Discovery of omega meson, first neutral vector meson

International Nuclear Information System (INIS)

Anon.

1976-01-01

A personal account of the discovery of the ω meson is given by researcher B. Maglich. His account includes such topics as early and unsuccessful searches for a neutral vector meson (by himself and others), eventual discovery of the rho meson, the Goldhaber effect, and the observation and characterization of the ω meson. Explanatory physics notes on electromagnetic structure experiments and the determination of the quantum numbers of the ω meson are provided for nonspecialists. Also included are an outline of the relation between vector mesons and nuclear forces, a reprint of the Physical Review Letter on Evidence for a T = 0 three-pion resonance, and a scientific autobiography of the researcher. 14 figures, 1 table

Disparity, decimation and the Cambrian "explosion": comparison of early Cambrian and Present faunal communities with emphasis on velvet worms (Onychophora

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Julián Monge-Nájera

2000-06-01

Full Text Available The controversy about a Cambrian "explosion" of morphological disparity (followed by decimation, cladogenesis and fossilization is of central importance for the history of life. This paper revisits the controversy (with emphasis in onychophorans, which include emblematic organisms such as Hallucigenia, presents new data about the Chengjiang (Cambrian of China faunal community and compares it and the Burgess Shale (Cambrian of Canada with an ecologically similar but modern tropical marine site where onychophorans are absent, and with a modern neotropical terrestrial onychophoran community. Biovolume was estimated from material collected in Costa Rica and morphometric measurements were made on enlarged images of fossils. Cambrian tropical mudflats were characterized by the adaptive radiation of two contrasting groups: the vagile arthropods and the sessile poriferans. Arthropods were later replaced as the dominant benthic taxon by polychaetes. Vagility and the exoskeleton may explain the success of arthropods from the Cambrian to the modern marine and terrestrial communities, both in population and biovolume. Food ecological displacement was apparent in the B. Shale, but not in Chengjiang or the terrestrial community. When only hard parts were preserved, marine and terrestrial fossil deposits of tropical origin are even less representative than deposits produced by temperate taxa, Chengjiang being an exception. Nutrient limitations might explain why deposit feeding is less important in terrestrial onychophoran communities, where carnivory, scavenging and omnivory (associated with high motility and life over the substrate became more important. Fossil morphometry supports the interpretation of "lobopod animals" as onychophorans, whose abundance in Chengjiang was equal to their abundance in modern communities. The extinction of marine onychophorans may reflect domination of the infaunal habitat by polychaetes. We conclude that (1 a mature ecological

Modern optics in exceptionally preserved eyes of Early Cambrian arthropods from Australia

Science.gov (United States)

Lee, Michael S. Y.; Jago, James B.; García-Bellido, Diego C.; Edgecombe, Gregory D.; Gehling, James G.; Paterson, John R.

2011-06-01

Despite the status of the eye as an ``organ of extreme perfection'', theory suggests that complex eyes can evolve very rapidly. The fossil record has, until now, been inadequate in providing insight into the early evolution of eyes during the initial radiation of many animal groups known as the Cambrian explosion. This is surprising because Cambrian Burgess-Shale-type deposits are replete with exquisitely preserved animals, especially arthropods, that possess eyes. However, with the exception of biomineralized trilobite eyes, virtually nothing is known about the details of their optical design. Here we report exceptionally preserved fossil eyes from the Early Cambrian (~515 million years ago) Emu Bay Shale of South Australia, revealing that some of the earliest arthropods possessed highly advanced compound eyes, each with over 3,000 large ommatidial lenses and a specialized `bright zone'. These are the oldest non-biomineralized eyes known in such detail, with preservation quality exceeding that found in the Burgess Shale and Chengjiang deposits. Non-biomineralized eyes of similar complexity are otherwise unknown until about 85 million years later. The arrangement and size of the lenses indicate that these eyes belonged to an active predator that was capable of seeing in low light. The eyes are more complex than those known from contemporaneous trilobites and are as advanced as those of many living forms. They provide further evidence that the Cambrian explosion involved rapid innovation in fine-scale anatomy as well as gross morphology, and are consistent with the concept that the development of advanced vision helped to drive this great evolutionary event.

In-medium QCD sum rules for {omega} meson, nucleon and D meson

Energy Technology Data Exchange (ETDEWEB)

Thomas, Ronny

2008-07-01

The modifications of hadronic properties caused by an ambient nuclear medium are investigated within the scope of QCD sum rules. This is exemplified for the cases of the {omega} meson, the nucleon and the D meson. By virtue of the sum rules, integrated spectral densities of these hadrons are linked to properties of the QCD ground state, quantified in condensates. For the cases of the {omega} meson and the nucleon it is discussed how the sum rules allow a restriction of the parameter range of poorly known four-quark condensates by a comparison of experimental and theoretical knowledge. The catalog of independent four-quark condensates is covered and relations among these condensates are revealed. The behavior of four-quark condensates under the chiral symmetry group and the relation to order parameters of spontaneous chiral symmetry breaking are outlined. In this respect, also the QCD condensates appearing in differences of sum rules of chiral partners are investigated. Finally, the effects of an ambient nuclear medium on the D meson are discussed and relevant condensates are identified. (orig.)

Meson-meson scattering in lattice QED2+1

International Nuclear Information System (INIS)

Fiebig, H.R.; Woloshyn, R.M.

1993-01-01

Scattering phase shifts of a meson-meson system in staggered 3-dimensional lattice QED are computed. The main task of the simulation is to obtain a discrete set of two-body energy levels. These are extracted from a 4-point time correlation matrix and then used to obtain scattering phase shifts. The results for the l = 0 and l = 2 partial waves are consistent with short-range repulsion and intermediate-range attraction of the residual meson-meson interaction. (orig.)

Meson-nucleus potentials and the search for meson-nucleus bound states

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Metag, V.; Nanova, M.; Paryev, E. Ya.

2017-11-01

Recent experiments studying the meson-nucleus interaction to extract meson-nucleus potentials are reviewed. The real part of the potentials quantifies whether the interaction is attractive or repulsive while the imaginary part describes the meson absorption in nuclei. The review is focused on mesons which are sufficiently long-lived to potentially form meson-nucleus quasi-bound states. The presentation is confined to meson production off nuclei in photon-, pion-, proton-, and light-ion induced reactions and heavy-ion collisions at energies near the production threshold. Tools to extract the potential parameters are presented. In most cases, the real part of the potential is determined by comparing measured meson momentum distributions or excitation functions with collision model or transport model calculations. The imaginary part is extracted from transparency ratio measurements. Results on K+ ,K0 ,K- , η ,η‧ , ω, and ϕ mesons are presented and compared with theoretical predictions. The interaction of K+ and K0 mesons with nuclei is found to be weakly repulsive, while the K- , η ,η‧ , ω and ϕ meson-nucleus potentials are attractive, however, with widely different strengths. Because of meson absorption in the nuclear medium the imaginary parts of the meson-nucleus potentials are all negative, again with a large spread. An outlook on planned experiments in the charm sector is given. In view of the determined potential parameters, the criteria and chances for experimentally observing meson-nucleus quasi-bound states are discussed. The most promising candidates appear to be the η and η‧ mesons.

Proterozoic and early Cambrian protists: evidence for accelerating evolutionary tempo

Science.gov (United States)

Knoll, A. H.

1994-01-01

In rocks of late Paleoproterozoic and Mesoproterozoic age (ca. 1700-1000 million years ago), probable eukaryotic microfossils are widespread and well preserved, but assemblage and global diversities are low and turnover is slow. Near the Mesoproterozoic-Neoproterozoic boundary (1000 million years ago), red, green, and chromophytic algae diversified; molecular phylogenies suggest that this was part of a broader radiation of "higher" eukaryotic phyla. Observed diversity levels for protistan microfossils increased significantly at this time, as did turnover rates. Coincident with the Cambrian radiation of marine invertebrates, protistan microfossils again doubled in diversity and rates of turnover increased by an order of magnitude. Evidently, the Cambrian diversification of animals strongly influenced evolutionary rates, within clades already present in marine communities, implying an important role for ecology in fueling a Cambrian explosion that extends across kingdoms.

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.

Stratigraphic significance of Cruziana: New data concerning the Cambrian-Ordovician ichnostratigraphic paradigm

Energy Technology Data Exchange (ETDEWEB)

Magwood, J.P.A.; Pemberton, S.G. (Univ. of Alberta, Edmonton (Canada))

1990-08-01

The classic Cambrian-Ordovician ichnostratigraphic paradigm originally developed in Europe is based on the assumption that Cruziana - ichnofossils presumably produced by trilobites - can be used in much the same way as trilobite body fossils have been used in chronostratigraphy. That these ichnofossils can be found in many otherwise unfossiliferous, shallow-marine siliciclastic deposits has made them extremely valuable as correlation tools. The paradigm has been used to date lower Paleozoic units in eastern Canada and Europe. It has also been used as supporting evidence to show close affinities between (1) eastern North America, Wales, and Spain and (2) Spain, northern Africa, and southern Asia. Ichnospecies indicative of the Lower Ordovician (Tremadocian and Arenigian), according to the paradigm, have been recovered from the Lower Cambrian (Atdabanian) Gog Group, near Lake Louise, Alberta, Canada. This discovery indicates that these ichnospecies cannot be used as global Lower Ordovician index fossils.

Syn-rift unconformities punctuating the lower-middle Cambrian transition in the Atlas Rift, Morocco

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Álvaro, J. Javier; Ezzouhairi, Hassan; Clausen, Sébastien; Ribeiro, M. Luisa; Solá, Rita

2015-04-01

The Cambrian Tamdroust and Bab n'Ali Volcanic Complexes represent two magmatic episodes developed in the latest Ediacaran-Cambrian Atlas Rift of Morocco. Their rifting pulses were accompanied by accumulation of volcanosedimentary edifices (dominated by effusive lava flows in the former and explosive acidic aprons in the latter) associated with active tilting and uplift. Sealing of their peneplaned horst-and-graben palaeotopographies led to the onset of distinct onlapping geometries and angular discordances capping eroded basements ranging from the Ediacaran Ouarzazate Supergroup to the Cambrian Asrir Formation. Previous interpretations of these discordances as pull-apart or compressive events are revised here and reinterpreted in an extensional (rifting) context associated with active volcanism. The record of erosive unconformities, stratigraphic gaps, condensed beds and onlapping patterns across the traditional "lower-middle Cambrian" (or Cambrian Series 2-3) transition of the Atlas Rift must be taken into consideration for global chronostratigraphic correlation based on their trilobite content.

The sedimentological characteristics of microbialites of the Cambrian in the vicinity of Beijing, China

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Yin-Ye Wu

2017-04-01

Full Text Available With oil and gas exploration transferring to deeper and more ancient marine strata, more researches have been conducted about the Meso–Neoproterozoic and Cambrian microbial carbonate rocks by petroleum geologists. The Cambrian deposits experienced the first transgression of the Paleozoic, with shallow marine facies depositing in most areas, which are favorable for different kinds of biological reproduction. The Lower Cambrian in Beijing area is lithologically dominated by purple red shales interbedded with limestones, the Middle Cambrian is mainly composed of thick oolitic limestones, and the Upper Cambrian consists of thin limestones and flat-pebble conglomerates. Two beds of microbial carbonate rocks were discovered in the Cambrian outcrops in the vicinity of Beijing. One is from the Zhangxia Formation of Middle Cambrian, and the other is from the Gushan Formation of Upper Cambrian. The microbialites are characterized by combination of multiple stromatolites forming different bioherms. The bioherms are mostly in oval shape and with different sizes, which are 3–4 m long, and 1–3 m high. The surrounding strata beneath the bioherms are oolitic limestones. A central core of flat-pebble conglomerates occurred within each bioherm. Wavy or columnar stromatolites grow on the basis of flat-pebble conglomerates, with dentate erosional surfaces. The bioherm carbonate rocks are interpreted as products from a deep ramp sedimentary environment where potential oil and gas reservoirs can be found. The analysis of sedimentological characteristics of bioherm carbonate rocks and its lithofacies palaeogeography has significant implication for petroleum exploration. Research on geological record of microbialites is beneficial to investigating the Earth evolution, biodiversity, palaeoenvironment and palaeoclimate change, as well as biological extinction event during geological transitions. It also gives warning to human beings of modern biological crisis.

Early Cambrian oxygen minimum zone-like conditions at Chengjiang

DEFF Research Database (Denmark)

Hammarlund, Emma U.; Gaines, Robert R.; Prokopenko, Maria G.

2017-01-01

in early Cambrian marine settings and the relationship of those conditions to early metazoan ecosystems is still emerging. Here, we report multi-proxy geochemical data from two drill cores through the early Cambrian (Series 2) Yu’anshan Formation of Yunnan, China. Results reveal dynamic water...... oxygen-minimum zones. The oxygenated benthic environments in which the Chengjiang biota thrived were proximal to, but sharply separated from, the open ocean by a persistent anoxic water mass that occupied a portion of the outer shelf. Oxygen depletion in the lower water column developed dynamically...

A review of the Late Cambrian (Furongian) palaeogeography in the western Mediterranean region, NW Gondwana

Science.gov (United States)

Álvaro, J. Javier; Ferretti, Annalisa; González-Gómez, Cristina; Serpagli, Enrico; Tortello, M. Franco; Vecoli, Marco; Vizcaïno, Daniel

2007-11-01

The Cambrian-Ordovician transition of the western Mediterranean region (NW Gondwana) is characterized by the record of major erosive unconformities with gaps that range from a chronostratigraphic stage to a series. The hiatii are diachronous and involved progressively younger strata along the Gondwanan margin, from SW (Morocco) to NE (Montagne Noire). They can be related to development of a multi-stage rifting (further North), currently connected to the opening of the Rheic Ocean, and concomitant erosion on southern rift shoulders. The platforms of this margin of Gondwana occupied temperate-water, mid latitudes and were dominated by siliciclastic sedimentation, while carbonate factories were only episodically active in the Montagne-Noire platform. The Upper Cambrian is devoid of significant gaps in the southern Montagne Noire and the Iberian Chains. There, the sedimentation took place in a transgressive-dominated depositional system, with common offshore deposits and clayey substrates, and was bracketed by two major regressive trends. The Late Cambrian is also associated with the record of volcanic activity ( e.g., in the Cantabrian and Ossa-Morena zones, and the northern Montagne Noire), and widespread development of a tectonic instability that led to the episodic establishment of palaeotopographies and record of slope-related facies associations. Several immigration events are recognized throughout the latest Middle Cambrian, Late Cambrian and Tremadocian. The trilobites show a stepwise replacement of Acado-Baltic-type families ( e.g., the conocoryphid-paradoxidid-solenopleurid assemblage) characterized by: (i) a late Languedocian (latest Middle Cambrian) co-occurrence of Middle Cambrian trilobite families with the first anomocarid, dorypygid and proasaphiscid invaders; (ii) a Late Cambrian immigration replacing previous faunas, composed of trilobites (aphelaspidids, catillicephalids, ceratopygids, damesellids, eulomids, idahoiids, linchakephalids, lisariids

Early Cambrian pentamerous cubozoan embryos from South China.

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Jian Han

Full Text Available BACKGROUND: Extant cubozoans are voracious predators characterized by their square shape, four evenly spaced outstretched tentacles and well-developed eyes. A few cubozoan fossils are known from the Middle Cambrian Marjum Formation of Utah and the well-known Carboniferous Mazon Creek Formation of Illinois. Undisputed cubozoan fossils were previously unknown from the early Cambrian; by that time probably all representatives of the living marine phyla, especially those of basal animals, should have evolved. METHODS: Microscopic fossils were recovered from a phosphatic limestone in the Lower Cambrian Kuanchuanpu Formation of South China using traditional acetic-acid maceration. Seven of the pre-hatched pentamerous cubozoan embryos, each of which bears five pairs of subumbrellar tentacle buds, were analyzed in detail through computed microtomography (Micro-CT and scanning electron microscopy (SEM without coating. RESULTS: The figured microscopic fossils are unequivocal pre-hatching embryos based on their spherical fertilization envelope and the enclosed soft-tissue that has preserved key anatomical features arranged in perfect pentaradial symmetry, allowing detailed comparison with modern cnidarians, especially medusozoans. A combination of features, such as the claustrum, gonad-lamella, suspensorium and velarium suspended by the frenula, occur exclusively in the gastrovascular system of extant cubozoans, indicating a cubozoan affinity for these fossils. Additionally, the interior anatomy of these embryonic cubozoan fossils unprecedentedly exhibits the development of many new septum-derived lamellae and well-partitioned gastric pockets unknown in living cubozoans, implying that ancestral cubozoans had already evolved highly specialized structures displaying unexpected complexity at the dawn of the Cambrian. The well-developed endodermic lamellae and gastric pockets developed in the late embryonic stages of these cubozoan fossils are comparable with

Moulting in the lobopodian Onychodictyon from the lower Cambrian of Greenland

DEFF Research Database (Denmark)

Topper, Timothy Paul; Skovsted, Christian B.; Peel, John S.

2013-01-01

A number of lobopodian taxa from the Cambrian display pairs of sclerotized plates symmetrically positioned along the dorsum of the animal, predominantly above the walking appendages. Most genera were described from complete body fossils exquisitely preserved in the famous Cambrian Lagerstatten, b...

Tetraquarks in the 1/N expansion and meson-meson resonances

Energy Technology Data Exchange (ETDEWEB)

Maiani, L. [Dipartimento di Fisica and INFN, ‘Sapienza’ Università di Roma, P.le Aldo Moro 5, I-00185 Roma (Italy); Polosa, A.D. [Dipartimento di Fisica and INFN, ‘Sapienza’ Università di Roma, P.le Aldo Moro 5, I-00185 Roma (Italy); CERN Theory Department, CH-1211 Geneva 23 (Switzerland); Riquer, V. [Dipartimento di Fisica and INFN, ‘Sapienza’ Università di Roma, P.le Aldo Moro 5, I-00185 Roma (Italy)

2016-06-27

Diquarks are found to have the right degrees of freedom to describe the tetraquark poles in hidden-charm to open-charm meson-meson amplitudes. Compact tetraquarks result as intermediate states in non-planar diagrams of the 1/N expansion and the corresponding resonances are narrower than what estimated before. The proximity of tetraquarks to meson-thresholds has an apparent role in this analysis and, in the language of meson molecules, an halving rule in the counting of states is obtained.

Tetraquarks in the 1/N expansion and meson-meson resonances

International Nuclear Information System (INIS)

Maiani, L.; Polosa, A.D.; Riquer, V.

2016-01-01

Diquarks are found to have the right degrees of freedom to describe the tetraquark poles in hidden-charm to open-charm meson-meson amplitudes. Compact tetraquarks result as intermediate states in non-planar diagrams of the 1/N expansion and the corresponding resonances are narrower than what estimated before. The proximity of tetraquarks to meson-thresholds has an apparent role in this analysis and, in the language of meson molecules, an halving rule in the counting of states is obtained.

Early Cambrian sipunculan worms from southwest China.

Science.gov (United States)

Huang, Di-Ying; Chen, Jun-Yuan; Vannier, Jean; Saiz Salinas, J I

2004-08-22

We report the discovery of sipunculan worms from the Lower Cambrian Maotianshan Shale, near Kunming (southwest China). Their sipunculan identity is evidenced by the general morphology of the animals (sausage-shaped body with a slender retractable introvert and a wider trunk) and by other features, both external (e.g. perioral crown of tentacles, and hooks, papillae and wrinkle rings on the body surface) and internal (U-shaped gut, and the anus opening near the introvert-trunk junction). The three fossil forms (Archaeogolfingia caudata gen. et sp. nov., Cambrosipunculus tentaculatus gen. et sp. nov. and Cambrosipunculus sp.) have striking similarities to modern sipunculans, especially the Golfingiidae to which their evolutionary relationships are discussed. This study suggests that most typical features of extant sipunculans have undergone only limited changes since the Early Cambrian, thus indicating a possible evolutionary stasis over the past 520 Myr.

Relationship between the Neoproterozoic snowball Earth and Cambrian explosion

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Maruyama, S.; Yoshihara, A.; Isozaki, Y.

2007-12-01

Origin of snowball Earth has been debated in terms of greenhouse gas (e.g., Hoffman and Schrag), obliqueness of Earth's rotation axis (Williams, 1975), true polar wander (Evans, 2003), Galactic cosmic ray radiation (Shaviv and Veizer, 2003; Svensmark, 2006), or weakened geomagnetism (Maruyama and Yoshihara, 2003). A major difficulty for the greenhouse gas hypothesis is the on-off switch causing decrease and increase of appropriate amounts of CO2 by plume- and plate tectonics, and also in available amount of CO2 in atmosphere to be consistent with the observations. In contrast, the cosmic ray radiation models due to the star burst peaked at 2.5- 2.1 Ga and 1.4-0.8 Ga can explain on-off switch more easily than the greenhouse gas model. Cosmic ray radiations, however, must be modified by the geomagnetic intensity, fluctuating 150"% to cause the snowball Earth. Time difference between the Neoproterozoic snowball Earth and Cambrian explosion is as large as 250 millions years, and this refuses their direct close-relationship. Role of frequent mass extinctions, i.e., 8 times during 100 m.y. from 585 Ma to 488 Ma, during the Ediacaran and Cambrian, has been proposed (Zhu et al., 2007). This frequency is one order of magnitude higher compared to that in the post-Ordovician time. Yet, the Cambrian explosion cannot be explained by mass extinction which replaced the vacant niches shortly after the mass extinction and never created a new animal with a new body plan. A new model proposed herein is derived from weakened geomagnetism and resultant extensive cosmic radiation to alter gene and genome for a long period over advancement of low magnetic intensity and cosmic radiations (Svensmark, 2006) from 1.2-0.8Ga. As to the new body plans of animals, it took an appreciably long time to prepare all 34 genometypes before the apparent Cambrian explosion. Geochemically extreme conditions and widened shallow marine environment on continental shelf by the return-flow of sweater into

On the mesonic-exchange currents in the photomesic reactions

International Nuclear Information System (INIS)

Lazard, C.; Maric, Z.; Zivanovic, D.

1979-02-01

The γd→π 0 d reaction is analysed in the framework of the relativistic many-body theory with mesonic degrees of freedom explicitly present. It is shown that the mesonic correlations can be grouped into transition operators containing vertices of some elementary reactions between photon, nucleons and pions. The wave function corrections due to meson exchange currents are included in the transition operators and the S-matrix is obtained with the non relativistic deuteron wave function

Nonleptonic decay of charmed mesons and chiral lagrangians

International Nuclear Information System (INIS)

Kalinovskij, Yu.L.; Pervushin, V.N.

1978-01-01

Nonleptonic decays of charmed mesons in chiral theory are considered. The lagrangian of strong interaction is taken to be invariant under the SU(4)xSU(4) group. Symmetry breaking is chosen according to the (4,4sup(*))+(4sup(*),4) simplest representation of the SU(4)xSU(4) group. The lagrangian of weak interaction is taken in the ''current x current'' form and satisfies exactly the rule probabilities of decays for D and F mesons are compared with available experimental data

Cambrian and ordovician systems around the pacific basin (part 3)

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Teiichi

1987-10-25

This report describes the history of the studies made about old rocks and Cambrian and Ordovician Systems in North America. In last century, development of the Pre-Canbrian stratigraphy and mineral resources was started in Canada, while the New York System was instituted in the middle and east areas of North America, and it was later correlated to the European sequence. Walcott who published many reports including the vental anatomy of trilobites made invaluable contribution on the study of Cambrian geology. The Cambro-Ordovician faunas which distributed in the Appalachian mountains and further westerly beyond the lower Mississipy river were related to the European ones. The systems in the Cordilleran geosyncline was also described. Stratigraphy in the western sites is followed on the Alaskan faunas in the north which were allied to the Siberian faunas and later to the Eastern Asiatic ones. Lastly, Circum-Pacific Cambro-Ordovician belt was taken up. The eastern side of the Circum-Pacific Cambrian belt belonged to Olenellian province, and the other side constituted the Redlichia province. (2 figs, 5 tabs, 101 refs)

Life cycle and morphology of a cambrian stem-lineage loriciferan.

Science.gov (United States)

Peel, John S; Stein, Martin; Kristensen, Reinhardt Møbjerg

2013-01-01

Cycloneuralians form a rich and diverse element within Cambrian assemblages of exceptionally preserved fossils. Most resemble priapulid worms whereas other Cycloneuralia (Nematoda, Nematomorpha, Kinorhyncha, Loricifera), well known at the present day, have little or no fossil record. First reports of Sirilorica Peel, 2010 from the lower Cambrian Sirius Passet fauna of North Greenland described a tubular lorica covering the abdomen and part of a well developed introvert with a circlet of 6 grasping denticles near the lorica. The introvert is now known to terminate in a narrow mouth tube, while a conical anal field is also developed. Broad muscular bands between the plates in the lorica indicate that it was capable of movement by rhythmic expansion and contraction of the lorica. Sirilorica is regarded as a macrobenthic member of the stem-lineage of the miniaturised, interstitial, present day Loricifera. Like loriciferans, Sirilorica is now known to have grown by moulting. Evidence of the life cycle of Sirilorica is described, including a large post-larval stage and probably an initial larva similar to that of the middle Cambrian fossil Orstenoloricusshergoldii.

Life cycle and morphology of a cambrian stem-lineage loriciferan.

Directory of Open Access Journals (Sweden)

John S Peel

Full Text Available Cycloneuralians form a rich and diverse element within Cambrian assemblages of exceptionally preserved fossils. Most resemble priapulid worms whereas other Cycloneuralia (Nematoda, Nematomorpha, Kinorhyncha, Loricifera, well known at the present day, have little or no fossil record. First reports of Sirilorica Peel, 2010 from the lower Cambrian Sirius Passet fauna of North Greenland described a tubular lorica covering the abdomen and part of a well developed introvert with a circlet of 6 grasping denticles near the lorica. The introvert is now known to terminate in a narrow mouth tube, while a conical anal field is also developed. Broad muscular bands between the plates in the lorica indicate that it was capable of movement by rhythmic expansion and contraction of the lorica. Sirilorica is regarded as a macrobenthic member of the stem-lineage of the miniaturised, interstitial, present day Loricifera. Like loriciferans, Sirilorica is now known to have grown by moulting. Evidence of the life cycle of Sirilorica is described, including a large post-larval stage and probably an initial larva similar to that of the middle Cambrian fossil Orstenoloricusshergoldii.

Arthropod eyes: The early Cambrian fossil record and divergent evolution of visual systems.

Science.gov (United States)

Strausfeld, Nicholas J; Ma, Xiaoya; Edgecombe, Gregory D; Fortey, Richard A; Land, Michael F; Liu, Yu; Cong, Peiyun; Hou, Xianguang

2016-03-01

Four types of eyes serve the visual neuropils of extant arthropods: compound retinas composed of adjacent facets; a visual surface populated by spaced eyelets; a smooth transparent cuticle providing inwardly directed lens cylinders; and single-lens eyes. The first type is a characteristic of pancrustaceans, the eyes of which comprise lenses arranged as hexagonal or rectilinear arrays, each lens crowning 8-9 photoreceptor neurons. Except for Scutigeromorpha, the second type typifies Myriapoda whose relatively large eyelets surmount numerous photoreceptive rhabdoms stacked together as tiers. Scutigeromorph eyes are facetted, each lens crowning some dozen photoreceptor neurons of a modified apposition-type eye. Extant chelicerate eyes are single-lensed except in xiphosurans, whose lateral eyes comprise a cuticle with a smooth outer surface and an inner one providing regular arrays of lens cylinders. This account discusses whether these disparate eye types speak for or against divergence from one ancestral eye type. Previous considerations of eye evolution, focusing on the eyes of trilobites and on facet proliferation in xiphosurans and myriapods, have proposed that the mode of development of eyes in those taxa is distinct from that of pancrustaceans and is the plesiomorphic condition from which facetted eyes have evolved. But the recent discovery of enormous regularly facetted compound eyes belonging to early Cambrian radiodontans suggests that high-resolution facetted eyes with superior optics may be the ground pattern organization for arthropods, predating the evolution of arthrodization and jointed post-protocerebral appendages. Here we provide evidence that compound eye organization in stem-group euarthropods of the Cambrian can be understood in terms of eye morphologies diverging from this ancestral radiodontan-type ground pattern. We show that in certain Cambrian groups apposition eyes relate to fixed or mobile eyestalks, whereas other groups reveal concomitant

Vector-meson dominance revisited

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Terschlüsen Carla

2012-12-01

Full Text Available The interaction of mesons with electromagnetism is often well described by the concept of vector-meson dominance (VMD. However, there are also examples where VMD fails. A simple chiral Lagrangian for pions, rho and omega mesons is presented which can account for the respective agreement and disagreement between VMD and phenomenology in the sector of light mesons.

The strata and palaeo-geomorphology framework at the end of neoproterozoic and development mode of source rocks at the beginning of Cambrian in Tarim Basin, China

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Xin Yang

2017-12-01

Full Text Available Referred to the new recognition from petroleum exploration of the Sinian to Cambrian in South China, it could be considered that the distribution of the early Cambrian source rocks was controlled by the palaeo-geomorphology at the end of Neoproterozoic in the Tarim Basin. Based on the zircon U-Pb dating of pyroclastic rock samples from the clastic rock stratum under the bottom of Cambrian carbonate rocks, the stratigraphic correlation of the Sinian to Cambrian was conducted to build the palaeo-geomorphology framework at the end of Neoproterozoic in Tarim Basin. Lastly, according to the development mode of source rocks at the beginning of Cambrian, the distribution of source rocks was predicted initially through the division of seismic facies. The youngest zircon concordia age of pyroclastic rocks from the bottom of well Tong 1 is 707±8Ma. It was revealed by the strata framework of the Sinian to Cambrian, the palaeo-geomorphology at the end of Neoproterozoic in Tarim Basin was characterized by an uplift highland in Bachu-Tazhong area, the south north high-low, and the west is higher than the east. The distribution of source rocks in the bottom of the Cambrian on the palaeo-platform and slopes was coincident with the Upper Sinian dolomite basically. But the contemporaneous sediment happened to be absent or changed in sedimentary facies on the uplift and its edges. From the seismic facies of the strata under the bottom of Cambrian, it could be concluded that source rocks in the type of the Xishanbraque Group (∈1xs was limited in the Manjiaer Depression, while the source rocks in the type of the Yuertusi Group (∈1y are widely distributed in south of Tabei Uplift, east Awat Depression, and even the Maigt Slope. However, among the west Awat Depression and western Tanguzibasi Depression, and the middle area of the Bachu-Tazhong Uplifts, the contemporaneous source rocks may have changed into sedimentary facies of tidal flat and lagoon, instead of

Antarctica, supercontinents and the palaeogeography of the Cambrian 'explosion'

Science.gov (United States)

Dalziel, Ian

2014-05-01

Laurentia is bordered by latest Precambrian-Cambrian rifted margins and must therefore have been located within a Precambrian supercontinent. Geochronologic and geochemical evidence indicates that it was attached to parts of the East Antarctic craton within the Rodinian supercontinent in the late Mesoproterozoic. The Mawson craton of Antarctica rifted from the proto-Pacific margin of Laurentia during the Neooproterozoic, colliding with the present 'southern cone' of Laurentia at ~600 Ma along the Shackleton Range suture zone as Gondwana and Laurentia amalgamated to form the ephemeral Pannotia supercontinental assembly at the end of the Precambrian. The abrupt appearance of almost all animal phyla in the fossil record is often colloquially referred to as the Cambrian 'explosion' of life on Earth. It is also named 'Darwin's dilemma,' as he appreciated that this seemingly mysterious event posed a major problem for his theory of evolution by natural selection. It coincided with a time of major marine transgression over all the continents. Although the metazoan 'explosion' is now seen as more protracted than formerly recognized, it is still regarded one of the most critical events in the history of the biosphere. One of the most striking aspects of the earliest Cambrian fossils is geographic differentiation. In particular, the first benthic trilobite faunas on Laurentia, ancestral North America, and the newly amalgamated southern supercontinent of Gondwana are distinctly different. This has led to the suggestion of an unknown vicariant event intervening between an ancestral trilobite clade and higher members that are represented in the fossil record, possibly one related to the breakup of a supercontinent. Igneous rocks along the Panthalassic margin of Gondwana, including South America, southernmost Africa and the Ellsworth-Whitmore crustal block of Antarctica, and along the proto-Appalachian margin of Laurentia indicate that final separation of Laurentia from

Temperature-dependent cross sections for meson-meson nonresonant reactions in hadronic matter

International Nuclear Information System (INIS)

Zhang Yiping; Xu Xiaoming; Ge Huijun

2010-01-01

We present a potential of which the short-distance part is given by one gluon exchange plus perturbative one- and two-loop corrections and of which the large-distance part exhibits a temperature-dependent constant value. The Schroedinger equation with this temperature-dependent potential yields a temperature dependence of the mesonic quark-antiquark relative-motion wave function and of meson masses. The temperature dependence of the potential, the wave function and the meson masses brings about temperature dependence of cross sections for the nonresonant reactions ππ→ρρ for I=2, KK→K*K* for I=1, KK*→K*K* for I=1, πK→ρK* for I=3/2, πK*→ρK* for I=3/2, ρK→ρK* for I=3/2 and πK*→ρK for I=3/2. As the temperature increases, the rise or fall of peak cross sections is determined by the increased radii of initial mesons, the loosened bound states of final mesons, and the total-mass difference of the initial and final mesons. The temperature-dependent cross sections and meson masses are parametrized.

MesonNet Workshop on Meson Transition Form Factors

CERN Document Server

Eidelman, S; Hanhart, C; Kubis, B; Kupsc, A; Leupold, S; Moskal, P; Schadmand, S

2012-01-01

The mini-proceedings of the Workshop on Meson Transition Form Factors held in Cracow from May 29th to 30th, 2012 introduce the meson transition form factor project with special emphasis on the interrelations between the various form factors (on-shell, single off-shell, double off-shell). Short summaries of the talks presented at the workshop follow.

Composite vector mesons and string models

International Nuclear Information System (INIS)

Mandelstam, S.

1985-01-01

The author discusses the general question of gauge mesons in extended supergravities, and whether such theories can produce the gauge mesons corresponding to a group at least as large as SU(3) x SU(2) x U(1). An exciting conjecture in this direction was made a few years ago by previous authors, who suggested that there might be composite SU(8) gauge mesons in a supergravity model known as the N=8 model. Until we have a consistent, renormalizable theory of supergravity we cannot really obtain any indication of the truth or falseness of that conjecture. One form of the Neveu-Schwarz string model has been shown to be a theory of supergravity; it is finite at the one-loop level and probably in any order of perturbation theory. The discussion is within the framework of this model. The author questions whether massive vector mesons can possibly lose their mass due to interactions. Arguments have been given on both sides of this question, and the author believes that this can occur under certain circumstances. Our conclusions is that the FNNS mechanism will create a gauge symmetry in addition to the rigid symmetry

Biofacies evidence for Late Cambrian low-paleolatitude oceans, western United State and central Asia

Energy Technology Data Exchange (ETDEWEB)

Taylor, M.E. (Geological Survey, Denver, CO (United States)); Cook, H.E. (Geological Survey, Menlo Park, CA (United States)); Melnikova, L. (Palaeontological Inst., Moscow (Russian Federation))

1991-02-01

Biofacies that formed on carbonate platform-margin slopes adjacent to an early Paleozoic, low-paleolatitude paleoocean are contained in the Upper Cambrian Swarbrick Formation, Tyby Shale, and Upper Cambrian-lowest Ordovician Hales Limestone of the Hot Creek Range, Nevada, and the Upper Cambrian-lowest Ordovician part of the Shabakty Suite of the Malyi Karatau, southern Kazakhstan. These in-situ limestones formed in platform-margin slope and basin-plain environments. Shoal-water faunal assemblages occur in carbonate-turbidite and debris-flow deposits interbedded with in-situ deeper water assemblages of the submarine-fan facies. Abundant sponge spicules, geographically widespread benthic trilobites, and rare ostracodes occur in some of the in-situ beds. In contrast, the shoal-water platform environments were well oxygenated and contain mainly endemic trilobite assemblages. These biofacies characteristics support an interpretation that Late Cambrian oceans were poorly oxygenated, but not anoxic, below the surface mixing layer and that benthic trilobite faunas were widely distributed in response to the more-or-less continuous deep water, low-oxygen habitats. Elements of the Late Cambrian low-oxygen biofacies are widespread in the Tien Shan structural belt of China and the Soviet Union, in central and eastern China, and along the western margin of early Paleozoic North America. This facies distribution pattern defines the transition from low-paleolatitude, shoal-water carbonate platforms to open oceans which have since been destroyed by pre-Late Ordovician and pre-middle Paleozoic Paleotectonic activity.

The mixing of scalar mesons and the baryon-baryon interaction

International Nuclear Information System (INIS)

Dai, L.R.

