, T.; Bydžovský, Petr; Dobashi, K.; Endo, S.; Fujii, Y.; Hashimoto, O.; Ishikawa, T.; Itoh, K.; Kanda, H.

    2007-01-01

    Roč. 651, č. 4 (2007), s. 269-274 ISSN 0370-2693 R&D Projects: GA ČR GA202/05/2142 Institutional research plan: CEZ:AV0Z10480505 Keywords : photo-production * neutral kaon * quasi-free reaction Subject RIV: BE - Theoretical Physics Impact factor: 4.189, year: 2007

  14. The investigation of strangeness photoproduction in the threshold region at ELPH-Tohoku

    Czech Academy of Sciences Publication Activity Database

    Kaneta, M.; Beckford, B.; Bydžovský, Petr; Fujibayashi, T.; Fujii, T.; Fujii, Y.; Futatsukawa, K.; Gogami, T.; Han, Y. C.; Hashimoto, O.; Hirose, K.; Hosomi, K.; Honda, R.; Iguchi, A.; Ishikawa, T.; Kanda, H.; Kaneko, Y.; Kasai, Y.; Kawasaki, T.; Kimura, C.; Kiyokawa, S.; Koike, T.; Maeda, K.; Maruyama, N.; Matsubara, M.; Miwa, K.; Miyagi, Y.; Nagao, S.; Nakamura, S. N.; Okuyama, A.; Sotona, Miloslav; Tamae, T.; Tamura, H.; Tsukada, K.; Terada, N.; Wang, T. S.; Yamamoto, F.; Yamamoto, T.; Yamazaki, H.

    2013-01-01

    Roč. 914, SEP (2013), s. 69-73 ISSN 0375-9474 Institutional support: RVO:61389005 Keywords : strangeness * photoproduction * tagged photon beam * lambda detection Subject RIV: BE - Theoretical Physics Impact factor: 2.499, year: 2013 http://www.sciencedirect.com/science/article/pii/S0375947413005344

  15. Photoproduction of colored pseudo-Goldstone bosons at very high energy

    International Nuclear Information System (INIS)

    Grifols, J.A.; Mendez, A.

    1982-01-01

    We estimate the photoproduction cross section of the color-octet pseudo-Goldstone bosons P 0 8 and P 3 8 in e-p collisions at very high energy. The calculated rates are within detectability limits, especially for the P 3 8 state which, besides, cannot be produced in hadron-hardon interactions

  16. 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.; Bahr, J.; Baranov, P.; Barrelet, E.; Bartel, W.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boenig, M.O.; Boudry, V.; Bracinik, J.; Brisson, V.; Broker, H.B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Chekelian, V.; 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.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dodonov, V.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; 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.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Gabathuler, E.; Gabathuler, K.; Garutti, E.; Garvey, J.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Goerlich, L.; Gogitidze, N.; Gorbounov, S.; Grab, C.; Grassler, H.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Heremans, R.; Herrera, G.; Herynek, I.; Heuer, R.D.; Hildebrandt, M.; Hiller, K.H.; Hladky, J.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kennedy, J.; Kenyon, I.R.; Kiesling, Christian M.; 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.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lueders, H.; Luke, 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, Matthias Ulrich; Muller, K.; Murin, P.; Nagovizin, V.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul 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.; Perez, E.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Poschl, 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.; 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.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Spitzer, H.; Stamen, R.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vargas Trevino, A.; Vassiliev, S.; Vazdik, Y.; Veelken, C.; Vest, A.; Vichnevski, 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, Ch.; Woehrling, E.E.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhokin, A.; Zohrabyan, H.; 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.

  17. 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.

  18. Final states in electroproduction and photoproduction at low and medium energies

    International Nuclear Information System (INIS)

    Marshall, R.

    1977-01-01

    A review is given of electroproduction and photoproduction at photon energies extending from the resonance region up to about 10 GeV. Comparisons are made between the various experiments and the appropriate theories in an attempt to understand more about the different production mechanisms - s channel resonances, t and u channel exchanges and quark-parton effects. (orig.) [de

  19. Q.C.D. predictions for the forward photoproduction of heavy vector mesons

    International Nuclear Information System (INIS)

    Navelet, H.; Peschanski, R.

    1984-03-01

    From the inelastic QantiQ-Nucleon cross section, we get predictions for the forward photoproduction of heavy QantiQ mesons by using V.D.M. and the optical theorem. These cross sections are computed from perturbative Q.C.D. through gluon radiation mechanism

  20. Solar Hydrogen Reaching Maturity

    Directory of Open Access Journals (Sweden)

    Rongé Jan

    2015-09-01

    Full Text Available Increasingly vast research efforts are devoted to the development of materials and processes for solar hydrogen production by light-driven dissociation of water into oxygen and hydrogen. Storage of solar energy in chemical bonds resolves the issues associated with the intermittent nature of sunlight, by decoupling energy generation and consumption. This paper investigates recent advances and prospects in solar hydrogen processes that are reaching market readiness. Future energy scenarios involving solar hydrogen are proposed and a case is made for systems producing hydrogen from water vapor present in air, supported by advanced modeling.

  1. Transient shielded liquid hydrogen containers

    International Nuclear Information System (INIS)

    Varghese, A.P.; Herring, R.H.

    1990-01-01

    The storage of hydrogen in the liquid phase has been limited in duration due to the thermal performance constraints of conventional Liquid Hydrogen containers available. Conventional Liquid Hydrogen containers lose hydrogen because of their relatively high heat leak and variations in usage pattern of hydrogen due to shutdowns. Local regulations also discourage venting of hydrogen. Long term storage of Liquid Hydrogen without product loss was usually accomplished using Liquid Nitrogen sacrificial shields. This paper reports on a new low heat leak container developed and patented that will extend the storage time of liquid hydrogen by five hundred percent. The principle of operation of the Transient Shields which makes the extraordinary performance of this container feasible is described in this paper. Also covered are the impact of this new container on present applications of hydrogen and the new opportunities afforded to Liquid hydrogen in the world hydrogen market

  2. Genetic exchanges caused by ultraviolet photoproducts in phage lamda DNA molecules: the role of DNA replication

    International Nuclear Information System (INIS)

    Lin, P.F.; Howard-Flanders, P.; Yale Univ., New Haven, Conn.

    1976-01-01

    Genetic recombination induced by structural damage in DNA molecules was investigated in E. coli K12(lamda) lysogens infected with genetically marked phage lamda. Photoproducts were induced in the phage DNA before infection by exposing them either to 313 nm light in the presence of acetophenone or to 254 nm light. To test the role of the replication of the damage phage DNA on the frequency of the induced recombination , both heteroimmune and homoimmune crosses were performed, and scored for P + recombinants. In heteroimmune crosses, recombination was less frequent in infected cells exposed to visible light and in wild type cells able to perform excision repair than in excision-defective lysogens. Therefore, much of the induced recombination can be attributed to the pyrimidine dimers in the phage DNA. In homoimmune crosses, replication of the phage DNA containing ultraviolet photoproducts was represented by lamda immunity, and was further blocked by the lack of the P gene product needed for replication. The 254 nm photoproducts increased the frequency of recombination in these homoimmune crosses, even though phage DNA replication was blocked. Irradiation with 313 nm light and acetophenone M, which produces dimers and unknown photoproducts, was not as effective per dimer as the 254 nm light. It is concluded from these results that certain unidentified 254 nm photoproducts can cause recombination even in the absence of DNA replication. They are not pyrimidine dimers, as they are not susceptible to excision repair or photoreactivation. In contrast, pyrimidine dimers appear to cause recombination only when the DNA containing them undergoes replication. (orig./MG) [de

  3. An unusual diphosphatase from the PhnP family cleaves reactive FAD photoproducts.

    Science.gov (United States)

    Beaudoin, Guillaume A W; Li, Qiang; Bruner, Steven D; Hanson, Andrew D

    2018-01-11

    Flavins are notoriously photolabile, but while the photoproducts derived from the iso -alloxazine ring are well known the other photoproducts are not. In the case of FAD, typically the main cellular flavin, the other photoproducts are predicted to include four- and five-carbon sugars linked to ADP. These FAD photoproducts were shown to be potent glycating agents, more so than ADP-ribose. Such toxic compounds would require disposal via an ADP-sugar diphosphatase or other route. Comparative analysis of bacterial genomes uncovered a candidate disposal gene that is chromosomally clustered with genes for FAD synthesis or transport and is predicted to encode a protein of the PhnP cyclic phosphodiesterase family. The representative PhnP family enzyme from Koribacter versatilis (here named Fpd, F AD p hotoproduct d iphosphatase) was found to have high, Mn 2+ -dependent diphosphatase activity against FAD photoproducts, FAD, and ADP-ribose, but almost no phosphodiesterase activity against riboflavin 4',5'-cyclic phosphate, a chemical breakdown product of FAD. To provide a structural basis of the unique Fpd activity, the crystal structure of K. versatilis Fpd was determined. The results place Fpd in the broad metallo-β-lactamase-like family of hydrolases, a diverse family commonly using two metals for hydrolytic catalysis. The active site of Fpd contains two Mn 2+ ions and a bound phosphate, consistent with a diphosphatase mechanism. Our results characterize the first PhnP family member that is a diphosphatase rather than a cyclic phosphodiesterase and suggest its involvement in a cellular damage-control system that efficiently hydrolyzes the reactive, ADP-ribose-like products of FAD photodegradation. © 2018 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.

  4. High transverse momentum dijet cross section measurements in photoproduction at HERA

    International Nuclear Information System (INIS)

    Dossanov, Aziz

    2013-06-01

    The measurement of high transverse momentum differential dijet cross sections in photoproduction at HERA in the γp center-of-mass energy 101 γp + p mode during the year 2006, collecting an integrated luminosity of 92.4 pb -1 . The results correspond to a kinematic range of photon virtualities Q 2 2 and inelasticities 0.1 perpendicular to algorithm, and a minimum transverse momentum of the two leading jets, P T,1st,2nd >15.0 GeV and pseudorapidities in the range of -0.5 1st,2nd 12 >40.0 GeV is required. Single differential dijet cross sections are measured, including cross sections in the direct and resolved photon enhanced regions. In order to study the contribution of partons interacting in the hard process, which are sensitive to the jet pseudorapidities, three different topologies of jets pseudorapidities are investigated. Single differential cross sections as a function of proton momentum fraction, taken by the interacting parton, x P , the fraction of photon momentum, x γ , the angle between the incoming and outgoing partons in the hard scatter, vertical stroke cos θ * vertical stroke are presented. Additionally, the cross sections as a function of the invariant mass of dijets, M 12 , anti η=(η 1st +η 2nd )/2, anti P T =(P T,1st +P T,2nd )/2 and P T,1st are also presented. The data are compared to predictions from the Pythia event generator, based on the LO matrix elements and parton showers, and to the NLO QCD calculations corrected for hadronization effects.

  5. Sensitizing effect of Z,Z-bilirubin IXα and its photoproducts on enzymes in model solutions

    Science.gov (United States)

    Plavskii, V. Yu.; Mostovnikov, V. A.; Tret'yakova, A. I.; Mostovnikova, G. R.

    2008-05-01

    In model systems, we have studied side effects which may be induced by light during phototherapy of hyperbilirubinemia (jaundice) in newborn infants, with the aim of reducing the Z,Z-bilirubin IXα (Z,Z-BR IXα) level. We have shown that the sensitizing effect of Z,Z-BR IXα, localized at strong binding sites of the human serum albumin (HSA) macromolecule, is primarily directed at the amino acid residues of the carrier protein and does not involve the molecules of the enzyme (lactate dehydrogenase (LDH)) present in the buffer solution. The detected photodynamic damage to LDH is due to sensitization by bilirubin photoisomers, characterized by lower HSA association constants and located (in contrast to native Z,Z-BR IXα) on the surface of the HSA protein globule. Based on study of the spectral characteristics of the photoproducts of Z,Z-BR IXα and comparison of their accumulation kinetics in solution and the enzyme photo-inactivation kinetics, we concluded that the determining role in sensitized damage to LDH is played by lumirubin. The photosensitization effect depends on the wavelength of the radiation used for photoconversion of bilirubin. When (at the beginning of exposure) we make sure that identical numbers of photons are absorbed by the pigment in the different spectral ranges, the side effect is minimal for radiation corresponding to the long-wavelength edge of the bilirubin absorption band. We have shown that for a bilirubin/HSA concentration ratio >2 (when some of the pigment molecules are sorbed on the surface of the protein globule), the bilirubin can act as a photosensitizing agent for the enzyme present in solution. We discuss methods for reducing unfavorable side effects of light on the body of newborn infants during phototherapy of hyperbilirubinemia.

  6. Hydrogen energy assessment

    Energy Technology Data Exchange (ETDEWEB)

    Salzano, F J; Braun, C [eds.

    1977-09-01

    The purpose of this assessment is to define the near term and long term prospects for the use of hydrogen as an energy delivery medium. Possible applications of hydrogen are defined along with the associated technologies required for implementation. A major focus in the near term is on industrial uses of hydrogen for special applications. The major source of hydrogen in the near term is expected to be from coal, with hydrogen from electric sources supplying a smaller fraction. A number of potential applications for hydrogen in the long term are identified and the level of demand estimated. The results of a cost benefit study for R and D work on coal gasification to hydrogen and electrolytic production of hydrogen are presented in order to aid in defining approximate levels of R and D funding. A considerable amount of data is presented on the cost of producing hydrogen from various energy resources. A key conclusion of the study is that in time hydrogen is likely to play a role in the energy system; however, hydrogen is not yet competitive for most applications when compared to the cost of energy from petroleum and natural gas.

  7. All the states of the nucleon. Nucleon spectroscopy through the production of mesons; Le nucleon dans tous ses etats. Etude de la spectroscopie du nucleon via la photoproduction de mesons

    Energy Technology Data Exchange (ETDEWEB)

    Rebreyend, D

    2006-10-15

    The photoproduction of mesons on the nucleon gives a direct access to its spectroscopy and is a promising way for the study of the structure of the nucleon. The GRAAL experiment uses a tagged and polarized photon beam produced through the Compton diffusion of laser photons on the electrons circulating in the ESRF storage ring. The combination of this photon beam and an efficient detection system has allowed a series of measurements concerning the photoproduction of light mesons on the proton and on the neutron. The first 4 chapters are dedicated to the nucleon spectroscopy: the nucleon models and their consequences on the excited levels are recalled, the experimental technique used is described and the difficulties due to the extraction of relevant data are presented. Highly accurate measurements of cross-sections, {sigma} asymmetry beams and resonance parameters have been performed. The last part is dedicated to the principle of the measurement of the electric dipole momentum of the neutron. (A.C.)

  8. Hydrogen system (hydrogen fuels feasibility)

    International Nuclear Information System (INIS)

    Guarna, S.