2011-01-01

By introducing the mixing of scalar mesons in the chiral SU(3) quark model, we dynamically investigate the baryon-baryon interaction. The hyperon-nucleon and nucleon-nucleon interactions are studied by solving the resonating group method (RGM) equation in a coupled-channel calculation. In our present work, the experimental lightest pseudoscalar π, K, η, η' mesons correspond exactly to the chiral nonet pseudoscalar fields π, K, η, η' in the chiral SU(3) quark model. The η, η' mesons are considered as the mixing of singlet and octet mesons, and the mixing angle θ ps is taken to be -23 . For scalar nonet mesons, we suppose that there exists a correspondence between the experimental lightest scalar f 0 (600), κ, a 0 (980), f 0 (980) mesons and the theoretical scalar nonet σ, κ, σ', ε fields in the chiral SU(3) quark model. For scalar mesons, we consider two different mixing cases: one is the ideal mixing and another is the θ s = 19 mixing. The masses of the σ' and ε mesons are taken to be 980MeV, which are just the masses of the experimental a 0 (980), f 0 (980) mesons. The mass of the σ meson is an adjustable parameter and is decided by fitting the binding energy of the deuteron, the masses of 560MeV and 644MeV are obtained for the ideal mixing and the θ s = 19 mixing, respectively. We find that, in order to reasonably describe the YN interactions, the mass of the κ meson is near 780MeV for the ideal mixing. However, we must enhance the mass of the κ meson for the θ s = 19 mixing, the 1050MeV is favorably used in the present work. The experimental σ and κ scalar mesons are very strange, both have larger widths. Hence, no matter what kind of mixing is considered, all the masses of scalar mesons we used in the present work seem to be consistent with the present PDG information. (orig.)

Decay of the Ds-meson

International Nuclear Information System (INIS)

Duong Van Phi; Duong Anh Duc

1993-08-01

The decay channels of the D s -meson are deduced from a Selection Rule and a Lagrangian, formed on L*O(4) group invariance and on principle of minimal structure. A comparison of the results with experimental data is made. (author). 4 refs

Mesonic effects in nuclear physics

International Nuclear Information System (INIS)

Johnson, M.

1978-01-01

The relation between mesons and nucleons and the properties of nuclear matter, as presently understood, is considered in these lectures. Feynman diagrams, meson theoretical nucleon-nucleon interactions, mesonic components in nuclear wave functions, direct observation of mesonic components in NN scattering above the pion production threshold, nuclear matter theory, and pion condensation are treated. 120 references

A theory of scalar mesons

International Nuclear Information System (INIS)

Hooft, G. t'; Isidori, G.; Maiani, L.; Polosa, A.D.; Riquer, V.

2008-01-01

We discuss the effect of the instanton induced, six-fermion effective Lagrangian on the decays of the lightest scalar mesons in the diquark-antidiquark picture. This addition allows for a remarkably good description of light scalar meson decays. The same effective Lagrangian produces a mixing of the lightest scalars with the positive parity qq-bar states. Comparing with previous work where the qq-bar mesons are identified with the nonet at 1200-1700 MeV, we find that the mixing required to fit the mass spectrum is in good agreement with the instanton coupling obtained from light scalar decays. A coherent picture of scalar mesons as a mixture of tetraquark states (dominating in the lightest mesons) and heavy qq-bar states (dominating in the heavier mesons) emerges

Charmed meson production at LHCb

International Nuclear Information System (INIS)

Müller, Dominik

2016-01-01

Measurements of charm meson production are important tests for QCD predictions and LHCb is uniquely suited to perform these measurements in the forward region. This paper summarises recent charm meson production measurements performed by LHCb of J/ψ and open charm mesons and the associated production of ϒ and open charm mesons. The J/ψ and open charm meson measurements are performed with data recorded in Run 2 of the Large Hadron Collider. With proton-proton collisions at √s = 13 TeV, these open a new regime in which QCD predictions for charm meson production may be precisely tested. Furthermore, ratios of cross-sections at different centre-of-mass energies benefit of cancellation of both experimental and theoretical uncertainties, providing a new sensitive test of the QCD calculations. Measurements of ϒ and open charm meson associated production are performed using √s = 7 TeV and √s = 8 TeV data and constitute the first observation of this production channel.

Oxygen, ecology, and the Cambrian radiation of animals

Science.gov (United States)

Sperling, Erik A.; Frieder, Christina A.; Raman, Akkur V.; Girguis, Peter R.; Levin, Lisa A.; Knoll, Andrew H.

2013-08-01

The Proterozoic-Cambrian transition records the appearance of essentially all animal body plans (phyla), yet to date no single hypothesis adequately explains both the timing of the event and the evident increase in diversity and disparity. Ecological triggers focused on escalatory predator-prey "arms races" can explain the evolutionary pattern but not its timing, whereas environmental triggers, particularly ocean/atmosphere oxygenation, do the reverse. Using modern oxygen minimum zones as an analog for Proterozoic oceans, we explore the effect of low oxygen levels on the feeding ecology of polychaetes, the dominant macrofaunal animals in deep-sea sediments. Here we show that low oxygen is clearly linked to low proportions of carnivores in a community and low diversity of carnivorous taxa, whereas higher oxygen levels support more complex food webs. The recognition of a physiological control on carnivory therefore links environmental triggers and ecological drivers, providing an integrated explanation for both the pattern and timing of Cambrian animal radiation.

Perspective of meson science

International Nuclear Information System (INIS)

Yamazaki, T.; Nagamine, K.

1992-01-01

Unstable particles such as mesons and muons are now used in various research domains of physics, chemistry, engineering, and life sciences. This book is aimed at summarizing the present exploratory activities and giving future perspectives from a very broad scope. It contains 27 contributions in a wide range of subjects, such as μSR studies of superconductivities, magnetism, muon beam and μSr methodology, theoretical accounts of muon hyperfine interactions, muon catalyzed fusion processes, metastable exotic atoms, medical diagnostics, strangeness nuclear physics, mesons in nuclei, meson-related nuclear reactions and structure, and exotic decays of mesons

PROPERTIES OF THE $omega$ MESON

Energy Technology Data Exchange (ETDEWEB)

Shafer, J. B.; Murray, J. J.; Ferro-Luzzi, M.; Huwe, D. O.

1963-06-15

Properties of the omega meson were studied from the reaction K/sup -/ + p yields LAMBDA + omega in a 72-in. hydrogen bubble chamber. The momentum of the K/sup -/ mesons was 1.2 to 1.75 Bev/c. The mass of the omega meson is found to be 782 Mev with a width, predominated by three-meson( pi ) decay mode, estimated to be less than 4 Mev. Branching ratios for omega -meson decay into pi /sup +/ pi /sup -/ pi /sup o/, pi /sup o/ gamma , pi /sup +/ i/ sup -/, and e/sup +/e/sup -o/ were determined. (R.E.U.)

Cambrian trace fossil Zoophycos from the Czech Republic

Czech Academy of Sciences Publication Activity Database

Doucek, J.; Mikuláš, Radek

2014-01-01

Roč. 65, č. 6 (2014), s. 403-409 ISSN 1335-0552 R&D Projects: GA ČR GA205/09/1521 Institutional support: RVO:67985831 Keywords : Cambrian * Bohemian Massif * Železné hory * ichnology * marine settings * Zoophycos Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.761, year: 2014

The mixing of scalar mesons and the baryon-baryon interaction

Energy Technology Data Exchange (ETDEWEB)

Dai, L.R. [Liaoning Normal University, Department of Physics, Dalian (China)

2011-02-15

By introducing the mixing of scalar mesons in the chiral SU(3) quark model, we dynamically investigate the baryon-baryon interaction. The hyperon-nucleon and nucleon-nucleon interactions are studied by solving the resonating group method (RGM) equation in a coupled-channel calculation. In our present work, the experimental lightest pseudoscalar {pi}, K, {eta}, {eta}' mesons correspond exactly to the chiral nonet pseudoscalar fields {pi}, K, {eta}, {eta}' in the chiral SU(3) quark model. The {eta}, {eta}' mesons are considered as the mixing of singlet and octet mesons, and the mixing angle {theta}{sub ps} is taken to be -23 . For scalar nonet mesons, we suppose that there exists a correspondence between the experimental lightest scalar f{sub 0}(600), {kappa}, a{sub 0}(980), f{sub 0}(980) mesons and the theoretical scalar nonet {sigma}, {kappa}, {sigma}', {epsilon} fields in the chiral SU(3) quark model. For scalar mesons, we consider two different mixing cases: one is the ideal mixing and another is the {theta}{sub s} = 19 mixing. The masses of the {sigma}' and {epsilon} mesons are taken to be 980MeV, which are just the masses of the experimental a{sub 0}(980), f{sub 0}(980) mesons. The mass of the {sigma} meson is an adjustable parameter and is decided by fitting the binding energy of the deuteron, the masses of 560MeV and 644MeV are obtained for the ideal mixing and the {theta}{sub s} = 19 mixing, respectively. We find that, in order to reasonably describe the YN interactions, the mass of the {kappa} meson is near 780MeV for the ideal mixing. However, we must enhance the mass of the {kappa} meson for the {theta}{sub s} = 19 mixing, the 1050MeV is favorably used in the present work. The experimental {sigma} and {kappa} scalar mesons are very strange, both have larger widths. Hence, no matter what kind of mixing is considered, all the masses of scalar mesons we used in the present work seem to be consistent with the present PDG information

Proposal for the systematic naming of mesons and baryons

International Nuclear Information System (INIS)

Porter, F.C.; Hernandez, J.J.; Montanet, L.

1984-10-01

Twenty years ago, the Particle Data Group adopted a systematic naming convention for baryons: the symbols N, Δ, Λ, Σ, Ψ, and Ω were to identify the isospin and strangeness, The mesons, by contrast, have become an alphabet soup of uninformative names - theta, iota, xi, zeta, g/sub T/, g/sub s/, H, E, delta, h, g, r, kappa, etc. -, and in some cases identical names are used for mesons with different quantum numbers (A, B, and D). Furthermore, experimentalists are now discovering baryons that contain heavy quarks. It is therefore timely to consider systematic naming conventions both for mesons and for baryons with heavy quarks. The Particle Data Group is circulating this proposal in the hope of generating feedback, and we attach a sheet for responses. It should be emphasized that the Particle Tables would show both the old and new names for some time

Evolution of oceanic molybdenum and uranium reservoir size around the Ediacaran-Cambrian transition: Evidence from western Zhejiang, South China

Science.gov (United States)

Xiang, Lei; Schoepfer, Shane D.; Shen, Shu-zhong; Cao, Chang-qun; Zhang, Hua

2017-04-01

The "Cambrian explosion" is one of the most fascinating episodes of diversification in the history of life; however, its relationship to the oxygenation of the oceans and atmosphere around the Ediacaran-Cambrian transition is not fully understood. Marine inventories of redox-sensitive trace elements reflect the relative balance of oxidative weathering on land and deposition in anoxic water masses, and can be used to explore the evolution of oceanic and atmospheric redox conditions. For this study, we conducted a series of geochemical analyses on the upper Lantian, Piyuancun, and Hetang formations in the Chunye-1 well, part of the lower Yangtze Block in western Zhejiang. Iron speciation results indicate that the entire studied interval was deposited under anoxic conditions, with three intervals of persistent euxinia occurring in the uppermost Lantian Fm., the lower Hetang Formation (Fm.), and the upper Hetang Fm. Molybdenum (Mo) and uranium (U) contents and Mo/TOC and U/TOC ratios from the anoxic/euxinic intervals of the Chunye-1 well, combined with published data from the sections in the middle and upper Yangtze Block, suggest that the oceanic Mo reservoir declined consistently from the Ediacaran to Cambrian Stage 3, while the size of the oceanic U reservoir remained relatively constant. Both metals were depleted in the ocean in lower Cambrian Stage 4, before increasing markedly at the end of Stage 4. The lack of an apparent increase in the size of the marine Mo and U reservoir from the upper Ediacaran to Cambrian Stage 3 suggests that oxic water masses did not expand until Cambrian Stage 4. The increase in marine Mo and U availability in the upper Hetang Fm. may have been due to the expansion of oxic water masses in the oceans, associated with oxygenation of the atmosphere during Cambrian Stage 4. This expansion of oxic waters in the global ocean postdates the main phase of Cambrian diversification, suggesting that pervasive oxygenation of the ocean on a large

Syn-rift unconformities punctuating the lower-middle Cambrian transition in the Atlas Rift, Morocco

OpenAIRE

Álvaro, J. Javier; Ezzouhairi, Hassan; Clausen, Sébastien; Ribeiro, Maria Luísa; Solá, Ana Rita

2015-01-01

The Cambrian Tamdroust and Bab n’Ali Volcanic Complexes represent two magmatic episodes developed in the latest Ediacaran–Cambrian Atlas Rift of Morocco. Their rifting pulses were accompanied by accumulation of volcanosedimentary edifices (dominated by effusive lava flows in the former and explosive acidic aprons in the latter) associated with active tilting and uplift. Sealing of their peneplaned horst-and-graben palaeotopographies led to the onset of distinct onlapping geometrie...

Issues in light meson spectroscopy: The case for meson spectroscopy at CEBAF

Energy Technology Data Exchange (ETDEWEB)

Godfrey, S. [Carleton Univ., Ottawa (Canada)

1994-04-01

The author reviews some outstanding issues in meson spectroscopy. The most important qualitative issue is whether hadrons with explicit gluonic degrees of freedom exist. To answer this question requires a much better understanding of conventional q{bar q} mesons. The author therefore begins by examining the status of conventional meson spectroscopy and how the situation can be improved. The expected properties of gluonic excitations are discussed with particular emphasis on hybrids to give guidance to experimental searches. Multiquark systems are commented upon as they are likely to be important in the mass region under study and will have to be understood better. In the final section the author discusses the opportunities that CEBAF can offer for the study of meson spectroscopy.

Delocalized SYZ mirrors and confronting top-down SU(3)-structure holographic meson masses at finite g and Nc with P(article) D(ata) G(roup) values

International Nuclear Information System (INIS)

Yadav, Vikas; Sil, Karunava; Misra, Aalok

2017-01-01

Meson spectroscopy at finite gauge coupling - whereat any perturbative QCD computation would break down - and finite number of colors, from a top-down holographic string model, has thus far been entirely missing in the literature. This paper fills this gap. Using the delocalized type IIA SYZ mirror (with SU(3) structure) of the holographic type IIB dual of large-N thermal QCD of Mia et al. (Nucl Phys B 839:187. arXiv:0902.1540 [hep-th], 2010) as constructed in Dhuria and Misra (JHEP 1311:001. arXiv:1306.4339 [hep-th], 2013) at finite coupling and number of colors (N c = number of D5(D5)-branes wrapping a vanishing two-cycle in the top-down holographic construct of Mia et al. (Nucl Phys B 839:187. arXiv:0902.1540 [hep-th], 2010) = O(1) in the IR in the MQGP limit of Dhuria and Misra (JHEP 1311:001. arXiv:1306.4339 [hep-th], 2013) at the end of a Seiberg-duality cascade), we obtain analytical (not just numerical) expressions for the vector and scalar meson spectra and compare our results with previous calculations of Sakai and Sugimoto (Prog Theor Phys 113:843. doi:10.1143/PTP.113.843 arXiv:hep-th/0412141, 2005) and Dasgupta et al. (JHEP 1507:122. doi:10.1007/JHEP07(2015)122 arXiv:1409.0559 [hep-th], 2015), and we obtain a closer match with the Particle Data Group (PDG) results of Olive et al. (Particle Data Group) (Chin Phys C 38:090001, 2014). Through explicit computations, we verify that the vector and scalar meson spectra obtained by the gravity dual with a black hole for all temperatures (small and large) are nearly isospectral with the spectra obtained by a thermal gravity dual valid for only low temperatures; the isospectrality is much closer for vector mesons than scalar mesons. The black-hole gravity dual (with a horizon radius smaller than the deconfinement scale) also provides the expected large-N suppressed decrease in vector meson mass with increase of temperature. (orig.)

Cambrian Evolutionary Radiation: Context, correlation, and chronostratigraphy—Overcoming deficiencies of the first appearance datum (FAD) concept

Science.gov (United States)

Landing, Ed; Geyer, Gerd; Brasier, Martin D.; Bowring, Samuel A.

2013-08-01

Use of the first appearance datum (FAD) of a fossil to define a global chronostratigraphic unit's base can lead to intractable correlation and stability problems. FADs are diachronous—they reflect species' evolutionary history, dispersal, biofacies, preservation, collection, and taxonomy. The Cambrian Evolutionary Radiation is characterised by diachronous FADs, biofacies controls, and provincialism of taxa and ecological communities that confound a stable Lower Cambrian chronostratigraphy. Cambrian series and stage definitions require greater attention to assemblage zone successions and non-biostratigraphic, particularly carbon isotope, correlation techniques such as those that define the Ediacaran System base. A redefined, basal Cambrian Trichophycus pedum Assemblage Zone lies above the highest Ediacaran-type biotas (vendobionts, putative metazoans, and calcareous problematica such as Cloudina) and the basal Asteridium tornatum-Comasphaeridium velvetum Zone (acritarchs). This definition and the likely close correspondence of evolutionary origin and local FAD of T. pedum preserves the Fortune Head, Newfoundland, GSSP of the Cambrian base and allows the presence of sub-Cambrian, branched ichnofossils. The sub-Tommotian-equivalent base of Stage 2 (a suggested "Laolinian Stage") should be defined by the I'/L4/ZHUCE δ13C positive peak, bracketed by the lower ranges of Watsonella crosbyi and Aldanella attleborensis (molluscs) and the Skiagia ornata-Fimbrioglomerella membranacea Zone (acritarchs). The W. crosbyi and A. attleborensis FADs cannot define a Stage 2 base as they are diachronous even in the Newfoundland "type" W. crosbyi Zone. The Series 2 base cannot be based on a species' FAD owing to the provincialism of skeletalised metazoans in the Terreneuvian-Series 2 boundary interval and global heterochrony of the oldest trilobites. A Series 2 and Stage 3 (a suggested "Lenaldanian Series" and "Zhurinskyan Stage," new) GSSP base is proposed at the Siberian lower

Chiral Quark-Meson model of N and DELTA with vector mesons

International Nuclear Information System (INIS)

Broniowski, W.; Banerjee, M.K.

1985-10-01

Vector mesons rho, A 1 and ω are introduced in the Chiral Quark-Meson Theory (CQMT) of N and Δ. We propose a new viewpoint for developing CQMT from QCD at the mean-field level. The SU(2) x SU(2) chiral Lagrangian incorporates universal coupling. Accordingly, rho is coupled to the conserved isospin current, A to the partially conserved axial-vector current (PCAC), and ω to the conserved baryon current. As a result the only parameter of the model not directly related to experiment is the quark-pion coupling constant. A fully self-consistent mean-field solution to the model is found for fields in the hedgehog ansatz. The vector mesons play a very important role in the system. They contribute significantly to the values of observables and produce a high-quality fit to many data. The classical stability of the system with respect to hedgehog excitations is analyzed through the use of the Quark-Meson RPA equations (QMRPA)

The Lower Cambrian of Scandinavia: Depositional environment, sequence stratigraphy and palaeogeography

Science.gov (United States)

Nielsen, Arne Thorshøj; Schovsbo, Niels Hemmingsen

2011-08-01

Lower Cambrian successions described from Scandinavia are reviewed and subjected to sequence stratigraphical analysis; comparisons are also made with successions described from northeast Poland, Estonia, Latvia and Lithuania. The treated stratigraphic interval is bounded upwards by a regional unconformity ascribed to the Hawke Bay Event. The East European regional stage classification, comprising the Rovnian, Lontovan, Dominopolian, Ljubomlian, Vergalian, Rausvian and Kibartian, is adopted for the Lower Cambrian of Scandinavia. These units are approximately equivalent to the Terreneuvian and Cambrian provisional series 2. The Rovnian and Lontovan stages are pre-trilobitic. The Dominopolian and 'Ljubomlian' stages encompass the ' Rusophycus' and Schmidtiellus mickwitzi zones; whether the former zone is of pre-trilobitic age is uncertain but possible. The 'Ljubomlian' is treated informally because the definition adopted in this paper does not correspond to the original concept of the stage. The Vergalian and Rausvian are for the time being classified as one combined stage. The lower main part of the Vergalian-Rausvian corresponds to the new informal Holmia kjerulfi- 'Ornamentaspis' linnarssoni zone, whereas the upper part is separated as the new informal Comluella?-Ellipsocephalus lunatus zone. This zone also includes the Kibartian Stage. Volborthella and poorly known olenellid trilobites range into the Kibartian and the stage is considered of Early Cambrian age. The Holmia inusitata Zone is abandoned; it is contemporaneous with the traditional ' O.' linnarssoni Zone. The autochthonous strata underlying the Hawke Bay unconformity in the Laisvall sector, Swedish Lapland, are assigned to the Laisberg and Grammajukku formations and it is proposed to abandon the Laisvall and Såvvare formations. The Laisberg Fm can locally be divided into the Ackerselet, Saivatj, Maiva, Kautsky Ore, Tjalek, Nadok Ore and Assjatj members. The Vakkejokk Breccia near Luopakte is likely

Replacement of benthic communities in two Neoproterozoic-Cambrian subtropical-to-temperate rift basins, High Atlas and Anti-Atlas, Morocco

Science.gov (United States)

Clausen, Sébastien; Álvaro, J. Javier; Zamora, Samuel

2014-10-01

The ‘Cambrian explosion’ is often introduced as a major shift in benthic marine communities with a coeval decline of microbial consortia related to the diversification of metazoans and development of bioturbation (‘Agronomic Revolution’). Successive community replacements have been reported along with ecosystem diversification and increase in guild complexity from Neoproterozoic to Cambrian times. This process is recorded worldwide but with regional diachroneities, some of them directly controlled by the geodynamic conditions of sedimentary basins. The southern High Atlas and Anti-Atlas of Morocco record development of two rifts, Tonian (?) - early Cryogenian and latest Ediacarian-Cambrian in age, separated by the onset of the Pan-African Orogeny. This tectonically controlled, regional geodynamic change played a primary control on pattern and timing of benthic ecosystem replacements. Benthic communities include microbial consortia, archaeocyathan-thromboid reefal complexes, chancelloriid-echinoderm-sponge meadows, and deeper offshore echinoderm-dominated communities. Microbial consortia appeared in deeper parts of the Tonian (?) - early Cryogenian fluvio-deltaic progradational rift sequences, lacustrine environments of the Ediacaran Volcanic Atlasic Chain (Ouarzazate Supergroup) and the Ediacaran-Cambrian boundary interval, characterized by the peritidal-dominated Tifnout Member (Adoudou Formation). They persisted and were largely significant until Cambrian Age 3, as previous restricted marine conditions precluded the immigration of shelly metazoans in the relatively shallow epeiric parts of the Cambrian Atlas Rift. Successive Cambrian benthic communities were replaced as a result of distinct hydrodynamic and substrate conditions, which allow identification of biotic (e.g., antagonistic relationships between microbial consortia and echinoderms, and taphonomic feedback patterns in chancelloriid-echinoderm-sponge meadows) and abiotic (e.g., rifting

Exotic hybrid mesons in hard electroproduction

CERN Document Server

Anikin, I V; Szymanowski, L; Teryaev, O V; Wallon, S

2005-01-01

We estimate the sizeable cross section for deep exclusive electroproduction of an exotic $J^{PC}=1^{-+}$ hybrid meson in the Bjorken regime. The production amplitude scales like the one for usual meson electroproduction, i.e. as $1/Q^2$. This is due to the non-vanishing leading twist distribution amplitude for the hybrid meson, which may be normalized thanks to its relation to the energy momentum tensor and to the QCD sum rules technique. The hard amplitude is considered up to next-to-leading order in $\\alpha_{S}$ and we explore the consequences of fixing the renormalization scale ambiguity through the BLM procedure. We study the particular case where the hybrid meson decays through a $\\pi\\eta $ meson pair. We discuss the $\\pi\\eta$ generalized distribution amplitude and then calculate the production amplitude for this process. We propose a forward-backward asymmetry in the production of $\\pi$ and $\\eta$ mesons as a signal for the hybrid meson production. We briefly comment on hybrid electroproduction at very ...

Delocalized SYZ mirrors and confronting top-down SU(3)-structure holographic meson masses at finite g and N_c with P(article) D(ata) G(roup) values

Science.gov (United States)

Yadav, Vikas; Misra, Aalok; Sil, Karunava

2017-10-01

Meson spectroscopy at finite gauge coupling - whereat any perturbative QCD computation would break down - and finite number of colors, from a top-down holographic string model, has thus far been entirely missing in the literature. This paper fills this gap. Using the delocalized type IIA SYZ mirror (with SU(3) structure) of the holographic type IIB dual of large- N thermal QCD of Mia et al. (Nucl Phys B 839:187. arXiv:0902.1540 [hep-th], 2010) as constructed in Dhuria and Misra (JHEP 1311:001. arXiv:1306.4339 [hep-th], 2013) at finite coupling and number of colors (N_c = number of D5(\\overline{D5})-branes wrapping a vanishing two-cycle in the top-down holographic construct of Mia et al. (Nucl Phys B 839:187. arXiv:0902.1540 [hep-th], 2010) = O(1) in the IR in the MQGP limit of Dhuria and Misra (JHEP 1311:001. arXiv:1306.4339 [hep-th], 2013) at the end of a Seiberg-duality cascade), we obtain analytical (not just numerical) expressions for the vector and scalar meson spectra and compare our results with previous calculations of Sakai and Sugimoto (Prog Theor Phys 113:843. doi: 10.1143/PTP.113.843 arXiv:hep-th/0412141, 2005) and Dasgupta et al. (JHEP 1507:122. doi: 10.1007/JHEP07(2015)122 arXiv:1409.0559 [hep-th], 2015), and we obtain a closer match with the Particle Data Group (PDG) results of Olive et al. (Particle Data Group) (Chin Phys C 38:090001, 2014). Through explicit computations, we verify that the vector and scalar meson spectra obtained by the gravity dual with a black hole for all temperatures (small and large) are nearly isospectral with the spectra obtained by a thermal gravity dual valid for only low temperatures; the isospectrality is much closer for vector mesons than scalar mesons. The black-hole gravity dual (with a horizon radius smaller than the deconfinement scale) also provides the expected large- N suppressed decrease in vector meson mass with increase of temperature.

Meson spectroscopy at the Serpukhov accelerator

International Nuclear Information System (INIS)

Prokoshkin, Yu.D.

1987-01-01

At present meson spectroscopy is a dominating direction of experimental studies at the IHEP accelerator. The main attention is paid to the search and study of exotic meson states. This report presents some new results obtained recently at the IHEP accelerator. First, observation is made of a narrow 1750 MeV meson decays into ηη. Above |t| ∼ 0.2 (GeV-c) 2 (t: a square of 4-momentum transferred to a neutron), a clear narrow peak appears in Mηη mass spectrum at a mass of 1750 MeV. Second, 2.22 GeV narrow meson decaying into η'η is described. At present only premature conclusions have been obtained in this area and the situation with ζ is not clear. Third, a study is made on new exotic tensor meson χ(1810) decaying into 4π deg and ηη channels. The decay M deg → 4π deg is a very promissing instrument in search for exotic mesons. Next, G(1590)-meson as a scalar glueball is discussed. BR(G → 4π deg) has a large value, an independent evidence of the exotic nature of G(1590)-meson. Experimental data obtained on all essential decay channels of G(1590)-meson allows to give a selfconsistent description of its production and decay as the scalar glueball, a particle with the dominating gluon component. The final two parts deal with exotic vector meson C(1480) decaying into ψπ deg and observation of D(1285) → ψγ decay. (Nogami, K.)

Spin-zero mesons and current algebras

International Nuclear Information System (INIS)

Wellner, M.

1977-01-01

Large chiral algebras, using the f and d coefficients of SU(3) can be constructed with spin-1/2 baryons. Such algebras have been found useful in some previous investigations. This article examines under what conditions similar or identical current algebras may be realized with spin-0 mesons. A curious lack of analogy emerges between meson and baryon currents. Second-class currents, made of mesons, are required in some algebras. If meson and baryon currents are to satisfy the same extended SU(3) algebra, four meson nonets are needed, in terms of which we give an explicit construction for the currents

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

Deep electroproduction of exotic hybrid mesons

International Nuclear Information System (INIS)

Anikin, I.V.; Pire, B.; Szymanowski, L.; Teryaev, O.V.; Wallon, S.

2004-01-01

We evaluate the leading order amplitude for the deep exclusive electroproduction of an exotic hybrid meson in the Bjorken regime. We show that, contrarily to naive expectation, this amplitude factorizes at the twist 2 level and thus scales like usual meson electroproduction when the virtual photon and the hybrid meson are longitudinally polarized. Exotic hybrid mesons may thus be studied in electroproduction experiments at JLAB, HERA (HERMES) or CERN (Compass)

Exotic hybrid mesons in hard electroproduction

International Nuclear Information System (INIS)

Anikin, I.V.; Pire, B.; Szymanowski, L.; Teryaev, O.V.; Wallon, S.

2005-01-01

We estimate the sizeable cross section for deep exclusive electroproduction of an exotic J PC =1 -+ hybrid meson in the Bjorken regime. The production amplitude scales like the one for usual meson electroproduction, i.e., as 1/Q 2 . This is due to the nonvanishing leading twist distribution amplitude for the hybrid meson, which may be normalized thanks to its relation to the energy-momentum tensor and to the QCD sum rules technique. The hard amplitude is considered up to next-to-leading order in α S and we explore the consequences of fixing the renormalization scale ambiguity through the Brodsky-Lepage-Mackenzie (BLM) procedure. We study the particular case where the hybrid meson decays through a πη meson pair. We discuss the πη generalized distribution amplitude and then calculate the production amplitude for this process. We propose a forward-backward asymmetry in the production of π and η mesons as a signal for the hybrid meson production. We briefly comment on hybrid electroproduction at very high energy, in the diffractive limit where a QCD Odderon exchange mechanism should dominate. The conclusion of our study is that hard electroproduction is a promising way to study exotic hybrid mesons, in particular, at JLAB, HERA (HERMES), or CERN (Compass)

Review of the Cambrian volcanic activity in Morocco: geochemical fingerprints and geotectonic implications for the rifting of West Gondwana

Science.gov (United States)

Pouclet, André; El Hadi, Hassan; Álvaro, J. Javier; Bardintzeff, Jacques-Marie; Benharref, Mohammed; Fekkak, Abdelilah

2018-03-01

Volcanic activities related to the opening of a Cambrian rift in Morocco were widespread from the Fortunian to the Cambrian Epoch 3. Numerous data are available from northwestern volcanic sites, particularly in the western High Atlas, but they are scarce from the southeastern sites. New data are documented here from the volcanic formations exposed in the Jbel Tazoult n'Ouzina of the Tafilalt Province, eastern Anti-Atlas and dated to Cambrian Epoch 2-3. The Cambrian volcanic activities recorded in the High Atlas, Anti-Atlas, and Coastal Meseta are synthesized to refine their stratigraphic setting and to characterize their magmatic affinities and fingerprints. Six volcanic pulses are determined as tholeiitic, transitional, and alkaline suites. The tholeiitic and transitional magmas originated from primitive mantle and E-MORB-type sources with a spinel- and garnet-bearing lherzolite composition. Some of them were modified by assimilation-fractional crystallisation processes during crust-mantle interactions. The alkaline magmas fit with an OIB-type and a garnet-bearing lherzolite source. The palaeogeographic distribution of the magmatic suites was controlled by the lithospheric thinning of the Cambrian Atlas Rift and lithospheric constraints of the Pan-African metacraton and West African craton.

Nature of the light scalar mesons

International Nuclear Information System (INIS)

Vijande, J.; Valcarce, A.; Fernandez, F.; Silvestre-Brac, B.

2005-01-01

Despite the apparent simplicity of meson spectroscopy, light scalar mesons cannot be accommodated in the usual qq structure. We study the description of the scalar mesons below 2 GeV in terms of the mixing of a chiral nonet of tetraquarks with conventional qq states. A strong diquark-antidiquark component is found for several states. The consideration of a glueball as dictated by quenched lattice QCD drives a coherent picture of the isoscalar mesons

Strange mesonic transition form factor

International Nuclear Information System (INIS)

Goity, J.L.; Musolf, M.J.

1996-01-01

The strange-quark vector current ρ-to-π meson transition form factor is computed at one-loop order using strange meson intermediate states. A comparison is made with a φ-meson dominance model estimate. We find that one-loop contributions are comparable in magnitude to those predicted by φ-meson dominance. It is possible that the one-loop contribution can make the matrix element as large as those of the electromagnetic current mediating vector meson radiative decays. However, due to the quadratic dependence of the one-loop results on the hadronic form factor cutoff mass, a large uncertainty in the estimate of the loops is unavoidable. These results indicate that non-nucleonic strange quarks could contribute appreciable in moderate-parallel Q 2 parallel parity-violating electron-nucleus scattering measurements aimed at probing the strange-quark content of the nucleon. copyright 1996 The American Physical Society

Sequence stratigraphy of the Upper Cambrian (Furongian; Jiangshanian and Sunwaptan) Tunnel City Group, Upper Mississippi Valley: Transgressing assumptions of cratonic flooding

Science.gov (United States)

Eoff, Jennifer D.

2014-01-01

New data from detailed measured sections permit comprehensive analysis of the sequence framework of the Furongian (Upper Cambrian; Jiangshanian and Sunwaptan stages) Tunnel City Group (Lone Rock Formation and Mazomanie Formation) of Wisconsin and Minnesota. The sequence-stratigraphic architecture of the lower part of the Sunwaptan Stage at the base of the Tunnel City Group, at the contact between the Wonewoc Formation and Lone Rock Formation, records the first part of complex polyphase flooding (Sauk III) of the Laurentian craton, at a scale smaller than most events recorded by global sea-level curves. Flat-pebble conglomerate and glauconite document transgressive ravinement and development of a condensed section when creation of accommodation exceeded its consumption by sedimentation. Thinly-bedded, fossiliferous sandstone represents the most distal setting during earliest highstand. Subsequent deposition of sandstone characterized by hummocky or trough cross-stratification records progradational pulses of shallower, storm- and wave-dominated environments across the craton before final flooding of Sauk III commenced with carbonate deposition during the middle part of the Sunwaptan Stage. Comparison of early Sunwaptan flooding of the inner Laurentian craton to published interpretations from other parts of North America suggests that Sauk III was not a single, long-term accommodation event as previously proposed.

40Ar/39Ar dating of exceptional concentration of metals by weathering of Precambrian rocks at the Precambrian–Cambrian boundary

DEFF Research Database (Denmark)

Parnell, John; Mark, Darren F.; Frei, Robert

2014-01-01

The sub-Cambrian surface, including diverse metalliferous deposits, shows evidence of intense weathering of Precambrian rocks to form supergene-enriched ores and metalliferous placers, followed by widespread peneplanation. Much of the metal would have been flushed to the Cambrian ocean during...... with mobilization on land of redox sensitive metals by oxidative terrestrial weathering. This unprecedented flushing of metals from the weathered Precambrian surface would have contributed to the chemistry of the earliest Cambrian ocean at a time of marked faunal evolution....

Paleomagnetism of a well-dated marine succession in South China: A possible Late Cambrian true polar wander (TPW)

Science.gov (United States)

Jiao, Wen-Jun; Li, Yong-Xiang; Yang, Zhen-Yu

2018-04-01

The Cambrian true polar wander (TPW) hypothesis remains controversial largely because of the uncertainties in the quality and/or fidelity of the paleomagnetic data as well as their chronological control. Testing the TPW hypothesis requires high-quality paleomagnetic data of sufficient spatial and temporal resolutions. Here, we present paleomagnetic results of a continuous Cambrian shallow marine succession from South China where available detailed biostratigraphy provides exceptional chronological constraints. Forty-three sites of paleomagnetic samples were collected from this limestone-dominated succession. Stepwise thermal demagnetization generally reveals three-component magnetizations. Low- and intermediate-temperature components can be cleaned by ∼330 °C, and the high-temperature component (HTC) was isolated typically from ∼350 to ∼450 °C. A positive fold test and the presence of reversed polarity in the strata, together with rock magnetic data as well as the scanning electron microscopic (SEM) and transmission electron microscopic (TEM) results, collectively suggest that the HTCs are likely primary. A directional shift of the HTCs occurs between the lower-middle Cambrian and the upper Cambrian strata in the succession and is tentatively interpreted to indicate a ∼57° polar wander from ∼500.5 to 494 Ma. Because the rate of polar wander is too fast to be a tectonic origin, this polar wander is interpreted to represent a Late Cambrian TPW. This TPW appears coeval with the Steptoean positive carbon isotope excursion (SPICE) and the major trilobite mass extinctions, suggesting a potential link between the TPW and the Late Cambrian biotic and climatic changes. Because the proposed TPW event is exceptionally well-dated, it should be testable through examination of other worldwide sections.

Meson factories

International Nuclear Information System (INIS)

Dicello, J.F.; Zaider, M.; Bradbury, J.N.

1979-01-01

Technological improvements in accelerator design in the 1960's resulted in the capability to develop medium-energy proton accelerators with beam intensities of almost 1 mA. These beams are able to produce fluxes of secondary particles, including pions, muons, neutrinos, and neutrons, which are as much as 10,000 times as intense as those previously available. Those machines built for optimum meson production are commonly called meson factories. The characteristics of these facilities are reviewed, and the present programs in applied research, and some potential areas of future work are discussed

Phenomenological study of the isovector tensor meson family

Science.gov (United States)

Pang, Cheng-Qun; He, Li-Ping; Liu, Xiang; Matsuki, Takayuki

2014-07-01

In this work, we study all the observed a2 states and group them into the a2 meson family, where their total and two-body Okubo-Zweig-Iizuka allowed strong decay partial widths are calculated via the quark pair creation model. Taking into account the present experimental data, we further give the corresponding phenomenological analysis, which is valuable to test whether each a2 state can be assigned into the a2 meson family. What is more important is that the prediction of their decay behaviors will be helpful for future experimental study of the a2 states.

Workshop on mesons and mesonic states up to slightly above 1 GeV/c2

International Nuclear Information System (INIS)

Oelert, W.; Sefzick, T.

1991-04-01

The new accelerator COSY-Juelich will provide protons with momenta up to 3.3 GeV/c. Thus an effective mass slightly above 1 GeV/c 2 can be produced in the pp-interaction. Employing higher mass targets also heavier mesons can be observed. The production of single mesons and of mesonic states with and without strangeness can be investgated at COSY. The structure of some mesons in the mass range of 950 McV/c 2 to 1020 MeV/c 2 is still not well understood. While the Φ(1020) at the upper limit of this range is believed to be of rahter pure santi s nature the content of the η'(958) meson at the lower limit of this range is still under discussion. New results suggest that what is called the f o meson (former notation S*) consists in reality of two close and narrow states; one of them being a santi s - quarks configuration while the other should be a flavour singlet which couples to ππ and Kanti K with similar strengths. Also the discussion on possible gluonium candidates is still alive. It is speculated that some of these mesons - till now supposed to have widths of 30 to 50 MeV/c 2 - could rather be an overlay of structures with much smaller widths. Another features of resonances in this region is their partial decay into the Kanti K channel if their actual mass is large enough. Strong decays in Kanti K could be a signal of a Kanti K 'molecular' nature of the resonance. In particular the atomic K + K - structure should exist. In order to have review of the physics related to these problems there was a workshop held on: MESONS and MESONIC STATES up to slightly above 1 GeV/c 2 at the ZEL - Forschungszentrum - Juelich February 19 to 20, 1990. The following contains copies of the shown transparencies and short write-ups as far as available. (orig.)

The Cambrian-Ordovician rocks of Sonora, Mexico, and southern Arizona, southwestern margin of North America (Laurentia): chapter 35

Science.gov (United States)

Page, William R.; Harris, Alta C.; Repetski, John E.; Derby, James R.; Fritz, R.D.; Longacre, S.A.; Morgan, W.A.; Sternbach, C.A.

2013-01-01

Cambrian and Ordovician shelf, platform, and basin rocks are present in Sonora, Mexico, and southern Arizona and were deposited on the southwestern continental margin of North America (Laurentia). Cambrian and Ordovician rocks in Sonora, Mexico, are mostly exposed in scattered outcrops in the northern half of the state. Their discontinuous nature results from extensive Quaternary and Tertiary surficial cover, from Tertiary and Mesozoic granitic batholiths in western Sonora, and from widespread Tertiary volcanic deposits in the Sierra Madre Occidental in eastern Sonora. Cambrian and Ordovician shelf rocks were deposited as part of the the southern miogeocline on the southwestern continental margin of North America.

QCD bosonization and the meson effective action

International Nuclear Information System (INIS)

Praschifka, J.; Roberts, C.D.; Cahill, R.T.

1987-01-01

A bosonization of quantum chromodynamics (QCD) is employed to derive a meson effective action, thus providing a direct link between QCD and meson phenomenology. As an example of this approach expressions are obtained for the meson parameters associated with the analysis of ω→3π decay. The bosonization also directly motivates a divergence-free, global color-symmetry model for mesons, which is seen to be a generalization of various phenomenological models. Good estimates are obtained for the values of several of the meson parameters

Decoupling of body-plan diversification and ecological structuring during the Ediacaran-Cambrian transition: evolutionary and geobiological feedbacks.

Science.gov (United States)

Mángano, M Gabriela; Buatois, Luis A

2014-04-07

The rapid appearance of bilaterian clades at the beginning of the Phanerozoic is one of the most intriguing topics in macroevolution. However, the complex feedbacks between diversification and ecological interactions are still poorly understood. Here, we show that a systematic and comprehensive analysis of the trace-fossil record of the Ediacaran-Cambrian transition indicates that body-plan diversification and ecological structuring were decoupled. The appearance of a wide repertoire of behavioural strategies and body plans occurred by the Fortunian. However, a major shift in benthic ecological structure, recording the establishment of a suspension-feeder infauna, increased complexity of the trophic web, and coupling of benthos and plankton took place during Cambrian Stage 2. Both phases were accompanied by different styles of ecosystem engineering, but only the second one resulted in the establishment of the Phanerozoic-style ecology. In turn, the suspension-feeding infauna may have been the ecological drivers of a further diversification of deposit-feeding strategies by Cambrian Stage 3, favouring an ecological spillover scenario. Trace-fossil information strongly supports the Cambrian explosion, but allows for a short time of phylogenetic fuse during the terminal Ediacaran-Fortunian.

Mesons in the Eguchi Kawai model

International Nuclear Information System (INIS)

Haan, O.

1985-09-01

Fermions in the fundamental representation of the SU(N) gauge group are incorporated into the Eguchi Kawai reduction scheme. The proof for the equivalence of reduced and extended theories is given. This equivalence can be used, to calculate chiral condensate and meson propagators from the fermion matrix of a partially reduced TEK model. (orig.)

Arachnostega Bertling, 1992 in the Drumian (Cambrian) sediments of the Teplá-Barrandian region (Czech Republic)

Czech Academy of Sciences Publication Activity Database

Fatka, O.; Mikuláš, Radek; Szabad, M.; Micka, V.; Valent, M.

2011-01-01

Roč. 61, č. 4 (2011), s. 367-381 ISSN 0001-5709 R&D Projects: GA ČR GA205/06/0395; GA ČR GA205/09/1521 Institutional research plan: CEZ:AV0Z30130516 Keywords : Cambrian * Teplá-Barrandian region * ichnofossils * Jince Formation * Buchava Formation * Arachnostega * Cambrian (Czech Republic) Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.565, year: 2011 https://geojournals.pgi.gov.pl/agp/article/view/9705

Mesons and quarks in nuclei

International Nuclear Information System (INIS)

Oset, E.

1980-01-01

A short review of the topic of mesons in nuclei is exposed paying particular attention to the relationship between several mesonic processes. Special emphasis is put into the microscopic pictures that can ultimately relate all these processes with the elementary coupling of mesons to the nuclear hadronic components. The importance of the short range part of the nuclear interaction opens the doors to a more basic understanding in terms of the quark components of nucleons and isobars. (orig.)

Towers of hybrid mesons

International Nuclear Information System (INIS)

Semay, Claude; Buisseret, Fabien; Silvestre-Brac, Bernard

2009-01-01

A hybrid meson is a quark-antiquark pair in which, contrary to ordinary mesons, the gluon field is in an excited state. In the framework of constituent models, the interaction potential is assumed to be the energy of an excited string. An approximate, but accurate, analytical solution of the Schroedinger equation with such a potential is presented. When applied to hybrid charmonia and bottomonia, towers of states are predicted in which the masses are a linear function of a harmonic oscillator band number for the quark-antiquark pair. Such a formula could be a reliable guide for the experimental detection of heavy hybrid mesons.

Charge parity exotic mesons

International Nuclear Information System (INIS)

Burden, C.J.

1998-01-01

Full text: Evidence for a meson with exotic quantum numbers J PC 1 -+ , the ρ(1405), has been observed at the AGS at Brookhaven and Crystal Barrel at CERN. This meson is exotic to the extent that its quantum numbers are not consistent with the generalised Pauli exclusion principle applied to the naive constituent quark model. In a fully relativistic field theoretic treatment, however, there is nothing in principle to preclude the existence of charge parity exotics. Using our earlier covariant Bethe-Salpeter model of light-quark mesons with no new parameter fitting we demonstrate the existence of a q - q-bar bound state with the quantum numbers of the ρ

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

Meson-meson bound state in a 2+1 lattice QCD model with two flavors and strong coupling

International Nuclear Information System (INIS)

Faria da Veiga, Paulo A.; O'Carroll, Michael; Neto, Antonio Francisco

2005-01-01

We consider the existence of bound states of two mesons in an imaginary-time formulation of lattice QCD. We analyze an SU(3) theory with two flavors in 2+1 dimensions and two-dimensional spin matrices. For a small hopping parameter and a sufficiently large glueball mass, as a preliminary, we show the existence of isoscalar and isovector mesonlike particles that have isolated dispersion curves (upper gap up to near the two-particle threshold ∼-4lnκ). The corresponding meson masses are equal up to and including O(κ 3 ) and are asymptotically of order -2lnκ-κ 2 . Considering the zero total isospin sector, we show that there is a meson-meson bound state solution to the Bethe-Salpeter equation in a ladder approximation, below the two-meson threshold, and with binding energy of order bκ 2 ≅0.02359κ 2 . In the context of the strong coupling expansion in κ, we show that there are two sources of meson-meson attraction. One comes from a quark-antiquark exchange. This is not a meson exchange, as the spin indices are not those of the meson particle, and we refer to this as a quasimeson exchange. The other arises from gauge field correlations of four overlapping bonds, two positively oriented and two of opposite orientation. Although the exchange part gives rise to a space range-one attractive potential, the main mechanism for the formation of the bound state comes from the gauge contribution. In our lattice Bethe-Salpeter equation approach, this mechanism is manifested by an attractive distance-zero energy-dependent potential. We recall that no bound state appeared in the one-flavor case, where the repulsive effect of Pauli exclusion is stronger

Search for rare B meson decays into Ds+ mesons

International Nuclear Information System (INIS)

Albrecht, H.; Ehrlichmann, H.; Hamacher, T.; Hofmann, R.P.; Kirchhoff, T.; Nau, A.; Nowak, S.; Schroeder, H.; Schulz, H.D.; Walter, M.; Wurth, R.; Appuhn, R.D.; Hast, C.; Kolanoski, H.; Lange, A.; Lindner, A.; Mankel, R.; Schieber, M.; Siegmund, T.; Spaan, B.; Thurn, H.; Toepfer, D.; Walther, A.; Wegener, D.; Britton, D.I.; Charlesworth, C.E.K.; Edwards, K.W.; Hyatt, E.R.F.; Kapitza, H.; Krieger, P.; MacFarlane, D.B.; Patel, P.M.; Prentice, J.D.; Saull, P.R.B.; Tzamariudaki, K.; Van de Water, R.G.; Yoon, T.S.; Ressing, D.; Schmidtler, M.; Schneider, M.; Schubert, K.R.; Strahl, K.; Waldi, R.; Weseler, S.; Balagura, V.; Belyaev, I.; Chechelnitsky, S.; Danilov, M.; Droutskoy, A.; Gershtein, Yu.; Golutvin, A.; Gorelov, I.; Kostina, G.; Lubimov, V.; Pakhlov, P.; Ratnikov, F.; Semenov, S.; Shibaev, V.; Soloshenko, V.; Tichomirov, I.; Zaitsev, Yu.

1993-01-01

A search has been performed for rare B meson decays into D s + mesons arising from b→u transitions, W exchange modes, B + annihilation processes, and decays where the D s + is not produced via a W→c anti s quark pair coupling, using the ARGUS detector operating on the Y(4S) resonance at the e + e - storage ring DORIS II. Upper limits for individual decay modes are obtained. In addition, from a study of D s + l - correlations an upper limit of BR(B→D s + l - X)<1.2%(90% CL) is determined. (orig.)

From meson- and photon-nucleon scattering to vector mesons in nuclear matter

International Nuclear Information System (INIS)

Wolf, Gy.; Lutz, M.F.M.; Friman, B.

2003-01-01

A relativistic and unitary approach to pion- and photon-nucleon scattering taking into account the πN, ρN, ωN, ηN, πΔ, KΛ and KΣ channels is presented. The scheme dynamically generates the s- and d-wave baryon resonances N(1535), N(1650), N(1520) and N(1700) and as well as Δ(1620) and Δ(1700) in terms of quasi-local two-body interaction terms. A fair description of the experimental data relevant to the properties of slow vector mesons in nuclear matter is obtained. The resulting s-wave ρ- and ω-meson-nucleon scattering amplitudes which define the leading density modification of the ρ- and ω-meson spectral functions in nuclear matter are presented. (author)

Mesons above the deconfining transition

International Nuclear Information System (INIS)

De Forcrand, P.; Garcia Perez, M.; Hashimoto, T.

1999-01-01

We analyze temporal and spatial meson correlators in quenched lattice QCD at T > 0. Above T c we find different masses and (spatial) 'screening masses', signals of plasma formation, and indication of persisting 'mesonic' excitations. (author)

Delocalized SYZ mirrors and confronting top-down SU(3)-structure holographic meson masses at finite g and N{sub c} with P(article) D(ata) G(roup) values

Energy Technology Data Exchange (ETDEWEB)

Yadav, Vikas; Sil, Karunava [Indian Institute of Technology, Department of Physics, Roorkee, Uttarakhand (India); Misra, Aalok [Indian Institute of Technology, Department of Physics, Roorkee, Uttarakhand (India); McGill University, Physics Department, Montreal, QC (Canada)

2017-10-15

Meson spectroscopy at finite gauge coupling - whereat any perturbative QCD computation would break down - and finite number of colors, from a top-down holographic string model, has thus far been entirely missing in the literature. This paper fills this gap. Using the delocalized type IIA SYZ mirror (with SU(3) structure) of the holographic type IIB dual of large-N thermal QCD of Mia et al. (Nucl Phys B 839:187. arXiv:0902.1540 [hep-th], 2010) as constructed in Dhuria and Misra (JHEP 1311:001. arXiv:1306.4339 [hep-th], 2013) at finite coupling and number of colors (N{sub c} = number of D5(D5)-branes wrapping a vanishing two-cycle in the top-down holographic construct of Mia et al. (Nucl Phys B 839:187. arXiv:0902.1540 [hep-th], 2010) = O(1) in the IR in the MQGP limit of Dhuria and Misra (JHEP 1311:001. arXiv:1306.4339 [hep-th], 2013) at the end of a Seiberg-duality cascade), we obtain analytical (not just numerical) expressions for the vector and scalar meson spectra and compare our results with previous calculations of Sakai and Sugimoto (Prog Theor Phys 113:843. doi:10.1143/PTP.113.843 arXiv:hep-th/0412141, 2005) and Dasgupta et al. (JHEP 1507:122. doi:10.1007/JHEP07(2015)122 arXiv:1409.0559 [hep-th], 2015), and we obtain a closer match with the Particle Data Group (PDG) results of Olive et al. (Particle Data Group) (Chin Phys C 38:090001, 2014). Through explicit computations, we verify that the vector and scalar meson spectra obtained by the gravity dual with a black hole for all temperatures (small and large) are nearly isospectral with the spectra obtained by a thermal gravity dual valid for only low temperatures; the isospectrality is much closer for vector mesons than scalar mesons. The black-hole gravity dual (with a horizon radius smaller than the deconfinement scale) also provides the expected large-N suppressed decrease in vector meson mass with increase of temperature. (orig.)

Scattering amplitudes to all orders in meson exchange

International Nuclear Information System (INIS)

Silbar, R.R.; Mattis, M.P.

1990-01-01

As the number of colors in QCD, N C , becomes large, it is possible to sum up all meson-exchange contributions, however arbitrarily complicated, to meson-baryon and baryon-baryon scattering. A semi-classical structure for the two-flavor theory emerges, in close correspondence to vector-meson-augmented Skyrme models. In this limit, baryons act as extended static sources for the classical meson fields. This leads to non-linear differential equations for the classical meson fields which can be solved numerically for static radial (hedgehog-like) solutions. The non-linear terms in the equations of motion for the quantized meson fields can then be simplified, to leading order in 1/N C , by replacing all factors of the meson field but one by the previously-found classical field. This results in linear, Schroedinger-like equations, which are easily solved. For the meson-baryon case the solution can be subsequently analyzed to obtain the phase shifts for the scattering and, from these, the baryon resonance spectrum of the model. As the warm-up, we have carried out this calculation for the simple case of σ mesons only, finding sensible results. 8 refs., 3 figs

Selenium and hazardous elements distribution in plant-soil-water system and human health risk assessment of Lower Cambrian, Southern Shaanxi, China.

Science.gov (United States)

Du, Yajun; Luo, Kunli; Ni, Runxiang; Hussain, Rahib

2018-03-01

The natural selenium poisoning due to toxic Se levels in food chain had been observed in humans and animals in Lower Cambrian outcrop areas in Southern Shaanxi, China. To find out the distribution pattern of selenium and other hazardous elements in the plant, soil and water of Lower Cambrian in Southern Shaanxi, China, and their possible potential health risk, a total of 30 elements were analyzed and the health risk assessment of 18 elements was calculated. Results showed that the soil, plant and natural water of Lower Cambrian all had relatively high Se levels. In Lower Cambrian, the soil was enriched with Se, As, Ba, Cu, Mo, Ni, Zn, Ga, Cd and Cr (1.68 food intake was the major pathway. For minimizing potential health risk, the local inhabitants should use the mix-imported food with local growing foods.

Studies on inclusive meson resonance and particle production

International Nuclear Information System (INIS)

Saarikko, Heimo

1978-01-01

Production and decay of meson resonances are studied in medium energy meson-proton collisions. Strong evidence is found that hadronic collisions are dominated by resonance production. Especially the vector mesons have often large inclusive cross sections, typically of the order of few millibarns at the present energies. In all, a majority of pions and kaons appear to be decay products of resonances or other unstable particles. The detailed kinematics of the parent resonance's decays is found to play an important role in determining inclusive pion spectra. The squared transverse momentum distributions of hadrons heavier than the pion appear to have in common an exponential behaviour, with a universal slope for the esponential fall-off. The observed vector meson yields suggest that only a small fraction of the direct lepton production observed at large transverse momentum in nucleon-nucleon interactions is accounted for by the ''old'' vector mesons. An attempt has been made to separate out the central production and fragmentation components of the meson production. Both the central production and the fragmentation of the incoming meson are found to be important mechanisms in the non-strange meson production whereas the central production of strange meson resonances is rare at our energies. The ratios of the observed meson yields are found to be generally in good agreement with a simple quark-counting model. (author)

Tensor meson dominance and e+e--physics

International Nuclear Information System (INIS)

Genz, H.; Karlsruhe Univ.; Mallik, S.

1983-01-01

The phenomenological status of tensor meson dominance is reported. Some new results concerning hadronic decays of the 2 ++ -meson chi 2 (3.55) and the heavy lepton tau are also included. Considering experimental errors, tensor meson dominance is in agreement with experiment. (author)

Single spin asymmetry for charm mesons

Energy Technology Data Exchange (ETDEWEB)

Dominguez Zacarias, G. [PIMAyC, Eje Central Lazaro Cardenas No. 152, Apdo. Postal 14-805, D.F. (Mexico); Herrera, G.; Mercado, J. [Centro de Investigacion y de Estudios Avanzados, Apdo. Postal 14-740, D.F. (Mexico)

2007-08-15

We study single spin asymmetries of D{sup 0} and D{sup -} mesons in polarized proton-proton collisions. A two component model is used to describe charm meson production. The production of D mesons occurs by recombination of the constituents present in the initial state as well as by fragmentation of quarks in the final state. This model has proved to describe the production of charm. The recombination component involves a mechanism of spin alignment that ends up in a single spin asymmetry. Experimental measurements of single spin asymmetry for pions at RHIC are compared with the model. Predictions for the asymmetry in D mesons are presented. (orig.)

Single spin asymmetry for charm mesons

International Nuclear Information System (INIS)

Dominguez Zacarias, G.; Herrera, G.; Mercado, J.

2007-01-01

We study single spin asymmetries of D 0 and D - mesons in polarized proton-proton collisions. A two component model is used to describe charm meson production. The production of D mesons occurs by recombination of the constituents present in the initial state as well as by fragmentation of quarks in the final state. This model has proved to describe the production of charm. The recombination component involves a mechanism of spin alignment that ends up in a single spin asymmetry. Experimental measurements of single spin asymmetry for pions at RHIC are compared with the model. Predictions for the asymmetry in D mesons are presented. (orig.)

Meson Correlators in Finite Temperature Lattice QCD

CERN Document Server

De Forcrand, Philippe; Hashimoto, T; Hioki, S; Matsufuru, H; Miyamura, O; Nakamura, A; Takaishi, T; Umeda, T; Stamatescu, I O; CERN. Geneva; Forcrand, Ph. de

2001-01-01

We analyze temporal and spatial meson correlators in quenched lattice QCD at T>0. Below T_c we observe little change in the meson properties as compared with T=0. Above T_c we observe new features: chiral symmetry restoration and signals of plasma formation, but also indication of persisting mesonic (metastable) states and different temporal and spatial masses in the mesonic channels. This suggests a complex picture of QGP in the region 1 - 1.5 T_c.

Asymptotic energy scale factors for pseudoscalar meson scattering and charmed meson couplings

International Nuclear Information System (INIS)

Thews, R.L.

1977-01-01

Energy scale factors ν 0 for PP → PP scattering amplitudes are related via absence of exotic resonances of ratios of tensor to vector coupling strengths. These same ratios are extracted from FESR's for non-exotic reactions. The scale factors obtained are all of the order of 1.0 GeV 2 or less, indepedent of quantum numbers. This contradicts the expectations of dual amplitudes in which ν 0 =1/α', and trajectory slopes are smaller for charmed mesons. Decay widths for tensor mesons are predicted. An observed SU(3) violation for the ratio A 2 → KantiK/K** → Kπ is shown to be consistent with the FESR results. Charmed meson decays are predicted to be factors of 2 to 3 larger than those predicted by SU(4). (author)

Quantum field theory approaches to meson structure

International Nuclear Information System (INIS)

Branz, Tanja

2011-01-01

Meson spectroscopy became one of the most interesting topics in particle physics in the last ten years. In particular, the discovery of new unexpected states in the charmonium spectrum which cannot be simply explained by the constituent quark model attracted the interest of many theoretical efforts. In the present thesis we discuss different meson structures ranging from light and heavy quark-antiquark states to bound states of hadrons-hadronic molecules. Here we consider the light scalar mesons f 0 (980) and a 0 (980) and the charmonium-like Y(3940), Y(4140) and Z ± (4430) states. In the discussion of the meson properties like mass spectrum, total and partial decay widths and production rates we introduce three different theoretical methods for the treatment and description of hadronic structure. For the study of bound states of mesons we apply a coupled channel approach which allows for the dynamical generation of meson-meson resonances. The decay properties of meson molecules are further on studied within a second model based on effective Lagrangians describing the interaction of the bound state and its constituents. Besides hadronic molecules the effective Lagrangian approach is also used to study the radiative and strong decay properties of ordinary quark-antiquark (q anti q) states. The AdS/QCD model forms the completion of the three theoretical methods introduced in the present thesis. This holographic model provides a completely different ansatz and is based on extra dimensions and string theory. Within this framework we calculate the mass spectrum of light and heavy mesons and their decay constants.

Heavy meson observables and Dyson-Schwinger equations

International Nuclear Information System (INIS)

Ivanov, M. A.

1998-01-01

Dyson-Schwinger equation (DSE) studies show that the b-quark mass-function is approximately constant, and that this is true to a lesser extent for the c-quark. This observation provides the basis for a study of the leptonic and semileptonic decays of heavy pseudoscalar mesons using a ''heavy-quark'' limit of the DSES, which, when exact, reduces the number of independent form factors. Semileptonic decays with light mesons in the final state are also accessible because the DSES provide a description of light-quark propagation characteristics and light-meson structure. A description of B-meson decays is straightforward, however, the study of decays involving the D-meson indicates that c-quark mass-corrections are quantitatively important

Parity violating nuclear force by meson mixing

International Nuclear Information System (INIS)

Iqbal, M.J.; Niskanen, J.A.

1990-01-01

We study a mechanism for parity violation in the two nucleon meson-exchange interaction by way of the mixing of mesons of opposite parities. This mixing arises from parity violating W ± and Z exchange between the q bar q pair in the meson. Numerically its effect turns out to be as important as vector meson exchange with a weak meson-nucleon vertex and may partly be used to model this vertex. The calculation is performed using both the standard Born approximation adding the amplitude phases by Watson's theorem and also using the exact correlated two-nucleon wave functions. The effect of correlations and form factors is found to be crucially important at intermediate energies

Exotic meson spectroscopy with CLAS

Energy Technology Data Exchange (ETDEWEB)

Adams, G.; Napolitano, J. [Rensselaer Polytechnic Inst., Troy, NY (United States)

1994-04-01

The identification and study of mesons with explicit gluonic degrees of freedom will provide major constraints on nonperturbative QCD and models thereof. CLAS will provide a unique opportunity for studying these resonances by measuring photoproduction of multi-meson final states.

About oscillations in the system of K0 mesons

International Nuclear Information System (INIS)

Beshtoev, Kh.M.

2011-01-01

This work considers K 0 -, K 0 bar - meson mixings and oscillations via K 1 0 , K 2 0 - meson states at strangeness violation by the weak interactions and K 1 0 -, K 2 0 - meson mixings and oscillations via K S -, K L - meson states at CP violation by the weak interactions without and with taking into account decay widths. We work in the framework of the masses mixing scheme. It is shown that K 1 0 -(K S -) meson states appear at big distances from the K 0 -mesons source after their decays (τ L ≥ τ S (τ 2 ≥τ 1 )) due to oscillations of residual K 2 0 (K L ) mesons and then again we see short-living K 1 0 (K S ) mesons. It is implied that K L ↔K S meson oscillations are absent. The case is also considered when at CP violation unitarity is violated, but orthogonality of K S , K L states remains. The general expressions for probabilities of meson oscillations (transitions) are given

Exclusive φ meson production in HERMES

International Nuclear Information System (INIS)

Golembiovskaya, Mayya

2014-03-01

In the present work exclusive φ meson leptoproduction at HERMES experiment in DESY was studied using the data collected at HERA accelerator in the period from 1998 till 2000 and from 2006 till 2007 years. In the analysis unpolarized and longitudinally polarized hydrogen and deuteron targets were used, the beam consisted of longitudinally polarized leptons. Via measurement of the angular and momentum distribution of the φ meson decay products 23 spin density matrix elements (SDMEs) for the φ meson were obtained. The number of SDMEs was defined by the experiment conditions, e.g. by the beam and target polarization directions. For the mentioned time period φ meson SDMEs were defined at HERMES for the first time. The quantities U 1 , U 2 and U 3 which can be used to check presence of unnatural parity exchange (UPE) mechanism in phi meson production were calculated from SDMEs. All the results were obtained in 3 kinematic bins of Q 2 , 4 kinematic bins of t' and for the integrated kinematics. No statistically significant difference between the results for hydrogen and deuteron targets was observed. The UPE quantities were found to be zero within 2 σ for the integrated kinematics, indicating negligible contribution of UPE for the φ meson production which is in agreement with theory predictions. The test of s-channel helicity conservation hypothesis via comparison of corresponding SDME values showed helicity conservation for the φ meson production.

Exclusive φ meson production in HERMES

Energy Technology Data Exchange (ETDEWEB)

Golembiovskaya, Mayya

2014-03-15

In the present work exclusive φ meson leptoproduction at HERMES experiment in DESY was studied using the data collected at HERA accelerator in the period from 1998 till 2000 and from 2006 till 2007 years. In the analysis unpolarized and longitudinally polarized hydrogen and deuteron targets were used, the beam consisted of longitudinally polarized leptons. Via measurement of the angular and momentum distribution of the φ meson decay products 23 spin density matrix elements (SDMEs) for the φ meson were obtained. The number of SDMEs was defined by the experiment conditions, e.g. by the beam and target polarization directions. For the mentioned time period φ meson SDMEs were defined at HERMES for the first time. The quantities U{sub 1}, U{sub 2} and U{sub 3} which can be used to check presence of unnatural parity exchange (UPE) mechanism in phi meson production were calculated from SDMEs. All the results were obtained in 3 kinematic bins of Q{sup 2}, 4 kinematic bins of t' and for the integrated kinematics. No statistically significant difference between the results for hydrogen and deuteron targets was observed. The UPE quantities were found to be zero within 2 σ for the integrated kinematics, indicating negligible contribution of UPE for the φ meson production which is in agreement with theory predictions. The test of s-channel helicity conservation hypothesis via comparison of corresponding SDME values showed helicity conservation for the φ meson production.

Semileptonic decays of B mesons into excited charm mesons: leading order and 1/mc contributions

International Nuclear Information System (INIS)

Mannel, T.

1994-01-01

We use the heavy quark effective theory to investigate the form factors that describe the semileptonic decays of a B meson into excited daughter mesons. For an excited daughter meson with charm, a single form factor is needed at leading order, while five form factors and two dimensionful constants are needed to order 1/m c in the heavy quark expansion. For non-charmed final states, a total of four form factors are needed at leading order. For the process B→D(*)Xlν, four form factors are also needed at leading order. (orig.)

Discussion of the 3P0 model applied to the decay of mesons into two mesons

International Nuclear Information System (INIS)

Bonnaz, R.; Silvestre-Brac, B.

1999-01-01

The 3 P 0 model for the decay of a meson into two mesons is revisited. In particular, the formalism is extended in order to deal with an arbitrary form for the creation vertex and with the exact meson wave functions. A careful analysis of both effects is performed and discussed. The model is then applied to a large class of transitions known experimentally. Two types of quark-antiquark potentials have been tested and compared. (author)

Production of excited charmed mesons at LEP

CERN Document Server

Abbaneo, D

2000-01-01

Studies od the production of orbitally excited charmed and charmed strange mesons in e+e- collisions, performed by the LEP collaborations are reviewed. Measurements of the production rates of orbitally excited charmed mesons in semileptonic b decays are presented. Searches for charmed meson radial excitations are also briefly discussed.

Hard electroproduction of hybrid mesons

International Nuclear Information System (INIS)

Anikin, I.V.; LPT Universite Paris-Sud, Orsay; Szymanowski, L.; Teryaev, O.V.; ); Wallon, S.

2005-01-01

We estimate the sizeable cross section for deep exclusive electroproduction of an exotic J PC = 1 -+ hybrid meson in the Bjorken regime. The production amplitude scales like the one for usual meson electroproduction, i.e. as 1/Q 2 . This is due to the non-vanishing leading twist distribution amplitude for the hybrid meson, which may be normalized thanks to its relation to the energy momentum tensor and to the QCD sum rules technique. The hard amplitude is considered up to next-to-leading order in as and we explore the consequences of fixing the renormalization scale ambiguity through the BLM procedure. (author)

S-wave spectroscopy and Hyperne splitting of Bc meson

International Nuclear Information System (INIS)

Shah, Manan; Bhavsar, Tanvi; Vinodkumar, P.C.

2017-01-01

B c meson is the only heavy meson with two open flavours. This system is also interesting because they cannot annihilate into gluons. The mass spectra and hyperfine splitting of the B c meson are investigated in the Dirac framework with the help of linear + constant potential. The spin-spin interactions are also included in the calculation of the pseudoscalar and vector meson masses. Our computed result for the B c meson are in very good agreement with experimental results as well as other available theoretical result. Decay properties are also interesting because it is expected that decay of B c meson occur in to neutral meson. We hope our theoretical results are helpful for future experimental observations

Search for rare B meson decays into D+s mesons

International Nuclear Information System (INIS)

Albrecht, H.; Ehrlichmann, H.; Hamacher, T.

1993-04-01

A search has been performed for rare B meson decays into D s + mesons arising from b → u transitions, W exchange modes, B + annihilation processes, and decays where the D s + is not produced via a W → c anti s quark pair coupling, using the ARGUS detector operating on the Y(4S) resonance at the e + e - storage ring DORIS II. Upper limits for individual decay modes are obtained. In addition, from a study of D s + l - correlations an upper limit of BR(B → D s + l - X) < 1.2% (90% CL) is determined. (orig.)

Specific activity and hazards of Archeozoic-Cambrian rock samples collected from the Weibei area of Shaanxi (China))

International Nuclear Information System (INIS)

Xinwei, L.; Lingqing, W.; Xiaodan, J.; Leipeng, Y.; Gelian, D.

2006-01-01

The present work deals with the radioactivity of the Archeozoic-Cambrian rocks of the Weibei area, Shaanxi (China)). A total of 45 rock samples of Archeozoic-Cambrian strata were investigated. The radionuclides of the samples, in Bq kg -1 , have been measured using Na(I)Tl gamma-ray spectrometer. The concentration of 226 Ra, 232 Th and 40 K in the Archeozoic-Cambrian rock samples range from 12.3 to 55.4, from 2.4 to 98.7 and from 58.6 to 1613.3 Bq kg -1 , respectively. The measured activity concentrations for these radionuclides were compared with the typical world average values. To assess the radiological hazard of the natural radioactivity in the samples, the radium equivalent activity, the external hazard index, internal hazard index and the annual gonadal dose equivalent associated with the radionuclides were calculated and compared with the international recommended values. (authors)

Experiments on eta-meson production

International Nuclear Information System (INIS)

Peng, J.C.

1985-01-01

Following a review of some highlights of eta-meson characteristics, the status of eta-meson production experiments is reviewed. The physics motivations and first results of two LAMPF experiments on (π,eta) reactions are discussed. Possible future experiments are also discussed. 42 refs., 12 figs., 4 tabs

Antiproton-proton annihilation into light neutral meson pairs within an effective meson theory

Science.gov (United States)

Wang, Ying; Bystritskiy, Yury M.; Ahmadov, Azad I.; Tomasi-Gustafsson, Egle

2017-08-01

Antiproton-proton annihilation into light neutral mesons in the few GeV energy domain is investigated in view of a global description of the existing data and predictions for future work at the Antiproton Annihilation at Darmstadt (PANDA) experiment at the Facility for Antiproton and Ion Research (FAIR). An effective meson model earlier developed, with mesonic and baryonic degrees of freedom in s , t , and u channels, is applied here to π0π0 production. Form factors with logarithmic s and t (u ) dependencies are applied. A fair agreement with the existing angular distributions is obtained. Applying SU(3) symmetry, it is straightforward to recover the angular distributions for π0η and η η production in the same energy range. A good agreement is generally obtained with all existing data.

Estimation of porosity of Khewra sandstone of cambrian age by using helium porosimeter and its application in reservoir evaluation

International Nuclear Information System (INIS)

Khan, M.S.; Bhatti, A.A.; Gillani, S.T.A.; Raza, A.

2012-01-01

Estimation of petrophysical properties of the rock formations played decisive role in all the processes of petroleum exploration. The Cambrian sequence is well established as reservoir rocks in the various parts of the world from where petroleum is being tapped. The Cambrian sequence has been encountered in the Potwar area and limited petroleum is being produced from the Adhi Oil Field. The Khewra Sandstone of the Cambrian sequence is outcropped in the Khewra Gorge, Salt Range Pakistan below an unconformity qf the Tobra Formation. For the assessment of porosity and reservoir characterization Helium Porosimeter has been used, six samples Qf the upper horizon were collected from various locations of the Khewra Gorge and the Khewra Choha Sadden Shah road side section; cores were prepared from these samples according to the instrument standard. The results of this study revealed that the upper horizon Qf the Khewra Sandstone Formation has good porosity ranging from 18.76% to 21.07%, porosity varied in different parts of the formation. These results are in good agreement with the internationally reported values for petroleum reservoir of the Cambrian sandstone. (author)

Meson 2000 Conference Summary lite

International Nuclear Information System (INIS)

Barnes, T.

2000-01-01

This short contribution is a late MESON2000 conference summary. As appropriate for the 600th anniversary of the Jagiellonian University, it begins with a brief summary of the last 600 years of European history and its place in hadron physics. Next a ''physicist chirality'' order parameter PC is introduced. When applied to MESON2000 plenary speakers this order parameter illustrates the separation of hadron physicists into disjoint communities. The individual plenary talks in MESON2000 are next sorted according to the subconference associated with each of the 36 plenary speakers. Finally, I conclude with a previously unreported Feynman story regarding the use of models in hadron physics. (author)

Lower Cambrian-Ediacaran Paleogeography and True Polar Wander with New Paleomagnetic Constraints from West African Craton

Science.gov (United States)

Robert, B.; Besse, J.; Blein, O.; Greff-Lefftz, M.; Baudin, T.; Fernando, L.; Meslouh, S.; Belbadaoui, M.

2014-12-01

Paleomagnetic data from Laurentia and Baltica continents suggest fast large oscillations of the virtual geomagnetic poles (VGP) from high to low latitudes during the Ediacaran (635-542 Ma). These data are interpreted in the literature either as oscillations of the Earth magnetic dipole between polar and equatorial positions, or as True Polar Wander (TPW), implying a very fast tumbling of continents and perhaps, of whole Earth. In this study, we try to test these hypotheses by bringing new paleomagnetic data on volcanic series from another continent, the West African Craton (WAC). We have sampled well dated pyroclastic and lava flows from the Ouarzazate and Taroudant groups in the Anti-Atlas, (Morocco). 480 samples from 105 sites were thermally demagnetized in our laboratory. Our preliminary results highlight two major groups of directions, mainly carried by hematite, magnetite also contributing sometimes to the magnetization. The first group consists of a dual polarity high inclination direction that may represent the original magnetization. The observed paleolatitude is compatible with that predicted by the lower Cambrian-Ediacaran apparent polar wander path (APWP) of Gondwana, assuming that the WAC was already accreted to Gondwana at this age. Nevertheless, a complete agreement between our pole and the APWP needs a local rotation of around 80° on a vertical axis. The second group displays a single polarity direction, with a shallow inclination and a south-east declination. This direction is close to the expected direction derived from the Permo-Carboniferous segment of the Gondwana APWP, and may represent a remagnetization acquired during the Kiaman reversed polarity superchron. Our preliminary paleomagnetic results thus display large changes in the VGP position, as also evidenced by others on Baltica and Laurentia. However, their interpretation does not favor TPW episodes or equatorial Earth magnetic dipole during the lower Cambrian-Ediacaran periods, but

Late Ediacaran-Cambrian structures and their reactivation during the Variscan and Alpine cycles in the Anti-Atlas (Morocco)

Science.gov (United States)

Soulaimani, A.; Michard, A.; Ouanaimi, H.; Baidder, L.; Raddi, Y.; Saddiqi, O.; Rjimati, E. C.