    1991-07-01

    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

  9. Photoproduction of π{sup 0} -pairs off protons and off neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Dieterle, M.; Oberle, M.; Garni, S.; Kaeser, A.; Keshelashvili, I.; Krusche, B.; Maghrbi, Y.; Pheron, F.; Rostomyan, T.; Strub, T.; Walford, N.K.; Werthmueller, D.; Witthauer, L. [University of Basel, Department of Physics, Basel (Switzerland); Ahrens, J.; Arends, H.J.; Bartolome, P.A.; Heid, E.; Jahn, O.; Ostrick, M.; Otte, P.; Schumann, S.; Thomas, A. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); Annand, J.R.M.; Glazier, D.I.; Hamilton, D.; Howdle, D.; Livingston, K.; MacGregor, I.J.D.; Mancell, J.; McGeorge, J.C.; McNicoll, E.; Robinson, J. [University of Glasgow, SUPA School of Physics and Astronomy, Glasgow (United Kingdom); Bantawa, K.; Manley, D.M. [Kent State University, Kent, Ohio (United States); Beck, R.; Nikolaev, A. [University of Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Bekrenev, V. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Berghaeuser, H.; Drexler, P.; Metag, V.; Novotny, R.; Thiel, M. [University of Giessen, II. Physikalisches Institut, Giessen (Germany); Braghieri, A.; Costanza, S.; Mushkarenkov, A.; Pedroni, P. [INFN Sezione di Pavia, Pavia (Italy); Branford, D.; Jude, T.C.; Sikora, M.H.; Watts, D.P. [University of Edinburgh, SUPA School of Physics, Edinburgh (United Kingdom); Briscoe, W.J.; Demissie, B.; Marinides, Z. [The George Washington University, Center for Nuclear Studies, Washington, DC (United States); Brudvik, J.; Starostin, A. [University of California Los Angeles, Los Angeles, California (United States); Cherepnya, S.; Fil' kov, L.V. [Lebedev Physical Institute, Moscow (Russian Federation); Downie, E.J. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); University of Glasgow, SUPA School of Physics and Astronomy, Glasgow (United Kingdom); The George Washington University, Center for Nuclear Studies, Washington, DC (United States); Fix, A. [Tomsk Polytechnic University, Laboratory of Mathematical Physics, Tomsk (Russian Federation); Hornidge, D.; Middleton, D.G. [Mount Allison University, New Brunswick (Canada); Huber, G.M. [University of Regina, Regina (Canada); Kashevarov, V.L. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); Lebedev Physical Institute, Moscow (Russian Federation); Kondratiev, R.; Lisin, V.; Polonski, A. [Institute for Nuclear Research, Moscow (Russian Federation); Korolija, M.; Mekterovic, D.; Micanovic, S.; Supek, I. [Rudjer Boskovic Institute, Zagreb (Croatia); Oussena, B. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); The George Washington University, Center for Nuclear Studies, Washington, DC (United States); Prakhov, S. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); The George Washington University, Center for Nuclear Studies, Washington, DC (United States); University of California Los Angeles, Los Angeles, California (United States); Sober, D.I. [The Catholic University of America, Washington, DC (United States); Unverzagt, M. [University of Mainz, Institut fuer Kernphysik, Mainz (Germany); University of Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Collaboration: The A2 Collaboration

    2015-11-15

    Total cross sections, angular distributions, and invariant-mass distributions have been measured for the photoproduction of π{sup 0}π{sup 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 1557MeV, 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 region (final-state invariant masses up to ∼ 1550 MeV), where both reactions are dominated by the N(1520)3/2{sup -} → Δ(1232)3/2{sup +}π decay. At higher energies, angular and invariant-mass distributions are different. A simple analysis of the shapes of the invariant-mass distributions in the third resonance region is consistent with strong contributions of an N{sup *} → Nσ decay for the proton, while the reaction is dominated by a sequential decay via a Δπ intermediate state for the neutron. The data are compared to predictions from the Two-Pion-MAID model and the Bonn-Gatchina coupled-channel analysis. (orig.)

  10. Photoproduction of J/{psi} mesons at medium and low elasticities at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Salvaire, F.

    2007-09-15

    The first analysis of inelastic J/{psi} meson production in photoproduction (Q{sup 2}<2.5 GeV{sup 2}) of the H1 experiment for the second phase of HERA (HERA II) is presented. The analysis is carried out at low and medium elasticities. The production of heavy quarks (charm, or bottom) is of special interest since the mass of the quarks provides a hard scale for the application of perturbative QCD. The muonic decay channel is used to select the J/{psi} mesons. The data was collected by the H1 detector during the period 2003-2005, and corresponds to an integrated luminosity of 133 pb{sup -1}. However only a subset of this data could be analysed. At the start of HERA II the trigger system was affected by a sizeable background. Then a fault was introduced in the trigger software during the summer 2004 and was only discovered and solved in April 2006. This means that approximately 80 % of the triggered events at medium elasticities and 65 % at low elasticities was lost during this period. Moreover during the first half of 2005 the muon trigger was affected by faulty power supplies. Consequently two good data taking periods are analysed: a first period with an integrated luminosity of 23 pb{sup -1} collected in 2004, and a second period of 60 pb{sup -1} collected during the second half of 2005, which is however strongly affected by the malfunction of the trigger software. In the medium elasticity region the total photoproduction cross section as a function of the photon-proton centre-of-mass energy W and the single differential cross sections as functions of the transverse momentum squared of the J/{psi} meson Pt{sup 2}{sub t,{psi}} and the elasticity z are extracted. The analysis covers the kinematic range 0.3{<=}z{<=}0.9, 60{<=}W{sub {gamma}}{sub p}{<=}240 GeV, and Pt{sup 2}{sub t,{psi}}>1 GeV{sup 2}. The same analysis is performed at low elasticity for the kinematic region 0.05{<=}z{<=}0.45, 120{<=}W{sub {gamma}}{sub p}{<=}260 GeV, and Pt{sup 2}{sub t,{psi}}>1 Ge

  11. Hail hydrogen

    International Nuclear Information System (INIS)

    Hairston, D.

    1996-01-01

    After years of being scorned and maligned, hydrogen is finding favor in environmental and process applications. There is enormous demand for the industrial gas from petroleum refiners, who need in creasing amounts of hydrogen to remove sulfur and other contaminants from crude oil. In pulp and paper mills, hydrogen is turning up as hydrogen peroxide, displacing bleaching agents based on chlorine. Now, new technologies for making hydrogen have the industry abuzz. With better capabilities of being generated onsite at higher purity levels, recycled and reused, hydrogen is being prepped for a range of applications, from waste reduction to purification of Nylon 6 and hydrogenation of specialty chemicals. The paper discusses the strong market demand for hydrogen, easier routes being developed for hydrogen production, and the use of hydrogen in the future

  12. Sustainable hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Block, D.L.; Linkous, C.; Muradov, N.

    1996-01-01

    This report describes the Sustainable Hydrogen Production research conducted at the Florida Solar Energy Center (FSEC) for the past year. The report presents the work done on the following four tasks: Task 1--production of hydrogen by photovoltaic-powered electrolysis; Task 2--solar photocatalytic hydrogen production from water using a dual-bed photosystem; Task 3--development of solid electrolytes for water electrolysis at intermediate temperatures; and Task 4--production of hydrogen by thermocatalytic cracking of natural gas. For each task, this report presents a summary, introduction/description of project, and results.

  13. Hydrogen gains further momentum

    International Nuclear Information System (INIS)

    Anon.

    2017-01-01

    As first industrial production projects should become a reality in the next few years, hydrogen as a source of energy will find important applications with mobility, which momentum is rapid and irresistible. Next steps will be the (large capacity) storage of hydrogen associated to power-to-gas systems and the generalization of renewable energies. This document presents 5 articles, which themes are: Description and explanation of the process of hydrogen production; Presentation of the H2V project for the construction, in Normandy, of the first operational industrial hydrogen production plant using electric power 100 pc generated by renewable energies; The conversion of electric power from renewable energies through hydrogen storage and fuel cells for buildings applications (Sylfen project); The development of a reversible fuel cell at Mines-Paris Tech University, that will be adapted to the storage of renewable electric power; Hydrogen as a lever for the development of zero-emission vehicles, from trucks to cars and bicycles

  14. Photochemical hydrogen production system

    International Nuclear Information System (INIS)

    Copeland, R.J.

    1990-01-01

    Both technical and economic factors affect the cost of producing hydrogen by photochemical processes. Technical factors include the efficiency and the capital and operating costs of the renewable hydrogen conversion system; economic factors include discount rates, economic life, credit for co-product oxygen, and the value of the energy produced. This paper presents technical and economic data for a system that generates on-peak electric power form photochemically produced hydrogen

  15. Measurement of double polarization observables in 2π{sup 0}-photoproduction off the proton with the CBELSA/TAPS-experiment

    Energy Technology Data Exchange (ETDEWEB)

    Mahlberg, Philipp [Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Collaboration: CBELSA/TAPS-Collaboration

    2016-07-01

    In contrast to the atomic spectrum with its sharp and well defined excitation levels, the nucleon excitation spectrum is dominated by broad, overlapping resonances. Partial wave analyses are needed to extract the contributing resonances from the experimental data. In order to find an unambiguous solution, the measurement of polarization observables is indispensable. The Crystal Barrel/TAPS experiment at the electron accelerator ELSA is, due to its high photon detection efficiency and its almost complete solid angle coverage, ideally suited to measure neutral mesons decaying into photons. The measurement with double polarization, i.e. a circularly polarized photon beam and a longitudinally polarized target provides access to single and double polarization observables. At higher energies, the cross sections show that multi-meson decay channels gain in importance compared e.g. to single pseudoscalar meson photoproduction. In this talk, preliminary results for the helicity asymmetry E in 2π{sup 0}-photoproduction measured with the CBELSA/TAPS experiment are presented.

  16. Evidence for the monomerization of spore photoproduct to two thymines by the light-independent 'spore repair' process in Bacillus subtilis

    International Nuclear Information System (INIS)

    Van Wang, T.-C.; Rupert, C.S.

    1977-01-01

    Ultraviolet irradiation of bacterial spores induces a unique DNA photoproduct, which yields mostly 5-thyminyl-5,6-dihydrothymine (Thy(α-5)hThy, or TDHT) on acid hydrolysis. One of the possible mechanisms for the observed removal of the photoproduct on spore germination ivolves its direct conversion back to two adjacent thymine residues, and additional evidence is presented in support of this theory. Studies were made of the fate of the TDHT radioactivity in irradiated, germinated B. subtilis spores labelled with 3 H-thymine or 14 C-thymine, and of the homogeneity of the thymine-peak radioactivity. The radioactivity disappearing from the TDHT peak on germination seemed to be stoichiometrically recovered in the thymine peak, and no new materials were detected under the thymine-peak radioactivity. No intermediates were detected in B. subtilis mutant 25D4 (hcr 42 - recA 1 - ), a strain which had given some promise of accumulating intermediates from an incomplete repair process. (U.K.)

  17. Photoproduction asymmetries of the charm baryons Λc, Σc++ and Σc0 at the Fermilab experiment E831/focus

    International Nuclear Information System (INIS)

    Anjos, Joao dos; Estrada, Cecilia Uribe; Sheaff, Marleigh

    2000-01-01

    Full text follows: In photon-hadron collisions, it is expected that charm quarks are produced by the photon-gluon process. This process at leading order (LO) in perturbative quantum chromo-dynamics (QCD) predicts symmetric distributions for charm/anticharm quark production. Asymmetries introduced by next to leading order (NLO) calculations are expected to be negligibly small. However, when the charm/articharm quarks hadronize, non perturbative effects in the recombination process may induce an asymmetry between charm and anticharm final states. The measurement of photoproduction asymmetries could provide valuable information on the hadronization process, which is one of the least understood phenomena in QCD. We present a study on the charm-anticharm photoproduction asymmetry using Λ c + /Λ c - , Σ c ++ /Σ c -- and Σ c 0 /Σ-bar c 0 baryon candidates. Data used is from the E831/FOCUS experiment, collected during 1996-1997 Fermilab fixed target run. The asymmetry is studied in intervals of p T 2 , p L , and x F for the case of Λ c baryons, while global values are extracted for the Σ c baryons, due to the lack of statistics. (author)