2014-10-01

The post-Pan-African evolution of the northern border of the West African Craton is largely controlled by the remobilisation of Late Neoproterozoic basement faults. The Upper Ediacaran volcanic and volcano-sedimentary sequences of the Ouarzazate Group show dramatic and rapid thickness changes, consistent with active extensional faulting associated with post-orogenic collapse and incipient continental rifting. The geometry and kinematics of these faults differ from west to east in the Anti-Atlas. N- to NE-trending faults dominate in western Anti-Atlas in response to E-W to NW-SE pure extension, while a transtensive opening regime characterize the central (Bou Azzer) and eastern (Saghro-Ougnate) Anti-Atlas. The marine incursion in the west-central Anti-Atlas during the late Ediacaran-Early Cambrian occurred without major geodynamical break between the continental Ouarzazate Group and marine sediments of the Adoudou Fm. Extensional tectonics went on during the Early Cambrian, being concentrated in the western and central parts of the belt. From Middle Cambrian to Lower Devonian and mainly due to thermal subsidence, the Anti-Atlas basement was buried under marine sediments with dominant south-derived detrital input. Basement faults control the distribution of subsiding versus shallow areas. During the Middle-Late Devonian, the dislocation of the Saharan platform occurred, mainly in the eastern Anti-Atlas where Precambrian faults were also remobilized during the Early Carboniferous. During the Variscan orogeny, the Paleozoic series of the Anti-Atlas basin were involved in folding tectonics, concomitant with the uplift of Proterozoic basement blocks bounded by inherited basement faults. The pre-existing rift-related faults were variably inverted across the Anti-Atlas. In the westernmost part of the belt, Variscan shortening induced positive inversions along the remobilized basement faults, but in some cases, some faults preserved an apparently normal throw. Some hidden

The phi-meson and Chiral-mass-meson production in heavy-ion collisions as potential probes of quark-gluon-plasma and Chiral symmetry transitions

Science.gov (United States)

Takahashi, Y.; Eby, P. B.

1985-01-01

Possibilities of observing abundances of phi mesons and narrow hadronic pairs, as results of QGP and Chiral transitions, are considered for nucleus-nucleus interactions. Kinematical requirements in forming close pairs are satisfied in K+K decays of S(975) and delta (980) mesons with small phi, and phi (91020) mesons with large PT, and in pi-pi decays of familiar resonance mesons only in a partially restored chiral symmetry. Gluon-gluon dominance in QGP can enhance phi meson production. High hadronization rates of primordial resonance mesons which form narrow hadronic pairs are not implausible. Past cosmic ray evidences of anomalous phi production and narrow pair abundances are considered.

The η' meson from lattice QCD

International Nuclear Information System (INIS)

Jansen, K.; Michael, C.; Urbach, C.

2008-04-01

We study the flavour singlet pseudoscalar mesons from first principles using lattice QCD. With N f =2 flavours of light quark, this is the so-called η 2 meson and we discuss the phenomenological status of this. Using maximally twisted-mass lattice QCD, we extract the mass of the η 2 meson at two values of the lattice spacing for lighter quarks than previously discussed in the literature. We are able to estimate the mass value in the limit of light quarks with their physical masses. (orig.)

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)

Meson spectroscopy experiment at KEK - E/iota puzzle

International Nuclear Information System (INIS)

Tsuru, Tsuneaki

1985-01-01

Physics interests at the KEK (National Laboratory for High Energy Physics) are (1) search for exotic mesons such as glueballs (gg), meiktons (q anti q g) and multiquark states (q sup(2 - )q 2 ), (2) search for missing ordinary mesons (q anti q) and confirmation of unestablished mesons, and (3) new informations of quark contents of mesons, mixing angles of SU(3) singlet-octet and tests of conservations law. Special interest is in search for exotics such as glueballs and meiktons. (2) is a so-called meson spectroscopy experiment. This is important not only in itself but also in identifying newly discovered states as exotics because exotics have often same quantum numbers as ordinary mesons. Contents are the following: glueballs and E/iota puzzles, spectrometer system, experiments, performance of the spectrometer, physics outputs, E/iota puzzles and πI experiment, future plans. (Mori, K.)

Temperature, chemical potential and the ρ meson

International Nuclear Information System (INIS)

Roberts, C. D.; Schmidt, S. M.

2000-01-01

Models of QCD must confront nonperturbative phenomena such as confinement, dynamical chiral symmetry breaking (DCSB) and the formation of bound states. In addition, a unified approach should describe the deconfinement and chiral symmetry restoring phase transition exhibited by strongly-interacting matter under extreme conditions of temperature and density. Nonperturbative Dyson-Schwinger equation (DSE) models provide insight into a wide range of zero temperature hadronic phenomena; e.g., non-hadronic electroweak interactions of light- and heavy-mesons, and diverse meson-meson and meson-nucleon form factors. This is the foundation for their application at nonzero-(T, μ). Herein the authors describe the calculation of the reconfinement and chiral symmetry restoring phase boundary, and the medium dependence of ρ-meson properties. They also introduce an extension to describe the time-evolution in the plasma of the quark's scalar and vector self energies based on a Vlasov equation

Spin O decay angular distribution for interfering mesons in electroproduction

Energy Technology Data Exchange (ETDEWEB)

Funsten, H.; Gilfoyle, G.

1994-04-01

Self analyzing meson electroproduction experiments are currently being planned for the CEBAF CLAS detector. These experiments deduce the spin polarization of outgoing unstable spin s (?)0 mesons from their decay angular distribution, W({theta},{psi}). The large angular acceptance of the CLAS detector permits kinematic tracking of a sufficient number of these events to accurately determine electroproduction amplitudes from the deduced polarization. Maximum polarization information is obtained from W({theta},{psi}) for decay into spin 0 daughters. The helicity of the decaying meson is transferred to the daughter`s relative orbital angular momentum m-projection; none is {open_quotes}absorbed{close_quotes} into daughter helicities. The decaying meson`s helicity maximally appears in W({theta},{psi}). W({theta},{psi}) for spin 0 daughters has been derived for (1) vector meson electroproduction and (2) general interfering mesons produced by incident pions. This paper derives W({theta},{psi}) for electroproduction of two interfering mesons that decay into spin 0 daughters. An application is made to the case of interfering scalar and vector mesons. The derivation is an extension of work by Schil using the general decay formalism of Martin. The expressions can be easily extended to the case of N interfering mesons since interference occurs pairwise in the observable W ({theta},{psi}), a quadratic function of the meson amplitudes. The derivation uses the virtual photon density matrix of Schil which is transformed by a meson electroproduction transition operator, T. The resulting density matrix for the interfering mesons is then converted into a corresponding statistical tensor and contracted into the efficiency tensor for spin 0 daughters.

The light scalar mesons as tetraquarks

Directory of Open Access Journals (Sweden)

Gernot Eichmann

2016-02-01

Full Text Available We present a numerical solution of the four-quark Bethe–Salpeter equation for ground-state scalar tetraquarks with JPC=0++. We find that the four-body equation dynamically generates pseudoscalar-meson poles in the Bethe–Salpeter amplitude. The resulting tetraquarks are genuine four-quark states that are dominated by pseudoscalar meson–meson correlations. Diquark–antidiquark contributions are subleading because of their larger mass scale. In the light quark sector, the sensitivity of the tetraquark wave function to the pion poles leads to an isoscalar tetraquark mass Mσ∼350 MeV which is comparable to that of the σ/f0(500. The masses of its multiplet partners κ and a0/f0 follow a similar pattern. This provides support for a tetraquark interpretation of the light scalar meson nonet in terms of ‘meson molecules’.

Finding a rational nomenclature for mesons and baryons

International Nuclear Information System (INIS)

Barnett, R.M.; Cahn, R.N.; Gidal, G.

1985-05-01

A history of the Particle Data Group's efforts to find a rational and systematic convention for naming mesons and baryons is given. Several versions of our proposal are reviewed, and name changes which would occur are summarized. Some of the mail we have received is described. We hope to stimulate additional feedback

Light Vector Mesons in the Nuclear Medium

Energy Technology Data Exchange (ETDEWEB)

Wood, Michael; Nasseripour, Rakhsha; Weygand, Dennis; Djalali, Chaden; Tur, Clarisse; Mosel, Ulrich; Muehlich, Pascal; Adams, Gary; Amaryan, Moscov; Amaryan, Moskov; Ambrozewicz, Pawel; Anghinolfi, Marco; Asryan, Gegham; Avagyan, Harutyun; Baghdasaryan, Hovhannes; Baillie, Nathan; Ball, James; Baltzell, Nathan; Barrow, Steve; Battaglieri, Marco; Bedlinskiy, Ivan; Bektasoglu, Mehmet; Bellis, Matthew; Benmouna, Nawal; Berman, Barry; Biselli, Angela; Blaszczyk, Lukasz; Bouchigny, Sylvain; Boyarinov, Sergey; Bradford, Robert; Branford, Derek; Briscoe, William; Brooks, William; Burkert, Volker; Butuceanu, Cornel; Calarco, John; Careccia, Sharon; Carman, Daniel; Carnahan, Bryan; Casey, Liam; Chen, Shifeng; Cheng, Lu; Cole, Philip; Collins, Patrick; Coltharp, Philip; Crabb, Donald; Crannell, Hall; Crede, Volker; Cummings, John; Dashyan, Natalya; De Vita, Raffaella; De Sanctis, Enzo; Degtiarenko, Pavel; Denizli, Haluk; Dennis, Lawrence; Deur, Alexandre; Dharmawardane, Kahanawita; Dickson, Richard; Dodge, Gail; Doughty, David; Dugger, Michael; Dytman, Steven; Dzyubak, Oleksandr; Egiyan, Hovanes; Egiyan, Kim; Elfassi, Lamiaa; Elouadrhiri, Latifa; Eugenio, Paul; Fedotov, Gleb; Feldman, Gerald; Feuerbach, Robert; Fradi, Ahmed; Funsten, Herbert; Garcon, Michel; Gavalian, Gagik; Gilfoyle, Gerard; Giovanetti, Kevin; Girod, Francois-Xavier; Goetz, John; Gordon, Christopher; Gothe, Ralf; Griffioen, Keith; Guidal, Michel; Guler, Nevzat; Guo, Lei; Gyurjyan, Vardan; Hadjidakis, Cynthia; Hafidi, Kawtar; Hakobyan, Hayk; Hakobyan, Rafael; Hanretty, Charles; Hardie, John; Hassall, Neil; Hersman, F.; Hicks, Kenneth; Hleiqawi, Ishaq; Holtrop, Maurik; Hyde, Charles; Ilieva, Yordanka; Ireland, David; Ishkhanov, Boris; Isupov, Evgeny; Ito, Mark; Jenkins, David; Jo, Hyon-Suk; Johnstone, John; Joo, Kyungseon; Juengst, Henry; Kalantarians, Narbe; Kellie, James; Khandaker, Mahbubul; Khetarpal, Puneet; Kim, Wooyoung; Klein, Andreas; Klein, Franz; Klimenko, Alexei; Kossov, Mikhail; Krahn, Zebulun; Kramer, Laird; Kubarovsky, Valery; Kuhn, Joachim; Kuhn, Sebastian; Kuleshov, Sergey; Lachniet, Jeff; Laget, Jean; Langheinrich, Jorn; Lawrence, David; Li, Ji; Livingston, Kenneth; Lu, Haiyun; MacCormick, Marion; Markov, Nikolai; Mattione, Paul; McAleer, Simeon; McKinnon, Bryan; McNabb, John; Mecking, Bernhard; Mehrabyan, Surik; Melone, Joseph; Mestayer, Mac; Meyer, Curtis; Mibe, Tsutomu; Mikhaylov, Konstantin; Minehart, Ralph; Mirazita, Marco; Miskimen, Rory; Mokeev, Viktor; Moriya, Kei; Morrow, Steven; Moteabbed, Maryam; Mueller, James; Munevar Espitia, Edwin; Mutchler, Gordon; Nadel-Turonski, Pawel; Niccolai, Silvia; Niculescu, Gabriel; Niculescu, Maria-Ioana; Niczyporuk, Bogdan; Niroula, Megh; Niyazov, Rustam; Nozar, Mina; Osipenko, Mikhail; Ostrovidov, Alexander; Park, Kijun; Pasyuk, Evgueni; Paterson, Craig; Pereira, Sergio; Pierce, Joshua; Pivnyuk, Nikolay; Pocanic, Dinko; Pogorelko, Oleg; Pozdnyakov, Sergey; Preedom, Barry; Price, John; Prok, Yelena; Protopopescu, Dan; Raue, Brian; Riccardi, Gregory; Ricco, Giovanni; Ripani, Marco; Ritchie, Barry; Ronchetti, Federico; Rosner, Guenther; Rossi, Patrizia; Sabatie, Franck; Salamanca, Julian; Salgado, Carlos; Santoro, Joseph; Sapunenko, Vladimir; Schumacher, Reinhard; Serov, Vladimir; Sharabian, Youri; Sharov, Dmitri; Shvedunov, Nikolay; Smith, Elton; Smith, Lee; Sober, Daniel; Sokhan, Daria; Stavinsky, Aleksey; Stepanyan, Stepan; Stepanyan, Samuel; Stokes, Burnham; Stoler, Paul; Strakovski, Igor; Strauch, Steffen; Taiuti, Mauro; Tedeschi, David; Tkabladze, Avtandil; Tkachenko, Svyatoslav; Todor, Luminita; Ungaro, Maurizio; Vineyard, Michael; Vlassov, Alexander; Watts, Daniel; Weinstein, Lawrence; Williams, Michael; Wolin, Elliott; Yegneswaran, Amrit; Zana, Lorenzo; Zhang, Bin; Zhang, Jixie; Zhao, Bo; Zhao, Zhiwen

2008-07-01

The light vector mesons ($\\rho$, $\\omega$, and $\\phi$) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the $\\rho$ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to $e^{+}e^{-}$. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The $\\rho$ meson mass spectrum was extracted after the $\\omega$ and $\\phi$ signals were removed in a nearly model-independent way. Comparisons were made between the $\\rho$ mass spectra from the heavy targets ($A > 2$) with the mass spectrum extracted from the deuterium target. With respect to the $\\rho$-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body eff

Meson spectroscopy, quark mixing and quantum chromodynamics

International Nuclear Information System (INIS)

Filippov, A.T.

1979-01-01

A semiphenomenological theory of mass spectrum for mesons, consisting of a quark-antiquark pair, is presented. Relativistic kinematical effects of the quark mass differences, the SU(3)-symmetry breaking in slopes of the Regge trajectories and in radially excited states are taken into account. The OZI-rule breaking is taken into account by means of the mixing matrix for the quark wave functions, whose form is suggested by the quantum chromodynamics. A simple extrapolation of expression, given by the quantum chromodynamics from the ''asymptotic freedom'' region to the ''infrared slavery'' region is proposed to describe the dependence of the mixing parameters on the meson masses. To calculate masses and mixing angles for pseudoscalar mesons a condition is proposed that the pion mass is minimal. In this situation the eta-meson mass is near the maximal value. The predictions of the theory for masses and mixing angles of the mesons are in good agreement with the experiment

Rapidity resummation for B-meson wave functions

Directory of Open Access Journals (Sweden)

Shen Yue-Long

2014-01-01

Full Text Available Transverse-momentum dependent (TMD hadronic wave functions develop light-cone divergences under QCD corrections, which are commonly regularized by the rapidity ζ of gauge vector defining the non-light-like Wilson lines. The yielding rapidity logarithms from infrared enhancement need to be resummed for both hadronic wave functions and short-distance functions, to achieve scheme-independent calculations of physical quantities. We briefly review the recent progress on the rapidity resummation for B-meson wave functions which are the key ingredients of TMD factorization formulae for radiative-leptonic, semi-leptonic and non-leptonic B-meson decays. The crucial observation is that rapidity resummation induces a strong suppression of B-meson wave functions at small light-quark momentum, strengthening the applicability of TMD factorization in exclusive B-meson decays. The phenomenological consequence of rapidity-resummation improved B-meson wave functions is further discussed in the context of B → π transition form factors at large hadronic recoil.

Charged track multiplicity in B meson decay

International Nuclear Information System (INIS)

Brandenburg, G.; Ershov, A.; Gao, Y. S.; Kim, D. Y.-J.; Wilson, R.; Browder, T. E.; Li, Y.; Rodriguez, J. L.; Yamamoto, H.; Bergfeld, T.

2000-01-01

We have used the CLEO II detector to study the multiplicity of charged particles in the decays of B mesons produced at the Υ(4S) resonance. Using a sample of 1.5x10 6 B meson pairs, we find the mean inclusive charged particle multiplicity to be 10.71±0.02 -0.15 +0.21 for the decay of the pair. This corresponds to a mean multiplicity of 5.36±0.01 -0.08 +0.11 for a single B meson. Using the same data sample, we have also extracted the mean multiplicities in semileptonic and nonleptonic decays. We measure a mean of 7.82±0.05 -0.19 +0.21 charged particles per BB(bar sign) decay when both mesons decay semileptonically. When neither B meson decays semileptonically, we measure a mean charged particle multiplicity of 11.62±0.04 -0.18 +0.24 per BB(bar sign) pair. (c) 2000 The American Physical Society

Further evidence for magnetic charge from meson spectroscopy

International Nuclear Information System (INIS)

Akers, D.

1987-01-01

Recently evidence was presented for the existence of magnetic charge from Zeeman splitting in meson states. The model by Akers predicted the existence of a new eta meson at 1814 MeV with I/sup G/ (J/sup PC/) = O + (O -+ ). Experimental evidence for this new meson is cited and discussed

The Meson Spectroscopy Program at the Jefferson Laboratory

Energy Technology Data Exchange (ETDEWEB)

Filippi, Alessandro [Istituto Nazionale di Fisica Nucleare (INFN), Torino (Italy). et al.

2015-06-01

The experimental techniques that will be applied by the next generation meson spectroscopy experiments at JLab are described. For the first time, these experiments will be able to exploit the features of a photon beam of unprecedented intensity and momentum resolution, that will allow to perform precision studies of meson states with masses below 3 GeV/c². Photon induced reactions will enhance the production of spin-1 mesons, that are of particular interest according to the most recent Lattice QCD calculations of the lightest exotic hybrid meson.

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.)

Isotopic investigation of the late neoproterozoic and early cambrian carbon cycle on the northern Yangtze platform, south China

International Nuclear Information System (INIS)

Guo Qingjun; Liu Congqiang; Harald Strauss; Tatiana Goldberg

2003-01-01

The Precambrian-Cambrian transition is one of the critical time intervals in Earth history. Profound geotectonic, climatic and biological changes occur during the late Neoproterozoic and its transition into the early Cambrian. This study has researched on paired carbonate and organic carbon isotope determinations from Nanjiang, Sichuan Province of the Yangtze Platform, and provided a preliminary geochemical explanation for environmental variations and bio-events observed on the northern Yangtze Platform during the Precambrian-Cambrian transitional interval and their causal relationship. Organic carbon isotopic compositions on sediments vary from -35.8 to -30.1‰ at Nanjiang section; carbonate carbon isotopic compositions change between -3.5 and +0.5‰. Various carbon and sulphur isotopic compositions, different pyrite and organic matter content reflect changing environment and burial of organic matter in the Dengying Fm., the lower and upper part of Niutitang Fm. Anoxic conditions result in widespread preservation of organic rich sediments and pyrites in the black shales on the Yangtze Platform. (authors)

Meson facility. Powerful new research tool

International Nuclear Information System (INIS)

Lobashev, V.M.; Tavkhelidze, A.N.

A meson facility is being built at the Institute of Nuclear Research, USSR Academy of Sciences, in Troitsk, where the Scientific Center, USSR Academy of Sciences is located. The facility will include a linear accelerator for protons and negative hydrogen ions with 600 MeV energy and 0.5-1 mA beam current. Some fundamental studies that can be studied at a meson facility are described in the areas of elementary particles, neutron physics, solid state physics, and applied research. The characteristics of the linear accelerator are given and the meson facility's experimental complex is described

Search for radiative B meson decays

International Nuclear Information System (INIS)

Lesiak, T.; Muryn, B.; Nowak, G.; Antreasyan, D.; Irion, J.; McBride, P.; Strauch, K.; Bartels, H.W.; Bienlein, J.K.; Brockmueller, K.; Jakubowski, Z.; Karch, K.; Kloiber, T.; Koch, W.; Maschmann, W.; Meyer, H.; Skwarnicki, T.; Trost, H.J.; Voigt, A.; Wachs, K.; Zschorsch, P.; Besset, D.; Cabenda, R.; Cowan, R.; Bieler, C.; Graaf, K.; Heinsius, F.H.; Kiel, T.; Krueger, S.; Lekebusch, R.; Nernst, R.; Sievers, D.; Stock, V.; Strohbusch, U.; Bloom, E.D.; Clare, R.; Cooper, S.; Fairfield, K.; Fridman, A.; Gaiser, J.; Gelphman, D.; Godfrey, G.; Hofstadter, R.; Kirkbride, I.; Lee, R.; Leffler, S.; Litke, A.M.; Lockman, W.; Lowe, S.; Niczyporuk, B.; Pollock, B.; Schwarz, A.; Tompkins, J.; Van Uitert, B.; Wacker, K.; Brock, I.; Engler, A.; Kraemer, R.W.; Marlow, D.; Messing, F.; Prindle, D.; Renger, B.; Rippich, C.; Vogel, H.; Cavalli-Sforza, M.; Coyne, D.; Folger, G.; Glaser, G.; Kobel, M.; Lurz, B.; Schuette, J.; Volland, U.; Wegener, H.; Janssen, H.; Koenig, A.C.; Metzger, W.J.; Reidenbach, M.; Schotanus, J.; Walle, R.T. van de; Walk, W.; Keh, S.; Kilian, H.; Koenigsmann, K.; Scheer, M.; Schmitt, P.; Marsiske, H.; Williams, D.A.

1992-01-01

The Crystal Ball detector at the e + e - storage ring DORIS-II has been used to search for radiative B meson decays, especially of the type b→sγ. No mono-energetic γ-lines have been found in the inclusive photon spectrum from Υ(4S) decays, and upper limits are obtained for radiative decays of B mesons to various strange mesons and to the D*. Integrating the photon spectrum over the corresponding energy range, we find BR(B→γX) -3 , at 90% confidence level for the mass range 892 MeV≤M X ≤2045 MeV. (orig.)

Search for radiative B meson decays

International Nuclear Information System (INIS)

Lesiak, T.; Muryn, B.; Nowak, G.; Antreasyan, D.; Irion, J.; McBride, P.; Strauch, K.; Bartels, H.W.; Bienlein, J.K.; Brockmueller, K.; Jakubowski, Z.; Karch, K.; Kloiber, T.; Koch, W.; Maschmann, W.; Meyer, H.; Skwarnicki, T.; Trost, H.J.; Voigt, A.; Wachs, K.; Zschorsch, P.; Besset, D.; Cabenda, R.; Cowan, R.; Bieler, C.; Graaf, K.; Heinsius, F.H.; Kiel, T.; Krueger, S.; Lekebusch, R.; Nernst, R.; Sievers, D.; Stock, V.; Strohbusch, U.; Bloom, E.D.; Clare, R.; Cooper, S.; Fairfield, K.; Fridman, A.; Gaiser, J.; Gelphman, D.; Godfrey, G.; Hofstadter, R.; Kirkbride, I.; Lee, R.; Leffler, S.; Litke, A.M.; Lockman, W.; Lowe, S.; Niczyporuk, B.; Pollock, B.; Schwarz, A.; Tompkins, J.; Van Uitert, B.; Wacker, K.; Brock, I.; Engler, A.; Kraemer, R.W.; Marlow, D.; Messing, F.; Prindle, D.; Renger, B.; Rippich, C.; Vogel, H.; Cavalli-Sforza, M.; Coyne, D.; Folger, G.; Glaser, G.; Kobel, M.; Lurz, B.; Schuette, J.; Volland, U.; Wegener, H.; Janssen, H.; Koenig, A.C.; Metzger, W.J.; Reidenbach, M.; Schotanus, J.; Walle, R.T. van de; Walk, W.; Keh, S.; Kilian, H.; Koenigsmann, K.; Scheer, M.; Schmitt, P.; Marsiske, H.; Peck, C.; Porter, F.C.; Ratoff, P.; Williams, D.A.

1991-07-01

The Crystal Ball detector at the ε + ε - storage ring DORIS-II has been used to search for radiative B meson decays, especially of the type b→sγ. No mono-energetic γ-lines have been found in the inclusive photon spectrum from Υ(4S) decays, and upper limits are obtained for radiative decays of B mesons to various strange mesons and to the D*. Integrating the photon spectrum over the corresponding energy range, we find BR(B→γX) -3 at 90% confidence level for the mass range 892 MeV≤M X ≤2045 MeV. (orig.)

Quantum chromodynamics with infinite number of vector mesons

International Nuclear Information System (INIS)

Geshkenbejn, B.V.

1988-01-01

Families of vector mesons Ρ,Ψ,Υ, contain an infinite number of resonances with gradually increasing widths are considered. The asymptotic freedom requirement involves a relationship between the electric width of k-th resonance and its mass M k derivative over the number k. It is shown that for the families of Ψ and Υ mesons the moment from experimental function R(s) is equal to the sum of the moment from a bare quark loop and the edge term which stems from replacing of summation by integration. These equalities are fulfilled up to 1% for 60 moments in the Ψ-meson family and up to 2% for 96 moments in the Υ-meson family. The electronic widths of the resonances and the Ρ-meson mass are calculated. 7 refs

Is a charmed axial-vector meson already found

International Nuclear Information System (INIS)

Matsuda, S.

1976-12-01

A calculation is presented of the production rate via e + e - annihilation for a charmed p-wave meson of Jsup(P) = 1 + , based on a non-relativistic quark model of charmed hadrons. The results strongly suggest that the charmed axial-vector meson should be found copiously in association with a ground-state charmed meson. (author)

Search for scalar mesons

International Nuclear Information System (INIS)

Pennington, M.R.

1989-01-01

The search for I = 0 0 ++ mesons is described. The crucial role played by the states in the 1 GeV region is highlighted. An analysis program that with unimpeachable data would produce definitive results on these is outlined and shown with present data to provide prima facie evidence for dynamics beyond that of the quark model. The authors briefly speculate on the current status of the lowest mass scalar mesons and discuss how experiment can resolve the unanswered issues. 30 references, 6 figures, 1 table

Fock exchange in meson theories of nuclei

International Nuclear Information System (INIS)

Bolsterli, M.

1986-01-01

The Fock exchange term in meson field theories of nuclear systems is shown to arise from a two-loop ground-state self-energy diagram. Evaluation of this diagram gives the relativistic or semirelativistic analog of the Fock exchange energy; it differs from the nucleon-nucleon Fock energy in including retardation effects. In finite meson-field theories of nuclear systems, the variational nature of the meson-field analog of the Hartree-Fock energy functional can be further elucidated. 4 refs

On some rare weak decays of vector mesons

International Nuclear Information System (INIS)

Kurdadze, L.M.; Silagadze, Z.K.

2000-01-01

Some semileptonic weak decays of vector mesons are considered in the framework of the most popular quark models. Two the most popular models go give more elaborated estimates for the vector meson semileptonic decay rates are used. Unfortunately the predicted branching ratios are too small to make a study of these decays realistic at meson factories under construction [ru

Neutral and charged scalar mesons, pseudoscalar mesons, and diquarks in magnetic fields

Science.gov (United States)

Liu, Hao; Wang, Xinyang; Yu, Lang; Huang, Mei

2018-04-01

We investigate both (pseudo)scalar mesons and diquarks in the presence of external magnetic field in the framework of the two-flavored Nambu-Jona-Lasinio (NJL) model, where mesons and diquarks are constructed by infinite sum of quark-loop chains by using random phase approximation. The polarization function of the quark-loop is calculated to the leading order of 1 /Nc expansion by taking the quark propagator in the Landau level representation. We systematically investigate the masses behaviors of scalar σ meson, neutral and charged pions as well as the scalar diquarks, with respect to the magnetic field strength at finite temperature and chemical potential. It is shown that the numerical results of both neutral and charged pions are consistent with the lattice QCD simulations. The mass of the charge neutral pion keeps almost a constant under the magnetic field, which is preserved by the remnant symmetry of QCD ×QED in the vacuum. The mass of the charge neutral scalar σ is around two times quark mass and increases with the magnetic field due to the magnetic catalysis effect, which is an typical example showing that the polarized internal quark structure cannot be neglected when we consider the meson properties under magnetic field. For the charged particles, the one quark-antiquark loop contribution to the charged π± increases essentially with the increase of magnetic fields due to the magnetic catalysis of the polarized quarks. However, the one quark-quark loop contribution to the scalar diquark mass is negative comparing with the point-particle result and the loop effect is small.

Rare meson decays into very light neutralinos

Energy Technology Data Exchange (ETDEWEB)

Dreiner, H.K.; Grab, S. [Bonn Univ. (Germany). Bethe Center for Theoretical Physics und Physikalisches Inst.; Koschade, D. [RWTH Aachen Univ. (Germany). Inst. fuer Theoretische Physik; London Univ. (United Kingdom). Centre for Reserach in String Theory; Kraemer, M.; O' Leary, B. [RWTH Aachen Univ. (Germany). Inst. fuer Theoretische Physik; Langenfeld, U. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

2009-05-15

We investigate the bounds on the mass of the lightest neutralino from rare meson decays within the MSSM with and without minimal flavor violation. We present explicit formulae for the two-body decays of mesons into light neutralinos and perform the first complete calculation of the loop-induced decays of kaons to pions and light neutralinos and B mesons to kaons and light neutralinos. We find that the supersymmetric branching ratios are strongly suppressed within the MSSM with minimal flavor violation, and that no bounds on the neutralino mass can be inferred from experimental data, i.e. a massless neutralino is allowed. The branching ratios for kaon and B meson decays into light neutralinos may, however, be enhanced when one allows for non-minimal flavor violation. We find new constraints on the MSSM parameter space for such scenarios and discuss prospects for future kaon and B meson experiments. Finally, we comment on the search for light neutralinos in monojet signatures at the Tevatron and at the LHC. (orig.)

Meson exchange corrections in deep inelastic scattering on deuteron

International Nuclear Information System (INIS)

Kaptari, L.P.; Titov, A.I.

1989-01-01

Starting with the general equations of motion of the nucleons interacting with the mesons the one-particle Schroedinger-like equation for the nucleon wave function and the deep inelastic scattering amplitude with the meson-exchange currents are obtained. Effective pion-, sigma-, and omega-meson exchanges are considered. It is found that the mesonic corrections only partially (about 60%) restore the energy sum rule breaking because of the nucleon off-mass-shell effects in nuclei. This results contradicts with the prediction based on the calculation of the energy sum rule limited by the second order of the nucleon-meson vertex and static approximation. 17 refs.; 3 figs

Unified Chiral models of mesons and baryons

International Nuclear Information System (INIS)

Mendez-Galain, R.; Ripka, G.

1990-01-01

Unified Chiral models of mesons and baryons are presented. Emphasis is placed on the underlying quark structure of hadrons including the Skyrmion. The Nambu Jona-Lasinio model with vector mesons is discussed

Search for gluonic excitations in light unconventional mesons

Energy Technology Data Exchange (ETDEWEB)

Paul Eugenio

2007-07-01

Studies of meson spectra via strong decays provide insight regarding QCD at the confinement scale. These studies have led to phenomenologicalmodels for QCD such as the constituent quark model. However, QCD allows for a much richer spectrum of meson states which include extra states such as exotics, hybrids, multi-quarks, and glueballs. First discussion of the status of exotic meson searches is given followed by a discussion of plans at Jefferson Lab to double the energy of the machine to 12 GeV, which will allow us to access photoproduction of mesons in search for gluonic excited states.

Sigma meson in heavy ion collision

International Nuclear Information System (INIS)

Cristian, Ivan; Fuchs, Christian

2004-01-01

We want to present a short theoretical prediction of the behaviour of the sigma meson in heavy ion collisions. It is considered that the sigma meson is a pion-pion correlation, resulting from the decay of the N*(1440) resonance. There will be presented some QMD simulations. (authors)

Sedimentary facies of the upper Cambrian (Furongian; Jiangshanian and Sunwaptan) Tunnel City Group, Upper Mississippi Valley: new insight on the old stormy debate

Science.gov (United States)

Eoff, Jennifer D.

2014-01-01

New data from detailed measured sections permit a comprehensive revision of the sedimentary facies of the Furongian (upper Cambrian; Jiangshanian and Sunwaptan stages) Tunnel City Group (Lone Rock Formation and Mazomanie Formation) of Wisconsin and Minnesota. Heterogeneous sandstones, comprising seven lithofacies along a depositional transect from shoreface to transitional-offshore environments, record sedimentation in a storm-dominated, shallow-marine epicontinental sea. The origin of glauconite in the Birkmose Member and Reno Member of the Lone Rock Formation was unclear, but its formation and preserved distribution are linked to inferred depositional energy rather than just net sedimentation rate. Flat-pebble conglomerate, abundant in lower Paleozoic strata, was associated with the formation of a condensed section during cratonic flooding. Hummocky cross-stratification was a valuable tool used to infer depositional settings and relative paleobathymetry, and the model describing formation of this bedform is expanded to address flow types dominant during its genesis, in particular the importance of an early unidirectional component of combined flow. The depositional model developed here for the Lone Rock Formation and Mazomanie Formation is broadly applicable to other strata common to the early Paleozoic that document sedimentation along flooded cratonic interiors or shallow shelves.

Diachronism in the late Neoproterozoic-Cambrian arc-rift transition of North Gondwana: A comparison of Morocco and the Iberian Ossa-Morena Zone

Science.gov (United States)

Álvaro, J. Javier; Bellido, Félix; Gasquet, Dominique; Pereira, M. Francisco; Quesada, Cecilio; Sánchez-García, Teresa

2014-10-01

In the northwestern border of the West African craton (North Gondwana), a transition from late Neoproterozoic subduction/collision to Cambrian rift processes was recorded in the Anti-Atlas (Morocco) and in the Ossa-Morena Zone (Iberia). Cambrian rifting affected both Pan-African and Cadomian basements in a stepwise and diachronous way. Subsequently, both areas evolved into a syn-rift margin episodically punctuated by uplift and tilting that precluded Furongian sedimentation. A comparison of sedimentary, volcanic and geodynamic evolution is made in the late Neoproterozoic (Pan-African and Cadomian) belts and Cambrian rifts trying to solve the apparent diachronous (SW-NE-trending) propagation of an early Palaeozoic rifting regime that finally led to the opening of the Rheic Ocean.

Old tensor mesons in QCD sum rules

International Nuclear Information System (INIS)

Aliev, T.M.; Shifman, M.A.

1981-01-01

Tensor mesons f, A 2 and A 3 are analyzed within the framework of QCD sum rules. The effects of gluon and quark condensate is accounted for phenomenologically. Accurate estimates of meson masses and coupling constants of the lowest-lying states are obtained. It is shown that the masses are reproduced within theoretical uncertainty of about 80 MeV. The coupling of f meson to the corresponding quark current is determined. The results are in good aqreement with experimental data [ru

Why do nucleons cling. [Meson theory

Energy Technology Data Exchange (ETDEWEB)

Kumar, N [Hindu Coll., Delhi (India)

1976-10-01

The nature of the forces which bind nucleons together within the nucleus of an atom have been discussed in detail. The characteristic properties of the nucleons, such as spin, interaction range etc. and the meson theory of nuclear forces are described. The present researches indicate that the force between two nucleons in a many-nucleon system is not very different from the force between two free nucleons. Researches related to the origin of nuclear forces based on the meson theory are now mainly concerned with the role played by the heavier mesons and the two pion exchanges in the middle region around 0.7 fm. (10/sup -13/ cm).

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

Production and decay rates of the iota meson

International Nuclear Information System (INIS)

Frank, M.; O'Donnell, P.J.; Toronto Univ., Ontario

1984-01-01

We correlate the results for the mass spectrum of low lying isoscalar-pseudoscalar mesons with the production decay rates from J/psi->γP, with P=eta 1 , eta' 1 , eta 2 and iota and study the radiative decays of the iota meson. We conclude that the iota meson has to be interpreted as having a strong gluonium component. (orig.)

Tensor meson dominance and e/sup +/e/sup -/-physics

Energy Technology Data Exchange (ETDEWEB)

Genz, H [Miami Univ., Coral Gables, FL (USA). Center for Theoretical Studies; Karlsruhe Univ. (T.H.) (Germany, F.R.). Inst. fuer Theoretische Kernphysik); Mallik, S [Karlsruhe Univ. (T.H.) (Germany, F.R.). Inst. fuer Theoretische Kernphysik

1983-01-01

The phenomenological status of tensor meson dominance is reported. Some new results concerning hadronic decays of the 2/sup + +/-meson chi/sub 2/(3.55) and the heavy lepton tau are also included. Considering experimental errors, tensor meson dominance is in agreement with experiment.

Genesis of early Cambrian phosphorite of Krol Belt, Lesser Himalaya

Digital Repository Service at National Institute of Oceanography (India)

Mazumdar, A.; Banerjee, D.M.

depositional en- vironment. Similar shallow marine character for Late Vendian and Early Cambrian phosphorites have been recorded from Yangtze Basin (South China), Khub- shugul Basin (Mongolia), Karatau Basin (Kazakh- stan), Soltaniah Basin (Iran), Tal Basin.... This characteris- tic of microbial mats may enable them to bind the franco- lite microcrysts on their surfaces, giving rise to microbial laminations. The capacity of microbiota, viz. bacteria, fungi and cyanobacterial mat-forming microphytes to trap and bind...

Radiative decays of vector mesons in the chiral bag model

International Nuclear Information System (INIS)

Tabachenko, A.N.

1988-01-01

A new model of radiative π-meson decays of vector mesons in the chiral bag model is proposed. The quark-π-meson interaction has the form of a pseudoscalar coupling and is located on the bag surface. The vector meson decay width depends on the quark masses, the π-meson decay constant, the radius of the bag, and the free parameter Z 2 , which specifies the disappearance of the bag during the decay. The obtained results for the omega- and p-decay widths are in satisfactory agreement with the experiment

Nd-Sr isotopic and geochemical systematics in Cambrian boninites and tholeiites from Victoria, Australia

Science.gov (United States)

Nelson, D. R.; Crawford, A. J.; McCulloch, M. T.

1984-11-01

Rocks with boninitic affinities have been recognised in a number of “ophiolites”, including the Cambrian Heathcote and Mt Wellington Greenstone Belts of Victoria. Boninites and high-Mg andesites from the Heathcote Greenstone Belt show a restricted range of initial ɛ Nd values of between +3.3 to +5.8. Extremely refractory boninites from the Mt Wellington Greenstone Belt have ɛ Nd ranging from +1.3 to -9. Ti/Zr is positively correlated with Sm/Nd with the Heathcote lavas generally possessing greater depletion of Ti and enrichment of Zr relative to the middle and heavy REE with increasing LREE/HREE. These data are consistent with the generation of boninites by partial melting of refractory peridotite following invasion by LREE- and Zr-enriched, low ɛ Nd fluids. Tholeiites overlying the boninites in both greenstone belts have flat REE patterns and ɛ Nd˜+5, lower than that anticipated for lavas derived from depleted MORB source reservoirs in the Cambrian, suggesting that their source was also contaminated by a LREE-enriched, low ɛ Nd component similar to that involved in the generation of the Howqua boninites. The added components have characteristics compatible with their derivation from subducted altered oceanic crust and/or from wet subducted sediments. The identification of boninites and other low-Ti lavas in the Victorian greenstone belts is strong evidence for island arc development in southeastern Australia during the Lower Cambrian and provides further support for a subduction-related origin for many ophiolites.

Inclusive spectra of hadrons in B-meson decays

International Nuclear Information System (INIS)

Dobrovol'skaya, A.V.; Ter-Martirosyan, K.A.; Zoller, V.R.

1989-01-01

The inclusive spectra of hadrons (mainly pions) produced in the semileptonic and nonleptonic decays of B-mesons are calculated. Parameters of spectra for different types of hard qq-bar-strings, appearing in the B-meson decays, are determined using the data on e+e-annihilation. Numerical results for B-meson decay induced by both b→b and b→u transitions are presented. 10 refs.; 5 figs

Meson Spectroscopy in the Light Quark Sector

Science.gov (United States)

De Vita, R.

2014-03-01

Understanding the hadron spectrum is one of the fundamental issues in modern particle physics. We know that existing hadron configurations include baryons, made of three quarks, and mesons, made of quark-antiquark pairs. However most of the mass of the hadrons is not due to the mass of these elementary constituents but to their binding force. Studying the hadron spectrum is therefore a tool to understand one of the fundamental forces in nature, the strong force, and Quantum Chromo Dynamics (QCD), the theory that describes it. This investigation can provide an answer to fundamental questions as what is the origin of the mass of hadrons, what is the origin of quark confinement, what are the relevant degrees of freedom to describe these complex systems and how the transition between the elementary constituents, quarks and gluons, and baryons and mesons occurs. In this field a key tool is given by meson spectroscopy. Mesons, being made by a quark and an anti-quark, are the simplest quark bound system and therefore the ideal benchmark to study the interaction between quarks and understand what the role of gluons is. In this investigation, it is fundamental to precisely determine the spectrum and properties of mesons but also to search for possible unconventional states beyond the qbar q configuration as tetraquarks (qqoverline{qq}), hybrids (qbar qg) and glueballs. These states can be distinguished unambiguously from regular mesons when they have exotic quantum numbers, i.e. combinations of total angular momentum, spin and parity that are not allowed for qbar q states. These are called exotic quantum numbers and the corresponding states are referred to as exotics. The study of the meson spectrum and the search for exotics is among the goals of several experiments in the world that exploit different reaction processes, as e+e- annihilation, pbar p annihilation, pion scattering, proton-proton scattering and photo-production, to produce meson states. This intense effort is

SACLAY: Eta mesons at Saturne

Energy Technology Data Exchange (ETDEWEB)

Anon.

1992-05-15

Using a nuclear reaction, the new tagged eta meson facility now operating at the French Saturne National Laboratory in Saclay produces eta mesons (together with recoil helium-3 nuclei) by proton bombardment of a deuterium target. The proton beam is extracted from the Saturne synchrotron at 893 MeV, stabilized to 80 keV. This is a scant 1.5 MeV above the reaction threshold and close to the energy where eta production peaks.

SACLAY: Eta mesons at Saturne

International Nuclear Information System (INIS)

Anon.

1992-01-01

Using a nuclear reaction, the new tagged eta meson facility now operating at the French Saturne National Laboratory in Saclay produces eta mesons (together with recoil helium-3 nuclei) by proton bombardment of a deuterium target. The proton beam is extracted from the Saturne synchrotron at 893 MeV, stabilized to 80 keV. This is a scant 1.5 MeV above the reaction threshold and close to the energy where eta production peaks

Multistrange Meson-Baryon Dynamics and Resonance Generation

Science.gov (United States)

Khemchandani, K. P.; Martínez Torres, A.; Hosaka, A.; Nagahiro, H.; Navarra, F. S.; Nielsen, M.

2018-05-01

In this talk I review our recent studies on meson-baryon systems with strangeness - 1 and - 2. The motivation of our works is to find resonances generated as a consequence of coupled channel meson-baryon interactions. The coupled channels are all meson-baryon systems formed by combining a pseudoscalar or a vector meson with an octet baryon such that the system has the strange quantum number equal to - 1 or - 2. The lowest order meson-baryon interaction amplitudes are obtained from Lagrangians based on the chiral and the hidden local symmetries related to the vector mesons working as the gauge bosons. These lowest order amplitudes are used as an input to solve the Bethe-Salpeter equation and a search for poles is made in the resulting amplitudes, in the complex plane. In case of systems with strangeness - 1, we find evidence for the existence of some hyperons such as: Λ(2000), Σ(1750), Σ(1940), Σ(2000). More recently, in the study of strangeness - 2 systems we have found two narrow resonances which can be related to Ξ (1690) and Ξ(2120). In this latter work, we have obtained the lowest order amplitudes relativistically as well as in the nonrelativistic approximation to solve the scattering equations. We find that the existence of the poles in the complex plane does not get affected by the computation of the scattering equation with the lowest order amplitudes obtained in the nonrelativistic approximation.

Relativistic meson spectroscopy in momentum space

International Nuclear Information System (INIS)

Hersbach, H.

1994-01-01

In this paper a relativistic constituent-quark model based on the Ruijgrok--de Groot formalism is presented. The quark model is not defined in configuration space, but in momentum space. The complete meson spectrum, with the exception of the self-conjugate light unflavored mesons, is calculated. The potential used consists of a one-gluon exchange (OGE) part and a confining part. For the confining part a relativistic generalization of the linear plus constant potential was used, which is well defined in momentum space without introducing any singularities. For the OGE part several potentials were investigated. Retardations were included at all places. By the use of a fitting procedure involving 52 well-established mesons, but results were obtained for a potential consisting of a purely vector Richardson potential and a purely scalar confining potential. Reasonable results were also obtained for a modified Richardson potential. Most meson masses, with the exception of the π, the K, and the K 0 * , were found to be quite well described by the model

Asymptotics of Heavy-Meson Form Factors

CERN Document Server

Grozin, A.G.; Grozin, Andrey G.; Neubert, Matthias

1997-01-01

Using methods developed for hard exclusive QCD processes, we calculate the asymptotic behaviour of heavy-meson form factors at large recoil. It is determined by the leading- and subleading-twist meson wave functions. For $1\\ll |v\\cdot v'|\\ll m_Q/\\Lambda$, the form factors are dominated by the Isgur--Wise function, which is determined by the interference between the wave functions of leading and subleading twist. At $|v\\cdot v'|\\gg m_Q/\\Lambda$, they are dominated by two functions arising at order $1/m_Q$ in the heavy-quark expansion, which are determined by the leading-twist wave function alone. The sum of these contributions describes the form factors in the whole region $|v\\cdot v'|\\gg 1$. As a consequence, there is an exact zero in the form factor for the scattering of longitudinally polarized $B^*$ mesons at some value $v\\cdot v'\\sim m_b/\\Lambda$, and an approximate zero in the form factor of $B$ mesons in the timelike region ($v\\cdot v'\\sim -m_b/\\Lambda$). We obtain the evolution equations and sum rules ...

C(1480) meson and electromagnetic processes

International Nuclear Information System (INIS)

Landsberg, L.G.

1992-01-01

Possible processes of production of the vector meson C(1480) → var-phi π, a candidate for exotic states, in electromagnetic processes are considered [photoproduction, e + e - →C(1480) → var-phi π 0 , and the reaction of production of C(1480) in the Coulomb field of a nucleus]. It is shown that coherent Coulomb production of the C(1480) meson allows one to determine the absolute value of BR[C(1480) → var-phi π], which is essential for the interpretation of the nature of this hadron. Possibilities of observing C(1480) mesons in e + e - collisions at the var-phi factory DAΦNE are studied. 27 refs., 12 figs., 1 tab

Radiative decay of light and heavy mesons

International Nuclear Information System (INIS)

Barik, N.; Dash, P.C.

1994-01-01

The M1 transition among the vector (V) and pseudoscalar (P) mesons in the light and heavy flavor sectors has been investigated in a potential model of independent quarks. Going beyond the static approximation, to add some momentum dependence due to the recoil effect in a more realistic calculation, we find an improvement in the results for the radiative decay of light flavored mesons. However, our prediction on the decay rates for the mesons (D * and B * ) in the heavy flavor sector remains unaffected and compares well with those of other model calculations

In-medium meson properties and screening correlators

International Nuclear Information System (INIS)

Bazavov, A; Karsch, F; Mukherjee, Swagato; Petreczky, P; Maezawa, Y

2014-01-01

We study spatial meson correlation functions consisting of strange quarks, strange and charm quarks and charm quarks in (2 + 1)-flavor QCD using the highly improved staggered quark action. We find that the in-medium modification of the meson correlators decreases with increasing charm quark content and decreasing size. In particular, we find strong in-medium modification of φ and D s meson correlators around the chiral transition temperature T c , while J/ψ and η c correlators show strong in-medium modification only at temperatures of 1.4T c .

Review of meson resonance radiative decays

International Nuclear Information System (INIS)

Thorndike, E.H.

1977-01-01

The radiative decays of meson resonances can be studied by three different approaches, it is noted. These are the meson-exchange, Primakoff effect, and the production of the desired resonance and subsequent observation of its decay. These approaches are criticized and examples of them are reviewed. Mass distributions are shown and branching ratios discussed. 21 references

Meson masses and decay constants from unquenched lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Jansen, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); McNeile, C. [Glasgow Univ. (United Kingdom). Dept. of Physics and Astronomy; Michael, C. [Liverpool Univ. (United Kingdom). Theoretical Physics Div., Dept. of Mathematical Sciences; Urbach, C. [Humboldt Univ. Berlin (Germany). Inst. fuer Physik

2009-06-15

We report results for the masses of the flavour non-singlet light 0{sup ++}, 1{sup --}, and 1{sup +-} mesons from unquenched lattice QCD at two lattice spacings. The twisted mass formalism was used with two flavours of sea quarks. For the 0{sup ++} and 1{sup +-} mesons we look for the effect of decays on the mass dependence. For the light vector mesons we study the chiral extrapolations of the mass. We report results for the leptonic and transverse decay constants of the meson. We test the mass dependence of the KRSF relations. (orig.)

Meson masses and decay constants from unquenched lattice QCD

International Nuclear Information System (INIS)

Jansen, K.; McNeile, C.; Michael, C.; Urbach, C.

2009-06-01

We report results for the masses of the flavour non-singlet light 0 ++ , 1 -- , and 1 +- mesons from unquenched lattice QCD at two lattice spacings. The twisted mass formalism was used with two flavours of sea quarks. For the 0 ++ and 1 +- mesons we look for the effect of decays on the mass dependence. For the light vector mesons we study the chiral extrapolations of the mass. We report results for the leptonic and transverse decay constants of the meson. We test the mass dependence of the KRSF relations. (orig.)

Inclusive decays of the B meson and possible life-time difference between Bd0 and B± mesons

International Nuclear Information System (INIS)

Tanimoto, Morimitsu

1992-01-01

We study branching ratios of the inclusive semileptonic decay and the inclusive anti ccanti s decay of the B meson in the spectator model, focusing on the life-time difference between B d 0 and B + mesons. In the case of τsub(B ± )/τsub(B d 0 )=1, it is impossible to get the branching ratio below 12% for B→eνX without going over 20% for B→anti ccanti s, which is unfavored by the inclusive K - decay of the B meson. It is found that the sizable life-time difference leads to the reasonable inclusive semileptonic decay rate and the inclusive anti ccanti s decay rate. (orig.)

Observation and study of bottom-meson decays to a charm meson, a proton-antiproton pair, and pions

Energy Technology Data Exchange (ETDEWEB)

Hong, Tae Min [Univ. of California, Santa Barbara, CA (United States)

2010-04-27

Bottom-meson decays with baryons show two unusual features—the branching fractions are enhanced for multibody decays and the baryon-antibaryon subsystem recoils against the other decay products—and their reasons are not yet well understood. Moreover, measurements using explicit reconstruction techniques constitute only about 1% out of about 8% of such decays. This Dissertation reports the study of ten bottom-meson decays (labeled 0– 9) to a proton-antiproton pair, a charm meson, and a system of up to two pions, using the BABAR Experiment’s 455×10⁶ BB pairs produced with the PEP-II asymmetric-energy e⁺e^- collider at the Stanford Linear Accelerator Center.

CORNELL: CLEO discovers B meson penguins

Energy Technology Data Exchange (ETDEWEB)

Anon.

1993-06-15

The CLEO collaboration at Cornell's CESR electron-positron storage ring has discovered a rare type of B meson decay in which only a high energy photon and a K* meson are produced. These decays provide the first unambiguous evidence for an alternative route for heavy quark decay that has been given the whimsical name ''penguin diagram''. In the mid-1970s penguin diagrams were proposed to explain the puzzling strangeness quantum number selection rules in the decay of K mesons. At the same time it was realized that penguin diagrams could also be important in the CP violation seen in neutral K meson decay. CP violation, an asymmetry between matter and antimatter, is an essential ingredient in understanding why there is much more matter than antimatter in the universe. CP violation introduces a definite direction to the arrow of time, which could otherwise point equally forwards or backwards. In addition, penguin decays are very sensitive to some extensions of the Standard Model of weak decay. Although penguin diagrams were first proposed to explain an effect in K meson decay, the K system gives no unique signature for them, and verification of penguin processes meant looking elsewhere. In the Standard Model, quarks decay under the influence of the weak force, emitting a W boson. Since the W is charged, the charge of the initial quark differs from that of the final quark, so the charge of the quark changes as well as its flavour.

Medium modifications of mesons. Chiral symmetry restoration, in-medium QCD sum rules for D and ρ mesons, and Bethe-Salpeter equations

Energy Technology Data Exchange (ETDEWEB)

Hilger, Thomas Uwe

2012-04-11

The interplay of hadron properties and their modification in an ambient nuclear medium on the one hand and spontaneous chiral symmetry breaking and its restoration on the other hand is investigated. QCD sum rules for D and B mesons embedded in cold nuclear matter are evaluated. We quantify the mass splitting of D- anti D and B- anti B mesons as a function of the nuclear matter density and investigate the impact of various condensates in linear density approximation. The analysis also includes D{sub s} and D{sup *}{sub 0} mesons. QCD sum rules for chiral partners in the open-charm meson sector are presented at nonzero baryon net density or temperature. We focus on the differences between pseudo-scalar and scalar as well as vector and axial-vector D mesons and derive the corresponding Weinberg type sum rules. Based on QCD sum rules we explore the consequences of a scenario for the ρ meson, where the chiral symmetry breaking condensates are set to zero whereas the chirally symmetric condensates remain at their vacuum values. The complementarity of mass shift and broadening is discussed. An alternative approach which utilizes coupled Dyson-Schwinger and Bethe-Salpeter equations for quark-antiquark bound states is investigated. For this purpose we analyze the analytic structure of the quark propagators in the complex plane numerically and test the possibility to widen the applicability of the method to the sector of heavy-light mesons in the scalar and pseudo-scalar channels, such as the D mesons, by varying the momentum partitioning parameter. The solutions of the Dyson-Schwinger equation in the Wigner-Weyl phase of chiral symmetry at nonzero bare quark masses are used to investigate a scenario with explicit but without dynamical chiral symmetry breaking.

Basalts and picrites from a plume-type ophiolite in the South Qilian Accretionary Belt, Qilian Orogen: Accretion of a Cambrian Oceanic Plateau?

Science.gov (United States)

Zhang, Yuqi; Song, Shuguang; Yang, Liming; Su, Li; Niu, Yaoling; Allen, Mark B.; Xu, Xin

2017-05-01

Oceanic plateaus with high-Mg rocks in the present-day oceanic crust have attracted much attention for their proposed mantle-plume origins and abnormally high mantle potential temperatures (Tp). However, equivalent rocks in ancient oceanic environments are usually poorly preserved because of deformation and metamorphism. Here we present petrological, geochronological and geochemical data for pillow lavas from Cambrian ophiolites in the Lajishan and Yongjing regions of the South Qilian Accretionary Belt (SQAB), from the southern part of the Qilian Orogen, northern China. Three rock groups can be identified geochemically: (1) sub-alkaline basalts with enriched mid- ocean ridge basalt (E-MORB) affinity; (2) alkaline basalts with oceanic island basalt (OIB) features, probably derived from partial melting of an enriched mantle source; and (3) picrites with MgO (18-22 wt%). Cr-numbers [Cr# = Cr/(Cr + Al)] of spinels from the picrites suggest 18-21% degree of partial melting at the estimated mantle potential temperature (Tp) of 1489-1600 °C, equivalent to values of Cenozoic Hawaiian picrites (1500-1600 °C). Zircons from one gabbro sample yielded a U-Pb Concordia age of 525 ± 3 Ma, suggesting the oceanic crust formed in the Cambrian. Available evidence suggests that Cambrian mantle plume activity is preserved in the South Qilian Accretionary Belt, and influenced the regional tectonics: "jamming" of the trench by thick oceanic crust explains the emplacement and preservation of the oceanic plateau, and gave rise to the generation of concomitant Ordovician inner-oceanic island arc basalts via re-organisation of the subduction zones in the region.

Meson phase space density from interferometry

International Nuclear Information System (INIS)

Bertsch, G.F.

1993-01-01

The interferometric analysis of meson correlations a measure of the average phase space density of the mesons in the final state. The quantity is a useful indicator of the statistical properties of the systems, and it can be extracted with a minimum of model assumptions. Values obtained from recent measurements are consistent with the thermal value, but do not rule out superradiance effects

Vector mesons on the light front

International Nuclear Information System (INIS)

Naito, K.; Maedan, S.; Itakura, K.

2004-01-01

We apply the light-front quantization to the Nambu-Jona-Lasinio model with the vector interaction, and compute vector meson's mass and light-cone wavefunction in the large N limit. Following the same procedure as in the previous analyses for scalar and pseudo-scalar mesons, we derive the bound-state equations of a qq-bar system in the vector channel. We include the lowest order effects of the vector interaction. The resulting transverse and longitudinal components of the bound-state equation look different from each other. But eventually after imposing an appropriate cutoff, one finds these two are identical, giving the same mass and the same (spin-independent) light-cone wavefunction. Mass of the vector meson decreases as one increases the strength of the vector interaction

Cambrian and Ordovician Fossil-Lagerstätten in the Barrandian area

Czech Academy of Sciences Publication Activity Database

Fatka, O.; Budil, P.; Kraft, P.; Mergl, M.; Mikuláš, Radek; Valent, M.; Lajblová, K.; Rak, Š.; Steinová, M.; Szabad, M.; Micka, V.; Aubrechtová, M.; Lajbl, L.; Nohejlová, M.; Vodička, J.

2012-01-01

Roč. 18, č. 1 (2012), s. 22-25 ISSN 1212-6209. [Congress of CGS and SGS. Moninec, 2011.09.22-2011.09.25] R&D Projects: GA ČR GA205/06/0395; GA ČR GA205/09/1521 Institutional research plan: CEZ:AV0Z30130516 Keywords : Cambrian * Ordovician * Fossil-Lagerstätten Subject RIV: DB - Geology ; Mineralogy http://www.sci.muni.cz/gap/casop/

Self-regulation of trilobite diversity in Murero (middle Cambrian, Spain) due to compensatory extinction

Energy Technology Data Exchange (ETDEWEB)

Lopez-Villalta, J.S.

2016-07-01

As species accumulate in a community, competition for available ecospace is expected to prevent the addition of new species and to facilitate species extinction, thus producing a dynamic equilibrium of diversity. This mechanism remains under debate since its empirical support comes mainly from indirect or partial evidence, with very few direct tests at the species level. Here a new method is described to detect the presence of selfregulation feedbacks between species richness and turnover rates. It consists of Monte Carlo simulations which randomize the distribution of species ranges among stratigraphic intervals, providing predictions which allow the detection of genuine self-regulation feedbacks in the real data. Since the simulations include any potential bias due to preservation, sampling, or change in depositional environment, and these biases would also affect the real dataset, they are thus ruled out as explanations for any difference found. This method is applied to one of the best known fossiliferous sequences worldwide, the Rambla de Valdemiedes in Murero (RV1 section, middle Cambrian, Spain), a classic locality that has been studied for more than 150 years and which stands out due to its excellent sampling density, continuous deposition, and homogeneous fossil preservation. The results show that trilobite species richness was self-regulated due to positive feedback with extinction rate, which implies that compensatory extinction regulated this fauna in spite of the on-going Cambrian radiation. The lack of evidence of any origination feedback suggests ecological opportunities were not limiting for new species to colonize this Cambrian community. (Author)

Stratigraphic framework of Cambrian and Ordovician rocks in the central Appalachian Basin from Medina County, Ohio, through southwestern and south-central Pennsylvania to Hampshire County, West Virginia

Science.gov (United States)

Ryder, Robert T.; Harris, Anita G.; Repetski, John E.; revised and digitized by Crangle, Robert D.

2003-01-01

are identified by the following descriptive names: (1) sandstone, shale, limestone, and dolomite unit, (2) dolomite and sandstone unit, (3) limestone and black shale unit, and (4) shale and sandstone unit. Each of these units and their associated subunits thicken from west to east across the restored section to a maximum near the depositional axis of the Rome trough and then thin eastward to the end of the section. The sandstone, shale, limestone, and dolomite unit is largely confined to the asymmetric graben that marks the initial phase of the Rome trough. This unit is Early and Middle Cambrian in age and consists, in ascending order, of a basal sandstone unit (undrilled but probably present), the Tomstown Dolomite (undrilled but probably present), the Waynesboro Formation, and the Pleasant Hill Limestone and its equivalent lower one-third of the Elbrook Formation at the eastern end of the section. The dolomite and sandstone unit forms the core of the Cambrian and Ordovician sequence. In the Rome trough and on the adjoining South-central Pennsylvania arch, this unit consists, in ascending order, of the Middle and Upper Cambrian Warrior Formation and the equivalent upper two-thirds of the Elbrook Formation at the eastern end of the section, the Upper Cambrian Gatesburg Formation, and the Lower Ordovician and Middle Ordovician (Whiterockian and Chazyan) Beekmantown Group. West of the Ohio-West Virginia hinge zone, the dolomite and sandstone unit consists, in ascending order, of the Conasauga Formation of Janssens (1973), the Krysik sandstone of driller's usage, the B zone of Calvert (1964), the Knox Dolomite and the associated Rose Run Sandstone Member, and the Wells Creek Formation. The widespread Knox unconformity is located at the base of the Wells Creek Formation and at or near the top of the adjoining Beekmantown Group, except near the depositional axis of the Rome trough, where the unconformity seems to be absent. The limestone and black shale unit i

High statistics inclusive φ meson production at SPS energies

International Nuclear Information System (INIS)

Dijkstra, H.; Belau, E.

1986-01-01

Inclusive φ meson production has been measured for 100 GeV/c and 200 GeV/c incident π - , anti p and K - , and for 120 GeV/c and 200 GeV/c incident π + , p and K + , using a Be target. A total of 630,000 φ mesons has been recorded in the kinematic range 0 F F and dσ/dp T 2 . The longitudinal momentum distributions show that the strange valence quarks of the incident K mesons play an important role in φ meson production, even at small x F . The decay angular distribution of the φ meson is evaluated in the Gottfried-Jackson frame and is expressed in the elements of the density matrix. There is a small but significant cos 2 θ GJ dependence for small p T , which decreases for increasing p T . (Auth.)

Molecular components in P-wave charmed-strange mesons

CERN Document Server

Ortega, Pablo G.

2016-10-26

Results obtained by various experiments show that the $D_{s0}^{\\ast}(2317)$ and $D_{s1}(2460)$ mesons are very narrow states located below the $DK$ and $D^{\\ast}K$ thresholds, respectively. This is markedly in contrast with the expectations of naive quark models and heavy quark symmetry. Motivated by a recent lattice study which addresses the mass shifts of the $c\\bar{s}$ ground states with quantum numbers $J^{P}=0^{+}$ ($D_{s0}^{\\ast}(2317)$) and $J^{P}=1^{+}$ ($D_{s1}(2460)$) due to their coupling with $S$-wave $D^{(\\ast)}K$ thresholds, we perform a similar analysis within a nonrelativistic constituent quark model in which quark-antiquark and meson-meson degrees of freedom are incorporated. The quark model has been applied to a wide range of hadronic observables and thus the model parameters are completely constrained. The coupling between quark-antiquark and meson-meson Fock components is done using a modified version of the $^{3}P_{0}$ decay model. We observe that the coupling of the $0^{+}$ $(1^{+})$ mes...

Ichnologic evidence of a Cambrian age in the southern Amazon Craton: Implications for the onset of the Western Gondwana history

Science.gov (United States)

Santos, Hudson P.; Mángano, M. Gabriela; Soares, Joelson L.; Nogueira, Afonso C. R.; Bandeira, José; Rudnitzki, Isaac D.

2017-07-01

Colonization of the infaunal ecospace by burrowing bilaterians is one of the most important behavioral innovations during the Ediacaran-Cambrian transition. The establishment of vertical burrows by suspension feeders in high-energy nearshore settings during Cambrian Age 2 is reflected by the appearance of the Skolithos Ichnofacies. For the first time, unquestionable vertical burrows typical of the Skolithos Ichnofacies, such as Skolithos linearis, Diplocraterion parallelum and Arenicolites isp., are recorded from nearshore siliciclastic deposits of the Raizama Formation, southeastern Amazon Craton, Brazil. Integration of ichnologic and sedimentologic datasets suggests that these trace fossils record colonization of high-energy and well-oxygenated nearshore sandy environments. Chronostratigraphically, the presence of these vertical burrows indicates an age not older than early Cambrian for the Raizama Formation, which traditionally has been regarded as Ediacaran. Therefore, the Raizama ichnofauna illustrates the advent of modern Phanerozoic ecology marked by the Agronomic Revolution. The discovery of the Skolithos Ichnofacies in these shallow-marine strata suggests possible connections between some central Western Gondwana basins.

First lattice calculation of the B-meson binding and kinetic energies

CERN Document Server

Crisafulli, M; Martinelli, G; Sachrajda, Christopher T C

1995-01-01

We present the first lattice calculation of the B-meson binding energy \\labar and of the kinetic energy -\\lambda_1/2 m_Q of the heavy-quark inside the pseudoscalar B-meson. This calculation has required the non-perturbative subtraction of the power divergences present in matrix elements of the Lagrangian operator \\bar h D_4 h and of the kinetic energy operator \\bar h \\vec D^2 h. The non-perturbative renormalisation of the relevant operators has been implemented by imposing suitable renormalisation conditions on quark matrix elements, in the Landau gauge. Our numerical results have been obtained from several independent numerical simulations at \\beta=6.0 and 6.2, and using, for the meson correlators, the results obtained by the APE group at the same values of \\beta. Our best estimate, obtained by combining results at different values of \\beta, is \\labar =190 \\err{50}{30} MeV. For the \\overline{MS} running mass, we obtain \\overline {m}_b(\\overline {m}_b) =4.17 \\pm 0.06 GeV, in reasonable agreement with previous...

[Medium energy meson research

International Nuclear Information System (INIS)

Crowe, K.M.

1992-01-01

The activities of this group are primarily concerned with experiments using the Crystal Barrel Detector. This detector is installed and operating at the Low Energy Antiproton Ring (LEAR) at CERN. QCD, the modem theory of the strong interaction, is reasonably well understood at high energies, but unfortunately, low-energy QCD is still not well understood, and is far from being adequately tested. The Crystal Barrel experiments are designed to provide some of the tests. The basic line of research involves meson spectroscopy, analyses bearing on the quark and/or gluon content of nuclear states, and the exploration of mechanisms and rules which govern p bar p annihilation dynamics. The Crystal Barrel Detector detects and identifies charged and neutral particles with a geometric acceptance close to 100%. The principal component of the detector is an array of 1,380 CsI(TI) crystals. These crystals surround a Jet Drift Chamber (JDC), located in a 1.5 Tesla magnetic field, which measures the momentum and dE/dx of charged particles. One of the very interesting physics goals of the detector is a search for exotic mesonic states -- glueballs and hybrids. Annihilation at rest will be studied with both liquid and gaseous hydrogen targets. The gaseous target offers the possibility of triggering on atomic L-shell X rays so that specific initial angular momentum states can be studied.These topics as well as other related topics are discussed in this report

CORNELL: CLEO discovers B meson penguins

International Nuclear Information System (INIS)

Anon.

1993-01-01

The CLEO collaboration at Cornell's CESR electron-positron storage ring has discovered a rare type of B meson decay in which only a high energy photon and a K* meson are produced. These decays provide the first unambiguous evidence for an alternative route for heavy quark decay that has been given the whimsical name ''penguin diagram''. In the mid-1970s penguin diagrams were proposed to explain the puzzling strangeness quantum number selection rules in the decay of K mesons. At the same time it was realized that penguin diagrams could also be important in the CP violation seen in neutral K meson decay. CP violation, an asymmetry between matter and antimatter, is an essential ingredient in understanding why there is much more matter than antimatter in the universe. CP violation introduces a definite direction to the arrow of time, which could otherwise point equally forwards or backwards. In addition, penguin decays are very sensitive to some extensions of the Standard Model of weak decay. Although penguin diagrams were first proposed to explain an effect in K meson decay, the K system gives no unique signature for them, and verification of penguin processes meant looking elsewhere. In the Standard Model, quarks decay under the influence of the weak force, emitting a W boson. Since the W is charged, the charge of the initial quark differs from that of the final quark, so the charge of the quark changes as well as its flavour

Quark-gluon mixing in scalar mesons

International Nuclear Information System (INIS)

Eremyan, Sh.S.; Nazaryan, A.E.

1986-01-01

Scalar mesons are considered within the quark-gluon mixing model. It is shown that there exists decouplet of scalar particles consisting of S* (975), ε (1400), S*' (1700), δ (980) and κ (1350) resonances. It has turned out that the long ago known S* (975)-resonance is a nearly pure glouball. A good description of all available experimental data on scalar meson decays is obtained

Bs mesons: semileptonic and nonleptonic decays

Directory of Open Access Journals (Sweden)

Albertus C.

2014-01-01

Full Text Available In this contribution we compute some nonleptonic and semileptonic decay widths of Bs mesons, working in the context of constituent quark models [1, 2]. For the case of semileptonic decays we consider reactions leading to kaons or different Jπ Ds mesons. The study of nonleptonic decays has been done in the factorisation approximation and includes the final states enclosed in Table 2.

SU(4) flavor symmetry breaking in D-meson couplings to light hadrons

Energy Technology Data Exchange (ETDEWEB)

Fontoura, C.E. [Instituto Tecnologico da Aeronautica, DCTA, Sao Jose dos Campos, SP (Brazil); Universidade Estadual Paulista, Instituto de Fisica Teorica, Sao Paulo, SP (Brazil); Haidenbauer, J. [Institute for Advanced Simulation, Institut fuer Kernphysik, and Juelich Center for Hadron Physics, Forschungszentrum Juelich, Juelich (Germany); Krein, G. [Universidade Estadual Paulista, Instituto de Fisica Teorica, Sao Paulo, SP (Brazil)

2017-05-15

The validity of SU(4)-flavor symmetry relations of couplings of charmed D-mesons to light mesons and baryons is examined with the use of {sup 3}P{sub 0} quark-pair creation model and nonrelativistic quark-model wave functions. We focus on the three-meson couplings ππρ, KKρ and DDρ and baryon-baryon-meson couplings NNπ, NΛK and NΛ{sub c}D. It is found that SU(4)-flavor symmetry is broken at the level of 30% in the DDρ tree-meson couplings and 20% in the baryon-baryon-meson couplings. Consequences of these findings for DN cross sections and existence of bound states D-mesons in nuclei are discussed. (orig.)

Study of light mesons with WASA-at-COSY

Science.gov (United States)

Prencipe, Elisabetta

2014-06-01

The WASA detector, operating at the COSY facility in Jülich (Germany) has been collecting data since 2007. The experiment allows to perform studies of light mesons, such as π0, η and ω rare decay processes, in order to perform precise measurements of branching ratios, determine Dalitz plot parameters, test symmetry and symmetry breaking, and evaluate transition form factors. In the experiments a proton or deuteron beam impinged on a pellet target of hydrogen or deuterium, which allows the reactions proton-proton (pp) or proton-deuteron (pd). A high-statistics sample of η mesons has been collected: in the reaction pd →3He η, 3×107η mesons were tagged at a beam energy of 1.0 GeV, while 5×108η mesons were produced in the reaction pp → ppη at 1.4 GeV. This corresponds to the production of 10 η/s and 100 η/s, respectively, for the two reaction processes. In the pp dataset a higher background level is found compared to the pd data set. In both cases, we identify the η mesons by means of the missing mass derived from the recoil particles. A kinematic fit largely rejects the background in our analysis. The advantage in using the pp dataset is that the production of η mesons is almost a factor of 10 higher than in the pd fusion to 3He. As we plan to measure the branching ratios of very rare processes, high statistics is needed. A summary of the recent activity on the study of light mesons with WASA-at-COSY here is given.

Study of light mesons with WASA-at-COSY

Directory of Open Access Journals (Sweden)

Prencipe Elisabetta

2014-06-01

Full Text Available The WASA detector, operating at the COSY facility in Jülich (Germany has been collecting data since 2007. The experiment allows to perform studies of light mesons, such as π0, η and ω rare decay processes, in order to perform precise measurements of branching ratios, determine Dalitz plot parameters, test symmetry and symmetry breaking, and evaluate transition form factors. In the experiments a proton or deuteron beam impinged on a pellet target of hydrogen or deuterium, which allows the reactions proton-proton (pp or proton-deuteron (pd. A high-statistics sample of η mesons has been collected: in the reaction pd →3He η, 3×107η mesons were tagged at a beam energy of 1.0 GeV, while 5×108η mesons were produced in the reaction pp → ppη at 1.4 GeV. This corresponds to the production of 10 η/s and 100 η/s, respectively, for the two reaction processes. In the pp dataset a higher background level is found compared to the pd data set. In both cases, we identify the η mesons by means of the missing mass derived from the recoil particles. A kinematic fit largely rejects the background in our analysis. The advantage in using the pp dataset is that the production of η mesons is almost a factor of 10 higher than in the pd fusion to 3He. As we plan to measure the branching ratios of very rare processes, high statistics is needed. A summary of the recent activity on the study of light mesons with WASA-at-COSY here is given.