  18. Exclusive $J/\\psi$ photoproduction off protons in ultra-peripheral p-Pb collisions at $\\sqrt{s_{NN}}$=5.02 TeV

    CERN Document Server

    Abelev, Betty Bezverkhny; Adamova, Dagmar; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agostinelli, Andrea; Agrawal, Neelima; Ahammed, Zubayer; Ahmad, Nazeer; Ahmed, Ijaz; Ahn, Sang Un; Ahn, Sul-Ah; Aimo, Ilaria; Aiola, Salvatore; Ajaz, Muhammad; Akindinov, Alexander; Alam, Sk Noor; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Armesto Perez, Nestor; Arnaldi, Roberta; Aronsson, Tomas; Arsene, Ionut Cristian; Arslandok, Mesut; Augustinus, Andre; Averbeck, Ralf Peter; Awes, Terry; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Baldisseri, Alberto; Baltasar Dos Santos Pedrosa, Fernando; Baral, Rama Chandra; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartke, Jerzy Gustaw; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batista Camejo, Arianna; Batyunya, Boris; Batzing, Paul Christoph; Baumann, Christoph Heinrich; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bellwied, Rene; Belmont Moreno, Ernesto; Belmont Iii, Ronald John; Belyaev, Vladimir; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Berger, Martin Emanuel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Bjelogrlic, Sandro; Blanco, Fernando; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boggild, Hans; Bogolyubskiy, Mikhail; Boehmer, Felix Valentin; Boldizsar, Laszlo; Bombara, Marek; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Bossu, Francesco; Botje, Michiel; Botta, Elena; Boettger, Stefan; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calero Diaz, Liliet; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Carena, Francesco; Carena, Wisla; Castillo Castellanos, Javier Ernesto; Casula, Ester Anna Rita; Catanescu, Vasile Ioan; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chelnokov, Volodymyr; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Chochula, Peter; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortese, Pietro; Cortes Maldonado, Ismael; Cosentino, Mauro Rogerio; Costa, Filippo; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dainese, Andrea; Dang, Ruina; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Kushal; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; Delagrange, Hugues; Deloff, Andrzej; Denes, Ervin Sandor; D'Erasmo, Ginevra; De Caro, Annalisa; De Cataldo, Giacinto; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; De Rooij, Raoul Stefan; Diaz Corchero, Miguel Angel; Dietel, Thomas; Dillenseger, Pascal; Divia, Roberto; Di Bari, Domenico; Di Liberto, Sergio; Di Mauro, Antonio; Di Nezza, Pasquale; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Dorheim, Sverre; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Dutt Mazumder, Abhee Kanti; Hilden, Timo Eero; Ehlers Iii, Raymond James; Elia, Domenico; Engel, Heiko; Erazmus, Barbara Ewa; Erdal, Hege Austrheim; Eschweiler, Dominic; Espagnon, Bruno; Esposito, Marco; Estienne, Magali Danielle; Esumi, Shinichi; Evans, David; Evdokimov, Sergey; Fabris, Daniela; Faivre, Julien; Falchieri, Davide; Fantoni, Alessandra; Fasel, Markus; Fehlker, Dominik; Feldkamp, Linus; Felea, Daniel; Feliciello, Alessandro; Feofilov, Grigory; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floratos, Emmanouil; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Furs, Artur; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Gao, Chaosong; Garabatos Cuadrado, Jose; Garcia-Solis, Edmundo Javier; Gargiulo, Corrado; Garishvili, Irakli; Gerhard, Jochen; Germain, Marie; Gheata, Andrei George; Gheata, Mihaela; Ghidini, Bruno; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez Ramirez, Andres; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gorlich, Lidia Maria; Gotovac, Sven; Graczykowski, Lukasz Kamil; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grynyov, Borys; Grion, Nevio; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Guilbaud, Maxime Rene Joseph; Gulbrandsen, Kristjan Herlache; Gulkanyan, Hrant; Gumbo, Mervyn; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Khan, Kamal; Haake, Rudiger; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hanratty, Luke David; Hansen, Alexander; Harris, John William; Hartmann, Helvi; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Heide, Markus Ansgar; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hippolyte, Boris; Hladky, Jan; Hristov, Peter Zahariev; Huang, Meidana; Humanic, Thomas; Hussain, Nur; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Ilkiv, Iryna; Inaba, Motoi; Innocenti, Gian Michele; Ionita, Costin; Ippolitov, Mikhail; Irfan, Muhammad; Ivanov, Marian; Ivanov, Vladimir; Jacholkowski, Adam Wlodzimierz; Jacobs, Peter Martin; Jahnke, Cristiane; Jang, Haeng Jin; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jung, Hyungtaik; Jusko, Anton; Kadyshevskiy, Vladimir; Kalcher, Sebastian; Kalinak, Peter; Kalweit, Alexander Philipp; Kamin, Jason Adrian; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Keil, Markus; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Beomkyu; Kim, Do Won; Kim, Dong Jo; Kim, Jinsook; Kim, Mimae; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Jochen; Klein-Boesing, Christian; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Kobdaj, Chinorat; Kofarago, Monika; Kohler, Markus Konrad; Kollegger, Thorsten; Kolozhvari, Anatoly; Kondratev, Valerii; Kondratyeva, Natalia; Konevskikh, Artem; Kovalenko, Vladimir; Kowalski, Marek; Kox, Serge; Koyithatta Meethaleveedu, Greeshma; Kral, Jiri; Kralik, Ivan; Kravcakova, Adela; Krelina, Michal; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Kryshen, Evgeny; Krzewicki, Mikolaj; Kucera, Vit; Kucheryaev, Yury; Kugathasan, Thanushan; Kuhn, Christian Claude; Kuijer, Paulus Gerardus; Kulakov, Igor; Kumar, Jitendra; Kurashvili, Podist; Kurepin, Alexander; Kurepin, Alexey; Kuryakin, Alexey; Kushpil, Svetlana; Kweon, Min Jung; Kwon, Youngil; Ladron De Guevara, Pedro; Lagana Fernandes, Caio; Lakomov, Igor; Langoy, Rune; Lara Martinez, Camilo Ernesto; Lardeux, Antoine Xavier; Lattuca, Alessandra; La Pointe, Sarah Louise; La Rocca, Paola; Lea, Ramona; Leardini, Lucia; Lee, Graham Richard; Legrand, Iosif; Lehnert, Joerg Walter; Lemmon, Roy Crawford; Lenti, Vito; Leogrande, Emilia; Leoncino, Marco; Leon Monzon, Ildefonso; Levai, Peter; Li, Shuang; Lien, Jorgen Andre; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Ljunggren, Hans Martin; Lodato, Davide Francesco; Lonne, Per-Ivar; Loggins, Vera Renee; Loginov, Vitaly; Lohner, Daniel; Loizides, Constantinos; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lu, Xianguo; Luettig, Philipp Johannes; Lunardon, Marcello; Luparello, Grazia; Ma, Rongrong; Maevskaya, Alla; Mager, Magnus; Mahapatra, Durga Prasad; Mahmood, Sohail Musa; Maire, Antonin; Majka, Richard Daniel; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Liudmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Manceau, Loic Henri Antoine; Manko, Vladislav; Manso, Franck; Manzari, Vito; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Marin, Ana Maria; Markert, Christina; Marquard, Marco; Martashvili, Irakli; Martin, Nicole Alice; Martinengo, Paolo; Martinez Hernandez, Mario Ivan; Martinez-Garcia, Gines; Martin Blanco, Javier; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Massacrier, Laure Marie; Mastroserio, Annalisa; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel Anthony; Mazzoni, Alessandra Maria; Meddi, Franco; Menchaca-Rocha, Arturo Alejandro; Meninno, Elisa; Mercado-Perez, Jorge; Meres, Michal; Miake, Yasuo; Mikhaylov, Konstantin; Milano, Leonardo; Milosevic, Jovan; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz Czeslaw; Mitra, Jubin; Mitu, Ciprian Mihai; Mlynarz, Jocelyn; Mohammadi, Naghmeh; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Montes Prado, Esther; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Moretto, Sandra; Morreale, Astrid; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhlheim, Daniel Michael; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Gameiro Munhoz, Marcelo; Murray, Sean; Musa, Luciano; Musinsky, Jan; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Nattrass, Christine; Nayak, Kishora; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Nicassio, Maria; Niculescu, Mihai; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Nilsen, Bjorn Steven; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Norman, Jaime; Nyanin, Alexander; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Okatan, Ali; Olah, Laszlo; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Onderwaater, Jacobus; Oppedisano, Chiara; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozdemir, Mahmut; Sahoo, Pragati; Pachmayer, Yvonne Chiara; Pachr, Milos; Pagano, Paola; Paic, Guy; Painke, Florian; Pajares Vales, Carlos; Pal, Susanta Kumar; Palmeri, Armando; Pant, Divyash; Papikyan, Vardanush; Pappalardo, Giuseppe; Pareek, Pooja; Park, Woojin; Parmar, Sonia; Passfeld, Annika; Patalakha, Dmitry; Paticchio, Vincenzo; Paul, Biswarup; Pawlak, Tomasz Jan; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitry Yurevich; Perez Lara, Carlos Eugenio; Pesci, Alessandro; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petran, Michal; Petris, Mariana; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; Pinazza, Ombretta; Pinsky, Lawrence; Piyarathna, Danthasinghe; Ploskon, Mateusz Andrzej; Planinic, Mirko; Pluta, Jan Marian; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Pohjoisaho, Esko Heikki Oskari; Polishchuk, Boris; Poljak, Nikola; Pop, Amalia; Porteboeuf, Sarah Julie; Porter, R Jefferson; Potukuchi, Baba; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puddu, Giovanna; Pujahari, Prabhat Ranjan; Punin, Valery; Putschke, Jorn Henning; Qvigstad, Henrik; Rachevski, Alexandre; Raha, Sibaji; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Rauf, Aamer Wali; Razazi, Vahedeh; Read, Kenneth Francis; Real, Jean-Sebastien; Redlich, Krzysztof; Reed, Rosi Jan; Rehman, Attiq Ur; Reichelt, Patrick Simon; Reicher, Martijn; Reidt, Felix; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Rettig, Felix Vincenz; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riabov, Viktor; Ricci, Renato Angelo; Richert, Tuva Ora Herenui; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Rivetti, Angelo; Rocco, Elena; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roeed, Ketil; Rogochaya, Elena; Sharma, Rohni; Rohr, David Michael; Roehrich, Dieter; Romita, Rosa; Ronchetti, Federico; Ronflette, Lucile; Rosnet, Philippe; Rossi, Andrea; Roukoutakis, Filimon; Roy, Ankhi; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Ryabov, Yury; Rybicki, Andrzej; Sadovskiy, Sergey; Safarik, Karel; Sahlmuller, Baldo; Sahoo, Raghunath; Sahu, Pradip Kumar; Saini, Jogender; Sakai, Shingo; Salgado Lopez, Carlos Alberto; Salzwedel, Jai Samuel Nielsen; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sanchez Rodriguez, Fernando Javier; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Santagati, Gianluca; Sarkar, Debojit; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schuchmann, Simone; Schukraft, Jurgen; Schulc, Martin; Schuster, Tim Robin; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Rebecca Michelle; Segato, Gianfranco; Seger, Janet Elizabeth; Sekiguchi, Yuko; Selyuzhenkov, Ilya; Seo, Jeewon; Serradilla Rodriguez, Eulogio; Sevcenco, Adrian; Shabetai, Alexandre; Shabratova, Galina; Shahoyan, Ruben; Shangaraev, Artem; Sharma, Natasha; Sharma, Satish; Shigaki, Kenta; Shtejer Diaz, Katherin; Sibiryak, Yury; Siddhanta, Sabyasachi; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine Micaela; Simatovic, Goran; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Bikash; Sarkar - Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Skjerdal, Kyrre; Slupecki, Maciej; Smirnov, Nikolai; Snellings, Raimond; Soegaard, Carsten; Soltz, Ron Ariel; Song, Jihye; Song, Myunggeun; Soramel, Francesca; Sorensen, Soren Pontoppidan; Spacek, Michal; Spiriti, Eleuterio; Sputowska, Iwona Anna; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stefanek, Grzegorz; Steinpreis, Matthew Donald; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Stolpovskiy, Mikhail; Strmen, Peter; Alarcon Do Passo Suaide, Alexandre; Sugitate, Toru; Suire, Christophe Pierre; Suleymanov, Mais Kazim Oglu; Sultanov, Rishat; Sumbera, Michal; Susa, Tatjana; Symons, Timothy; Szabo, Alexander; Szanto De Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szymanski, Maciej Pawel; Takahashi, Jun; Tangaro, Marco-Antonio; Tapia Takaki, Daniel Jesus; Tarantola Peloni, Attilio; Tarazona Martinez, Alfonso; Tarzila, Madalina-Gabriela; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terrevoli, Cristina; Thaeder, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony Robert; Toia, Alberica; Trubnikov, Victor; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ullaland, Kjetil; Uras, Antonio; Usai, Gianluca; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; Vande Vyvre, Pierre; Van Der Maarel, Jasper; Van Hoorne, Jacobus Willem; Van Leeuwen, Marco; Diozcora Vargas Trevino, Aurora; Vargyas, Marton; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vechernin, Vladimir; Veldhoen, Misha; Velure, Arild; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara Limon, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Viinikainen, Jussi Samuli; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Vinogradov, Alexander; Vinogradov, Leonid; Vinogradov, Yury; Virgili, Tiziano; Viyogi, Yogendra; Vodopyanov, Alexander; Volkl, Martin Andreas; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; Von Haller, Barthelemy; Vorobyev, Ivan; Vranic, Danilo; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Boris; Wagner, Jan; Wagner, Vladimir; Wang, Mengliang; Wang, Yifei; Watanabe, Daisuke; Weber, Michael; Wessels, Johannes Peter; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Yaldo, Chris G; Yamaguchi, Yorito; Yang, Hongyan; Yang, Ping; Yang, Shiming; Yano, Satoshi; Yasnopolskiy, Stanislav; Yi, Jungyu; Yin, Zhongbao; Yoo, In-Kwon; Yushmanov, Igor; Zaccolo, Valentina; Zach, Cenek; Zaman, Ali; Zampolli, Chiara; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, Fengchu; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zhu, Xiangrong; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zoccarato, Yannick Denis; Zyzak, Maksym

    2014-12-05

    We present the first measurement at the LHC of exclusive J/$\\psi$ photoproduction off protons, in ultra-peripheral proton-lead collisions at $\\sqrt{s_{\\rm NN}}=5.02$ TeV. Events are selected with a dimuon pair produced either in the rapidity interval, in the laboratory frame, $2.5photoproduction cross section in $\\gamma {\\rm p}$ energies from about 20 to 700 GeV, or equivalently, from Bjorken-$x$ between $\\sim 2\\times 10^{-2}$ to $\\sim 2\\times 10...

  19. Exclusive J/ψ photoproduction off protons in ultraperipheral p-Pb collisions at √(s(NN))=5.02 TeV.

    Science.gov (United States)