Interference in Exclusive Vector Meson Production in Heavy-Ion Collisions

International Nuclear Information System (INIS)

Klein, Spencer R.; Nystrand, Joakim

2000-01-01

Vector mesons are produced copiously in peripheral relativistic heavy-ion collisions. Virtual photons from one ion can fluctuate into quark-antiquark pairs and scatter from the second ion, emerging as vector mesons. The emitter and target are indistinguishable, so emission from the two ions will interfere. Vector mesons have negative parity so the interference is destructive, reducing the production of mesons with small transverse momentum. The mesons are short lived, and decay before emission from the two ions can overlap. However, the decay-product wave functions overlap and interfere since they are produced in an entangled state, providing an example of the Einstein-Podolsky-Rosen paradox. (c) 2000 The American Physical Society

Mass shifts and decay widths of ψ mesons due to OZI-allowed decay channels

International Nuclear Information System (INIS)

Yabusaki, N.; Kato, K.; Hirano, M.; Sakai, M.; Matsuda, Y.

2000-01-01

Using effective quark-quark interactions proposed by the Cornell group and by Barbour and Gilchrist, we study the open-channel effects of the ψ states. We take into account the meson-meson final-state interaction in open channels, which is derived microscopically from the quark-level one-boson-exchange model. By applying the complex scaling transformation to the coupled-channel equation, mass shifts and OZI-allowed decay widths of the ψ states are simultaneously evaluated. Agreement with the experimental data is improved considerably. Refs. 20 (author)

The search for scalar mesons

International Nuclear Information System (INIS)

Pennington, M.R.

1988-09-01

The search of I = 0 0 ++ mesons is described. We highlight the crucial role played by the states in the 1 GeV region. An analysis program that with unimpeachable data would produce definitive results on these is outlined and shown with present data to provide prima facie evidence for dynamics beyond that of the quark model. We briefly speculate on the current status of the lowest mass scalar mesons and discuss how experiment can resolve the unanswered issues. 30 refs., 6 figs., 1 tab

Meson spectral functions at finite temperature

International Nuclear Information System (INIS)

Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S.

2001-10-01

The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T c . The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64) 3 x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature. (orig.)

Meson spectral functions at finite temperature

International Nuclear Information System (INIS)

Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S.

2002-01-01

The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T c . The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64) 3 x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature

Meson spectral functions at finite temperature

Energy Technology Data Exchange (ETDEWEB)

Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S

2002-03-01

The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T{sub c}. The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64){sup 3} x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature.

Meson spectral functions at finite temperature

Energy Technology Data Exchange (ETDEWEB)

Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S. [Bielefeld Univ. (Germany). Fakultaet fuer Physik

2001-10-01

The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T{sub c}. The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64){sup 3} x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature. (orig.)

A unified model of K- and π-mesons

International Nuclear Information System (INIS)

Skyrme, T.H.R.

1994-01-01

On the foundation of an antecedent non-linear meson field theory it is suggested that the π-meson field may be described in terms of collective motions of the K-meson fields. A particular model of the K-nucleon interaction is considered whose collective π-modes have symmetrical PV coupling with the nucleon system; parity is conserved to a great extent for the π-nucleon system in the absence of strange particles. The direct K-nucleon interactions do not conserve parity; their sign and symmetry are qualitatively acceptable. The masses and coupling constants of the meson fields are determinate in terms of one universal coupling constant and a cut-off. The structure of this model suggests a natural way for the introduction of the 'spurion', describing weak interactions that violate strangeness. (author). 6 refs

Measurement of elastic electroproduction of $\\phi$ 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.; 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.; 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.; 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.; 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, 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.; 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.; 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.

2000-01-01

The elastic electroproduction of phi mesons is studied at HERA with the H1 detector for photon virtualities 1 < Q^2 < 15 GeV^2 and hadronic centre of mass energies 40 < W < 130 GeV. The Q^2 and t dependences of the cross section are extracted (t being the square of the four-momentum transfer to the target proton). When plotted as function of (Q^2 + M_V^2) and scaled by the appropriate SU(5) quark charge factor, the phi meson cross section agrees within errors with the cross sections of the vector mesons V = rho, omega and J/psi. A detailed analysis is performed of the phi meson polarisation state and the ratio of the production cross sections for longitudinally and transversely polarised phi mesons is determined. A small but significant violation of s-channel helicity conservation (SCHC) is observed.

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.

Semileptonic B-meson decays in SU(3)

International Nuclear Information System (INIS)

Li Zuohong; Hou Yunzhi

1994-01-01

Based on the SU(3) approximate symmetry in the strong interaction three-body and four-body semileptonic B-meson decays are analyzed. Relations between decay rates are derived. Some of these relations may provide information on the nature of various competing dynamical effects that can occur in semileptonic B-meson decays

Decays of mesons with charm quarks on the lattice

International Nuclear Information System (INIS)

Ali Khan, A.; Braun, V.; Burch, T.; Goeckeler, M.; Schaefer, A.; Schierholz, G.

2007-10-01

We investigate mesons containing charm quarks on fine lattices with a -1 ∝ 5 GeV. The quenched approximation is employed using theWilson gauge action at β = 6.6 and nonperturbatively O(a) improvedWilson quarks. We present results for decay constants using various interpolating fields and give preliminary results for form factors of semileptonic decays of D s mesons to light pseudoscalar mesons. (orig.)

Electroproduction of pseudoscalar mesons at large transverse momenta

Energy Technology Data Exchange (ETDEWEB)

Domokos, G.; Kovesi-Domokos, S.; Yunn, B. C.

1973-07-15

Inclusive electroproduction of spinless (pseudoscalar) mesons at large transverse momenta is studied in the framework of local scale invariance. Scaling laws are established for the structure iunctions and approximate analytic expressions are derived for the scaling functions. It is predicted that the cross section decreases essentially according to a power law as a function of the transverse momentum of the observed meson, similarly to hadronic cross sections. The production rate of heavy mesons is found to rise slowly with the laboratory energy of the virtual photon. (auth)

Meson-mass generation by instantons, 2

Energy Technology Data Exchange (ETDEWEB)

Saito, T [Kyoto Prefectural Univ. of Medicine (Japan); Shigemoto, K

1979-05-01

In a previous work we discussed how pseudo-scalar mesons and scalar mesons acquire their masses by instantons in the colored gauge field. We considered there the two-flavor model with chiral U(2) x U(2) symmetry. In the present paper the same problem is discussed, including the chiral flavor U(3) x U(3) symmetry. An importance of non-local effects due to instantons is emphasized.

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

The interpretation of the iota meson

International Nuclear Information System (INIS)

Frank, M.

1985-01-01

The authors analyze the iota (1440) meson in a non-relativistic quark model. The authors review the experimental data, then attempt to incorporate it in the mass spectrum and radiative decays of the low-lying pseudoscalar and vector mesons. Correlating these results with production decay rates from J/psi and the radiative decays of iota, the authors conclude that the iota has to be interpreted as having a strong gluonium component

Excited charmed mesons

International Nuclear Information System (INIS)

Butler, J.N.; Shukla, S.

1995-05-01

The experimental status of excited charmed mesons is reviewed and is compared to theoretical expectations. Six states have been observed and their properties are consistent with those predicted for excited charmed states with orbital angular momentum equal to one

Detrital zircon U-Pb geochronology of Cambrian to Triassic miogeoclinal and eugeoclinal strata of Sonora, Mexico

Science.gov (United States)

Gehrels, G.E.; Stewart, John H.

1998-01-01

One hundred and eighty two individual detrital zircon grains from Cambrian through Permian miogeoclinal strata, Ordovician eugeoclinal rocks, and Triassic post-orogenic sediments in northwestern Sonora have been analyzed. During Cambrian, Devonian, Permian, and Triassic time, most zircons accumulating along this part of the Cordilleran margin were shed from 1.40-1.45 and 1.62-1.78 Ga igneous rocks that are widespread in the southwestern United States and northwestern Mexico. Zircons with ages of approximately 1.11 Ga are common in Cambrian strata and were apparently shed from granite bodies near the sample site. The sources of 225-280 Ma zircons in our Triassic sample are more problematic, as few igneous rocks of these ages are recognized in northwestern Mexico. Such sources may be present but unrecognized, or the grains could have been derived from igneous rocks of the appropriate ages to the northwest in the Mojave Desert region, to the east in Chihuahua and Coahuila, or to the south in accreted(?) arc-type terranes. Because the zircon grains in our Cambrian and Devonian to Triassic samples could have accumulated in proximity to basement rocks near their present position or in the Death Valley region of southern California, our data do not support or refute the existence of the Mojave-Sonora megashear. Ordovician strata of both miogeoclinal and eugeoclinal affinity are dominated by >1.77 Ga detrital zircons, which are considerably older than most basement rocks in the region. Zircon grains in the miogeoclinal sample were apparently derived from the Peace River arch area of northwestern Canada and transported southward by longshore currents. The eugeoclinal grains may also have come from the Peace River arch region, with southward transport by either sedimentary or tectonic processes, or they may have been shed from off-shelf slivers of continents (perhaps Antarctica?) removed from the Cordilleran margin during Neoproterozoic rifting. It is also possible that the

Late Cambrian - Early Ordovician turbidites of Gorny Altai (Russia): Compositions, sources, deposition settings, and tectonic implications

Science.gov (United States)

Kruk, Nikolai N.; Kuibida, Yana V.; Shokalsky, Sergey P.; Kiselev, Vladimir I.; Gusev, Nikolay I.

2018-06-01

The Cambrian-Ordovician transition was the time of several key events in the history of Central Asia. They were the accretion of Mariana-type island arc systems to the Siberian continent, the related large-scale orogeny and intrusions of basaltic and granitic magma and the formation of a huge turbidite basin commensurate with the Bengal Gulf basin in the western part of the Central Asian orogenic belt (CAOB). The structure of the basin, as well as the sources and environments of deposition remain open to discussion. This paper presents new major- and trace-element data on Late-Cambrian-Early Ordovician turbidites from different parts of the Russian Altai and a synthesis of Nd isotope composition and ages of detrital zircons. The turbidites share chemical similarity with material shed from weathered continental arcs. Broad variations of CIA (39-73) and ICV (0.63-1.66) signatures in sandstones suggest origin from diverse sources and absence of significant sorting. Trace elements vary considerably and have generally similar patterns in rocks from different terranes. On the other hand, there are at least two provinces according to Nd isotope composition and age of detrital zircons. Samples from eastern Russian Altai contain only Phanerozoic zircons and have Nd isotope ratios similar to those in Early Cambrian island arcs (εNdt + 4.4… + 5.4; TNd(DM)-2-st = 0.8-0.9 Ga). Samples from central, western, and southern parts of Russian Altai contain Precambrian zircons (some as old as Late Archean) and have a less radiogenic Nd composition (εNdt up to -3.6; TNd(DM)-2-st up to 1.5 Ga). The chemical signatures of Late Cambrian to Early Ordovician turbidites indicate a provenance chemically more mature than the island arc rocks, and the presence of zircons with 510-490 Ma ages disproves their genetic relation with island arcs. The turbidite basin formed simultaneously with peaks of granitic and alkali-basaltic magmatism in the western Central Asian orogen and resulted from

A unitarized meson model including color Coulomb interaction

International Nuclear Information System (INIS)

Metzger, Kees.

1990-01-01

Ch. 1 gives a general introduction into the problem field of the thesis. It discusses in how far the internal structure of mesons is understood theoretically and which models exist. It discusses from a phenomenological point of view the problem of confinement indicates how quark models of mesons may provide insight in this phenomenon. In ch. 2 the formal theory of scattering in a system with confinement is given. It is shown how a coupled channel (CC) description and the work of other authors fit into this general framework. Explicit examples and arguments are given to support the CC treatment of such a system. In ch. 3 the full coupled-channel model as is employed in this thesis is presented. On the basis of arguments from the former chapters and the observed regularities in the experimental data, the choices underlying the model are supported. In this model confinement is described with a mass-dependent harmonic-oscillator potential and the presence of open (meson-meson) channels plays an essential role. In ch. 4 the unitarized model is applied to light scalar meson resonances. In this regime the contribution of the open channels is considerable. It is demonstrated that the model parameters as used for the description of the pseudo-scalar and vector mesons, unchanged can be used for the description of these mesons. Ch. 5 treats the color-Coulomb interaction. There the effect of the Coulomb interaction is studied in simple models without decay. The results of incorporating the color-Coulomb interaction into the full CC model are given in ch.6. Ch. 7 discusses the results of the previous chapters and the present status of the model. (author). 182 refs.; 16 figs.; 33 tabs

J/Ψ decays, quark-gluon mixing in light mesons and glueball interpretation of L(1440), Θ(1720) and S*(980)-mesons

International Nuclear Information System (INIS)

Eremyan, Sh.S.; Nazaryan, A.Eh.

1987-01-01

The mixing angles for pseudoscalar, tensor and scalar meson multiplets are obtained in assumption on existence of a glueball component. The results are shown to be independent on the kind of the mixing matrix. It turned out that L(1440), Θ(1720) and S*(980) mesons are quite real candidates for glueballs. All the available experimental data on two-particle decays of 0 - , 2 + and 0 + -mesons are described and predictions for a large of such decays are given. 13 refs.; 6 figs.; 9 tabs

Studies of Excited $D$ mesons in $B$ meson decays

CERN Document Server

AUTHOR|(CDS)2082679

This thesis documents the studies of several three-body B + meson decays, each with a charged charmed meson in the final state. All analyses presented use a data sample recorded by the LHCb detector in 2011 and 2012, corresponding to an integrated luminosity of 3.0 $fb^{-1}$ of $pp$ collision data. The $B^{+} \\to D^{-}K^{+}\\pi^{+}$ and $B^{+} \\to D^{+}K^{+}\\pi^{-}$ decay modes are observed for the first time. The branching fraction of the favoured $B^{+} \\to D^{-}K^{+}\\pi^{+}$ decay mode is measured relative to the topologically similar $B^{+} \\to D^{-}\\pi^{+}\\pi^{+}$ decay and the $B^{+} \\to D^{-}K^{+}\\pi^{+}$ final state is used as a normalisation channel for the suppressed $B^{+} \\to D^{+}K^{+}\\pi^{-}$ decay branching fraction measurement. Searches are performed for the quasi-two-body decays $B^{+} \\to D^{+}K^{*}(892)^{0}$ and $B^{+} \\to D_{2}^{*}(2460)^{0}K^{+}$, using the sample of $B^{+} \\to D^{+}K^{+}\\pi^{-}$ candidate decays. No significant signals are observed for either decay mode and upper limits a...

Meson-Meson molecules and compact four-quark states

International Nuclear Information System (INIS)

Vijande, J.; Valcarce, A.

2010-01-01

The physics of charm has become one of the best laboratories exposing the limitations of the naive constituent quark model and also giving hints into a more mature description of meson spectroscopy, beyond the simple quark-antiquark configurations. In this talk we review some recent studies of multiquark components in the charm sector and discuss in particular exotic and non-exotic four-quark systems.

Self-consistent descriptions of vector mesons in hot matter reexamined

International Nuclear Information System (INIS)

Riek, Felix; Knoll, Joern

2010-01-01

Technical concepts are presented that improve the self-consistent treatment of vector mesons in a hot and dense medium. First applications concern an interacting gas of pions and ρ mesons. As an extension of earlier studies, we thereby include random-phase-approximation-type vertex corrections and further use dispersion relations to calculate the real part of the vector-meson self-energy. An improved projection method preserves the four transversality of the vector-meson polarization tensor throughout the self-consistent calculations, thereby keeping the scheme void of kinematical singularities.

Experimental evidence for hadroproduction of exotic mesons

International Nuclear Information System (INIS)

G. S. Adams; T. Adams; Z. Bar-Yam; J. M. Bishop; V. A. Bodyagin; B. B. Brabson; D. S. Brown; N. M. Cason; S. U. Chung; R. R. Crittenden; J. P. Cummings; K. Danyo; S. Denisov; V. Dorofeev; J. P. Dowd; A. R. Dzierba; P. Eugenio; J. Gunter; R. W. Hackenburg; M. Hayek; E. I. Ivanov; I. Kachaev; W. Kern; E. King; O. L. Kodolova; V. L. Korotkikh; M. A. Kostin; J. Kuhn; R. Lindenbusch; V. Lipaev; J. M. LoSecco; J. J. Manak; J. Napolitano; M. Nozar; C. Olchanski; A. I. Ostrovidov; T. K. Pedlar; A. Popov; D. R. Rust; D. Ryabchikov; A. H. Sanjari; L. I. Sarycheva; E. Scott; K. K. Seth; N. Shenhav; W. D. Shephard; N. B. Sinev; J. A. Smith; P. T. Smith; D. L. Stienike; T. Sulanke; S. A. Taegar; S. Teige; D. R. Thompson; I. N. Vardanyan; D. P. Weygand; D. White; H. J. Willutzki; J. Wise; M. Witkowski; A. A. Yershov; D. Zhao

2001-01-01

New measurements of peripheral meson production are presented. The data confirm the existence of exotic mesons at 1.4 and 1.6 GeV/c2. The latter state dominates the eta'pi- decay spectrum. The data on eta pi+pi-pi- decay show large strength in several exotic (Jpc = 1- +) waves as well

LAMPF: the meson factory. A LASL monograph

International Nuclear Information System (INIS)

Allred, J.C.

1977-08-01

A general and simplified introduction to the entire concept of LAMPF is given in terms of its experimental capabilities. Parts of the current experimental program are used as illustrative examples. Topics discussed include: (1) the evolution of the meson factory; (2) accelerator construction; (3) strong focusing; (4) accelerator innovations at LAMPF; (5) photons and pions; (6) muons as nuclear probes; (7) nuclear chemistry; (8) radiobiology and medical applications; (9) radioisotope production; (10) materials testing; and (11) LAMPF management and users group

LAMPF: the meson factory. A LASL monograph

Energy Technology Data Exchange (ETDEWEB)

Allred, J.C.

1977-08-01

A general and simplified introduction to the entire concept of LAMPF is given in terms of its experimental capabilities. Parts of the current experimental program are used as illustrative examples. Topics discussed include: (1) the evolution of the meson factory; (2) accelerator construction; (3) strong focusing; (4) accelerator innovations at LAMPF; (5) photons and pions; (6) muons as nuclear probes; (7) nuclear chemistry; (8) radiobiology and medical applications; (9) radioisotope production; (10) materials testing; and (11) LAMPF management and users group. (PMA)

QED effects in the pseudoscalar meson sector

Energy Technology Data Exchange (ETDEWEB)

Horsley, R. [School of Physics and Astronomy, University of Edinburgh, Peter Guthrie Tait Road, Edinburgh, EH9 3FD (United Kingdom); Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe, Hyogo, 650-0047 (Japan); Perlt, H. [Institut für Theoretische Physik, Universität Leipzig, Brüderstrasse 16, Leipzig, 04109 (Germany); Pleiter, D. [Jülich Supercomputer Centre, Forschungszentrum Jülich, Jülich, 52425 (Germany); Institut für Theoretische Physik, Universität Regensburg, Regensburg, 93040 (Germany); Rakow, P.E.L. [Theoretical Physics Division, Department of Mathematical Sciences, University of Liverpool, Peach Street , Liverpool, L69 3BX (United Kingdom); Schierholz, G. [Deutsches Elektronen-Synchrotron DESY, Hamburg, 22603 (Germany); Schiller, A. [Institut für Theoretische Physik, Universität Leipzig, Brüderstrasse 16, Leipzig, 04109 (Germany); Stokes, R. [CSSM, Department of Physics, University of Adelaide, Adelaide, SA, 5005 (Australia); Stüben, H. [Regionales Rechenzentrum, Universität Hamburg, Hamburg, 20146 (Germany); Young, R.D.; Zanotti, J.M. [CSSM, Department of Physics, University of Adelaide, Adelaide, SA, 5005 (Australia); Collaboration: the QCDSF and UKQCD collaboration

2016-04-15

In this paper we present results on the pseudoscalar meson masses from a fully dynamical simulation of QCD+QED, concentrating particularly on violations of isospin symmetry. We calculate the π{sup +}–π{sup 0} splitting and also look at other isospin violating mass differences. We have presented results for these isospin splittings in http://arxiv.org/abs/1508.06401. In this paper we give more details of the techniques employed, discussing in particular the question of how much of the symmetry violation is due to QCD, arising from the different masses of the u and d quarks, and how much is due to QED, arising from the different charges of the quarks. This decomposition is not unique, it depends on the renormalisation scheme and scale. We suggest a renormalisation scheme in which Dashen’s theorem for neutral mesons holds, so that the electromagnetic self-energies of the neutral mesons are zero, and discuss how the self-energies change when we transform to a scheme such as (MS)-bar , in which Dashen’s theorem for neutral mesons is violated.

Cambrian rivers and floodplains: the significance of microbial cementation, groundwater and aeolian sediment transport

Science.gov (United States)

Reesink, A. J. H.; Best, J.; Freiburg, J. T.; Nathan, W.

2016-12-01

Rivers that existed before land plants colonized the Earth are commonly considered to be unaffected by microbial activity on their floodplains, because the limited cementation produced by microbial activity is insufficient to stabilize the river banks. Although this assumption is likely correct, such emphasis on channel dynamics ignores the potential role of floodplain dynamics as an integral component of the river system. Detailed analysis of cores from the Cambrian Mount Simon Sandstone, Illinois, suggests that a significant proportion of the terrestrial sequence is composed of flat-bedded `crinkly' structures that provide evidence of cementation by soil crusts and microbial biofilms, and that promoted the adhesion of sediment to sticky surfaces. Wind ripples and local desert pavements were abundant. These findings highlight that sediment deposition on Cambrian floodplains was often dominated by wind in locations where the ground water table reached the surface, and was thus likely independent of sediment transport within the river channel. Erosion by wind would thus have been hindered by surface cementation and the formation of desert pavements. Such ground water control on deposition, and resistance to erosion by floodplain surface hardening, appear to have been the primary controls on Cambrian floodplain topography. Because floodplain topography poses a key control on channel and floodplain flow, these processes may have affected patterns of erosion and deposition, as well as reach-scale dynamics such as channel avulsions. The autonomous operation of wind-and-groundwater controlled floodplains makes pre-vegetated river systems more sensitive to climatic conditions such as precipitation and evaporation, and strikingly different from those that occurred after the development of land plants.

Oscillations of neutral B mesons systems

CERN Document Server

Boucrot, J.

1999-01-01

The oscillation phenomenon in the neutral B mesons systems is now well established. The motivations and principles of the measurements are given; then the most recent results from the LEP experiments, the CDF collaboration at Fermilab and the SLD collaboration at SLAC are reviewed. The present world average of the $\\bd$ meson oscillation frequency is $\\dmd = 0.471 \\pm 0.016 \\ps$ and the lower limit on the $\\bs$ oscillation frequency is

Hybrid mesons with auxiliary fields

International Nuclear Information System (INIS)

Buisseret, F.; Mathieu, V.

2006-01-01

Hybrid mesons are exotic mesons in which the color field is not in the ground state. Their understanding deserves interest from a theoretical point of view, because it is intimately related to nonperturbative aspects of QCD. Moreover, it seems that some recently detected particles, such as the π 1 (1600) and the Y(4260), are serious hybrid candidates. In this work, we investigate the description of such exotic hadrons by applying the auxiliary fields technique (also known as the einbein field method) to the widely used spinless Salpeter Hamiltonian with appropriate linear confinement. Instead of the usual numerical resolution, this technique allows to find simplified analytical mass spectra and wave functions of the Hamiltonian, which still lead to reliable qualitative predictions. We analyse and compare two different descriptions of hybrid mesons, namely a two-body q system with an excited flux tube, or a three-body qg system. We also compute the masses of the 1 -+ hybrids. Our results are shown to be in satisfactory agreement with lattice QCD and other effective models. (orig.)

Le volcanisme cambrien du Maroc central : implications géodynamiquesThe Central Morocco Cambrian volcanism: geodynamic implications

Science.gov (United States)

Ouali, Houssa; Briand, Bernard; Bouchardon, Jean-Luc; Capiez, Paul

2003-05-01

In southeastern Central Morocco, the Bou-Acila volcanic complex is considered of Cambrian age. In spite of low-grade metamorphic effect, initial volcanic texture and mineralogy can be recognized and volcanic rocks are dominated by dolerites and porphyric dolerites. The initial mineralogy is composed of plagioclases, pyroxenes and dark minerals. A secondary mineral assemblage is composed of albite, epidote, chlorite and calcite. According to their immobile elements compositions, the southeastern central Morocco metavolcanites are of within-plate continental tholeiites. This volcanism and those recognized in many other areas in Morocco confirm a Cambrian extensive episode within the Gondwana supercontinent. To cite this article: H. Ouali et al., C. R. Geoscience 335 (2003).To cite this article: H. Ouali et al., C. R. Geoscience 335 (2003).

High-Precision U-Pb Geochronology and Correlation: An example Using the Neoproterozic-Cambrian Transition

Science.gov (United States)

Bowring, S. A.; Grotzinger, J. P.; Amthor, J.; Martin, M. E.

2001-05-01

The precise, global correlation of Precambrian and Paleozoic sedimentary rocks can be achieved using temporally calibrated chemostratigraphic records. This approach is essential for determining rates and causes of environmental and faunal change, including mass extinctions. For example, The Neoproterozoic is marked by major environmental change, including periods of global glaciation, large fluctuations in the sequestration of carbon and major tectonic reorganization followed by the explosive diversification of animals in the earliest Cambrian. The extreme climatic change associated with these glaciations have been implicated as a possible trigger for the Cambrian explosion. The recognition of thin zircon-bearing air-fall ash in Neoproterozoic and Cambrian rocks has allowed the establishment of a high-precision temporal framework for animal evolution and is helping to untangle the history of glaciations. In some cases analytical uncertainties translate to age uncertainties of less than 1 Ma and when integrated with chemostratigraphy, the potential for global correlations at even higher resolution. Progress in the global correlation of Neoproterozoic strata has been achieved through the use of C and Sr isotope chemostratigraphy although it has been hampered by a lack of precise geochronological and faunal control. For example, the period from ca 800-580 Ma is characterized by at least two and perhaps as many as four glacial events that are interpreted by many to be global glaciations on a "Snowball Earth". A lack of precise chronological constraints on the number and duration of glaciations, multiple large excursions in the carbon isotopic record, and an absence of detailed biostratigraphy have complicated global correlation and hindered our understanding of this important period of Earth history. However, the ongoing integration of chemostratigraphic and geochronological data are improving temporal resolution and detailed correlations. These data are critical for

On wave functions of mesons involving the s-, c- and b-quarks

International Nuclear Information System (INIS)

Zhitnitskij, A.R.; Zhitnitskij, I.R.; Chernyak, V.L.

1983-01-01

The wave function components of pseudoscalar and vestor mesons which are antisymmertric with respect to permutation of the quark momenta are studied. The results are as follows: elt xsub(s)-xsub(u) > sub(K) approximately equal to 0.11 for the K meson, sub(K*) approximately equal to 0.15-C.20 for the K* meson, being a mean fraction of the longitudinal momentum transferred by the s(u) quark. The following estimates are obtained: / approximately equal to 0.20-0.25; / approximately equal to 0.8x10 -2 . The asymptotics of the K 0 -meson form factor and the etasub(c) → KK* decay width are found. Properties of the wave functions of mesons which contain a light and a heavy quark (D, B, ...) are considered. For the B 0 meson approximately equal to 0.10 is found. Arguments are given supporting nonenhancement of the amplitudes of the processes involving D mesons compared to similar K-meson amplitudes. A simple way is suggested to determine the asymptotic form of various wave functions

A lattice QCD determination of potentials between pairs of static-light mesons

International Nuclear Information System (INIS)

Hetzenegger, Martin

2011-01-01

Potentials between pairs of static-light mesons are interesting in a sense that they give insights in the nature of strong interactions from first principles for multiquark systems. For large heavy quark masses, e.g., the spectra of heavy-light mesons are determined by excitations of the light quark and gluonic degrees of freedom. In particular, the vector-pseudoscalar splitting vanishes and a static-light meson can be interpreted as either a B, a B * , a D or a D * heavy-light meson. Calculating potentials between two static-light mesons also enables investigations of possible bound tetraquark states or for particles that are close to the meson-antimeson threshold, such as the X(3872) or the Z + (4430).

About direct CP violation in the system of K0 mesons

International Nuclear Information System (INIS)

Beshtoev, Kh.M.

2012-01-01

This work is devoted to computation of the parameter of direct CP violation by the weak interactions in the system of K 0 mesons at K 1 0 -, K 2 0 -meson mixings and oscillations via K S -, K L -meson states

Mesonic atom production in high-energy nuclear collisions

International Nuclear Information System (INIS)

Wakai, M.; Bando, H.; Sano, M.

1987-08-01

The production probability of π-mesonic atom in high-energy nuclear collisions is estimated by a coalescence model. The production cross section is calculated for p + Ne and Ne + Ne systems at 2.1 GeV/A and 5.0 GeV/A beam energy. It is shown that nuclear fragments with larger charge numbers have the advantage in the formation of π-mesonic atoms. The cross section is proportional to Z 3 and of the order of magnitude of 1 ∼ 10 μb in all the above cases. The production cross sections of K-mesonic atoms are also estimated. (author)

Light meson decays in CLAS and CLAS12

Energy Technology Data Exchange (ETDEWEB)

Kunkel, Michael [Forschungszentrum Juelich (Germany); Collaboration: CLAS Collaboration

2016-07-01

Photoproduction experiments with the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Facility produce data sets with competitive statistics of light mesons. With these data sets, measurements of transition form factors for η, ω, and η' mesons via conversion decays can be performed using the invariant mass distribution of the final state dileptons. Tests of fundamental symmetries and information on the light quark mass difference can be performed using a Dalitz plot analysis of the meson decay. An overview of preliminary results, from existing CLAS data, and future prospects within the newly upgraded CLAS12 apparatus are given.

Finite temperature QCD sum rule and the ρ-meson

International Nuclear Information System (INIS)

Liu Jueping; Jin Yaping

1995-01-01

The contributions from the three-gluon condensates to the finite temperature QCD sum rule for the ρ-meson are calculated, and then the dependence of the properties of the ρ-meson upon temperature is investigated in a string model of condensates. The results show that the parameters characterizing the properties of the ρ-meson change noticeably when the temperature closes to the critical temperature of the condensates, and if the critical temperatures of condensates are the same

Scalar meson field and many-body forces. Chapter 23

International Nuclear Information System (INIS)

Nyman, E.M.

1979-01-01

In applications of field theory to the theory of the nuclear forces, one has frequently assumed that there is a scalar meson. It will then be responsible for most of the medium-range attraction between the nucleons. According to current ideas, however, it is possible to account for the medium-range attraction without an elementary sigma meson. This approach requires a careful treatment of the exchange of interacting pairs of π mesons, such as to include those ππ interactions which are responsible for the formation and decay of the sigma meson. Recently, the scalar field in the nuclear many-body problem has begun to receive more attention. There are two reasons for this change of philosophy. One reason is the discovery of neutron stars. In neutron stars, the nucleon number density can be much higher than in nuclei. One therefore wants to derive the equation of state from a relativistic many-body theory. This forces one to deal explicitly with a set of mesons, such that in the non-relativistic limit one recovers the one-boson-exchange potential. (Auth.)

The Early Cambrian Mianyang-Changning Intracratonic Sag and Its Control on Petroleum Accumulation in the Sichuan Basin, China

Directory of Open Access Journals (Sweden)

Shugen Liu

2017-01-01

Full Text Available The older and deeper hydrocarbon accumulations receive increasing attention across the world, providing more technical and commercial challenges to hydrocarbon exploration. We present a study of an asymmetrical, N-S striking intracratonic sag which developed across the Sichuan basin, south China, from Late Ediacaran to Early Cambrian times. The Mianyang-Changning intracratonic sag is ~50 km wide, with its steepest part in the basin center. In particular the eastern margin shows its greatest steepness. Five episodes in the evolutions of the sag can be recognized. It begins in the Late Ediacaran with an uplift and erosion correlated to Tongwan movement. Initial extension occurred during the Early Cambrian Maidiping period, when more strata of the Maidiping Formation were deposited across the sag. Subsequently, maximum extension occurred during the Early Cambrian Qiongzhusi period that resulted in 450–1700 m thick Maidiping-Canglangpu Formations being deposited in the sag. Then, the sag disappeared at the Longwangmiao period, as it was infilled by the sediments. The intracratonic sag has significant influence on the development of high-quality reservoirs in the Dengying and Longwangmiao Formations and source-rock of the Niutitang Formation. It thus indicates that a high probability for oil/gas accumulation exists along the intracratonic sag, across the central Sichuan basin.

Scattering of vector mesons off nucleons

International Nuclear Information System (INIS)

Lutz, M.F.M.; Friman, B.; Wolf, G.

2001-12-01

We construct a relativistic and unitary approach to 'high' energy pion- and photon-nucleon reactions taking the πN, πΔ, ρN, ωN, ηN, K Λ, KΣ final states into account. Our scheme dynamically generates the s- and d-wave nucleon resonances N(1535), N(1650) and N(1520) and isobar resonances Δ(1620) and δ(1700) in terms of quasi-local interaction vertices. The description of photon-induced processes is based on a generalized vector-meson dominance assumption which directly relates the electromagnetic quasi-local 4-point interaction vertices to the corresponding vertices involving the ρ and ω fields. We obtain a satisfactory description of the elastic and inelastic pion- and photon-nucleon scattering data in the channels considered. The resulting s-wave ρ- and ω-nucleon scattering amplitudes are presented. Using these amplitudes we compute the leading density modification of the ρ and ω mass distributions in nuclear matter. We find a repulsive mass shift for the ω meson at small nuclear density but predict considerable strength in resonance-hole like ω-meson modes. Compared to previous calculations our result for the ρ-meson spectral function shows a significantly smaller in-medium effect. This reflects a not too large coupling strength of the N(1520) resonance to the ρN channel. (orig.)

Glueball-meson mixing

Energy Technology Data Exchange (ETDEWEB)

Vento, Vicente [Consejo Superior de Investigaciones Cientificas, Departamento de Fisica Teorica y Instituto de Fisica Corpuscular, Universidad de Valencia, Burjassot (Spain)

2016-01-15

Calculations in unquenched QCD for the scalar glueball spectrum have confirmed previous results of Gluodynamics finding a glueball at ∝1750 MeV. I analyze the implications of this discovery from the point of view of glueball-meson mixing in light of the experimental scalar spectrum. (orig.)

A lattice QCD determination of potentials between pairs of static-light mesons

Energy Technology Data Exchange (ETDEWEB)

Hetzenegger, Martin

2011-07-04

Potentials between pairs of static-light mesons are interesting in a sense that they give insights in the nature of strong interactions from first principles for multiquark systems. For large heavy quark masses, e.g., the spectra of heavy-light mesons are determined by excitations of the light quark and gluonic degrees of freedom. In particular, the vector-pseudoscalar splitting vanishes and a static-light meson can be interpreted as either a B, a B{sup *}, a D or a D{sup *} heavy-light meson. Calculating potentials between two static-light mesons also enables investigations of possible bound tetraquark states or for particles that are close to the meson-antimeson threshold, such as the X(3872) or the Z{sup +}(4430).

δ meson effects in the Nolen-Schiffer anomaly

International Nuclear Information System (INIS)

Menezes, D.P.; Avancini, S.S.; Vasconcellos, C.Z.; Razeira, M.

2009-01-01

In this work we revisit the Okamoto-Nolen-Schiffer (ONS) anomaly in the context of four parametrizations of effective hadronic models, two of them with constant couplings between the nucleons and the mesons and two with density-dependent couplings. A Thomas-Fermi approximation is performed and the effects of the isovector-scalar virtual δ (a 0 (980)) mesons are investigated since they influence directly the proton and neutron effective masses in opposite ways. The ρ-ω mixing term is claimed to be important in the explanation of the ONS anomaly and is added in our calculations. We have concluded that as far as the ρ-ω mixing term is included, Δ M(Z, N) is clearly larger in models with δ than in models where this meson is not considered, which is not always the case if the coupling is discarded. None of the models is good enough to describe all experimental data, but the models that better describe the experimental values include the δ mesons. (orig.)

Meson masses in electromagnetic fields with Wilson fermions

Science.gov (United States)

Bali, G. S.; Brandt, B. B.; Endrődi, G.; Gläßle, B.

2018-02-01

We determine the light meson spectrum in QCD in the presence of background magnetic fields using quenched Wilson fermions. Our continuum extrapolated results indicate a monotonous reduction of the connected neutral pion mass as the magnetic field grows. The vector meson mass is found to remain nonzero, a finding relevant for the conjectured ρ -meson condensation at strong magnetic fields. The continuum extrapolation was facilitated by adding a novel magnetic field-dependent improvement term to the additive quark mass renormalization. Without this term, sizable lattice artifacts that would deceptively indicate an unphysical rise of the connected neutral pion mass for strong magnetic fields are present. We also investigate the impact of these lattice artifacts on further observables like magnetic polarizabilities and discuss the magnetic field-induced mixing between ρ -mesons and pions. We also derive Ward-Takashi identities for QCD +QED both in the continuum formulation and for (order a -improved) Wilson fermions.

Vector meson decays in the chiral bag model

International Nuclear Information System (INIS)

Maxwell, O.V.; Jennings, B.K.