    Abelev, B; Adam, J; Adamová, D; Aggarwal, M M; Aglieri Rinella, G; Agnello, M; Agostinelli, A; Agrawal, N; Ahammed, Z; Ahmad, N; Ahmed, I; Ahn, S U; Ahn, S A; Aimo, I; Aiola, S; Ajaz, M; Akindinov, A; Alam, S N; Aleksandrov, D; Alessandro, B; Alexandre, D; Alici, A; Alkin, A; Alme, J; Alt, T; Altinpinar, S; Altsybeev, I; Alves Garcia Prado, C; Andrei, C; Andronic, A; Anguelov, V; Anielski, J; Antičić, T; Antinori, F; Antonioli, P; Aphecetche, L; Appelshäuser, H; Arcelli, S; Armesto, N; Arnaldi, R; Aronsson, T; Arsene, I C; Arslandok, M; Augustinus, A; Averbeck, R; Awes, T C; Azmi, M D; Bach, M; Badalà, A; Baek, Y W; Bagnasco, S; Bailhache, R; Bala, R; Baldisseri, A; Baltasar Dos Santos Pedrosa, F; Baral, R C; Barbera, R; Barile, F; Barnaföldi, G G; Barnby, L S; Barret, V; Bartke, J; Basile, M; Bastid, N; Basu, S; Bathen, B; Batigne, G; Batista Camejo, A; Batyunya, B; Batzing, P C; Baumann, C; Bearden, I G; Beck, H; Bedda, C; Behera, N K; Belikov, I; Bellini, F; Bellwied, R; Belmont-Moreno, E; Belmont, R; Belyaev, V; Bencedi, G; Beole, S; Berceanu, I; Bercuci, A; Berdnikov, Y; Berenyi, D; Berger, M E; Bertens, R A; Berzano, D; Betev, L; Bhasin, A; Bhat, I R; Bhati, A K; Bhattacharjee, B; Bhom, J; Bianchi, L; Bianchi, N; Bianchin, C; Bielčík, J; Bielčíková, J; Bilandzic, A; Bjelogrlic, S; Blanco, F; Blau, D; Blume, C; Bock, F; Bogdanov, A; Bøggild, H; Bogolyubsky, M; Böhmer, F V; Boldizsár, L; Bombara, M; Book, J; Borel, H; Borissov, A; Bossú, F; Botje, M; Botta, E; Böttger, S; Braun-Munzinger, P; Bregant, M; Breitner, T; Broker, T A; Browning, T A; Broz, M; Bruna, E; Bruno, G E; Budnikov, D; Buesching, H; Bufalino, S; Buncic, P; Busch, O; Buthelezi, Z; Caffarri, D; Cai, X; Caines, H; Calero Diaz, L; Caliva, A; Calvo Villar, E; Camerini, P; Carena, F; Carena, W; Castillo Castellanos, J; Casula, E A R; Catanescu, V; Cavicchioli, C; Ceballos Sanchez, C; Cepila, J; Cerello, P; Chang, B; Chapeland, S; Charvet, J L; Chattopadhyay, S; Chattopadhyay, S; Chelnokov, V; Cherney, M; Cheshkov, C; Cheynis, B; Chibante Barroso, V; Chinellato, D D; Chochula, P; Chojnacki, M; Choudhury, S; Christakoglou, P; Christensen, C H; Christiansen, P; Chujo, T; Chung, S U; Cicalo, C; Cifarelli, L; Cindolo, F; Cleymans, J; Colamaria, F; Colella, D; Collu, A; Colocci, M; Conesa Balbastre, G; Conesa Del Valle, Z; Connors, M E; Contreras, J G; Cormier, T M; Corrales Morales, Y; Cortese, P; Cortés Maldonado, I; Cosentino, M R; Costa, F; Crochet, P; Cruz Albino, R; Cuautle, E; Cunqueiro, L; Dainese, A; Dang, R; Danu, A; Das, D; Das, I; Das, K; Das, S; Dash, A; Dash, S; De, S; Delagrange, H; Deloff, A; Dénes, E; D'Erasmo, G; De Caro, A; de Cataldo, G; de Cuveland, J; De Falco, A; De Gruttola, D; De Marco, N; De Pasquale, S; de Rooij, R; Diaz Corchero, M A; Dietel, T; Dillenseger, P; Divià, R; Di Bari, D; Di Liberto, S; Di Mauro, A; Di Nezza, P; Djuvsland, Ø; Dobrin, A; Dobrowolski, T; Domenicis Gimenez, D; Dönigus, B; Dordic, O; Dørheim, S; Dubey, A K; Dubla, A; Ducroux, L; Dupieux, P; Dutta Majumdar, A K; Hilden, T E; Ehlers, R J; Elia, D; Engel, H; Erazmus, B; Erdal, H A; Eschweiler, D; Espagnon, B; Esposito, M; Estienne, M; Esumi, S; Evans, D; Evdokimov, S; Fabris, D; Faivre, J; Falchieri, D; Fantoni, A; Fasel, M; Fehlker, D; Feldkamp, L; Felea, D; Feliciello, A; Feofilov, G; Ferencei, J; Fernández Téllez, A; Ferreiro, E G; Ferretti, A; Festanti, A; Figiel, J; Figueredo, M A S; Filchagin, S; Finogeev, D; Fionda, F M; Fiore, E M; Floratos, E; Floris, M; Foertsch, S; Foka, P; Fokin, S; Fragiacomo, E; Francescon, A; Frankenfeld, U; Fuchs, U; Furget, C; Furs, A; Fusco Girard, M; Gaardhøje, J J; Gagliardi, M; Gago, A M; Gallio, M; Gangadharan, D R; Ganoti, P; Gao, C; Garabatos, C; Garcia-Solis, E; Gargiulo, C; Garishvili, I; Gerhard, J; Germain, M; Gheata, A; Gheata, M; Ghidini, B; Ghosh, P; Ghosh, S K; Gianotti, P; Giubellino, P; Gladysz-Dziadus, E; Glässel, P; Gomez Ramirez, A; González-Zamora, P; Gorbunov, S; Görlich, L; Gotovac, S; Graczykowski, L K; Grelli, A; Grigoras, A; Grigoras, C; Grigoriev, V; Grigoryan, A; Grigoryan, S; Grinyov, B; Grion, N; Grosse-Oetringhaus, J F; Grossiord, J-Y; Grosso, R; Guber, F; Guernane, R; Guerzoni, B; Guilbaud, M; Gulbrandsen, K; Gulkanyan, H; Gumbo, M; Gunji, T; Gupta, A; Gupta, R; Khan, K H; Haake, R; Haaland, Ø; Hadjidakis, C; Haiduc, M; Hamagaki, H; Hamar, G; Hanratty, L D; Hansen, A; Harris, J W; Hartmann, H; Harton, A; Hatzifotiadou, D; Hayashi, S; Heckel, S T; Heide, M; Helstrup, H; Herghelegiu, A; Herrera Corral, G; Hess, B A; Hetland, K F; Hippolyte, B; Hladky, J; Hristov, P; Huang, M; Humanic, T J; Hussain, N; Hutter, D; Hwang, D S; Ilkaev, R; Ilkiv, I; Inaba, M; Innocenti, G M; Ionita, C; Ippolitov, M; Irfan, M; Ivanov, M; Ivanov, V; Jachołkowski, A; Jacobs, P M; Jahnke, C; Jang, H J; Janik, M A; Jayarathna, P H S Y; Jena, C; Jena, S; Jimenez Bustamante, R T; Jones, P G; Jung, H; Jusko, A; Kadyshevskiy, V; Kalcher, S; Kalinak, P; Kalweit, A; Kamin, J; Kang, J H; Kaplin, V; Kar, S; Karasu Uysal, A; Karavichev, O; Karavicheva, T; Karpechev, E; Kebschull, U; Keidel, R; Keijdener, D L D; Keil Svn, M; Khan, M M; Khan, P; Khan, S A; Khanzadeev, A; Kharlov, Y; Kileng, B; Kim, B; Kim, D W; Kim, D J; Kim, J S; Kim, M; Kim, M; Kim, S; Kim, T; Kirsch, S; Kisel, I; Kiselev, S; Kisiel, A; Kiss, G; Klay, J L; Klein, J; Klein-Bösing, C; Kluge, A; Knichel, M L; Knospe, A G; Kobdaj, C; Kofarago, M; Köhler, M K; Kollegger, T; Kolojvari, A; Kondratiev, V; Kondratyeva, N; Konevskikh, A; Kovalenko, V; Kowalski, M; Kox, S; Koyithatta Meethaleveedu, G; Kral, J; Králik, I; Kravčáková, A; Krelina, M; Kretz, M; Krivda, M; Krizek, F; Kryshen, E; Krzewicki, M; Kučera, V; Kucheriaev, Y; Kugathasan, T; Kuhn, C; Kuijer, P G; Kulakov, I; Kumar, J; Kurashvili, P; Kurepin, A; Kurepin, A B; Kuryakin, A; Kushpil, S; Kweon, M J; Kwon, Y; Ladron de Guevara, P; Lagana Fernandes, C; Lakomov, I; Langoy, R; Lara, C; Lardeux, A; Lattuca, A; La Pointe, S L; La Rocca, P; Lea, R; Leardini, L; Lee, G R; Legrand, I; Lehnert, J; Lemmon, R C; Lenti, V; Leogrande, E; Leoncino, M; León Monzón, I; Lévai, P; Li, S; Lien, J; Lietava, R; Lindal, S; Lindenstruth, V; Lippmann, C; Lisa, M A; Ljunggren, H M; Lodato, D F; Loenne, P I; Loggins, V R; Loginov, V; Lohner, D; Loizides, C; Lopez, X; López Torres, E; Lu, X-G; Luettig, P; Lunardon, M; Luparello, G; Ma, R; Maevskaya, A; Mager, M; Mahapatra, D P; Mahmood, S M; Maire, A; Majka, R D; Malaev, M; Maldonado Cervantes, I; Malinina, L; Mal'Kevich, D; Malzacher, P; Mamonov, A; Manceau, L; Manko, V; Manso, F; Manzari, V; Marchisone, M; Mareš, J; Margagliotti, G V; Margotti, A; Marín, A; Markert, C; Marquard, M; Martashvili, I; Martin, N A; Martinengo, P; Martínez, M I; Martínez García, G; Martin Blanco, J; Martynov, Y; Mas, A; Masciocchi, S; Masera, M; Masoni, A; Massacrier, L; Mastroserio, A; Matyja, A; Mayer, C; Mazer, J; Mazzoni, M A; Meddi, F; Menchaca-Rocha, A; Meninno, E; Mercado Pérez, J; Meres, M; Miake, Y; Mikhaylov, K; Milano, L; Milosevic, J; Mischke, A; Mishra, A N; Miśkowiec, D; Mitra, J; Mitu, C M; Mlynarz, J; Mohammadi, N; Mohanty, B; Molnar, L; Montaño Zetina, L; Montes, E; Morando, M; Moreira De Godoy, D A; Moretto, S; Morreale, A; Morsch, A; Muccifora, V; Mudnic, E; Mühlheim, D; Muhuri, S; Mukherjee, M; Müller, H; Munhoz, M G; Murray, S; Musa, L; Musinsky, J; Nandi, B K; Nania, R; Nappi, E; Nattrass, C; Nayak, K; Nayak, T K; Nazarenko, S; Nedosekin, A; Nicassio, M; Niculescu, M; Nielsen, B S; Nikolaev, S; Nikulin, S; Nikulin, V; Nilsen, B S; Noferini, F; Nomokonov, P; Nooren, G; Norman, J; Nyanin, A; Nystrand, J; Oeschler, H; Oh, S; Oh, S K; Okatan, A; Olah, L; Oleniacz, J; Oliveira Da Silva, A C; Onderwaater, J; Oppedisano, C; Ortiz Velasquez, A; Oskarsson, A; Otwinowski, J; Oyama, K; Ozdemir, M; Sahoo, P; Pachmayer, Y; Pachr, M; Pagano, P; Paić, G; Painke, F; Pajares, C; Pal, S K; Palmeri, A; Pant, D; Papikyan, V; Pappalardo, G S; Pareek, P; Park, W J; Parmar, S; Passfeld, A; Patalakha, D I; Paticchio, V; Paul, B; Pawlak, T; Peitzmann, T; Pereira Da Costa, H; Pereira De Oliveira Filho, E; Peresunko, D; Pérez Lara, C E; Pesci, A; Peskov, V; Pestov, Y; Petráček, V; Petran, M; Petris, M; Petrovici, M; Petta, C; Piano, S; Pikna, M; Pillot, P; Pinazza, O; Pinsky, L; Piyarathna, D B; Płoskoń, M; Planinic, M; Pluta, J; Pochybova, S; Podesta-Lerma, P L M; Poghosyan, M G; Pohjoisaho, E H O; Polichtchouk, B; Poljak, N; Pop, A; Porteboeuf-Houssais, S; Porter, J; Potukuchi, B; Prasad, S K; Preghenella, R; Prino, F; Pruneau, C A; Pshenichnov, I; Puddu, G; Pujahari, P; Punin, V; Putschke, J; Qvigstad, H; Rachevski, A; Raha, S; Rak, J; Rakotozafindrabe, A; Ramello, L; Raniwala, R; Raniwala, S; Räsänen, S S; Rascanu, B T; Rathee, D; Rauf, A W; Razazi, V; Read, K F; Real, J S; Redlich, K; Reed, R J; Rehman, A; Reichelt, P; Reicher, M; Reidt, F; Renfordt, R; Reolon, A R; Reshetin, A; Rettig, F; Revol, J-P; Reygers, K; Riabov, V; Ricci, R A; Richert, T; Richter, M; Riedler, P; Riegler, W; Riggi, F; Rivetti, A; Rocco, E; Rodríguez Cahuantzi, M; Rodriguez Manso, A; Røed, K; Rogochaya, E; Rohni, S; Rohr, D; Röhrich, D; Romita, R; Ronchetti, F; Ronflette, L; Rosnet, P; Rossi, A; Roukoutakis, F; Roy, A; Roy, C; Roy, P; Rubio Montero, A J; Rui, R; Russo, R; Ryabinkin, E; Ryabov, Y; Rybicki, A; Sadovsky, S; Šafařík, K; Sahlmuller, B; Sahoo, R; Sahu, P K; Saini, J; Sakai, S; Salgado, C A; Salzwedel, J; Sambyal, S; Samsonov, V; Sanchez Castro, X; Sánchez Rodríguez, F J; Šándor, L; Sandoval, A; Sano, M; Santagati, G; Sarkar, D; Scapparone, E; Scarlassara, F; Scharenberg, R P; Schiaua, C; Schicker, R; Schmidt, C; Schmidt, H R; Schuchmann, S; Schukraft, J; Schulc, M; Schuster, T; Schutz, Y; Schwarz, K; Schweda, K; Scioli, G; Scomparin, E; Scott, R; Segato, G; Seger, J E; Sekiguchi, Y; Selyuzhenkov, I; Seo, J; Serradilla, E; Sevcenco, A; Shabetai, A; Shabratova, G; Shahoyan, R; Shangaraev, A; Sharma, N; Sharma, S; Shigaki, K; Shtejer, K; Sibiriak, Y; Siddhanta, S; Siemiarczuk, T; Silvermyr, D; Silvestre, C; Simatovic, G; Singaraju, R; Singh, R; Singha, S; Singhal, V; Sinha, B C; Sinha, T; Sitar, B; Sitta, M; Skaali, T B; Skjerdal, K; Slupecki, M; Smirnov, N; Snellings, R J M; Søgaard, C; Soltz, R; Song, J; Song, M; Soramel, F; Sorensen, S; Spacek, M; Spiriti, E; Sputowska, I; Spyropoulou-Stassinaki, M; Srivastava, B K; Stachel, J; Stan, I; Stefanek, G; Steinpreis, M; Stenlund, E; Steyn, G; Stiller, J H; Stocco, D; Stolpovskiy, M; Strmen, P; Suaide, A A P; Sugitate, T; Suire, C; Suleymanov, M; Sultanov, R; Šumbera, M; Susa, T; Symons, T J M; Szabo, A; Szanto de Toledo, A; Szarka, I; Szczepankiewicz, A; Szymanski, M; Takahashi, J; Tangaro, M A; Tapia Takaki, J D; Tarantola Peloni, A; Tarazona Martinez, A; Tarzila, M G; Tauro, A; Tejeda Muñoz, G; Telesca, A; Terrevoli, C; Thäder, J; Thomas, D; Tieulent, R; Timmins, A R; Toia, A; Trubnikov, V; Trzaska, W H; Tsuji, T; Tumkin, A; Turrisi, R; Tveter, T S; Ullaland, K; Uras, A; Usai, G L; Vajzer, M; Vala, M; Valencia Palomo, L; Vallero, S; Vande Vyvre, P; Van Der Maarel, J; Van Hoorne, J W; van Leeuwen, M; Vargas, A; Vargyas, M; Varma, R; Vasileiou, M; Vasiliev, A; Vechernin, V; Veldhoen, M; Velure, A; Venaruzzo, M; Vercellin, E; Vergara Limón, S; Vernet, R; Verweij, M; Vickovic, L; Viesti, G; Viinikainen, J; Vilakazi, Z; Villalobos Baillie, O; Vinogradov, A; Vinogradov, L; Vinogradov, Y; Virgili, T; Viyogi, Y P; Vodopyanov, A; Völkl, M A; Voloshin, K; Voloshin, S A; Volpe, G; von Haller, B; Vorobyev, I; Vranic, D; Vrláková, J; Vulpescu, B; Vyushin, A; Wagner, B; Wagner, J; Wagner, V; Wang, M; Wang, Y; Watanabe, D; Weber, M; Wessels, J P; Westerhoff, U; Wiechula, J; Wikne, J; Wilde, M; Wilk, G; Wilkinson, J; Williams, M C S; Windelband, B; Winn, M; Yaldo, C G; Yamaguchi, Y; Yang, H; Yang, P; Yang, S; Yano, S; Yasnopolskiy, S; Yi, J; Yin, Z; Yoo, I-K; Yushmanov, I; Zaccolo, V; Zach, C; Zaman, A; Zampolli, C; Zaporozhets, S; Zarochentsev, A; Závada, P; Zaviyalov, N; Zbroszczyk, H; Zgura, I S; Zhalov, M; Zhang, H; Zhang, X; Zhang, Y; Zhao, C; Zhigareva, N; Zhou, D; Zhou, F; Zhou, Y; Zhou, Zhuo; Zhu, H; Zhu, J; Zhu, X; Zichichi, A; Zimmermann, A; Zimmermann, M B; Zinovjev, G; Zoccarato, Y; Zyzak, M

    2014-12-05

    We present the first measurement at the LHC of exclusive J/ψ photoproduction off protons, in ultraperipheral proton-lead collisions at sqrt[s_{NN}]=5.02  TeV. Events are selected with a dimuon pair produced either in the rapidity interval, in the laboratory frame, 2.5photoproduction cross section in γp energies from about 20 to 700 GeV, or equivalently, from Bjorken x scaling variable between ∼2×10^{-2} and ∼2×10^{-5}, thus indicating no significant change in the gluon density behavior of the proton between HERA and LHC energies.

  20. Presentation of a reference material for the spatially resolved hydrogen analytics in near-surface layers by means of nuclear-reaction analysis; Darstellung eines Referenzmaterials fuer die ortsaufgeloeste Wasserstoffanalytik in oberflaechennahen Schichten mittels Kernreaktionsanalyse

    Energy Technology Data Exchange (ETDEWEB)

    Reinholz, U.

    2005-10-03

    The object of the thesis is the presentation of the theory of the {sup 15}N-reaction analysis (NRA), the experiemental construction of the corresponding beam pipe at the ion accelerator of the BAM and the evaluation of the measurement results. The aim is the first characterization of a reference material for the H analytics on the base of amorphous silicon (aSi) on a Si[100] substrate. The homogeneity of the aSi:H layers deposited by means of CVD was studied. For this pro substrate for about 30 samples the hydrogen depth profiles were measures, folded by means of a program created within the thesis and subjected to a statistical evaluation. The result were mean value ans standard deviation of the hydrogen concentration as well as an estimator for the contribution of the inhomogeneity to the measurement uncertainty. The stability of the potential reference material was proved by the constancy of result of repeated measurements of the hydrogen concentration during the application of a large dose of {sup 15}N ions. In an international ring experiment the reproducibility of the measurement results was proved. For the characterization of the aSi:H layers beside the NRA the white-light interferometry, ellipsometry, profilometry, and X-ray reflectometry, as well as the IR and Raman spectroscopy were used. The stoichiometry of the applied standard material kapton was checked by means of NMR spectroscopy and CHN analysis.

  1. Hydrogen Filling Station

    Energy Technology Data Exchange (ETDEWEB)

    Boehm, Robert F; Sabacky, Bruce; Anderson II, Everett B; Haberman, David; Al-Hassin, Mowafak; He, Xiaoming; Morriseau, Brian

    2010-02-24

    Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. The Freedom CAR and Freedom FUEL initiatives emphasize the importance of hydrogen as a future transportation fuel. Presently, Las Vegas has one hydrogen fueling station powered by natural gas. However, the use of traditional sources of energy to produce hydrogen does not maximize the benefit. The hydrogen fueling station developed under this grant used electrolysis units and solar energy to produce hydrogen fuel. Water and electricity are furnished to the unit and the output is hydrogen and oxygen. Three vehicles were converted to utilize the hydrogen produced at the station. The vehicles were all equipped with different types of technologies. The vehicles were used in the day-to-day operation of the Las Vegas Valley Water District and monitoring was performed on efficiency, reliability and maintenance requirements. The research and demonstration utilized for the reconfiguration of these vehicles could lead to new technologies in vehicle development that could make hydrogen-fueled vehicles more cost effective, economical, efficient and more widely used. In order to advance the development of a hydrogen future in Southern Nevada, project partners recognized a need to bring various entities involved in hydrogen development and deployment together as a means of sharing knowledge and eliminating duplication of efforts. A road-mapping session was held in Las Vegas in June 2006. The Nevada State Energy Office, representatives from DOE, DOE contractors and LANL, NETL, NREL were present. Leadership from the National hydrogen Association Board of Directors also attended. As a result of this session, a roadmap for hydrogen development was created. This roadmap has the ability to become a tool for use by other road-mapping efforts in the hydrogen community. It could also become a standard template for other states or even countries to approach planning for a hydrogen

  2. Double-polarization observable G in neutral-pion photoproduction off the proton

    Energy Technology Data Exchange (ETDEWEB)

    Thiel, A.; Lang, M.; Afzal, F.; Beck, R.; Boese, S.; Funke, C.; Gottschall, M.; Gruener, M.; Hammann, C.; Hannappel, J.; Hartmann, J.; Hoffmeister, P.; Honisch, C.; Kaiser, D.; Kalinowsky, H.; Kalischewski, F.; Klassen, P.; Klempt, E.; Koop, K.; Kube, M.; Mahlberg, P.; Mueller, J.; Muellers, J.; Piontek, D.; Schmidt, C.; Seifen, T.; Sokhoyan, V.; Spieker, K.; Thoma, U.; Urban, M.; Pee, H. van; Walther, D.; Wendel, C.; Winnebeck, A. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Eberhardt, H.; Bantes, B.; Dutz, H.; Elsner, D.; Ewald, R.; Fornet-Ponse, K.; Frommberger, F.; Goertz, S.; Hammann, D.; Hillert, W.; Jude, T.; Kammer, S.; Kleber, V.; Klein, F.; Reeve, S.; Runkel, S.; Schmieden, H. [Universitaet Bonn, Physikalisches Institut, Bonn (Germany); Anisovich, A.V.; Bayadilov, D.; Nikonov, V.; Sarantsev, A. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Bichow, M.; Meyer, W.; Reicherz, G. [Ruhr-Universitaet Bochum, Institut fuer Experimentalphysik I, Bochum (Germany); Brinkmann, K.T.; Gutz, E. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen und Kernphysik, Bonn (Germany); Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Crede, V. [Florida State University, Department of Physics, Tallahassee, FL (United States); Dieterle, M.; Keshelashvili, I.; Krusche, B.; Witthauer, L. [Universitaet Basel, Institut fuer Physik, Basel (Switzerland); Friedrich, S.; Makonyi, K.; Metag, V.; Nanova, M. [Universitaet Giessen, II. Physikalisches Institut, Giessen (Germany); Gridnev, A.; Lopatin, I. [Petersburg Nuclear Physics Institute, Gatchina (Russian Federation); Wilson, A. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Florida State University, Department of Physics, Tallahassee, FL (United States); Collaboration: The CBELSA/TAPS Collaboration

    2017-01-15

    This paper reports on a measurement of the double-polarization observable G in π{sup 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 diamond radiator of well-defined orientation. 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), Juelich-Bonn (JueBo), MAID and SAID partial wave analyses. Implications of the new data for the pion photoproduction multipoles are discussed. (orig.)