1985-01-01

Vector meson decays are examined in a model where a confined quark and antiquark annihilate, producing a pair of elementary pseudoscalar mesons. Two versions of the pseudoscalar meson-quark interaction are employed, one where the coupling is restricted to the bag surface and one where it extends throughout the bag volume. Energy conservation is ensured in the model through insertion of exponential factors containing the bag energy at each interaction vertex. To guarantee momentum conservation, a wave-packet description is utilized in which the decay widths are normalized by a factor involving the overlap of the initial bag state with the confined qanti q state of zero momentum. With either interaction, the model yields a value for the p-width that exceeds the empirical width by a factor two. For the Ksup(*) and PHI mesons, the computed widths depend strongly on the interaction employed. Implications of these results for chiral bag models are discussed. (orig.)

Skyrmions and vector mesons: a symmetric approach

International Nuclear Information System (INIS)

Caldi, D.G.

1984-01-01

We propose an extension of the effective, low-energy chiral Lagrangian known as the Skyrme model, to one formulated by a non-linear sigma model generalized to include vector mesons in a symmetric way. The model is based on chiral SU(6) x SU(6) symmetry spontaneously broken to static SU(6). The rho and other vector mesons are dormant Goldstone bosons since they are in the same SU(6) multiplet as the pion and other pseudoscalars. Hence the manifold of our generalized non-linear sigma model is the coset space (SU(6) x SU(6))/Su(6). Relativistic effects, via a spin-dependent mass term, break the static SU(6) and give the vectors a mass. The model can then be fully relativistic and covariant. The lowest-lying Skyrmion in this model is the whole baryonic 56-plet, which splits into the octet and decuplet in the presence of relativistic SU(6)-breaking. Due to the built-in SU(6) and the presence of vector mesons, the model is expected to have better phenomenological results, as well as providing a conceptually more unified picture of mesons and baryons. 29 references

Hard production of exotic hybrid mesons

Energy Technology Data Exchange (ETDEWEB)

Anikin, I.; Teryaev, O.V. [Bogoliubov Lab. of Theoretical Physics, JINR, Dubna (Russian Federation); Pire, B.; Anikin, I. [Ecole Polytechnique, CPHT, 91 - Palaiseau (France); Szymanowski, I. [Soltan Institute for Nuclear Studies, Warsaw (Poland); Liege Univ. (Belgium); Anikin, I.; Wallon, S. [Paris-11 Univ., Lab. de Physique Theorique, 91 - Orsay (France)

2005-07-01

Exotic hybrid mesons H, with quantum numbers J{sup PC} = 1{sup -+} may be copiously produced in the hard exclusive processes {gamma}{sup *}(Q{sup 2}){gamma} {yields} H and {gamma}{sup *}(Q{sup 2})P(p) {yields} HP(p') because they have a leading twist distribution amplitude with a sizable coupling constant f{sub H}, which may be estimated through QCD sum rules. The reaction rates scale in the same way as the corresponding rates for usual mesons. (authors)

Transitions between neutral mesons in multiquark schemes

International Nuclear Information System (INIS)

Volkov, G.G.; Liparteliani, A.G.; Monich, V.A.; Nikitin, Y.P.

1981-01-01

A six-quark scheme based on the gauge group SU(2)/sub L/ x U(1) is used to obtain expressions for the amplitudes of the transitions K 0 bold-arrow-left-right K-bar 0 , D 0 bold-arrow-left-right D-bar 0 , B 0 bold-arrow-left-right B-bar 0 , B/sub S/ 0 bold-arrow-left-right B-bar/sub S/ 0 , T 0 bold-arrow-left-right T-bar 0 , and T/sub C/ 0 bold-arrow-left-right T-bar/sub C/ 0 for finite 4-momenta of the external lines of the Feynman box diagrams. An estimate is made of the degree of applicability of the approximation of vanishingly small 4-momenta of the valence quarks which form the neutral mesons such as the K 0 and K-bar 0 mesons. Constraints are found on the parameters of the unitary matrix of the weak charged currents for arbitrary values of the t-quark mass. Estimates are given of the numerical values of the mixing and CP-violation parameters for neutral systems such as the K 0 --K-bar 0 system

D-meson production by muons in the COMPASS experiment at CERN

Energy Technology Data Exchange (ETDEWEB)

Zvyagin, Alexander

2011-01-21

One of the physics goals of the COMPASS experiment at CERN was to measure the contribution of gluons to the nucleon spin. To achieve this, it was proposed to scatter polarized 160 GeV/c muons on a polarized deuteron target and to detect D mesons in the final state. The underlying process in this D meson production is supposed to be the Photon-Gluon Fusion (PGF), where a virtual photon emitted by the muon interacts with a gluon from the target nucleon, producing a charm-anticharm quark pair. Fragmentation of a charm (anticharm) quark leads with high probability to the creation of a D{sup 0} or D{sup *} meson, which COMPASS detects via the D{sup 0}{yields}K{pi} and D{sup *}{yields}D{sup 0}{pi}{yields}K{pi}{pi} decay modes. From the longitudinal cross section spin asymmetries of the D meson production and theoretical predictions for the PGF cross section, the gluon contribution to the nucleon spin has been measured by the COMPASS experiment. The results presented in the thesis are the following. Based on data from the year 2004 a total visible cross section of 1.8{+-}0.4 nb, for the D{sup *} meson production, has been measured, with the error being dominated by systematic effects. It is validated that the D mesons are indeed produced through the PGF process, by comparison of measured D meson kinematic distributions to the ones predicted by a theory (AROMA generator). A good agreement was found for the distribution shapes, which confirms that PGF plays a major role. However, a 20% difference was found in the number of produced D{sup 0} and D{sup 0} mesons (and for the D{sup *+} and D{sup *-} mesons as well) which is significantly larger than predicted by AROMA. Kinematic distributions of D{sup 0} and D{sup *} mesons were compared with the background and also with the nearby K{sup *}{sub 2}(1430){sup 0} resonance, using all longitudinal data taken in 2002-2006. The particle-antiparticle asymmetry has been studied as a function of several kinematic variables. The 20

Light meson decays from photon-induced reactions with CLAS

Energy Technology Data Exchange (ETDEWEB)

Kunkel, Michael C. [Forschungszentrum Juelich (Germany); Collaboration: CLAS-Collaboration

2015-07-01

Photo-production experiments with the CEBAF Large Acceptance Spectrometer (CLAS) at the Thomas Jefferson National Laboratory produce data sets with unprecedented statistics of light mesons. With these data sets, measurements of transition form factors for η, ω, and η' via conversion decays are performed using a line shape analysis on the invariant mass of the final state dileptons. Tests of fundamental symmetries and information on the light quark mass difference are performed using a Dalitz plot analysis of the meson decay. In addition, the data allows for a search for dark matter, such as the heavy photon via conversion decays of light mesons and physics beyond the Standard Model is searched for via invisible decays of η mesons. An overview of the first results and future prospects is given.

QCD sum rules for the decay amplitudes of pseudoscalar mesons

International Nuclear Information System (INIS)

Narison, S.

1981-07-01

Bounds on the π and K meson decay amplitudes are obtained to a good accuracy from QCD sum rules of the Laplace transform type. A relation between fsub(π) and the rho meson coupling to the photon is given. Using the heavy quarks q 2 =0 sum rule to two loops we find our best bounds: fsub(D) approximately < (101+-25) MeV and fsub(F) approximately < (147+-41.6) MeV to be compared to fsub(π) approximately 93.3 MeV. We also derive a relation between the D and F meson masses and the charm quark mass. Our results are extended to the beautiful B mesons. (author)

Mesons versus quasi-normal modes: undercooling and overheating

NARCIS (Netherlands)

Paredes Galan, A.; Peeters, K.; Zamaklar, m.

2008-01-01

In holographic models of gauge theories with matter, there generically exists a first order phase transition in which mesons dissociate. We perform a careful analysis of the meson and quasi-particle spectra in the overheated resp. undercooled regimes close to the junction of the two phases. We show

Electro- and chromomagnetism in the charm meson spectrum

International Nuclear Information System (INIS)

Fritzsch, H.

1977-01-01

How the D and F meson spectrum is influenced by the chromomagnetic and electomagnetic hyperfine interaction is discussed. In particular a relation between the hyperfine splitting of charmed mesons and the magnetic moments of the baryons is derived. M(Fsub(+)*)-M(Fsub(+)) approximately 100+-8 MeV. (Auth.)

Composite mesons in self-confining chiral solitons

International Nuclear Information System (INIS)

Tandy, P.C.; Frank, M.R.

1991-01-01

Most quark-meson models for formation of a baryon as a bag or soliton solution begin with elementary local meson fields including a classical scalar configuration that provides repulsion of valence quarks from the vacuum. This presentation explores aspects of the very different formation mechanism that operates in a model where chiral effective meson fields are composite objects generated from bilocal qq-bar fluctuation fields and the dynamical quark mass can be self-confining. The focus is on the dynamical self-energy for quarks and the related distributed vertex for quark meson coupling. Initial numerical work to explore the practical consequences of these features is presented in the context of a static mean-field soliton. The particular method employed to identify the energy functional at the mean field or Hartree level is to obtain the standard effective action from the Legendre transformation with the help of a chemical potential constraint for the baryon number. The purpose of this approach is two-fold. First, a possible future consideration of radiative corrections might be undertaken by systematically continuing with the loop expansion beyond the lowest level. A second, more practical reason, is that in the presence of a general space-time dependent dynamical self-energy for quarks there are wavefunction renormalisation effects and energy self-consistencies to be defined and maintained for the valence quark states and eigenvalues. Speculations are made on whether this point of view can motivate meson-nucleon relativistic field models containing intrinsic cutoffs for use in nuclear physics. 29 refs., 5 figs

Semileptonic decays of the Bc meson

International Nuclear Information System (INIS)

Barik, N.; Naimuddin, Sk.; Dash, P. C.; Kar, Susmita

2009-01-01

We study the semileptonic transitions B c →η c ,J/Ψ,D,D*,B,B*,B s ,B s * in the leading order in the framework of a relativistic independent quark model based on a confining potential in the equally mixed scalar-vector harmonic form. We compute relevant weak form factors as overlap integrals of the meson-wave functions obtained in the relativistic independent quark model in the whole accessible kinematical range. We predict that the semileptonic transitions of the B c meson are mostly dominated by two Cabibbo-Kobayashi-Maskawa (CKM)-favored modes, B c →B s (B s *)eν, contributing about 77% of the total decay width, and its decays to vector meson final states take place in the predominantly transverse mode. Our predicted values for the total decay rates, branching ratios, polarization ratios, the forward-backward asymmetry factor, etc., are broadly in agreement with other model predictions.

Κ-meson decays and parity violation

International Nuclear Information System (INIS)

Dalitz, R.H.

1989-01-01

Between 1948 and 1954 many Κ-meson decay modes were observed, including the tau, pion and xi positives, in emulsion experiments all with masses around 500 MeV. An attempt was made to rationalize the various names for the new particles being discovered. A period of experimental consolidation followed. An attempt was then made to determine the spin parity of the three-pion system from tau plus decay using matrix calculations. New stripped emulsion techniques now permitted a secondary-particle track to be followed to its endpoint. Stacked emulsions were flown in balloons to study Κ mesons and hyperons using cosmic radiation. Later similar work used the new particle accelerators, the Cosmotron and the Bevatron as sources. The author showed that the tau plus and theta plus were competing decay modes of the same Κ + meson, but this meant that parity conservation was violated. Later theoreticians T D Lee and C N Yang provided evidence for this surprising idea from their work on semileptonic weak interactions. (UK)

{phi} meson electroproduction at small Bjorken-x

Energy Technology Data Exchange (ETDEWEB)

Kroll, P. [Wuppertal Univ., Fachbereich Physik (Germany)

2005-07-01

It is reported on an analysis of {phi}-meson electroproduction at small Bjorken-x(x{sub B{sub j}}) within the handbag approach. The amplitudes can be factorized into generalized parton distribution (GPDs) and a partonic subprocess, electroproduction off gluons. Cross-sections and spin density matrix elements are evaluated for {phi}-meson electroproduction and found to be in fair agreement with recent HERA data. (author)

MESON AND DI-ELECTRON PRODUCTION WITH HADES

Czech Academy of Sciences Publication Activity Database

Frohlich, I.; Agakishiev, G.; Agodi, C.; Balanda, A.; Bellia, G.; Belver, D.; Belyaev, A.; Blanco, A.; Böhmer, M.; Boyard, J. L.; Braun-Munzinger, P.; Cabanelas, P.; Castro, E.; Chernenko, S.; Christ, T.; Destefanis, M.; Díaz, J.; Dohrmann, F.; Dybczak, A.; Eberl, T.; Fabbietti, L.; Fateev, O.; Finocchiaro, P.; Fonte, P.; Friese, J.; Galatyuk, T.; Garzón, J.A.; Gernhäuser, R.; Gil, A.; Gilardi, C.; Golubeva, M.; Gonzalez-Diaz, D.; Grosse, E.; Guber, F.; Heilmann, M.; Hennino, T.; Holzmann, R.; Ierusalimov, A.; Iori, I.; Ivashkin, A.; Jurkovic, M.; Kämpfer, B.; Kanaki, K.; Karavicheva, T.; Kirschner, D.; Koenig, I.; Koenig, W.; Kolb, B.W.; Kotte, R.; Kozuch, A.; Krása, Antonín; Křížek, Filip; Krücken, R.; Kuhn, W.; Kugler, Andrej; Kurepin, A.; Lamas-Valverde, J.; Lang, S.; Lange, J.S.; Lapidus, K.; Lopes, L.; Maier, L.; Mangiarotti, A.; Marín, J.; Markert, J.; Metag, V.; Michalska, B.; Michel, J.; Mishra, D.; Moriniére, E.; Mousa, J.; Muntz, C.; Naumann, L.; Novotny, R.; Otwinowski, J.; Pachmayer, Y.C.; Palka, M.; Parpottas, Y.; Pechenov, V.; Pechenova, O.; Cavalcanti, T.P.; Pietraszko, J.; Przygoda, W.; Ramstein, B.; Reshetin, A.; Roy-Stephan, M.; Rustamov, A.; Sadovsky, A.; Sailer, B.; Salabura, P.; Schmah, A.; Simon, R. S.; Sobolev, Yuri, G.; Spataro, S.; Spruck, B.; Strobele, H.; Stroth, J.; Sturm, C.; Sudol, M.; Tarantola, A.; Teilab, K.; Tlustý, Pavel; Traxler, M.; Trebacz, R.; Tsertos, H.; Veretenkin, I.; Wagner, Vladimír; Wen, H.; Wisniowski, M.; Wojcik, T.; Wüstenfeld, J.; Yurevich, S.; Zanevsky, Yu.; Zhou, P.; Zumbruch, P.

2009-01-01

Roč. 24, 2-3 (2009), s. 317-326 ISSN 0217-751X. [Conference MESON 2008. Jagiellonian Univ, Cracow, 06.06.2008-10.06.2008] R&D Projects: GA AV ČR IAA100480803; GA MŠk LC07050 Institutional research plan: CEZ:AV0Z10480505 Keywords : Mesons * di-electrons * resonances Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.941, year: 2009

Beautiful mesons from QCD spectral sum rules

International Nuclear Information System (INIS)

Narison, S.

1991-01-01

We discuss the beautiful meson from the point of view of the QCD spectral sum rules (QSSR). The bottom quark mass and the mixed light quark-gluon condensates are determined quite accurately. The decay constant f B is estimated and we present some arguments supporting this result. The decay constants and the masses of the other members of the beautiful meson family are predicted. (orig.)

Interplay of mesonic and baryonic degrees of freedom in quark matter

Energy Technology Data Exchange (ETDEWEB)

Khan, Naseemuddin

2015-11-03

In this work we study the influence of mesonic and baryonic fluctuations on the phase diagram of quark matter with two flavors. By examining the hadronization process and related techniques, we derive effective low-energy models, where the gluons are integrated out. To be able to compare our model calculations with lattice results at finite chemical potential, we investigate a QCD-like theory with two colors, where the sign-problem is absent. To this end we introduce a quark-meson-diquark model, where the bosonic diquarks play the role of colorless, baryonic degrees of freedom competing with the mesons. To access the phase diagram and determine the phases of chiral and diquark condensation, we employ a functional renormalization group approach allowing for a systematic non-perturbative truncation scheme. Interesting phenomena arise that are known from condensed matter physics, as the BEC-BSC crossover and a phase of condensation within domains. We explore the impact of running wave function renormalizations and Yukawa couplings for the quarks and the boson fields on top of the scale dependence of the effective potential. In the course of this we discuss the Silver Blaze property and its realization within a functional approach. In parallel, we formulate a quark-meson-diquark-baryon model for physical QCD as a low-energy effective theory for baryonic matter at high density, and discuss the relevance of the diquark and baryon degrees of freedom. In this sense, we compute a phase diagram for QCD from functional methods, including a color superconducting phase.

Static-light meson masses from twisted mass lattice QCD

International Nuclear Information System (INIS)

Jansen, Karl; Michael, Chris; Shindler, Andrea; Wagner, Marc

2008-08-01

We compute the static-light meson spectrum using two-flavor Wilson twisted mass lattice QCD. We have considered five different values for the light quark mass corresponding to 300 MeV PS S mesons. (orig.)

Magnetic polarizabilities of light mesons in SU(3 lattice gauge theory

Directory of Open Access Journals (Sweden)

E.V. Luschevskaya

2015-09-01

Full Text Available We investigate the ground state energies of neutral pseudoscalar and vector meson in SU(3 lattice gauge theory in the strong abelian magnetic field. The energy of ρ0 meson with zero spin projection sz=0 on the axis of the external magnetic field decreases, while the energies with non-zero spins sz=−1 and +1 increase with the field. The energy of π0 meson decreases as a function of the magnetic field. We calculate the magnetic polarizabilities of pseudoscalar and vector mesons for lattice volume 184. For ρ0 with spin |sz|=1 and π0 meson the polarizabilities in the continuum limit have been evaluated. We do not observe any evidence in favour of tachyonic mode existence.

Fossil embryos from the Middle and Late Cambrian period of Hunan, south China.

Science.gov (United States)

Dong, Xi-Ping; Donoghue, Philip C J; Cheng, Hong; Liu, Jian-Bo

2004-01-15

Comparative embryology is integral to uncovering the pattern and process of metazoan phylogeny, but it relies on the assumption that life histories of living taxa are representative of their antecedents. Fossil embryos provide a crucial test of this assumption and, potentially, insight into the evolution of development, but because discoveries so far lack phylogenetic constraint, their significance is moot. Here we describe a collection of embryos from the Middle and Late Cambrian period (500 million years ago) of Hunan, south China, that preserves stages of development from cleavage to the pre-hatching embryo of a direct-developing animal comparable to living Scalidophora (phyla Priapulida, Kinorhyncha, Loricifera). The latest-stage embryos show affinity to the Lower Cambrian embryo Markuelia, whose life-history strategy contrasts both with the primitive condition inferred for metazoan phyla and with many proposed hypotheses of affinity, all of which prescribe indirect development. Phylogenetic tests based on these embryological data suggest a stem Scalidophora affinity. These discoveries corroborate, rather than contradict, the predictions of comparative embryology, providing direct historical support for the view that the life-history strategies of living taxa are representative of their stem lineages.

A survey of E/iota meson in hadroproduction

International Nuclear Information System (INIS)

Chung, S.U.

1987-01-01

The E(1420) meson has been around with us since 1963, when its observation was first reported by R. Armenteros et al. With the discovery of the iota(1460) in the same decay channel from J/ψ radiative decays in 1980, there has been a resurgence of interest in this meson because it may turn out to be a pseudoscalar glueball. This review covers the E/iota states seen in hadroproduction, while an update of the iota meson from J/ψ radiative decays is covered by D. Hitlin in this volume. The present review represents an updated version of the previous reviews given by the author at Lund, Leipzig, and Santander

Semileptonic Branching Fractions of Charged and Neutral B Mesons

International Nuclear Information System (INIS)

Athanas, M.; Brower, W.; Masek, G.; Paar, H.P.; Gronberg, J.; Kutschke, R.; Menary, S.; Morrison, R.J.; Nakanishi, S.; Nelson, H.N.; Nelson, T.K.; Qiao, C.; Richman, J.D.; Ryd, A.; Tajima, H.; Sperka, D.; Witherell, M.S.; Balest, R.; Cho, K.; Ford, W.T.; Johnson, D.R.; Lingel, K.; Lohner, M.; Rankin, P.; Smith, J.G.; Alexander, J.P.; Bebek, C.; Berkelman, K.; Bloom, K.; Browder, T.E.; Cassel, D.G.; Cho, H.A.; Coffman, D.M.; Crowcroft, D.S.; Drell, P.S.; Dumas, D.; Ehrlich, R.; Gaidarev, P.; Garcia-Sciveres, M.; Geiser, B.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Henderson, S.; Jones, C.D.; Jones, S.L.; Kandaswamy, J.; Katayama, N.; Kim, P.C.; Kreinick, D.L.; Ludwig, G.S.; Masui, J.; Mevissen, J.; Mistry, N.B.; Ng, C.R.; Nordberg, E.; Patterson, J.R.; Peterson, D.; Riley, D.; Salman, S.; Sapper, M.; Wuerthwein, F.; Avery, P.; Freyberger, A.; Rodriguez, J.; Yang, S.; Yelton, J.; Cinabro, D.; Liu, T.; Saulnier, M.; Wilson, R.; Yamamoto, H.; Bergfeld, T.; Eisenstein, B.I.; Gollin, G.; Ong, B.; Palmer, M.; Selen, M.; Thaler, J.J.; Edwards, K.W.; Ogg, M.; Bellerive, A.; Britton, D.I.; Hyatt, E.R.F.; MacFarlane, D.B.; Patel, P.M.; Spaan, B.; Sadoff, A.J.; Ammar, R.; Baringer, P.; Bean, A.; Besson, D.; Coppage, D.; Copty, N.; Davis, R.; Hancock, N.; Kelly, M.; Kotov, S.; Kravchenko, I.; Kwak, N.; Lam, H.; Kubota, Y.; Lattery, M.; Momayezi, M.; Nelson, J.K.; Patton, S.; Poling, R.; Savinov, V.; Schrenk, S.; Wang, R.; Alam, M.S.; Kim, I.J.; Ling, Z.; Mahmood, A.H.; O'Neill, J.J.; Severini, H.; Sun, C.R.; Wappler, F.; Crawford, G.; Daubenmier, C.M.; Fulton, R.; Fujino, D.; Gan, K.K.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Malchow, R.; Skovpen, Y.; Sung, M.; White, C.; Zoeller, M.M.; Butler, F.; Fu, X.; Nemati, B.; Ross, W.R.; Skubic, P.; Wood, M.; Bishai, M.; Fast, J.; Gerndt, E.; McIlwain, R.L.; Miao, T.; Miller, D.H.; Modesitt, M.; Payne, D.; Shibata, E.I.; Shipsey, I.P.J.; Wang, P.N.; Battle, M.; Ernst, J.; Gibbons, L.; Kwon, Y.

1994-01-01

An examination of leptons in Υ(4S) events tagged by reconstructed B meson decays yields semileptonic branching fractions of b - =(10.1±1.8±1.5)% for charged and b 0 =(10.9±0.7±1.1)% for neutral B mesons. This is the first measurement for charged B mesons. Assuming equality of the charged and neutral semileptonic widths, the ratio b - /b 0 =0.93±0.18±0.12 is equivalent to the ratio of lifetimes

Quasi-exotic open-flavor mesons

Energy Technology Data Exchange (ETDEWEB)

Hilger, T.; Krassnigg, A. [University of Graz, NAWI Graz, Institute of Physics, Graz (Austria)

2017-06-15

Meson states with exotic quantum numbers arise naturally in a covariant bound-state framework in QCD. We investigate the consequences of shifting quark masses such that the states are no longer restricted to certain C-parities, but only by J{sup P}. Then, a priori, one can no longer distinguish exotic or conventional states. In order to identify signatures of the different states to look for experimentally, we provide the behavior of masses, leptonic decay constants, and orbital-angular-momentum decomposition of such mesons, as well as the constellations in which they could be found. Most prominently, we consider the case of charged quasi-exotic excitations of the pion. (orig.)

A search for unconventional mesons

International Nuclear Information System (INIS)

Turnau, J.

1984-01-01

Selected problems of the fixed target meson spectroscopy connected with the issue of unconventional states glueballs, hybrides and four-quarks are discussed. The experimental basis of the dissertation consists of some results of the WA3 experiment performed by ACCMOR collaboration (Π - p→(3Π) - p, K - p→K - Π + Π - p, Π - p→K s o K s o n) and of the S136 experiment performed by CCM collaborations (Π - p↑→Π + Π - n, Π - p↑→K + K - n). Mesons with spin parities J PC = 0 -+ , 0 ++ , 1 ++ and 2 ++ are discussed from the point of view of the phenomenology of unconventional states. (author)

Properties of the ρ meson in dense nuclear matter

International Nuclear Information System (INIS)

Herrmann, M.

1992-05-01

In order to reach a description of the ρ meson, which is in accordance with the principles of the gauge invariance of the electromagnetic interaction, the vector-dominance hypothesis, and the unitarity a model for the ρ meson in the vacuum is developed. Thereafter follows the calculation of the properties of the ρ meson in nuclear matter. First the connection between the spectral function of the ρ meson and the dilepton production rate for an equilibrium state is derived. Then the model for the pion in nuclear matter is described. Following approximations are applied: The description of the pion-baryon interaction pursues non-relativistically and both the width of the delta resonance and the short-range repulsive delta-nucleon interaction is neglected. The self-energy of the ρ meson in nuclear matter following from this description is formally derived from the requirement to couple the ρ meson to a conserved current. The corrections for the 3-point and 4-point vertex resulting from this are calculated and discussed. Thereafter the physical consequences of the changed self-energy of the ρ meson in nuclear matter are considered. By means of the spectral function it is shown that up to the two-fold of the ground-state density the position of the resonance is nearly not changed. At still higher densities the resonances is a little shifted to higher energies. In the range of an invariant mass of about 400 meV a strong increasement concentrated on a small range results. This is caused by coupling to a naked delta-hole state and a pion. Finally the possibilities are discussed to apply the results of this thesis to the prediction of experimental data. Thereby it is proved to be necessary to base on a simulation of the heavy ion reaction. (orig./HSI) [de

Phases, quantum interferences and effective vector meson masses in nuclei

Energy Technology Data Exchange (ETDEWEB)

Soyeur, M.

1996-12-31

We discuss the prospects for observing the mass of {rho}- and {omega}-mesons around nuclear matter density by studying their coherent photoproduction in nuclear targets and subsequent in-medium decay into e{sup +}e{sup -}pairs. The quantum interference of {rho} and {omega}-mesons in the e{sup +}e{sup -}channel and the interference between Bethe-Heitler pairs and dielectrons from vector meson decays are of particular interest. (author). 21 refs.

Controls on gut phosphatisation: the trilobites from the Weeks Formation Lagerstätte (Cambrian; Utah.

Directory of Open Access Journals (Sweden)

Rudy Lerosey-Aubril

Full Text Available Despite being internal organs, digestive structures are frequently preserved in Cambrian Lagerstätten. However, the reasons for their fossilisation and their biological implications remain to be thoroughly explored. This is particularly true with arthropods--typically the most diverse fossilised organisms in Cambrian ecosystems--where digestive structures represent an as-yet underexploited alternative to appendage morphology for inferences on their biology. Here we describe the phosphatised digestive structures of three trilobite species from the Cambrian Weeks Formation Lagerstätte (Utah. Their exquisite, three-dimensional preservation reveals unique details on trilobite internal anatomy, such as the position of the mouth and the absence of a differentiated crop. In addition, the presence of paired pygidial organs of an unknown function is reported for the first time. This exceptional material enables exploration of the relationships between gut phosphatisation and the biology of organisms. Indeed, soft-tissue preservation is unusual in these fossils as it is restricted to the digestive structures, which indicates that the gut played a central role in its own phosphatisation. We hypothesize that the gut provided a microenvironment where special conditions could develop and harboured a source of phosphorus. The fact that gut phosphatization has almost exclusively been observed in arthropods could be explained by their uncommon ability to store ions (including phosphorous in their digestive tissues. However, in some specimens from the Weeks Formation, the phosphatisation extends to the entire digestive system, suggesting that trilobites might have had some biological particularities not observed in modern arthropods. We speculate that one of them might have been an increased capacity for ion storage in the gut tissues, related to the moulting of their heavily-mineralised carapace.

Observation of a New Narrow Axial-Vector Meson alpha(1)(1420)

Czech Academy of Sciences Publication Activity Database

Adolph, C.; Akhunzyanov, R.; Alexeev, M.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Austregesilo, A.; Azevedo, C.; Badelek, B.; Balestra, F.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bisplinghoff, J.; Bodlák, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Burtin, E.; Chang, W.-C.; Chiosso, M.; Choi, I.; Chung, S. U.; Cicuttin, A.; Crespo, M.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O.; Dhara, L.; Donskov, S. V.; Doshita, N.; Duic, V.; Dunnweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; Finger jr., M.; Fischer, H.; Franco, C.; Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Gnesi, I.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grosse-Perdekapm, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; von Harrach, D.; Hahne, D.; Hashimoto, R.; Heinsius, F. H.; Herrmann, E.; Hinterberger, F.; Horikawa, N.; d´Hose, N.; Hsieh, C.-Yu.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jarý, V.; Jörg, P.; Joosten, R.; Kabuss, E.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Y.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z. V.; Kuchinski, N.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A. A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.; Marchand, C.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neyret, D.; Nikolaenko, V. I.; Nový, J.; Nowak, W. D.; Nunes, A.S.; Olshevsky, A. G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Peshekhonov, D. V.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rocco, E.; Rossiyskaya, N. S.; Ryabchikov, D.; Rychter, A.; Samoylenko, V. D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I. A.; Sbrizzai, G.; Schiavon, P.; Schmeing, S.; Schmidt, K.; Schlüter, T.; Selyunin, A.; Schmieden, H.; Schönning, K.; Schopferer, S.; Shevchenko, O. Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sozzi, F.; Srnka, Aleš; Stolarski, M.; Šulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Ter Wolbeek, J.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Tskhay, V.; Uhl, S.; Veloso, J.; Virius, M.; Wallner, S.; Weisrock, T.; Wilfert, M.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.

2015-01-01

Roč. 115, č. 8 (2015), 082001:1-6 ISSN 0031-9007 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : COMPASS * pion-nucleon scattering * hadron spectroscopy * light-meson spectrum * axial-vector mesons * exotic mesons Subject RIV: BH - Optics, Masers, Lasers Impact factor: 7.645, year: 2015

Limits on rare exclusive decays of B mesons

International Nuclear Information System (INIS)

Avery, P.; Besson, D.; Bowcock, T.; Giles, R.T.; Hassard, J.; Kinoshita, K.; Pipkin, F.M.; Wilson, R.; Wolinski, J.; Xiao, D.; Gentile, T.; Haas, P.; Hempstead, M.; Jensen, T.; Kagan, H.; Kass, R.; Behrends, S.; Guida, J.M.; Guida, J.A.; Morrow, F.; Poling, R.; Thorndike, E.H.; Tipton, P.; Alam, M.S.; Katayama, N.; Kim, I.J.; Sun, C.R.; Tanikella, V.; Bortoletto, D.; Chen, A.; Garren, L.; Goldberg, M.; Holmes, R.; Horwitz, N.; Jawahery, A.; Lubrano, P.; Moneti, G.C.; Sharma, V.; Csorna, S.E.; Mestayer, M.D.; Panvini, R.S.; Word, G.B.; Bean, A.; Bobbink, G.J.; Brock, I.C.; Engler, A.; Ferguson, T.; Kraemer, R.W.; Rippich, C.; Vogel, H.; Bebek, C.; Berkelman, K.; Blucher, E.; Cassel, D.G.; Copie, T.; DeSalvo, R.; DeWire, J.W.; Ehrlich, R.; Galik, R.S.; Gilchriese, M.G.D.; Gittelman, B.; Gray, S.W.; Halling, A.M.; Hartill, D.L.; Heltsley, B.K.; Holzner, S.; Ito, M.; Kandaswamy, J.; Kowalewski, R.; Kreinick, D.L.; Kubota, Y.; Mistry, N.B.; Mueller, J.; Namjoshi, R.; Nordberg, E.; Ogg, M.; Perticone, D.; Peterson, D.; Pisharody, M.; Read, K.; Riley, D.; Silverman, A.; Stone, S.; Yi Xia; Sadoff, A.J.

1987-01-01

We have set upper limits for rare exclusive decays of B mesons arising from higher order processes in the standard model of electroweak interactions. Such decays may occur via ''penguin diagrams'' in B decay. We also set an upper limit on a lepton-number-violating decay mode of the neutral B meson. (orig.)

Test of scalar meson structure in φ radiative decays

International Nuclear Information System (INIS)

Kumano, S.

1992-12-01

We show that φ radiative decays into scalar mesons [f 0 (975), a 0 (980) ≡ S] can provide important clues on the internal structures of these mesons. Radiative decay widths vary widely: B.R. = 10 -4 -10 -6 depending on the substructures (qq-bar, qqq-barq-bar, KK-bar, glueball). Hence, we could discriminate among various models by measuring these widths at future φ factories. The understanding of these meson structures is valuable not only in hadron spectroscopy but also in nuclear physics in connection with the widely-used but little-understood σ meson. We also find that the decay φ→S γ →K 0 K-bar 0 γ is not strong enough to pose a significant background problem for studying CP violation via φ→K 0 K-bar 0 at the φ factories. (author)

Determining the meson-nucleus potential - on the way to mesic states

Energy Technology Data Exchange (ETDEWEB)

Metag, Volker, E-mail: volker.metag@exp2.physik.uni-giessen.de [Universität Giessen, II. Physikalisches Institut (Germany)

2015-08-15

Experimental approaches to determine the real and imaginary part of the meson-nucleus potential are described. The experiments have been performed with the Crystal Barrel/TAPS detector at the electron accelerator ELSA (Bonn) and the Crystal Ball/TAPS detector at MAMI (Mainz). Measuring the transparency ratio as well as the excitation function and momentum distribution for photo production of ω and η′ mesons, the imaginary part of the η′-nucleus potential is found to be smaller than the real part. In case of the ω meson the opposite is observed. This makes the η′ meson a good candidate for the search for meson-nucleus bound states while no resolved ω mesic states can be expected. The results are discussed and compared to theoretical predictions. An outlook on future experiments is given.

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).

Muoproduction of J/ψ-mesons and the gluon distribution in nucleons

International Nuclear Information System (INIS)

Jong, Maarten de.

1991-01-01

The cross sections for production of J/ψ-mesons in muon-scattering at hydrogen and deuterium have been measured at a muon-energy of 280 GeV in order to extract from these the momentum distribution of gluons in the nucleon. These cross sections turned out to be equal for protons and neutrons within the experimental error. In the framework of the colour singlet model the gluon distribution has been determined from the cross section for the inelastic production of J/ψ mesons. At small gluon impulses the distribution obtained resembles a brems-strahlung spectrum. This distribution decreases, according to a simple description (counting rules) at larger impulses. The same model however underestimates the cross section for elastic production of J/ψ-mesons seriously. It is found that in inelastic production of J/ψ-mesons both helicities of the meson occur equally. Also a correlation has been observed between the scattering plane and the plane in which the J/ψ meson decays. The production of J/ψ-mesons and ψ'-mesons has been investigated in muon scattering at concrete at the same incoming energy. The measured ratio of their cross sections agrees with the colour singlet model but disagrees with the simplified description which characterizes the 'photon-gluon fusion model'. The possible nuclear-mass dependence of the cross section for J/ψ-meson production has been investigated in interactions of muons with tin and carbon at an energy of 280 GeV. This possible dependence turns out to be absent which means that on the basis of the colour singlet model the distributions of the gluons in the nucleon are equal in tin and carbon. (author). 103 refs.; 60 figs.; 19 tabs

Nonleptonic B decays involving tensor mesons

Energy Technology Data Exchange (ETDEWEB)

Lopez Castro, G. [Departamento de Fisica, Cinvestav del IPN, Apdo. Postal 14-740, 07000 Mexico, D.F. (Mexico); Munoz, J.H. [Departamento de Fisica, Cinvestav del IPN, Apdo. Postal 14-740, 07000 Mexico, D.F. (Mexico)]|[Departamento de Fisica, Universidad del Tolima, A.A. 546, Ibague (Colombia)

1997-05-01

Two-body nonleptonic decays of B mesons into PT and VT modes are calculated using the nonrelativistic quark model of Isgur {ital et al.} The predictions obtained for B{r_arrow}{pi}D{sub 2}{sup {asterisk}},{rho}D{sub 2}{sup {asterisk}} are a factor of 3{endash}5 below present experimental upper limits. Interesting patterns are obtained for ratios of B decays involving mesons with different spin excitations and their relevance for additional tests of forms factor models are briefly discussed. {copyright} {ital 1997} {ital The American Physical Society}

submitter Time-dependent CP violation in charm mesons

CERN Document Server

Inguglia, Gianluca

CP violation is a well established phenomenon for B and K mesons, but for D0 mesons, bound states made up of a quark-antiquark pair containing a charm quark, a conclusive answer to the question whether there is CP vio- lation or not, has yet to be determined. I show here the phenomenology of time-dependent CP asymmetries in charm decays, and discuss the implica- tions of experimental tests aimed at the measurement of CP violation in the interference between mixing and decays of charm mesons, in particular when studying the decay channels D0 ! h+h (h = K; ). The decay channels considered can also be used to constrain quantities that are poorly measured or still to be investigated, such as MIX and c;eff , provided that the e ects of penguin pollution are ignored. I considered correlated production of D0 mesons at the SuperB experiment and its planned asymmetric run at the charm threshold and performed a study of simulated events, nding that a boost factor = 0:28 would not be su cient to produce competitive re- ...