  3. Enzymatic determination of photoproducts in DNA molecules damaged by UV radiation

    Energy Technology Data Exchange (ETDEWEB)

    Kleibl, K; Brozmanova, J [Slovenska Akademia Vied, Bratislava (Czechoslovakia). Ustav Experimentalnej Onkologie

    1981-01-01

    Two basic analytical procedures are described for the detection of photoproducts in UV-irradiated DNA. In the former, the selective release of thymine dimers of the cyclobutane type (TT) from the UV-irradiated DNA during excision repair can be measured by chromatographic analysis of radioactive DNA hydrolysis products. The technique allows studying TT irrespective of other products. It is only reliable for UV doses higher than 5 Jm/sup -2/. In the latter, a Micrococcus luteus extract containing specific enzymes, ie., endonucleases, for the repair of UV-induced damage of DNA is used for the enzyme determination of pyrimidine dimers. The endonucleotide analysis of DNA damage can be applied both in vitro and in vivo. In the in-vitro detection, the efficacy of photoproduct determination attains almost 100% while in the in-vivo detection it ranges between 30% and 70% in dependence on the method used. 31 references are given.

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

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2007-02-01

    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. (orig.)

  5. Inclusive transverse momentum distributions of charged particles in diffractive and non-diffractive photoproduction at HERA

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magill, S.

    1995-03-01

    Inclusive transverse momentum spectra of charged particles in photoproduction events in the laboratory pseudorapidity range -1.2 T =8 GeV using the ZEUS detector. Diffractive and non-diffractive reactions have been selected with an average γp centre of mass (c.m.) energy of =180 GeV. For diffractive reactions, the p T spectra of the photon dissociation events have been measured in two intervals of the dissociated photon mass with mean values X >=5 GeV and 10 GeV. The inclusive transverse momentum spectra fall exponentially in the low p T region. The non-diffractive data show a pronounced high p T tail departing from the exponential shape. The p T distributions are compared to lower energy photoproduction data and to hadron-hadron collisions at a similar c.m. energy. The data are also compared to the results of a next-to-leading order QCD calculation. (orig.)

  6. Photoproduction of Baryon Resonances First Results of the Crystal Barrel Experiment at ELSA

    International Nuclear Information System (INIS)

    Junkersfeld, J.

    2002-01-01

    Photoproduction data on various final states involving neutral mesons have been taken by the CB-ELSA-experiment at the Electron Stretcher Accelerator ELSA (Bonn). The data show clear structures due to resonance production. Evidence for successive decays of high-mass nucleon resonances via Δ(1232)π 0 , Δ(1232)η and N(1535)S 11 π 0 have been observed. There is evidence for production of a 0 (980)-mesons in their π 0 η decay. (author)

  7. Watson's theorem and resonant pion photoproduction amplitude in the delta channel

    International Nuclear Information System (INIS)

    Wittman, R.; Davidson, R.; Mukhopadhyay, N.C.

    1984-01-01

    The CGLN and BL theories of the pion photoproduction on nucleons, used in nuclear calculations, are examined regarding their predictions of the resonant M 1 + and E 1 + multipoles. The nonunitary BL approach violates Watson's theorem, and predicts these multipoles porly. In the static limit, the CGLN multipoles satisfy Watson's theorem and are in fine agreement with data. The unitarized BL multipoles agree with those from the Olsson theory and data. (orig.)

  8. Amplitude reconstruction from complete photoproduction experiments and truncated partial-wave expansions

    International Nuclear Information System (INIS)

    Workman, R. L.; Tiator, L.; Wunderlich, Y.; Doring, M.; Haberzettl, H.

    2017-01-01

    Here, we compare the methods of amplitude reconstruction, for a complete experiment and a truncated partial-wave analysis, applied to the photoproduction of pseudoscalar mesons. The approach is pedagogical, showing in detail how the amplitude reconstruction (observables measured at a single energy and angle) is related to a truncated partial-wave analysis (observables measured at a single energy and a number of angles).

  9. Scaled momentum distributions of charged particles in dijet photoproduction at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2009-04-01

    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 -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, Λ eff , and the LPHD parameter, κ ch , are extracted. (orig.)

  10. Measurement of J/ψ helicity distributions in inelastic photoproduction at HERA

    International Nuclear Information System (INIS)

    Chekanov, S.; Derrick, M.; Magill, S.

    2009-06-01

    The J/ψ decay angular distributions have been measured in inelastic photoproduction in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 468 pb -1 . The range in photon-proton centre-of-mass energy, W, was 50 + were measured in the J/ψ rest frame and compared to theoretical predictions at leading and next-to-leading order in QCD. (orig.)

  11. Inclusive photoproduction of delta(980) and B(1235) at high xsub(F)

    International Nuclear Information System (INIS)

    Lassalle, J.C.; Patrick, G.N.; Storr, K.M.; Atkinson, M.; Axon, T.J.; Barberis, D.; Brodbeck, T.J.; Brookes, G.R.; Bunn, J.J.; Bussey, P.J.; Clegg, A.B.; Dainton, J.B.; Davenport, M.; Dickinson, B.; Diekmann, B.; Donnachie, A.; Ellison, R.J.; Flower, P.; Flynn, P.J.; Galbraith, W.; Heinloth, K.; Henderson, R.C.W.; Hughes-Jones, R.E.; Hutton, J.S.; Ibbotson, M.; Jakob, H.P.; Jung, M.; Kumar, B.R.; Laberrigue, J.; Lafferty, G.D.; Lane, J.B.; Levy, J.M.; Liebenau, V.; McClatchey, R.; Mercer, D.; Morris, J.A.G.; Morris, J.V.; Newton, D.; Paterson, C.; Paul, E.; Raine, C.; Reidenbach, M.; Rotscheidt, H.; Schloesser, A.; Sharp, P.H.; Skillicorn, I.O.; Smith, K.M.; Thompson, R.J.; Vaissiere, C. de la; Waite, A.P.; Worsell, M.F.; Yiou, T.P.

    1984-01-01

    Inclusive photoproduction of deltasup(+-)(980) and Bsup(+-0) (1235) at high xsub(F) is reported. Production of B 0 is largely due to double diffractive dissociation. The charged states are produced as leading particles, their production being described by the quark recombination picture. The relatively strong production of the delta(980) by this process is evidence that it is a anti qanti q state rather than a qqanti qanti q state. (orig.)

  12. A peak in the ηω mass spectrum from diffractive photoproduction

    International Nuclear Information System (INIS)

    Atkinson, M.; Flower, P.; Hutton, J.S.; Kumar, B.R.; Morris, J.A.G.; Morris, J.V.; Sharp, P.H.; Barberis, D.; Davenport, M.; Lasalle, J.P.; Patrick, G.N.; Storr, K.M.; Brodbeck, T.J.; Clegg, A.B.; Flynn, P.J.; Henderson, R.C.W.; Ibbotson, M.; Newton, B.; Brookes, G.R.; Bunn, J.J.; Galbraith, W.; McClatchey, R.H.; Bussey, P.J.; Dainton, J.B.; Paterson, C.; Raine, C.; Skillicorn, I.O.; Smith, K.M.; Diekmann, B.; Heinloth, K.; Jakob, H.P.; Jung, M.; Liebenau, V.; Paul, E.; Reidenbach, M.; Rotscheidt, H.; Schloesser, A.

    1987-01-01

    The ηω mass spectrum resulting from diffractive photoproduction, by photons of 25-50 GeV, shows a peak at a mass of 1.61±0.04 GeV and width of 0.23±0.08 GeV. Comparison with the corresponding ηρ 0 mass spectrum suggests that a resonance interpretation is favoured. (orig.)

  13. Exclusive photoproduction of a γ ρ pair with a large invariant mass

    International Nuclear Information System (INIS)

    Boussarie, R.; Pire, B.; Szymanowski, L.; Wallon, S.

    2017-01-01

    Exclusive photoproduction of a γ ρ 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 α s and the differential cross sections for the process where the ρ−meson is either longitudinally or transversely polarized are estimated in the kinematics of the JLab 12-GeV experiments.

  14. Exclusive photoproduction of a γ ρ pair with a large invariant mass

    Energy Technology Data Exchange (ETDEWEB)

    Boussarie, R. [LPT, Université Paris-Sud, CNRS, Université Paris-Saclay,91405, Orsay (France); Pire, B. [Centre de Physique Théorique, Ecole polytechnique, CNRS, Université Paris-Saclay,91128 Palaiseau (France); Szymanowski, L. [National Center for Nuclear Research (NCBJ),00681 Warsaw (Poland); Wallon, S. [LPT, Université Paris-Sud, CNRS, Université Paris-Saclay,91405, Orsay (France); UPMC University Paris 06, Faculté de physique,4 place Jussieu, 75252 Paris Cedex 05 (France)

    2017-02-09

    Exclusive photoproduction of a γ ρ 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 α{sub s} and the differential cross sections for the process where the ρ−meson is either longitudinally or transversely polarized are estimated in the kinematics of the JLab 12-GeV experiments.

  15. Measurement of the G double-polarisation observable in pion photoproduction

    International Nuclear Information System (INIS)

    McAndrew, J.; Watts, D.; Pasyuk, E.

    2012-01-01

    The g9a experiment using the CLAS detector in Hall B of Jefferson Lab will measure double-polarization observables using a polarized energy-tagged photon beam in conjunction with the frozen spin target, FROST. This contribution describes the extraction of the G double polarization observable in the single pion photoproduction using a linearly polarized photon beam in the energy range 730-2300 MeV and the longitudinally polarized frozen spin target, FROST.

  16. 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.)

  17. 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.

  18. Inclusive Sigma- photoproduction on the neutron via the reaction gamma n (p) -→ K+ Sigma- (p)

    International Nuclear Information System (INIS)

    Jorn Langheinrich; Ana Lima; Barry Berman

    2006-01-01

    The analysis described here is part of a comprehensive survey of the elementary strangeness photoproduction cross sections on the nucleon. The six elementary strangeness reactions are γn → K 0 Λ and γp → K + Λ γn → K 0 Σ 0 and γp → K + Σ 0 γn → K + Σ - and γp → K 0 Σ| +

  19. Separation of minimum and higher twist in photoproduction of high-pT mesons

    International Nuclear Information System (INIS)

    Apsimon, R.J.; Flower, P.S.; Hallewell, G.; Morris, J.A.G.; Morris, J.V.; Paterson, C.N.; Sharp, P.H.; Atkinson, M.; Brook, N.; Coyle, P.; Dickinson, B.; Donnachie, A.; Doyle, A.T.; Ellison, R.J.; Foster, J.M.; Hughes-Jones, R.E.; Ibbotson, M.; Kolya, S.D.; Lafferty, G.D.; McCann, H.; McManus, C.; Mercer, D.; Ottewell, P.J.; Reid, D.; Thompson, R.J.; Waterhouse, J.; Barberis, D.; Davenport, M.; Eades, J.; Ingelman, G.; McClatchey, R.; Brodbeck, T.J.; Charity, T.; Clegg, A.B.; Henderson, R.C.W.; Hickman, M.T.; Keemer, N.R.; Newton, D.; O'Connor, A.; Wilson, G.W.; Danaher, S.; Galbraith, W.; Thacker, N.A.; Thompson, L.; Diekmann, B.; Gapp, C.; Gebert, F.; Heinloth, K.; Hoeger, K.C.; Holzkamp, A.; Holzkamp, S.; Jakob, H.P.; Joseph, D.; Kingler, J.; Koersgen, G.; Oedingen, R.; Paul, E.; Rotscheidt, H.; Soeldner-Rembold, S.; Weigend, A.S.

    1991-01-01

    Photo- and hadroproduction data in the beam energy range 65-175 GeV have been studied with a view to isolating higher-twist processes in photoproduction from other point-like and hadron-like contributions. With selection of charged tracks having p T >2 GeV/c and 0.28 F <0.84 indications of a higher twist contribution have been found at a level that is consistent with QCD expectations. (orig.)

  20. High transverse momentum dijet cross section measurements in photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Dossanov, Aziz

    2013-06-15

    The measurement of high transverse momentum differential dijet cross sections in photoproduction at HERA in the {gamma}p center-of-mass energy 101presented in this thesis. The data have been recorded with the H1 detector at the HERA collider in e{sup +}p mode during the year 2006, collecting an integrated luminosity of 92.4 pb{sup -1}. The results correspond to a kinematic range of photon virtualities Q{sup 2}<4.0 GeV{sup 2} and inelasticities 0.115.0 GeV and pseudorapidities in the range of -0.5<{eta}{sub 1st,2nd}<2.5 are required. In order to suppress background and be able to compare the cross sections with reliable and safe pQCD NLO predictions an invariant mass of the two leading jets M{sub 12}>40.0 GeV is required. Single differential dijet cross sections are measured, including cross sections in the direct and resolved photon enhanced regions. In order to study the contribution of partons interacting in the hard process, which are sensitive to the jet pseudorapidities, three different topologies of jets pseudorapidities are investigated. Single differential cross sections as a function of proton momentum fraction, taken by the interacting parton, x{sub P}, the fraction of photon momentum, x{sub {gamma}}, the angle between the incoming and outgoing partons in the hard scatter, vertical stroke cos {theta}{sup *} vertical stroke are presented. Additionally, the cross sections as a function of the invariant mass of dijets, M{sub 12}, anti {eta}=({eta}{sub 1st}+{eta}{sub 2nd})/2, anti P{sub T}=(P{sub T,1st}+P{sub T,2nd})/2 and P{sub T,1st} are also presented. The data are compared to predictions from the Pythia event generator, based on the LO matrix elements and parton showers, and to the NLO QCD calculations corrected for hadronization effects.

  1. Hydrogen and fuel cells

    International Nuclear Information System (INIS)

    2006-06-01

    This road-map proposes by the Group Total aims to inform the public on the hydrogen and fuel cells. It presents the hydrogen technology from the production to the distribution and storage, the issues as motor fuel and fuel cells, the challenge for vehicles applications and the Total commitments in the domain. (A.L.B.)

  2. Hydrogen highway

    International Nuclear Information System (INIS)

    Anon

    2008-01-01

    The USA Administration would like to consider the US power generating industry as a basis ensuring both the full-scale production of hydrogen and the widespread use of the hydrogen related technological processes into the economy [ru

  3. Hydrogen production from microbial strains

    Science.gov (United States)

    Harwood, Caroline S; Rey, Federico E

    2012-09-18

    The present invention is directed to a method of screening microbe strains capable of generating hydrogen. This method involves inoculating one or more microbes in a sample containing cell culture medium to form an inoculated culture medium. The inoculated culture medium is then incubated under hydrogen producing conditions. Once incubating causes the inoculated culture medium to produce hydrogen, microbes in the culture medium are identified as candidate microbe strains capable of generating hydrogen. Methods of producing hydrogen using one or more of the microbial strains identified as well as the hydrogen producing strains themselves are also disclosed.

  4. New hydrogen technologies

    International Nuclear Information System (INIS)

    1992-01-01

    This report presents an overview of the overall hydrogen system. There are separate sections for production, distribution, transport, storage; and applications of hydrogen. The most important methods for hydrogen production are steam reformation of natural gas and electrolysis of water. Of the renewable energy options, production of hydrogen by electrolysis using electricity from wind turbines or by gasification of biomass were found to be the most economic for Finland. Direct use of this electricity or the production of liquid fuels from biomass will be competing alternatives. When hydrogen is produced in the solar belt or where there is cheap hydropower it must be transported over long distances. The overall energy consumed for the transport is from 25 to 40 % of the initial available energy. Hydrogen storage can be divided into stationary and mobile types. The most economic, stationary, large scale hydrogen storage for both long and short periods is underground storage. When suitable sites are not available, then pressure vessels are the best for short period and liquid H 2 for long period. Vehicle storage of hydrogen is by either metal hydrides or liquid H 2 . Hydrogen is a very versatile energy carrier. It can be used to produce heat directly in catalytic burners without flame, to produce electricity in fuel cells with high efficiency for use in vehicles or for peak power shaving, as a fuel component with conventional fuels to reduce emissions, as a way to store energy and as a chemical reagent in reactions

  5. Hydrogen as automotive fuel

    International Nuclear Information System (INIS)

    Dini, D.; Ciancia, A.; Pede, G.; Sglavo, V.; ENEA, Rome

    1992-01-01

    An assessment of the technical/economic feasibility of the use of hydrogen as an automotive fuel is made based on analyses of the following: the chemical- physical properties of hydrogen in relation to its use in internal combustion engines; the modifications necessary to adapt internal combustion engines to hydrogen use; hydrogen fuel injection systems - with water vapour injection, cryogenic injection, and the low or high pressure injection of hydrogen directly into the combustion chamber; the current commercialization status of hydrogen automotive fuels; energy efficiency ratings; environmental impacts; in-vehicle storage systems - involving the use of hydrides, high pressure systems and liquid hydrogen storage systems; performance in terms of pay-load ratio; autonomous operation; and operating costs. The paper concludes that, considering current costs for hydrogen fuel production, distribution and use, at present, the employment of hydrogen fuelled vehicles is feasible only in highly polluted urban environments where the innovative vehicle's air pollution abatement characteristics would justify its high operating costs as compared with those of conventional automotive alternatives

  6. Hydrogen production methods

    International Nuclear Information System (INIS)

    Hammerli, M.

    1982-07-01

    Old, present and new proceses for producing hydrogen are assessed critically. The emphasis throughout is placed on those processes which could be commercially viable before the turn of the century for large-scale hydrogen manufacture. Electrolysis of water is the only industrial process not dependent on fossil resources for large-scale hydrogen production and is likely to remain so for the next two or three decades. While many new processes, including those utilizing sunlight directly or indirectly, are presently not considered to be commercially viable for large-scale hydrogen production, research and development effort is needed to enhance our understanding of the nature of these processes. Water vapour electrolysis is compared with thermochemical processes: the former has the potential for displacing all other processes for producing hydrogen and oxygen from water

  7. Determining the dominant partial wave contributions from angular distributions of single- and double-polarization observables in pseudoscalar meson photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Wunderlich, Y.; Afzal, F.; Thiel, A.; Beck, R. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany)

    2017-05-15

    This work presents a simple method to determine the significant partial wave contributions to experimentally determined observables in pseudoscalar meson photoproduction. First, fits to angular distributions are presented and the maximum orbital angular momentum L{sub max} needed to achieve a good fit is determined. Then, recent polarization measurements for γp → π{sup 0}p from ELSA, GRAAL, JLab and MAMI are investigated according to the proposed method. This method allows us to project high-spin partial wave contributions to any observable as long as the measurement has the necessary statistical accuracy. We show, that high precision and large angular coverage in the polarization data are needed in order to be sensitive to high-spin resonance states and thereby also for the finding of small resonance contributions. This task can be achieved via interference of these resonances with the well-known states. For the channel γp → π{sup 0}p, those are the N(1680)(5)/(2){sup +} and Δ(1950)(7)/(2){sup +}, contributing to the F-waves. (orig.)

  8. 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.

  9. Use of reiterative primer extension methodology to map UV-induced photoproducts at the nucleotide level in the laci gene from genomic DNA

    International Nuclear Information System (INIS)

    Chandrasekhar, D.; Houten, B. Van

    1994-01-01

    A newly developed reiterative primer extension assay has been employed to examine photoproduct formation and repair at the nucleotide level. Analysis of UV-induced DNA photoproduct hotspots in the first 184 base pairs of the laci genes of genomic E. coli DNA has revealed that photoproducts are formed linearly with dose and display a sequence-dependent increase. Generally, pyrimdine dimers were twice as frequent as all other UV-induced photoproducts. However, specific sites showed differing distributions. A post-irradiation recovery period revealed differences in the repair efficiency at individual nucleotides. Repair of photoproducts on the transcribed strand was generally twice as efficient as repair of photoproducts on the nontranscribed strand, indicating that strand-specific DNA repair occurs in the constitutively transcribed laci gene of E. coli. The UV-induced DNA photoproduct distribution following repair was well correlated with an established UV-induced mutation spectrum for wild-type E. coli cells. This analysis revealed that photoproduct hotspots on the efficiently repaired transcribed strand did not correlate with mutagenic hotspots. These data strongly support the hypothesis that mutations arise at inefficiently repaired sites on the nontranscribed strand

  10. Hydrogen safety

    International Nuclear Information System (INIS)

    Frazier, W.R.

    1991-01-01

    The NASA experience with hydrogen began in the 1950s when the National Advisory Committee on Aeronautics (NACA) research on rocket fuels was inherited by the newly formed National Aeronautics and Space Administration (NASA). Initial emphasis on the use of hydrogen as a fuel for high-altitude probes, satellites, and aircraft limited the available data on hydrogen hazards to small quantities of hydrogen. NASA began to use hydrogen as the principal liquid propellant for launch vehicles and quickly determined the need for hydrogen safety documentation to support design and operational requirements. The resulting NASA approach to hydrogen safety requires a joint effort by design and safety engineering to address hydrogen hazards and develop procedures for safe operation of equipment and facilities. NASA also determined the need for rigorous training and certification programs for personnel involved with hydrogen use. NASA's current use of hydrogen is mainly for large heavy-lift vehicle propulsion, which necessitates storage of large quantities for fueling space shots and for testing. Future use will involve new applications such as thermal imaging

  11. Hydrogen by water electrolysis

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    Hydrogen production by water electrolysis (aqueous solution of potassium hydroxide) is shortly presented with theoretical aspects (thermodynamics and kinetics), and components of the electrolytic cell (structural materials, cathodes, anodes, diaphragms), and examples of industrial processes. (A.B.). 4 figs

  12. Measurement of charm and beauty cross sections in photoproduction using events with muons and dijets at HERA

    Energy Technology Data Exchange (ETDEWEB)

    Kraemer, M.

    2009-09-15

    A measurement of open charm and beauty cross sections in photoproduction using dijet events containing a muon at the ep collider HERA is presented. The analysed data are collected with the H1 detector in the years 2006 and 2007, corresponding to an integrated luminosity of 179 pb{sup -1}. Events are selected, which contain at least two jets with transverse momenta of p{sub t}{sup jet1(2)}>7(6) GeV in the pseudorapidity region -2.5<{eta}{sup jet1(2)}<2.5. A muon with a minimal transverse momentum of p{sub t}{sup {mu}}>2.5 GeV in the pseudorapidity range -1.3<{eta}{sup {mu}}<1.5 is required. The muon is associated to one of the two selected jets. The method used to determine the fraction of events containing charm or beauty is based on the transverse momentum of the muon relative to its associated jet and the impact parameter of the muon track with respect to the primary vertex. Differential cross sections for charm and beauty are measured as a function of the transverse momentum of the muon, the pseudorapidity of the muon, the transverse momentum of the highest pt jet, the azimuthal angular separation of the two selected jets and the observable x{sub {gamma}}{sup obs}. Double differential cross sections for charm and beauty are measured in the region of direct and resolved processes. (orig.)

  13. J/ψ photoproduction in ultra-peripheral Pb-Pb and p-Pb collisions with the ALICE detector

    Directory of Open Access Journals (Sweden)

    Adam Jaroslav

    2014-04-01

    Full Text Available Ultra-relativistic heavy ions generate strong electromagnetic fields which offer the possibility to study gamma-gamma, gamma-nucleus and gamma-proton processes at the LHC in ultra-peripheral Pb-Pb and p-Pb collisions. Exclusive photoproduction of J/ψ vector mesons is sensitive to the gluon distribution of the target. Here we report on the ALICE measurement of J/ψ coherent photoproduction in Pb-Pb ultra-peripheral collisions at √sNN = 2.76 TeV for the rapidity ranges -3.6 < y < -2.6 and |y| < 0.9, and on preliminary results on the J/ψ photoproduction in p-Pb at √sNN = 5.02 TeV. The J/ψ mesons have been identified through their leptonic decays.

  14. Hydrogen storage using borohydrides

    International Nuclear Information System (INIS)

    Bernard BONNETOT; Laetitia LAVERSENNE

    2006-01-01

    The possibilities of hydrogen storage using borohydrides are presented and discussed specially in regard of the recoverable hydrogen amount and related to the recovering conditions. A rapid analysis of storage possibilities is proposed taking in account the two main ways for hydrogen evolution: the dehydrogenation obtained through thermal decomposition or the hydrolysis of solids or solutions. The recoverable hydrogen is related to the dehydrogenation conditions and the real hydrogen useful percentage is determined for each case of use. The high temperature required for dehydrogenation even when using catalyzed compounds lead to poor outlooks for this storage way. The hydrolysis conditions direct the chemical yield of the water consuming, and this must be related to the experimental conditions which rule the storage capacity of the 'fuel' derived from the borohydride. (authors)

  15. UV-visible degradation of boscalid--structural characterization of photoproducts and potential toxicity using in silico tests.

    Science.gov (United States)

    Lassalle, Yannick; Kinani, Aziz; Rifai, Ahmad; Souissi, Yasmine; Clavaguera, Carine; Bourcier, Sophie; Jaber, Farouk; Bouchonnet, Stéphane

    2014-05-30

    Boscalid is a carboximide fungicide mainly used for vineyard protection as well as for tomato, apple, blueberry and various ornamental cultivations. The structural elucidation of by-products arising from the UV-visible photodegradation of boscalid has been investigated by gas chromatography/multi-stage mass spectrometry (GC/MS(n) ) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) couplings. The potential toxicities of transformation products were estimated by in silico calculations. Aqueous solutions of boscalid were irradiated up to 150 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out using a gas chromatograph coupled with an ion trap mass spectrometer operated in both electron ionization (EI) and chemical ionization (CI) modes and a liquid chromatograph coupled with a quadrupole time-of-flight (Q-TOF) mass spectrometer operated in electrospray ionization (ESI) mode. Multiple-stage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. The QSAR (Quantitative Structure-Activity Relationship) T.E.S.T. program allowed the estimation of the toxicities of the by-products. Eight photoproducts were investigated. Chemical structures were proposed not only on the interpretation of multi-stage CID experiments, but also on kinetics data. These structures led us to suggest photodegradation pathways. Three photoproducts were finally detected in Lebanon in a real sample of grape leaves for which routine analysis had led to the detection of boscalid at 4 mg kg(-1). With one exception, the structures proposed for the photoproducts on the basis of mass spectra interpretation have not been reported in previous studies. In silico toxicity predictions showed that two photoproducts are potentially more toxic than the parent compound considering oral rat LD50 while five photoproducts may induce mutagenic toxicity. With the exception of one compound, all photoproducts may

  16. UV-visible degradation of boscalid- structural characterization of photoproducts and potential toxicity using in silico tests

    International Nuclear Information System (INIS)

    Rifai, A.; Jaber, F.; Lassalle, Y.; Kinani, A.; Souissi, Y.; Clavaguera, C.; Bourcier, S.; Bouchonnet, St.

    2014-01-01

    RATIONALE: Boscalid is a carboximide fungicide mainly used for vineyard protection as well as for tomato, apple, blueberry and various ornamental cultivations. The structural elucidation of by-products arising from the UV-visible photodegradation of boscalid has been investigated by gas chromatography/multi-stage mass spectrometry (GC/MSn) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) couplings. The potential toxicities of transformation products were estimated by in silico calculations. METHODS: Aqueous solutions of boscalid were irradiated up to 150 min in a self-made reactor equipped with a mercury lamp. Analyses were carried out using a gas chromatograph coupled with an ion trap mass spectrometer operated in both electron ionization (EI) and chemical ionization (CI) modes and a liquid chromatograph coupled with a quadrupole time-of-flight (Q-TOF) mass spectrometer operated in electrospray ionization (ESI) mode. Multiple-stage collision-induced dissociation (CID) experiments were performed to establish dissociation pathways of ions. The QSAR (Quantitative Structure-Activity Relationship) T.E.S.T. program allowed the estimation of the toxicities of the by-products. RESULTS: Eight photoproducts were investigated. Chemical structures were proposed not only on the interpretation of multi-stage CID experiments, but also on kinetics data. These structures led us to suggest photodegradation pathways. Three photoproducts were finally detected in Lebanon in a real sample of grape leaves for which routine analysis had led to the detection of boscalid at 4 mg kg1. CONCLUSIONS: With one exception, the structures proposed for the photoproducts on the basis of mass spectra interpretation have not been reported in previous studies. In silico toxicity predictions showed that two photoproducts are potentially more toxic than the parent compound considering oral rat LD50 while five photoproducts may induce mutagenic toxicity. With the exception of one compound

  17. Study of ultraviolet light-induced DNA damage and repair: the role of the (6-4) photoproduct

    International Nuclear Information System (INIS)

    Franklin, W.A.

    1985-01-01

    Ultraviolet light induces lethal, mutagenic, and carcinogenic effects to cells. These effects are a result of the induction of photoproducts in the cellular DNA. One class of photoproducts was found as alkaline labile lesions in DNA, and it was proposed that such lesions were precursor products to the 6,4'-[pyrimidin-2'-one]-pyrimidine class of photoproducts that have been previously shown to occur in UV light-irradiated DNA. Using a series of dinucleotide compounds, the precursor compounds were isolated, and were demonstrated to be alkaline labile. These products were named the UV light-induced pyrimidine-pyrimidone (6-4) photoproducts, and their chemistry of formation in dinucleotides and DNA was studied. The formation of these photoproducts under conditions of chemical photosensitization was also measured. The most abundant of the (6-4) photoproducts is the thymine-cytosine (6-4) product, and the molecular structure of this compounds was determined by the use of infrared spectroscopy, proton NMR, and mass spectroscopy. The (6-4) products have been recently shown to be the major UV light-induced premutagenic lesions in E. coli. In E. coli, the repair of the (6-4) products is under the control of the uvrABC excision pathway. The rate of removal of (6-4) products was measured in a series of human cells lines. The rate of removal of (6-4) products from the DNA of a xeroderma pigmentosum complementation group A cell line was nearly that of the normal cells, yet these cells are unable to excise cyclobutane pyrimidine dimers. These results suggest that the removal of cyclobutane pyrimidine dimers and (6-4) products may be controlled by separate enzymatic pathways

  18. Acclimation of green algae to sulfur deficiency: underlying mechanisms and application for hydrogen production.

    Science.gov (United States)

    Antal, Taras K; Krendeleva, Tatyana E; Rubin, Andrew B

    2011-01-01

    Hydrogen is definitely one of the most acceptable fuels in the future. Some photosynthetic microorganisms, such as green algae and cyanobacteria, can produce hydrogen gas from water by using solar energy. In green algae, hydrogen evolution is coupled to the photosynthetic electron transport in thylakoid membranes via reaction catalyzed by the specific enzyme, (FeFe)-hydrogenase. However, this enzyme is highly sensitive to oxygen and can be quickly inhibited when water splitting is active. A problem of incompatibility between the water splitting and hydrogenase reaction can be overcome by depletion of algal cells of sulfur which is essential element for life. In this review the mechanisms underlying sustained hydrogen photoproduction in sulfur deprived C. reinhardtii and the recent achievements in studying of this process are discussed. The attention is focused on the biophysical and physiological aspects of photosynthetic response to sulfur deficiency in green algae.

  19. Hydrogen millennium

    International Nuclear Information System (INIS)

    Bose, T.K.; Benard, P.

    2000-05-01

    The 10th Canadian Hydrogen Conference was held at the Hilton Hotel in Quebec City from May 28 to May 31, 2000. The topics discussed included current drivers for the hydrogen economy, the international response to these drivers, new initiatives, sustainable as well as biological and hydrocarbon-derived production of hydrogen, defense applications of fuel cells, hydrogen storage on metal hydrides and carbon nanostructures, stationary power and remote application, micro-fuel cells and portable applications, marketing aspects, fuel cell modeling, materials, safety, fuel cell vehicles and residential applications. (author)

  20. Jet shapes in charm photoproduction and deeply inelastic scattering at HERA

    International Nuclear Information System (INIS)

    Grell, Brian Rosenvold

    2010-09-01

    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 x γ 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 γ obs are observed for higher values of Q 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.)

  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. Unintegrated gluon distributions in D*± and dijet associated photoproduction at HERA

    International Nuclear Information System (INIS)

    Lipatov, A.V.; Zotov, N.P.

    2006-01-01

    We consider the photoproduction of D *± mesons associated with two hadron jets at HERA collider in the framework of the k T -factorization approach. The unintegrated gluon densities in a proton are obtained from the full CCFM, from unified BFKL-DGLAP evolution equations as well as from the Kimber-Martin-Ryskin prescription. Resolved photon contributions are reproduced by the initial-state gluon radiation. We investigate different production rates and make a comparison with the recent experimental data taken by the ZEUS collaboration. Special attention is given to the specific dijet correlations which can provide unique information about non-collinear gluon evolution dynamics. (orig.)

  3. Jet rates in photoproduction on proton and nuclei at the LHeC

    CERN Document Server

    Armesto, N

    2010-01-01

    I compute the inclusive jet rates in photoproduction for $e$p and $e$Pb collisions at the LHeC, within QCD at NLO. The results show that rates around $10^3$ jets per GeV are expected with $E_{Tjet}\\sim 95$ (80) GeV in $e$p ($e$Pb), for $|\\eta_{jet}|<3.1$ and an integrated luminosity of 2 fb$^{-1}$ per nucleon. The effect of the nuclear modification of parton densities and their uncertainties - the only ones considered in this exploratory study - are smaller than 10 \\%.

  4. Pion inelastic scattering, pion photoproduction and inelastic electron scattering on light nuclei

    International Nuclear Information System (INIS)

    Ehramzhyan, R.A.

    1985-01-01

    Partial transitions in pion photoproduction reaction on 6 Li, 10 B, 12 C nuclei are considered. Particular stress is paied to simultaneous analysis both of (γ, π) ad (e, e'), (π, π') reactions. Such analysis is concretely ixemplified with the use of both phenomenological and microscopic approaches. Microscopic analysis is shown to give correct representation of reaction mechanism (γ, π), (e, e') and (π, π') at intermediate energies. Spin-isospin dipole resonances in 1p-shell nuclei are considered. It is shown that nuclear system excitation spectrum gross-structure is a result of resonance configuration splitting

  5. Polarized photoproduction from nuclear targets with arbitrary spin and relation to deep inelastic scattering

    International Nuclear Information System (INIS)

    Hoodbhoy, P.; Massachusetts Inst. of Tech., Cambridge; Quaid-i-Azam Univ., Islamabad

    1990-01-01

    Inclusive photo-production from polarized targets of arbitrary spin is analyzed by using multipoles. The Drell-Hearn-Gerasimov sum rule, which was originally fromulated for spin-1/2 targets, is generalized to all spins and multipoles, and shown to have some interesting consequences. Measurements to test the new rules, or to derive nuclear structure information from them, could be incorporated into existing plans at electron accelerator facilities. Finally, the possible relevance of these generalized sum rules to sum rules measurable in polarized lepton-polarized target deep inelastic inclusive scattering is discussed. (orig.)

  6. Photoproduction of multi-jet events at HERA: A Monte Carlo simulation

    International Nuclear Information System (INIS)

    Butterworth, J.M.; Forshaw, J.R.

    1993-07-01

    We study the regime of high-energy photoproduction, currently under exploration at the DESY ep Collider, HERA. In particular we discuss the possible production of more than one pair of 'back-to-back' jets which may occur at reasonably high-p T as a consequence of the high parton density regime opened up at HERA centre-of-mass energies. We describe the construction of a multi-jet event generator based upon leading order QCD perturbation theory and an eikonal formalism, and show that the effect of multiple parton interactions on event shapes at HERA could indeed be significant. (orig.)

  7. 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.

  8. On the η and η′ photoproduction beam asymmetry at high energies

    Directory of Open Access Journals (Sweden)

    V. Mathieu

    2017-11-01

    Full Text Available We show that, in the Regge limit, beam asymmetries in η and η′ photoproduction are sensitive to hidden strangeness components. Under reasonable assumptions about the couplings we estimate the contribution of the ϕ Regge pole, which is expected to be the dominant hidden strangeness contribution. The ratio of the asymmetries in η′ and η production is estimated to be close to unity in the forward region 0<−t/GeV2≤1 at the photon energy Elab=9 GeV, relevant for the upcoming measurements at Jefferson Lab.

  9. Diffractive J/ψ photoproduction as a probe of the gluon density

    International Nuclear Information System (INIS)

    Ryskin, M.G.; Roberts, R.G.; Martin, A.D.; Levin, E.M.

    1995-11-01

    We use perturbative QCD beyond the leading Ln Q 2 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

  10. Virtual photoproduction of hadrons at large p/sub T/ as a probe for gluon bremsstrahlung

    CERN Document Server

    Floratos, Emmanuel G

    1978-01-01

    In a SU/sub 3, colour/ x SU/sub 3, flavour/ invariant interaction of quarks and gluons, where the colour degree of freedom is locally gauged, first-order corrections of the naive parton model are calculated for the one-hadron inclusive virtual photoproduction. The high p/sub T/ distribution of hadrons is studied and the kinetical region in which the prediction of the model dominates over the fall- off approximately exp(-bp/sub T//sup 2/) which seems to be supported by the low-p/sub T/ available experimental data is determined. (29 refs).

  11. Interference phenomena in the JP = 1/2- wave in η photoproduction

    International Nuclear Information System (INIS)

    Anisovich, A.V.; Nikonov, V.A.; Sarantsev, A.V.; Klempt, E.; Thoma, U.; Krusche, B.; Werthmueller, D.

    2015-01-01

    The recent precise experimental results for the photoproduction of η-mesons off the neutron measured with the Crystal Ball/TAPS calorimeter at the MAMI accelerator have been investigated in detail in the framework of the Bonn-Gatchina coupled-channel model. The main result is that the narrow structure observed in the excitation function of γη → nη can be reproduced fully with a particular interference pattern in the J P = 1/2 - partial wave. Introduction of the narrow resonance N(1685) with the properties reported in earlier publications deteriorates the quality of the fit. (orig.)

  12. Measurement of J/{psi} helicity distributions in inelastic photoproduction at HERA

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-06-15

    The J/{psi} decay angular distributions have been measured in inelastic photoproduction in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 468 pb{sup -1}. The range in photon-proton centre-of-mass energy, W, was 50

  13. Photoproduction of eta mesons from threshold to 1.2 GeV

    International Nuclear Information System (INIS)

    Rigney, A.; Breuer, M.; Hoffman-Rothe, P.; Anton, G.; Arends, J.; Berrier-Ronsin, G.; Beulertz, W.; Blanpied, G.; Bock, A.; Bruns, M.; Didelez, J.; Djaladi, C.; Edel, G.; Frascaria, R.; Maass, R.; Helbing, K.; Hey, J.; Noeldeke, G.; Hourani, E.; Mayers, M.; Preedom, B.; Ritchie, B.; Rosier, L.; Saghai, B.; Schumacher, M.; Smend, F.; Whisnant, S.

    1995-01-01

    We have measured total and differential cross sections for η-meson photo-production on 7 cm thick 1 H, 2 D, and 14 N liquid targets from threshold to 1.2 GeV, using the tagged Bremsstrahlung photon beam produced by the electrons extracted from the ELSA storage ring at Bonn. The photoreaction was identified by detecting the η decay products in the neutral meson spectrometer SPES0-2π, while the recoil baryons (proton, neutron, or deuteron) were detected by a variety of large angle scintillator detectors. Some of our recent preliminary results, both theoretical and experimental, will be discussed. copyright 1995 American Institute of Physics

  14. 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.)

  15. Off-shell effects in the coherent π0 photoproduction off nuclei

    International Nuclear Information System (INIS)

    Chumbalov, A.A.; Kamalov, S.S.

    1987-01-01

    A strong sensitivity of coherent π 0 -meson photoproduction on nuclei to different ω reaction energy change in elementary amplitude t πγ (ω) is demonstrated. Various assumptions concerning ω behaviour in the extraenergy area can change differential cross sections 1.5-2 times. The best agreement of the DWIA-results with experimental data is obtained at ω being equal to its own value of pion-nucleon system free relativistic Hamiltonian. Such a result agrees with relativistic potential theory effects

  16. Coherent $\\rho^0$ photoproduction in ultra-peripheral Pb-Pb collisions at $\\mathbf{\\sqrt{\\textit{s}_{\\rm NN}}} = 2.76$ TeV

    CERN Document Server

    Adam, Jaroslav; Aggarwal, Madan Mohan; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agrawal, Neelima; Ahammed, Zubayer; Ahn, Sang Un; Aimo, Ilaria; Aiola, Salvatore; Ajaz, Muhammad; Akindinov, Alexander; Alam, Sk Noor; Aleksandrov, Dmitry; Alessandro, Bruno; Alexandre, Didier; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Alme, Johan; Alt, Torsten; Altinpinar, Sedat; Altsybeev, Igor; Alves Garcia Prado, Caio; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshaeuser, Harald; Arcelli, Silvia; Armesto Perez, Nestor; Arnaldi, Roberta; Aronsson, Tomas; Arsene, Ionut Cristian; Arslandok, Mesut; Augustinus, Andre; Averbeck, Ralf Peter; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bagnasco, Stefano; Bailhache, Raphaelle Marie; Bala, Renu; Baldisseri, Alberto; Baltasar Dos Santos Pedrosa, Fernando; Baral, Rama Chandra; Barbano, Anastasia Maria; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Ramillien Barret, Valerie; Bartalini, Paolo; Barth, Klaus; Bartke, Jerzy Gustaw; Bartsch, Esther; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batista Camejo, Arianna; Batyunya, Boris; Batzing, Paul Christoph; Bearden, Ian Gardner; Beck, Hans; Bedda, Cristina; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bello Martinez, Hector; Bellwied, Rene; Belmont Iii, Ronald John; Belmont Moreno, Ernesto; Belyaev, Vladimir; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bertens, Redmer Alexander; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhat, Inayat Rasool; Bhati, Ashok Kumar; Bhattacharjee, Buddhadeb; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Biswas, Rathijit; Biswas, Saikat; Bjelogrlic, Sandro; Blanco, Fernando; Blau, Dmitry; Blume, Christoph; Bock, Friederike; Bogdanov, Alexey; Boggild, Hans; Boldizsar, Laszlo; Bombara, Marek; Book, Julian Heinz; Borel, Herve; Borissov, Alexander; Borri, Marcello; Bossu, Francesco; Botje, Michiel; Botta, Elena; Boettger, Stefan; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Broker, Theo Alexander; Browning, Tyler Allen; Broz, Michal; Brucken, Erik Jens; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Buncic, Predrag; Busch, Oliver; Buthelezi, Edith Zinhle; Buxton, Jesse Thomas; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calero Diaz, Liliet; Caliva, Alberto; Calvo Villar, Ernesto; Camerini, Paolo; Carena, Francesco; Carena, Wisla; Castillo Castellanos, Javier Ernesto; Castro, Andrew John; Casula, Ester Anna Rita; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Chartier, Marielle; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chelnokov, Volodymyr; Cherney, Michael Gerard; Cheshkov, Cvetan Valeriev; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Dobrigkeit Chinellato, David; Chochula, Peter; Choi, Kyungeon; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Zhang, Chunhui; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Colamaria, Fabio Filippo; Colella, Domenico; Collu, Alberto; Colocci, Manuel; Conesa Balbastre, Gustavo; Conesa Del Valle, Zaida; Connors, Megan Elizabeth; Contreras Nuno, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortes Maldonado, Ismael; Cortese, Pietro; Cosentino, Mauro Rogerio; Costa, Filippo; Crochet, Philippe; Cruz Albino, Rigoberto; Cuautle Flores, Eleazar; Cunqueiro Mendez, Leticia; Dahms, Torsten; Dainese, Andrea; Danu, Andrea; Das, Debasish; Das, Indranil; Das, Supriya; Dash, Ajay Kumar; Dash, Sadhana; De, Sudipan; De Caro, Annalisa; De Cataldo, Giacinto; De Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; De Marco, Nora; De Pasquale, Salvatore; Deisting, Alexander; Deloff, Andrzej; Denes, Ervin Sandor; D'Erasmo, Ginevra; Di Bari, Domenico; Di Mauro, Antonio; Di Nezza, Pasquale; Diaz Corchero, Miguel Angel; Dietel, Thomas; Dillenseger, Pascal; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Domenicis Gimenez, Diogenes; Donigus, Benjamin; Dordic, Olja; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Ehlers Iii, Raymond James; Elia, Domenico; Engel, Heiko; Erazmus, Barbara Ewa; Erhardt, Filip; Eschweiler, Dominic; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Eum, Jongsik; Evans, David; Evdokimov, Sergey; Eyyubova, Gyulnara; Fabbietti, Laura; Fabris, Daniela; Faivre, Julien; Fantoni, Alessandra; Fasel, Markus; Feldkamp, Linus; Felea, Daniel; Feliciello, Alessandro; Feofilov, Grigorii; Ferencei, Jozef; Fernandez Tellez, Arturo; Gonzalez Ferreiro, Elena; Ferretti, Alessandro; Festanti, Andrea; Figiel, Jan; Araujo Silva Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Fleck, Martin Gabriel; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Furs, Artur; Fusco Girard, Mario; Gaardhoeje, Jens Joergen; Gagliardi, Martino; Gago Medina, Alberto Martin; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Gao, Chaosong; Garabatos Cuadrado, Jose; Garcia-Solis, Edmundo Javier; Gargiulo, Corrado; Gasik, Piotr Jan; Germain, Marie; Gheata, Andrei George; Gheata, Mihaela; Ghosh, Premomoy; Ghosh, Sanjay Kumar; Gianotti, Paola; Giubellino, Paolo; Giubilato, Piero; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez Ramirez, Andres; Gonzalez Zamora, Pedro; Gorbunov, Sergey; Gorlich, Lidia Maria; Gotovac, Sven; Grabski, Varlen; Graczykowski, Lukasz Kamil; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoryev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grynyov, Borys; Grion, Nevio; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerzoni, Barbara; Gulbrandsen, Kristjan Herlache; Gulkanyan, Hrant; Gunji, Taku; Gupta, Anik; Gupta, Ramni; Haake, Rudiger; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Hanratty, Luke David; Hansen, Alexander; Harris, John William; Hartmann, Helvi; Harton, Austin Vincent; Hatzifotiadou, Despina; Hayashi, Shinichi; Heckel, Stefan Thomas; Heide, Markus Ansgar; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hilden, Timo Eero; Hillemanns, Hartmut; Hippolyte, Boris; Hristov, Peter Zahariev; Huang, Meidana; Humanic, Thomas; Hussain, Nur; Hussain, Tahir; Hutter, Dirk; Hwang, Dae Sung; Ilkaev, Radiy; Ilkiv, Iryna; Inaba, Motoi; Ionita, Costin; Ippolitov, Mikhail; Irfan, Muhammad; Ivanov, Marian; Ivanov, Vladimir; Izucheev, Vladimir; Jacobs, Peter Martin; Jahnke, Cristiane; Jang, Haeng Jin; Janik, Malgorzata Anna; Pahula Hewage, Sandun; Jena, Chitrasen; Jena, Satyajit; Jimenez Bustamante, Raul Tonatiuh; Jones, Peter Graham; Jung, Hyungtaik; Jusko, Anton; Kalinak, Peter; Kalweit, Alexander Philipp; Kamin, Jason Adrian; Kang, Ju Hwan; Kaplin, Vladimir; Kar, Somnath; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kebschull, Udo Wolfgang; Keidel, Ralf; Keijdener, Darius Laurens; Keil, Markus; Khan, Kamal; Khan, Mohammed Mohisin; Khan, Palash; Khan, Shuaib Ahmad; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Beomkyu; Kim, Do Won; Kim, Dong Jo; Kim, Hyeonjoong; Kim, Jinsook; Kim, Mimae; Kim, Minwoo; Kim, Se Yong; Kim, Taesoo; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Kiss, Gabor; Klay, Jennifer Lynn; Klein, Carsten; Klein, Jochen; Klein-Boesing, Christian; 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Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhlheim, Daniel Michael; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Mulligan, James Declan; Gameiro Munhoz, Marcelo; Murray, Sean; Musa, Luciano; Musinsky, Jan; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Naru, Muhammad Umair; Nattrass, Christine; Nayak, Kishora; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Nellen, Lukas; Ng, Fabian; Nicassio, Maria; Niculescu, Mihai; Niedziela, Jeremi; Nielsen, Borge Svane; Nikolaev, Sergey; Nikulin, Sergey; Nikulin, Vladimir; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Norman, Jaime; Nyanin, Alexander; Nystrand, Joakim Ingemar; Oeschler, Helmut Oskar; Oh, Saehanseul; Oh, Sun Kun; Ohlson, Alice Elisabeth; Okatan, Ali; Okubo, Tsubasa; Olah, Laszlo; Oleniacz, Janusz; Oliveira Da Silva, Antonio Carlos; Oliver, Michael Henry; Onderwaater, Jacobus; Oppedisano, Chiara; Ortiz Velasquez, Antonio; Oskarsson, Anders Nils Erik; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozdemir, Mahmut; Pachmayer, Yvonne Chiara; Pagano, Paola; Paic, Guy; Pajares Vales, Carlos; Pal, Susanta Kumar; Pan, Jinjin; Pandey, Ashutosh Kumar; Pant, Divyash; Papikyan, Vardanush; Pappalardo, Giuseppe; Pareek, Pooja; Park, Woojin; Parmar, Sonia; Passfeld, Annika; Paticchio, Vincenzo; Patra, Rajendra Nath; Paul, Biswarup; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitry Yurevich; Perez Lara, Carlos Eugenio; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petrov, Viacheslav; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Pikna, Miroslav; Pillot, Philippe; Pinazza, Ombretta; Pinsky, Lawrence; Piyarathna, Danthasinghe; Ploskon, Mateusz Andrzej; Planinic, Mirko; Pluta, Jan Marian; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polishchuk, Boris; Poljak, Nikola; Poonsawat, Wanchaloem; Pop, Amalia; Porteboeuf, Sarah Julie; Porter, R Jefferson; Pospisil, Jan; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puccio, Maximiliano; Puddu, Giovanna; Pujahari, Prabhat Ranjan; Punin, Valery; Putschke, Jorn Henning; Qvigstad, Henrik; Rachevski, Alexandre; Raha, Sibaji; Rajput, Sonia; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Read, Kenneth Francis; Real, Jean-Sebastien; Redlich, Krzysztof; Reed, Rosi Jan; Rehman, Attiq Ur; Reichelt, Patrick Simon; Reidt, Felix; Ren, Xiaowen; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Rettig, Felix Vincenz; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riabov, Viktor; Ricci, Renato Angelo; Richert, Tuva Ora Herenui; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Ristea, Catalin-Lucian; Rivetti, Angelo; Rocco, Elena; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roeed, Ketil; Rogochaya, Elena; Rohr, David Michael; Roehrich, Dieter; Romita, Rosa; Ronchetti, Federico; Ronflette, Lucile; Rosnet, Philippe; Rossi, Andrea; Roukoutakis, Filimon; Roy, Ankhi; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Ryabov, Yury; Rybicki, Andrzej; Sadovskiy, Sergey; Safarik, Karel; Sahlmuller, Baldo; Sahoo, Pragati; Sahoo, Raghunath; Sahoo, Sarita; Sahu, Pradip Kumar; Saini, Jogender; Sakai, Shingo; Saleh, Mohammad Ahmad; Salgado Lopez, Carlos Alberto; Salzwedel, Jai Samuel Nielsen; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Santagati, Gianluca; Sarkar, Debojit; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Christian Joachim; Schmidt, Hans Rudolf; Schuchmann, Simone; Schukraft, Jurgen; Schulc, Martin; Schuster, Tim Robin; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; 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Wang, Hongkai; Wang, Mengliang; Wang, Yifei; Watanabe, Daisuke; Weber, Michael; Weber, Steffen Georg; Wessels, Johannes Peter; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Grzegorz Andrzej; Wilkinson, Jeremy John; Williams, Crispin; Windelband, Bernd Stefan; Winn, Michael Andreas; Yaldo, Chris G; Yamaguchi, Yorito; Yang, Hongyan; Yang, Ping; Yano, Satoshi; Yin, Zhongbao; Yokoyama, Hiroki; Yoo, In-Kwon; Yurchenko, Volodymyr; Yushmanov, Igor; Zaborowska, Anna; Zaccolo, Valentina; Zaman, Ali; Zampolli, Chiara; Correia Zanoli, Henrique Jose; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zavyalov, Nikolay; Zbroszczyk, Hanna Paulina; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Haitao; Zhang, Xiaoming; Zhang, Yonghong; Zhao, Chengxin; Zhigareva, Natalia; Zhou, Daicui; Zhou, You; Zhou, Zhuo; Zhu, Hongsheng; Zhu, Jianhui; Zhu, Xiangrong; Zichichi, Antonino; Zimmermann, Alice; Zimmermann, Markus Bernhard; Zinovjev, Gennady; Zyzak, Maksym

    2015-09-15

    We report the first measurement at the LHC of coherent photoproduction of $\\rho^0$ mesons in ultra-peripheral Pb-Pb collisions. The invariant mass and transverse momentum distributions for $\\rho^0$ production are studied in the $\\pi^+ \\pi^-$ decay channel at mid-rapidity. The production cross section in the rapidity range $|y|<0.5$ is found to be $\\mathrm{d}\\sigma/\\mathrm{d}y = 425 \\pm 10 \\, (\\mathrm{stat.})$ $^{+42}_{-50} \\, (\\mathrm{sys.})$ mb. Coherent $\\rho^0$ production is studied with and without requirement of nuclear breakup, and the fractional yields for various breakup scenarios are presented. The results are compared with those from lower energies and with model predictions based on the Glauber model and the color dipole model. The measured cross section is found to be inconsistent with a scaling of the $\\gamma$-nucleon cross section using the Glauber model.

  17. Radiation-accompanied pion photoproduction on the proton

    International Nuclear Information System (INIS)

    Rost, M.

    2004-01-01

    In the year 1997, Tatischeff et al. found resonance-like states in the invariant mass spectrum of the missing particle X at M=1004, 1044 and 1094 MeV, utilizing the reaction pp→Xpπ + . Investigating the reaction pd→ppX, resonance structures have been observed at M=966, 986 and 1003 MeV in a further experiment by Filkov et al. Such kinds of exotic states contradict various nucleon models which describe the Δ(1232) resonance as the first excited state. Instead, quark cluster models with and without color-magnetic interactions have been formulated to explain these resonance structures. Lvov et al. argued that no such structure had been reported in real Compton scattering data. As a counter argument, Kobushkin suggested that these resonances have a total anti-symmetric spin-flavour wave function and therefore only the N-2γ decay channel is allowed. In this work, the reaction γp→X 0 π + →nγγπ + is utilized for the search of these exotic resonances. Data were taken in parallel with the pion polarizability experiment at the MAMI accelerator facility in Mainz. Real photons are created by the bremsstrahlung process of the electrons in a thin radiator foil. Their energy is determined by the A2 photon tagging facility (Glasgow tagger). A 10 cm long liquid hydrogen target was used as a proton target. Charged reaction products are detected in a multi wire proportional chamber in forward direction, at theta 2 crystals containing TAPS spectrometer at polar angles of theta >60 . For neutron detection, a time of flight detector with 111 single modules was used. Additionally, the reaction channels γp→pπ 0 and γp→nπ 0 π + are analysed to test the apparatuses. For single pion production, differential cross sections are obtained and compared with theoretical models as well as experimental data. For the γp→nπ 0 π + channel, invariant mass spectra of particles in the final state are determined and compared with simulation. The data indicate that the main

  18. Hydrogen exchange

    DEFF Research Database (Denmark)

    Jensen, Pernille Foged; Rand, Kasper Dyrberg

    2016-01-01

    Hydrogen exchange (HX) monitored by mass spectrometry (MS) is a powerful analytical method for investigation of protein conformation and dynamics. HX-MS monitors isotopic exchange of hydrogen in protein backbone amides and thus serves as a sensitive method for probing protein conformation...... and dynamics along the entire protein backbone. This chapter describes the exchange of backbone amide hydrogen which is highly quenchable as it is strongly dependent on the pH and temperature. The HX rates of backbone amide hydrogen are sensitive and very useful probes of protein conformation......, as they are distributed along the polypeptide backbone and form the fundamental hydrogen-bonding networks of basic secondary structure. The effect of pressure on HX in unstructured polypeptides (poly-dl-lysine and oxidatively unfolded ribonuclease A) and native folded proteins (lysozyme and ribonuclease A) was evaluated...

  19. Preliminary study on the photoproduction of hydroxyl radicals in aqueous solution with Aldrich humic acid, algae and Fe(III) under high-pressure mercury lamp irradiation.

    Science.gov (United States)

    Liu, Xianli; Xu, Dong; Wu, Feng; Liao, Zhenhuan; Liu, Jiantong; Deng, Nansheng

    2004-03-01

    Under a high-pressure mercury lamp (HPML) and using an exposure time of 4 h, the photoproduction of hydroxyl radicals (*OH) could be induced in an aqueous solution containing humic acid (HA). Hydroxyl radicals were determined by high-performance liquid chromatography using benzene as a probe. The results showed that *OH photoproduction increased from 1.80 to 2.74 microM by increasing the HA concentration from 10 to 40 mg L(-1) at an exposure time of 4 h (pH 6.5). Hydroxyl radical photoproduction in aqueous solutions of HA containing algae was greater than that in the aqueous solutions of HA without algae. The photoproduction of *OH in the HA solution with Fe(III) was greater than that of the solution without Fe(III) at pH ranging from 4.0 to 8.0. The photoproduction of *OH in HA solution with algae with or without Fe(III) under a 250 W HPML was greater than that under a 125 W HPML. The photoproduction of *OH in irradiated samples was influenced by the pH. The results showed that HPML exposure for 4 h in the 4-8 pH range led to the highest *OH photoproduction at pH 4.0.

  20. Asymmetry of the e+e- pair photoproduction in crystals with account of lepton spin

    International Nuclear Information System (INIS)

    Nadzhafov, I.M.; Mirantsev, L.V.

    1980-01-01

    Asymmetry eta of the e + e - pair photoproduction in single crystals is theoretically investigated with account of the lepton longitudinal polarization. The calculations are based on the expression for the effective differential cross section d σ of the e + e - pair photoproduction on a screened nucleus in the Born approximation with account of linear polarization of γ-quanta and longitudinal polarization of e + and e - . The resulting formulae make it possible to study the energy, angular (azimuthal) and spin dependences of d σ, as well as eta at the fixed angle PSIsub(+) between a positron emission plane dn a crystal plane. Using the formulae the energy and azimuthal dependences of eta have been calculated for a diamond crystal with and without account of the spin correlation. It is shown, that eta is strongly dependent of PSIsub(+) especially with account of the spin correlation. In the case when only thse pairs are registrated, the particles of which possess antiparallel spins (Ssub(+)Ssub(-)=-1), eta=0.35 at PSIsub(+)=90 deg (Esub(+)=Esub(-)=2.5 GeV), and era=0.06 at PSIsub(+)=0 deg, eta for single crystals being 3 times the value for an amorphous target

  1. Photoproduction of $\\rho^0$ in ultra--peripheral nuclear collisions at ALICE

    CERN Document Server

    Skjerdal, Kyrre

    2013-01-01

    Photoproduction of $\\rho^0$ mesons in ultra-peripheral Pb+Pb collisions has been studied by the ALICE Collaboration at the CERN LHC. The strong photon flux associated with relativistic charged nuclei leads to a very large cross section for exclusive photoproduction of $\\rho^0$ meson in interactions of the type $Pb + Pb \\rightarrow Pb + Pb + \\rho^0$. For a $\\rho^0$ produced at mid-rapidity at the LHC, the photon-nucleus center of mass energy is higher than in any previous experiment. The ALICE detector is a general purpose detector dedicated to study heavy--ion collisions. ALICE has excellent performance in the low $p_T$ region, and can reconstruct charged particle tracks with 0.1 GeV/c $\\leq p_T \\leq 100$ GeV/c. In this analysis all tracks were required to be within ALICE's central barrel. Analysis of data from the first heavy ion run at the LHC in 2010 will be discussed in this paper.

  2. Precise tests for the unitarized pion photoproduction impulse amplitude in exclusive nuclear reactions

    International Nuclear Information System (INIS)

    Wittman, R.

    1986-07-01

    An impulse amplitude for pion photoproduction, suitable for the nuclear problem, is constructed with improved background dynamics and unitarity. The superior features of the amplitude are demonstrated at energies between threshold (E/sub γ/ = 150 MeV) and the Δ(1232) resonance energy (E/sub γ/ = 320 MeV) by discussing their effects on partial cross sections relevant to exclusive transitions in the 1p-shell. The specific reactions of 13 C(γ,π - ) 13 N/sub g.s./ and 14 N(γ,π + ) 14 C/sub g.s./ are discussed in light of these more general partial cross sections. The nuclear structure of the A = 14 system helps to enhance the effects considered. At or near resonance, very sizable (20 to 30%) effects arise both from the unitarity and from the refined treatment of the pionic final state interaction generated in the Δ-hole approach. Other examples of charged pion photoproduction reactions for 1p-shell nuclei are discussed briefly. Future theoretical improvements and experimental possibilities are suggested. 61 refs., 58 figs

  3. Structure of the φ photoproduction amplitude at a few GeV

    International Nuclear Information System (INIS)

    Titov, A.I.; Toki, H.; Titov, A.I.; Streltsova, O.; Lee, T.H.

    1999-01-01

    The structure of the φ photoproduction amplitude in the √ (s) ∼2-5 GeV region is analyzed based on Pomeron-exchange and meson-exchange mechanisms. The SU(3) symmetry and the φ decay widths are exploited to determine the parameters that are needed to predict the amplitudes due to pseudoscalar mesons (π 0 ,η) exchange, scalar mesons (σ,a 0 ,f 0 ) exchange, and the φ radiation from the nucleon. In addition to the universally accepted Pomeron exchange with an intercept α(0)∼1.08, we investigate the role of a second Pomeron with α(0) π =0 + ,M b 2 ∼3 GeV 2 ) predicted by the lattice QCD calculation and dual Ginsburg-Landau model. It is found that the existing limited data at low energies near threshold can accommodate either the second Pomeron or the scalar mesons exchange. The differences between these two competing mechanisms are shown to have profound effects on various density matrices which can be used to calculate the cross sections as well as various single and double polarization observables. We predict a definite isotopic effect: polarization observables of φ photoproduction on the proton and neutron targets can have differences of a factor 2 and more. copyright 1999 The American Physical Society

  4. High-energy photoproduction of states containing heavy quarks and other rare phenomena

    International Nuclear Information System (INIS)

    Cumalat, J.; Butler, J.; Gaines, I.

    1981-01-01

    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 π 0 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 (> 10 6 ) 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

  5. An extended study of prompt photon photoproduction at HERA with k{sub T}-factorization

    Energy Technology Data Exchange (ETDEWEB)

    Lipatov, A.V.; Malyshev, M.A.; Zotov, N.P. [Moskovskij Gosudarstvennyj Univ., Moscow (Russian Federation). Nauchno-Issledovatel' skij Inst. Yadernoj Fiziki

    2013-08-15

    We reconsider the prompt photon photoproduction at HERA in the framework of the k{sub T}-factorization QCD approach. The proposed method is based on the O({alpha}{sup 2}{alpha}{sub s}) amplitudes for {gamma}q{yields}{gamma}gq and {gamma}g{sup *}{yields}{gamma}q anti q partonic subprocesses. Additionally, we take into account the O({alpha}{sup 2}{alpha}{sub s}{sup 2}) box contributions {gamma}g{yields}{gamma}g to the production cross sections. The unintegrated (or transverse momentum dependent) parton densities in the proton are determined using Kimber-Martin-Ryskin (KMR) prescription. Our consideration covers both inclusive and jet associated prompt photon photoproduction rates. We find that our numerical predictions agree well with the recent data taken by H1 and ZEUS collaborations at HERA. We demonstrate that the box contributions are sizeable and amount up to {proportional_to}15% of the calculated total cross section.

  6. Study of elastic ρ0 photoproduction at HERA using the ZEUS leading proton spectrometer

    International Nuclear Information System (INIS)

    Derrick, M.; Krakauer, D.; Magil, S.

    1996-08-01

    The differential cross section dσ/dt for elastic ρ 0 photoproduction, γp→ρ 0 p(ρ 0 →π + π - ), has been measured in ep interactions at HERA. The squared four-momentum exchanged at the proton vertex, t, has been determined directly by measuring the momentum of the scattered proton using the ZEUS leading proton spectrometer (LPS), a large scale system of silicon micro-strip detectors operating close to the HERA proton beam. The LPS allows the measurement of the momentum of high energy protons scattered at small angles with accuracies of 0.4% for the longitudinal momentum and 5 MeV for the transverse momentum. Photoproduction of ρ 0 mesons has been investigated in the interval 0.073 2 , for photon virtualities q 2 2 and photon-proton centre-of-mass energies between 50 and 100 GeV. In the measured range, the t distribution exhibits an exponential shape with a slope parameter b=9.8±0.8(stat.)±1.1(syst.) GeV -2 . The use of the LPS eliminates the contamination from events with diffractive dissociation of the proton into low mass states. (orig.)

  7. 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