Quasi two-body decays of D0 meson

International Nuclear Information System (INIS)

Terasaki, K.; Oneda, S.

1985-08-01

Quasi two-body decays of D 0 -meson are studied from an algebraic approach, using a hard meson extrapolation. In this innovation of old current algebra with new perspective, a reasonable unified description of K sub(S) → 2π and D 0 → K-barπ decays has been obtained previously, keeping only the contribution of ground state mesons to the now surviving surface term. In this paper, it is shown that quasi two-body decays can also be accomodated reasonably well in the same scheme. A distinctive feature of our result is that GAMMA(D 0 → phi K-bar 0 ) is sizable, while D 0 → rho 0 K-bar 0 is relatively suppressed. (author)

Accumulation conditions and enrichment patterns of natural gas in the Lower Cambrian Longwangmiao Fm reservoirs of the Leshan-Longnǚsi Palaeohigh, Sichuan Basin

Directory of Open Access Journals (Sweden)

Xu Chunchun

2014-10-01

Full Text Available As several major new gas discoveries have been made recently in the Lower Cambrian Longwangmiao Fm reservoirs in the Leshan-Longnǚsi Palaeohigh of the Sichuan Basin, a super-huge gas reservoir group with multiple gas pay zones vertically and cluster reservoirs laterally is unfolding in the east segment of the palaeohigh. Study shows that the large-scale enrichment and accumulation of natural gas benefits from the good reservoir-forming conditions, including: (1 multiple sets of source rocks vertically, among which, the high-quality Lower Paleozoic source rocks are widespread, and have a hydrocarbon kitchen at the structural high of the Palaeohigh, providing favorable conditions for gas accumulation near the source; (2 three sets of good-quality reservoirs, namely, the porous-vuggy dolomite reservoirs of mound-shoal facies in the 2nd and 4th members of the Sinian Dengying Fm as well as the porous dolomite reservoirs of arene-shoal facies in the Lower Cambrian Longwangmiao Fm, are thick and wide in distribution; (3 structural, lithological and compound traps developed in the setting of large nose-like uplift provide favorable space for hydrocarbon accumulation. It is concluded that the inheritance development of the Palaeohigh and its favorable timing configuration with source rock evolution are critical factors for the extensive enrichment of gas in the Lower Cambrian Longwangmiao Fm reservoirs. The structural high of the Palaeohigh is the favorable area for gas accumulation. The inherited structural, stratigraphic and lithological traps are the favorable sites for gas enrichment. The areas where present structures and ancient structures overlap are the sweet-spots of gas accumulation.

Stable isotope (δ13Cker, δ13Ccarb, δ18Ocarb distribution along a Cambrian outcrop section in the eastern Tarim Basin, NW China and its geochemical significance

Directory of Open Access Journals (Sweden)

Hu Liu

2017-01-01

Full Text Available This study investigated the geochemical features of the lower Paleozoic strata of Yaerdang Mountain outcrop along with the core samples from well TD2∈ in the eastern Tarim Basin, NW China. The total organic carbon abundance, hydrocarbon-generating precursor biospecies, and stable isotope ratios of organics and carbonate (δ13Cker, δ13Ccarb and δ18Ocarb were comprehensively studied for their possible correlative constraints during sedimentary evolution. The results revealed that the δ13Cker (VPDB of Cambrian kerogens along the outcrop section varied from −34.6‰ to −28.4‰, indicating an increasing tendency from the lower Cambrian to the upper Cambrian. This was on the whole accompanied by the variation in the δ13Ccarb and δ18Ocarb along the profile, which might be associated with the changes in the sea level and also in the compositional variation of benthic and planktonic biomass. The large variation in the stable carbon isotope ratios up to 6‰ along the outcrop section reflected the heterogeneity of the Cambrian source rocks from the eastern Tarim Basin. Hence, the 13C-enriched crude oils from well TD2∈ might have been derived from a localized stratum of Cambrian source rocks. The results from this study showed the possibility of multiple source kitchens in the Cambrian–lower Ordovician portion of Tarim Basin.

Light Meson Distribution Amplitudes

CERN Document Server

Arthur, R.; Brommel, D.; Donnellan, M.A.; Flynn, J.M.; Juttner, A.; de Lima, H.Pedroso; Rae, T.D.; Sachrajda, C.T.; Samways, B.

2010-01-01

We calculated the first two moments of the light-cone distribution amplitudes for the pseudoscalar mesons ($\\pi$ and $K$) and the longitudinally polarised vector mesons ($\\rho$, $K^*$ and $\\phi$) as part of the UKQCD and RBC collaborations' $N_f=2+1$ domain-wall fermion phenomenology programme. These quantities were obtained with a good precision and, in particular, the expected effects of $SU(3)$-flavour symmetry breaking were observed. Operators were renormalised non-perturbatively and extrapolations to the physical point were made, guided by leading order chiral perturbation theory. The main results presented are for two volumes, $16^3\\times 32$ and $24^3\\times 64$, with a common lattice spacing. Preliminary results for a lattice with a finer lattice spacing, $32^3\\times64$, are discussed and a first look is taken at the use of twisted boundary conditions to extract distribution amplitudes.

Chiral symmetry breaking and the spin content of the ρ and ρ' mesons

International Nuclear Information System (INIS)

Glozman, L.Ya.; Lang, C.B.; Limmer, M.

2011-01-01

Using interpolators with different SU(2) L xSU(2) R transformation properties we study the chiral symmetry and spin contents of the ρ and ρ ' mesons in lattice simulations with dynamical quarks. A ratio of couplings of the q-bar γ i τq and q-bar σ 0i τq interpolators to a given meson state at different resolution scales tells one about the degree of chiral symmetry breaking in the meson wave function at these scales. Using a Gaussian gauge invariant smearing of the quark fields in the interpolators, we are able to extract the chiral content of mesons up to the infrared resolution of ∼1 fm. In the ground state ρ meson the chiral symmetry is strongly broken with comparable contributions of both the (0,1)+(1,0) and (1/2,1/2) b chiral representations with the former being the leading contribution. In contrast, in the ρ ' meson the degree of chiral symmetry breaking is manifestly smaller and the leading representation is (1/2,1/2) b . Using a unitary transformation from the chiral basis to the 2S+1 L J basis, we are able to define and measure the angular momentum content of mesons in the rest frame. This definition is different from the traditional one which uses parton distributions in the infinite momentum frame. The ρ meson is practically a 3 S 1 state with no obvious trace of a 'spin crisis'. The ρ ' meson has a sizeable contribution of the 3 D 1 wave, which implies that the ρ ' meson cannot be considered as a pure radial excitation of the ρ meson.

Electro- and chromomagnetism in the charm meson spectrum

CERN Document Server

Fritzsch, Harald

1977-01-01

How the D and F meson spectrum is influenced by the chromomagnetic and electromagnetic hyperfine interaction is discussed. In particular a relation between the hyperfine splitting of charmed mesons and the magnetic moments of the baryons is derived. It is found that M(F/sub + /*)-M(F/sub +/) approximately=100+or-8 MeV. (12 refs).

Recent trends in the mesonic description of nuclei

International Nuclear Information System (INIS)

Delorme, J.

1985-07-01

A survey is given of some recent developments in the domain of meson induced phenomena in nuclei. The manifestations of mesonic degrees of freedom are considered in the context of exchange currents as well as that of effective interactions. The significance of past successes is reexamined in the light of recent progress towards a QCD based nuclear theory

First measurement of the B S meson mass

Science.gov (United States)

Buskulic, D.; De Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Minard, M.-N.; Pietrzyk, B.; Ariztizabal, F.; Comas, P.; Crespo, J. M.; Delfino, M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Gaitan, V.; Garrido, Ll.; Mattison, T.; Pacheco, A.; Padilla, C.; Pascual, A.; Creanza, D.; de Palma, M.; Farilla, A.; Iaselli, G.; Maggi, G.; Natali, S.; Nuzzo, S.; Quattromini, M.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Chai, Y.; Hu, H.; Huang, D.; Huang, X.; Lin, J.; Wang, T.; Xie, Y.; Xu, D.; Xu, R.; Zhang, J.; Zhang, L.; Zhao, W.; Blucher, E.; Bonvicini, G.; Boudreau, J.; Casper, D.; Drevermann, H.; Forty, R. W.; Ganis, G.; Gay, C.; Hagelberg, R.; Harvey, J.; Haywood, S.; Hilgart, J.; Jacobsen, R.; Jost, B.; Knobloch, J.; Lehraus, I.; Lohse, T.; Maggi, M.; Markou, C.; Martinez, M.; Mato, P.; Meinhard, H.; Minten, A.; Miotto, A.; Miquel, R.; Moser, H.-G.; Palazzi, P.; Pater, J. R.; Perlas, J. A.; Pusztaszeri, J.-F.; Ranjard, F.; Redlinger, G.; Rolandi, L.; Rothberg, J.; Ruan, T.; Saich, M.; Schlatter, D.; Schmelling, M.; Sefkow, F.; Tejessy, W.; Veenhof, R.; Wachsmuth, H.; Wiedenmann, W.; Wildish, T.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; Badaud, F.; Bardadin-Otwinowska, M.; El Fellous, R.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Prulhière, F.; Saadi, F.; Fearnley, T.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Møllerud, R.; Nilsson, B. S.; Kyriakis, A.; Simopoulou, E.; Vayaki, A.; Zachariadou, K.; Badier, J.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Fouque, G.; Orteu, S.; Rougé, A.; Rumpf, M.; Tanaka, R.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Veitch, E.; Focardi, E.; Moneta, L.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Ikeda, M.; Lannutti, J.; Levinthal, D.; Sawyer, L.; Wasserbaech, S.; Antonelli, A.; Baldini, R.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Cerutti, F.; Chiarella, V.; D'Ettorre-Piazzoli, B.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Picchi, P.; Colrain, P.; ten Have, I.; Lynch, J. G.; Maitland, W.; Morton, W. T.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Smith, M. G.; Thompson, A. S.; Turnbull, R. M.; Brandl, B.; Braun, O.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E. E.; Maumary, Y.; Putzer, A.; Rensch, B.; Stahl, A.; Tittel, K.; Wunsch, M.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Cattaneo, M.; Colling, D. J.; Dornan, P. J.; Greene, A. M.; Hassard, J. F.; Lieske, N. M.; Moutoussi, A.; Nash, J.; Patton, S.; Payne, D. G.; Phillips, M. J.; San Martin, G.; Sedgbeer, J. K.; Tomalin, I. R.; Wright, A. G.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bowdery, C. K.; Brodbeck, T. J.; Finch, A. J.; Foster, F.; Hughes, G.; Jackson, D.; Keemer, N. R.; Nuttall, M.; Patel, A.; Sloan, T.; Snow, S. W.; Whelan, E. P.; Kleinknecht, K.; Raab, J.; Renk, B.; Sander, H.-G.; Schmidt, H.; Steeg, F.; Walther, S. M.; Wanke, R.; Wolf, B.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Carr, J.; Coyle, P.; Drinkard, J.; Etienne, F.; Nicod, D.; Papalexiou, S.; Payre, P.; Roos, L.; Rousseau, D.; Schwemling, P.; Talby, M.; Adlung, S.; Assmann, R.; Bauer, C.; Blum, W.; Brown, D.; Cattaneo, P.; Dehning, B.; Dietl, H.; Dydak, F.; Frank, M.; Halley, A. W.; Jacobs, K.; Lauber, J.; Lütjens, G.; Lutz, G.; Männer, W.; Richter, R.; Schröder, J.; Schwarz, A. S.; Settles, R.; Seywerd, H.; Stierlin, U.; Stiegler, U.; St. Denis, R.; Wolf, G.; Alemany, R.; Boucrot, J.; Callot, O.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Jaffe, D. E.; Janot, P.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Schune, M.-H.; Veillet, J.-J.; Videau, I.; Zhang, Z.; Abbaneo, D.; Bagliesi, G.; Batignani, G.; Bottigli, U.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Dell'Orso, R.; Ferrante, I.; Fidecaro, F.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Mannelli, E. B.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Vannini, C.; Venturi, A.; Verdini, P. G.; Walsh, J.; Betteridge, A. P.; Carter, J. M.; Gao, Y.; Green, M. G.; March, P. V.; Mir, Ll. M.; Medcalf, T.; Quazi, I. S.; Strong, J. A.; West, L. R.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Norton, P. R.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Duarte, H.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J.-F.; Rosowsky, A.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Si Mohand, D.; Vallage, B.; Johnson, R. P.; Litke, A. M.; Taylor, G.; Wear, J.; Ashman, J. G.; Babbage, W.; Booth, C. N.; Buttar, C.; Cartwright, S.; Combley, F.; Dawson, I.; Thompson, L. F.; Barberio, E.; Böhrer, A.; Brandt, S.; Cowan, G.; Grupen, C.; Lutters, G.; Rivera, F.; Schäfer, U.; Smolik, L.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Ragusa, F.; Bellantoni, L.; Chen, W.; Cinabro, D.; Conway, J. S.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; Grahl, J.; Harton, J. L.; LeClaire, B. W.; Lishka, C.; Pan, Y. B.; Saadi, Y.; Schmitt, M.; Sharma, V.; Shi, Z. H.; Walsh, A. M.; Weber, F. V.; Wu, Sau Lan; Wu, X.; Zheng, M.; Zobernig, G.

1993-07-01

In a sample of about 1.1 million hadronic Z decays recorded with the ALEPH detector during the 1990-1992 running of LEP, two unambiguous B S meson candidates were observed. From these events the mass of the B S meson has been measured to be 5.3686 ± 0.0056 (stat.) ± 0.0015 (syst.) GeV.

Production of φ-Mesons in anti NN-Annihilation

International Nuclear Information System (INIS)

Sapozhnikov, M.G.

1994-01-01

Recent results from the experiments on the φ-meson production in the annihilation of stopped antiprotons have demonstrated a significant (by a factor of 30-50) violation of the OZI rule. Experimental information on the φ-meson production is discussed and possible theoretical explanations of the strong OZI rule violation are reviewed. 37 refs., 4 figs., 2 tabs

Perspectives of Scalar- and Vector- Meson Production in Hadron-Nucleus Reactions

International Nuclear Information System (INIS)

Cassing, W.

2000-01-01

The production and decay of vector mesons (ρ, ω) in pA reactions at COSY energies is studied with particular emphasis on their in-medium spectral functions. It is explored within transport calculations, if hadronic in-medium decays like π + π - or π 0 γ might provide complementary information to their dilepton (e + e - ) decays. Whereas the π + π - signal from the ρ-meson is found to be strongly distorted by pion rescattering, the ω- meson Dalitz decay to π 0 γ appears promising even for more heavy nuclei. The perspectives of scalar meson ( f 0 , a 0 ) production in pp reactions are investigated within a boson-exchange model indicating that the f 0 -meson might hardly be detected in these collisions in the K(anti)K or ππ decay channels whereas the exclusive channel pp→da 0 + looks very promising. (author)

The effect of meson wave function on heavy-quark fragmentation function

Energy Technology Data Exchange (ETDEWEB)

Moosavi Nejad, S.M. [Yazd University, Faculty of Physics (Iran, Islamic Republic of); Institute for Research in Fundamental Sciences (IPM), School of Particles and Accelerators, Tehran (Iran, Islamic Republic of)

2016-05-15

We calculate the process-independent fragmentation functions (FFs) for a heavy quark to fragment into heavy mesons considering the effects of meson wave function. In all previous works, where the FFs of heavy mesons or heavy baryons were calculated, a delta function form was approximated for the wave function of hadrons. Here, for the first time, we consider a typical mesonic wave function which is different from the delta function and is the nonrelativistic limit of the solution of Bethe-Salpeter equation with the QCD kernel. We present our numerical results for the heavy FFs and show how the proposed wave function improves the previous results. As an example, we focus on the fragmentation function for c-quark to split into S-wave D{sup 0} -meson and compare our results with experimental data from BELLE and CLEO. (orig.)

Meson life time in the anisotropic quark-gluon plasma

International Nuclear Information System (INIS)

Ali-Akbari, Mohammad; Allahbakhshi, Davood

2014-01-01

In the hot (an)isotropic plasma the meson life time τ is defined as a time scale after which the meson dissociates. According to the gauge/gravity duality, this time can be identified with the inverse of the imaginary part of the frequency of the quasinormal modes, ω_I, in the (an)isotropic black hole background. In the high temperature limit, we numerically show that at fixed temperature(entropy density) the life time of the mesons decreases(increases) as the anisotropy parameter raises. For general case, at fixed temperature we introduce a polynomial function for ω_I and observe that the meson life time decreases. Moreover, we realize that (s/T"3)"6, where s and T are entropy density and temperature of the plasma respectively, can be expressed as a function of anisotropy parameter over temperature. Interestingly, this function is a Padé approximant.

Meson-exchange N-N potential

International Nuclear Information System (INIS)

Nutt, W.T.

1976-01-01

A meson-theoretic model of the intermediate range nucleon-nucleon potential is presented with emphasis placed on the two-pion exchange contribution. The Bethe-Salpeter equation is reduced, by the Blankenbecler-Sugar technique, to a Lippmann-Schwinger equation, from which an approximate nonlocal, energy-dependent potential is obtained. The nucleon-antinucleon pair contribution, which plagues meson-theoretical two-pion calculations, is suppressed by the complex poles of the one-nucleon Green's function. The importance of the retention of the explicit energy dependence of the potential is demonstrated by calculating the off-shell scattering matrices. The potential is presented in a linearized (in energy) form with the core region adjusted to produce a fit to low energy data

The Rainich problem for coupled gravitational and scalar meson fields

International Nuclear Information System (INIS)

Hyde, J.M.

1975-01-01

The equations of the coupled gravitational and scalar meson fields in general relativity are considered. It is shown that the wave equation for the scalar meson field which is usually specified explicitly in addition to the Einstein field equations is implied by Einstein's equations. Using this result it is then shown how the scalar field may be eliminated explicitly from the field equations, thus solving the Rainich problem for the coupled gravitational and scalar meson fields. (author) [fr

Future prospects for studying CP violation in B-meson decays

International Nuclear Information System (INIS)

Nakada, T.

1997-01-01

Experimental prospects for observing CP violation in B-meson decays are reviewed. Comparisons are made for various options: experiments a e + e - B-Meson Factories, HERA and the TEVATRON will produce results n near future. They will have a good chance to discover CP violation in B-meson decays. On a longer time scale, experiments at the LHC will aim at accurate measurements to make a precision test of the standard model in CP violation. (author)

Proterozoic structure, cambrian rifting, and younger faulting as revealed by a regional seismic reflection network in the Southern Illinois Basin

Science.gov (United States)

Potter, C.J.; Drahovzal, James A.; Sargent, M.L.; McBride, J.H.

1997-01-01

Four high-quality seismic reflection profiles through the southern Illinois Basin, totaling 245 km in length, provide an excellent regional subsurface stratigraphic and structural framework for evaluation of seismic risk, hydrocarbon occurrence, and other regional geologic studies. These data provide extensive subsurface information on the geometry of the intersection of the Cambrian Reelfoot and Rough Creek rifts, on extensive Proterozoic reflection sequences, and on structures (including the Fluorspar Area Fault Complex and Hicks Dome) that underlie a transitional area between the well-defined New Madrid seismic zone (to the southwest) and a more diffuse area of seismicity in the southern Illinois Basin. Our principal interpretations from these data are listed here in order of geologic age, from oldest to youngest: 1. Prominent Proterozoic layering, possibly equivalent to Proterozoic (???1 Ga) Middle Run Formation clastic strata and underlying (1.3-1.5 Ga) volcanic rocks of the East Continent rift basin, has been strongly deformed, probably as part of the Grenville foreland fold and thrust belt. 2. A well-defined angular unconformity is seen in many places between Proterozoic and Cambrian strata; a post-Grenville Proterozoic sequence is also apparent locally, directly beneath the base of the Cambrian. 3. We infer a major reversal in Cambrian rift polarity (accommodation zone) in the Rough Creek Graben in western Kentucky. 4. Seismic facies analysis suggests the presence of basin-floor fan complexes at and near the base of the Cambrian interval and within parts of a Proterozoic post-Grenville sequence in several parts of the Rough Creek Graben. 5. There is an abrupt pinchout of the Mount Simon Sandstone against crystalline basement beneath the Dale Dome (near the Texaco no. 1 Cuppy well, Hamilton County) in southeastern Illinois, and a more gradual Mount Simon pinchout to the southeast. 6. Where crossed by the seismic reflection line in southeast Illinois, some

Magnetic monopole interactions: shell structure of meson and baryon states

International Nuclear Information System (INIS)

Akers, D.

1986-01-01

It is suggested that a low-mass magnetic monopole of Dirac charge g = (137/2)e may be interacting with a c-quark's magnetic dipole moment to produce Zeeman splitting of meson states. The mass M 0 = 2397 MeV of the monopole is in contrast to the 10 16 -GeV monopoles of grand unification theories (GUT). It is shown that shell structure of energy E/sub n/ = M 0 + 1/4nM 0 ... exists for meson states. The presence of symmetric meson states leads to the identification of the shell structure. The possible existence of the 2397-MeV magnetic monopole is shown to quantize quark masses in agreement with calculations of quantum chromodynamics (QCD). From the shell structure of meson states, the existence of two new mesons is predicted: eta(1814 +/- 50 MeV) with I/sup G/(J/sup PC/) = 0 + (0 -+ ) and eta/sub c/ (3907 +/- 100 MeV) with J/sup PC/ = 0 -+ . The presence of shell structure for baryon states is shown

Properties of rho and eta mesons in nuclear matter

International Nuclear Information System (INIS)

Herrmann, M.; Sauermann, C.; Friman, B.L.; Technische Hochschule Darmstadt; Noerenberg, W.; Technische Hochschule Darmstadt

1993-10-01

The properties of ρ- and η-mesons in nuclear matter are studied within the scope of hadronic models. Unknown model parameters are obtained from fits to scattering data. - The treatment of the ρ-meson includes the coupling to two pions which, in matter, are strongly mixed with delta-particle-nucleon-hole states. The ρ-meson self-energy is evaluated in a current conserving approximation with in-medium pion propagators and vertex corrections. While the position of the original peak in the spectral function remains almost unchanged, its width grows rapidly with increasing density. Consequently, the ρ-meson strength function is strongly dispersed at high densities. Due to vertex corrections a new peak at a mass around 3m π emerges with increasing density, while the spectral function around the two-pion threshold is found to be smooth at all densities. The η-meson is strongly mixed with N * (1535)-particle-nucleon-hole states in nuclear matter. The corresponding dispersion relations with an upper and a lower branch look similar to those of the (π, ΔN -1 )-modes. However, since the N * is an S-wave resonance in the ηN-channel, the repulsion of the two branches survives at zero momentum. (orig.)

Masses of scalar and axial-vector B mesons revisited

Energy Technology Data Exchange (ETDEWEB)

Cheng, Hai-Yang [Academia Sinica, Institute of Physics, Taipei (China); Yu, Fu-Sheng [Lanzhou University, School of Nuclear Science and Technology, Lanzhou (China)

2017-10-15

The SU(3) quark model encounters a great challenge in describing even-parity mesons. Specifically, the q anti q quark model has difficulties in understanding the light scalar mesons below 1 GeV, scalar and axial-vector charmed mesons and 1{sup +} charmonium-like state X(3872). A common wisdom for the resolution of these difficulties lies on the coupled channel effects which will distort the quark model calculations. In this work, we focus on the near mass degeneracy of scalar charmed mesons, D{sub s0}{sup *} and D{sub 0}{sup *0}, and its implications. Within the framework of heavy meson chiral perturbation theory, we show that near degeneracy can be qualitatively understood as a consequence of self-energy effects due to strong coupled channels. Quantitatively, the closeness of D{sub s0}{sup *} and D{sub 0}{sup *0} masses can be implemented by adjusting two relevant strong couplings and the renormalization scale appearing in the loop diagram. Then this in turn implies the mass similarity of B{sub s0}{sup *} and B{sub 0}{sup *0} mesons. The P{sub 0}{sup *}P{sub 1}{sup '} interaction with the Goldstone boson is crucial for understanding the phenomenon of near degeneracy. Based on heavy quark symmetry in conjunction with corrections from QCD and 1/m{sub Q} effects, we obtain the masses of B{sup *}{sub (s)0} and B{sup '}{sub (s)1} mesons, for example, M{sub B{sub s{sub 0{sup *}}}} = (5715 ± 1) MeV + δΔ{sub S}, M{sub B}{sup {sub '{sub s{sub 1}}}} = (5763 ± 1) MeV + δΔ{sub S} with δΔ{sub S} being 1/m{sub Q} corrections. We find that the predicted mass difference of 48 MeV between B{sup '}{sub s1} and B{sub s0}{sup *} is larger than that of 20-30 MeV inferred from the relativistic quark models, whereas the difference of 15 MeV between the central values of M{sub B}{sup {sub '{sub s{sub 1}}}} and M{sub B}{sup {sub '{sub 1}}} is much smaller than the quark model expectation of 60-100 MeV. Experimentally, it is important to have a precise

Study of the neutral meson spectrum near 1000 MeV

Energy Technology Data Exchange (ETDEWEB)

Leeper, R.J.

1975-12-01

The nonstrange neutral meson spectrum from 0.75 to 1.23 GeV/c was studied in the reaction negative pion plus proton goes to neutron plus missing mass at incident beam momenta of 1.98 and 2.41 GeV/c. Neutrons produced by beam interactions in the liquid hydrogen target were detected in the near forward direction in an array of plastic scintillation counters. The missing mass of the remaining particles produced in the final state was determined by a measurement of the neutron time-of-flight. In the case of genuine two-body processes, ..pi../sup -/p ..-->.. n + meson, the observed neutron corresponded to mesons produced forward in the center of mass system. Forward going secondary charge particles produced in the hydrogen target were detected and momentum analyzed by the Argonne Effective Mass Spectrometer. This allowed the isolation of several constrained final states. Arrays of scintillation detectors surrounding the target gave charged particle information and enabled the data to be differentiated into various topological subsamples. The well established ..omega../sup 0/ meson was detected. In addition, a sharp break in the ..pi../sup +/..pi../sup -/n mass spectrum and a rapid rise of the K/sup +/K/sup -/n spectrum just above threshold was observed. Both of these effects were associated with the S* meson. Finally, the absence of four previously observed narrow mesons is discussed.

Non prompt D-meson measurements with ALICE at the LHC

International Nuclear Information System (INIS)

Mazzilli, Marianna

2016-01-01

The production of hadrons with open heavy flavour (charm and beauty) in high-energy nucleus-nucleus collisions is a powerful tool to study the properties of the deconfined phase of strongly interacting matter known as the Quark-Gluon Plasma (QGP). The production of charm and beauty quarks occurs in hard partonic scattering processes in the early stage of the collisions. ALICE is the LHC experiment devoted to the study of heavy-ion physics. It is able to reconstruct charmed mesons in exclusive decays (e.g. D"0→K"−π"+) and beauty hadrons in semi-inclusive decays (e.g. B→eX, B→J/ψ X) . At LHC energies a significant component of the inclusive D-meson yield originates from the decay of beauty-flavoured hadrons, whose knowledge is essential to determine the production of prompt D mesons coming from charm quarks. A precise determination of the non-prompt fraction combined with the determination of the inclusive D-meson yield would allow a measurement of beauty production. A data-driven method that exploits the different shapes of the distributions of the transverse-plane impact parameter to the primary vertex of prompt and feed-down D mesons in p-Pb collisions is used in ALICE. An alternative approach based on the D-meson decay length for Pb–Pb collisions is under study.

Cabibbo-Kobayashi-Maskawa-favored B decays to a scalar meson and a D meson

Energy Technology Data Exchange (ETDEWEB)

Zou, Zhi-Tian; Li, Ying [Yantai University, Department of Physics, Yantai (China); Liu, Xin [Jiangsu Normal University, School of Physics and Electronic Engineering, Xuzhou (China)

2017-12-15

In this work, we attempt to study the Cabibbo-Kobayashi-Maskawa-favored B → anti DS (''S'' denoting the scalar meson) decays within the perturbative QCD approach at the leading order and the leading power. Although the light scalar mesons are widely perceived as primarily the four-quark bound states, in practice it is hard for us to make quantitative predictions based on the four-quark picture for light scalars. Hence, we calculate the decays with light scalars in the two-quark model. For the decays with scalar mesons above 1 GeV, we have explored two possible scenarios, depending on whether the light scalars are treated as the lowest lying q anti q states or four-quark particles. In total, we calculated the branching fractions of 72 decay modes, and most of them are in the range 10{sup -4}-10{sup -7}, which are measurable in the on-going LHCb experiment and the forthcoming Belle-II experiment. Moreover, since in the standard model these decays occur only through tree operators and have no CP asymmetries, any deviation will be a signal of new physics beyond the standard model. Despite large uncertainties induced by nonperturbative parameters and corrections of high order and high power, our results and discussions will be useful for the on-going LHCb and the forthcoming Belle-II experiments. (orig.)

Three-dimensionally preserved minute larva of a great-appendage arthropod from the early Cambrian Chengjiang biota

Science.gov (United States)

Liu, Yu; Melzer, Roland R.; Haug, Joachim T.; Haug, Carolin; Briggs, Derek E. G.; Hörnig, Marie K.; He, Yu-yang; Hou, Xian-guang

2016-05-01

A three-dimensionally preserved 2-mm-long larva of the arthropod Leanchoilia illecebrosa from the 520-million-year-old early Cambrian Chengjiang biota of China represents the first evidence, to our knowledge, of such an early developmental stage in a short-great-appendage (SGA) arthropod. The larva possesses a pair of three-fingered great appendages, a hypostome, and four pairs of well-developed biramous appendages. More posteriorly, a series of rudimentary limb Anlagen revealed by X-ray microcomputed tomography shows a gradient of decreasing differentiation toward the rear. This, and postembryonic segment addition at the putative growth zone, are features of late-stage metanauplii of eucrustaceans. L. illecebrosa and other SGA arthropods, however, are considered representative of early chelicerates or part of the stem lineage of all euarthropods. The larva of an early Cambrian SGA arthropod with a small number of anterior segments and their respective appendages suggests that posthatching segment addition occurred in the ancestor of Euarthropoda.

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.

The vector meson with anomalous magnetic moment

International Nuclear Information System (INIS)

Boyarkin, O.M.

1976-01-01

The possibility of introducing an anomalous magnetic moment into the Stuckelberg version of the charged vector meson theory is considered. It is shown that the interference of states with spins equal to one and zero is absent in the presence of an anomalous magnetic moment of a particle. The differential cross section of scattering on the Coulomb field of a nucleus is calculated, and so are the differential and integral cross sections of meson pair production on annihilation of two gamma quanta. The two-photon mechanism of production of a meson pair in colliding electron-positron beams is considered. It is shown that with any value of the anomalous magnetic moment the cross section of the esup(+)esup(-) → esup(+)esup(-)γsup(*)γsup(*) → esup(+)esup(-)Wsup(+)Wsup(-) reaction exceeds that of the esup(+)esup(-) → γsup(*) → Wsup(+)Wsup(-) at sufficiently high energies

Importance of Nonperturbative QCD Parameters for Bottom Mesons

Directory of Open Access Journals (Sweden)

A. Upadhyay

2014-01-01

Full Text Available The importance of nonperturbative quantum chromodynamics (QCD parameters is discussed in context to the predicting power for bottom meson masses and isospin splitting. In the framework of heavy quark effective theory, the work presented here focuses on the different allowed values of the two nonperturbative QCD parameters used in heavy quark effective theory formula, and using the best fitted parameter, masses of the excited bottom meson states in jp=1/2+ doublet in strange and nonstrange sectors are calculated here. The calculated masses are found to be matching well with experiments and other phenomenological models. The mass splitting and hyperfine splitting have also been analyzed for both strange and nonstrange heavy mesons with respect to spin and flavor symmetries.

Melting spectral functions of the scalar and vector mesons in a holographic QCD model

International Nuclear Information System (INIS)

Fujita, Mitsutoshi; Kikuchi, Toru; Fukushima, Kenji; Misumi, Tatsuhiro; Murata, Masaki

2010-01-01

We investigate the finite-temperature spectral functions of heavy quarkonia by using the soft-wall anti-de Sitter/QCD model. We discuss the scalar, the pseudoscalar, the vector, and the axial-vector mesons and compare their qualitative features of the melting temperature and growing width. We find that the axial-vector meson melts earlier than the vector meson, while there appears only a slight difference between the scalar and pseudoscalar mesons, which also melt earlier than the vector meson.

Paleomagnetism of Early Cambrian Itabaiana mafic dikes (NE Brazil) and the final assembly of Gondwana

Science.gov (United States)

Trindade, Ricardo I. F.; D'Agrella-Filho, Manoel S.; Epof, Igor; Brito Neves, Benjamim B.

2006-04-01

Paleomagnetic analysis on 15 early Cambrian mafic dikes from Itabaiana (Paraíba State) yielded a southern (northwestern) direction with steep upward (downward) inclination ( Dm = 167.5°, Im = - 63.7°, α95 = 7.3°). AF and Thermal demagnetization, thermomagnetic curves, and hysteresis results suggest that this component is dominantly carried by fine-grained SD magnetite. The high stability of this component and positive baked contact tests on three dikes indicate it represents a primary thermoremanent magnetization. Ar-Ar analysis on whole-rock samples from two sites provides a strong constraint on the age of the Itabaiana paleomagnetic pole (134.6° E, 34.9° S; A95 = 7.3, K = 28) defined by plateau ages of 525 ± 5 and 526 ± 4 Ma. This pole completely satisfies six out of the seven quality criteria proposed by Van der Voo [R. Van der Voo, The reliability of paleomagnetic data, Tectonophysics 184 (1990) 1-9.] and permits a tight constraint on the Early Cambrian sector of the Gondwana apparent polar wander path. Paleogeographic reconstructions consistent with the available paleomagnetic and geological record show that Gondwana was sutured along three major orogenies, the Mozambique (Brasilano/Pan-African) Orogeny (800-650 Ma), the Kuunga Orogeny (570-530 Ma) and the Pampean-Araguaia Orogeny (540-520 Ma). We suggest that after rifting away from Laurentia at the end of the Neoproterozoic, opening the Iapetus ocean, the Amazonian craton and minor adjoining blocks, such as Rio Apa and Pampia, collided with the proto-Gondwana by Cambrian times at ca. 530-520 Ma. Unless for small adjustments, Gondwana was completely formed by 525 Ma whose paleogeography is defined by the Itabaiana pole.

Controls on Gut Phosphatisation: The Trilobites from the Weeks Formation Lagerstätte (Cambrian; Utah)

Science.gov (United States)

Lerosey-Aubril, Rudy; Hegna, Thomas A.; Kier, Carlo; Bonino, Enrico; Habersetzer, Jörg; Carré, Matthieu

2012-01-01

Despite being internal organs, digestive structures are frequently preserved in Cambrian Lagerstätten. However, the reasons for their fossilisation and their biological implications remain to be thoroughly explored. This is particularly true with arthropods – typically the most diverse fossilised organisms in Cambrian ecosystems – where digestive structures represent an as-yet underexploited alternative to appendage morphology for inferences on their biology. Here we describe the phosphatised digestive structures of three trilobite species from the Cambrian Weeks Formation Lagerstätte (Utah). Their exquisite, three-dimensional preservation reveals unique details on trilobite internal anatomy, such as the position of the mouth and the absence of a differentiated crop. In addition, the presence of paired pygidial organs of an unknown function is reported for the first time. This exceptional material enables exploration of the relationships between gut phosphatisation and the biology of organisms. Indeed, soft-tissue preservation is unusual in these fossils as it is restricted to the digestive structures, which indicates that the gut played a central role in its own phosphatisation. We hypothesize that the gut provided a microenvironment where special conditions could develop and harboured a source of phosphorus. The fact that gut phosphatization has almost exclusively been observed in arthropods could be explained by their uncommon ability to store ions (including phosphorous) in their digestive tissues. However, in some specimens from the Weeks Formation, the phosphatisation extends to the entire digestive system, suggesting that trilobites might have had some biological particularities not observed in modern arthropods. We speculate that one of them might have been an increased capacity for ion storage in the gut tissues, related to the moulting of their heavily-mineralised carapace. PMID:22431989

On the possibility of thermalization of heavy mesons in ultrarelativistic nuclear collisions

Energy Technology Data Exchange (ETDEWEB)

Lokhtin, I. P., E-mail: Igor.Lokhtin@cern.ch; Belyaev, A. V. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Ponimatkin, G. [Czech Technical University in Prague, Faculty of Nuclear Sciences and Physical Engineering (Czech Republic); Pronina, E. Yu.; Eiyubova, G. Kh. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

2017-02-15

The phenomenological analysis and interpretation of experimental data from RHIC and LHC on the production of J/ψ and D mesons in heavy-ion collisions are performed within the two-component HYDJET++ model including the thermal and hard mechanisms of hadron production. It is shown that the thermal freeze-out of charmed mesons at RHIC energies occurs earlier than the thermal freeze-out of light hadrons (assumingly, simultaneously with chemical freeze-out), which indicates that J/ψ and D mesons are not in kinetic equilibrium with the formed hadronic matter. At the same time, a significant part of D mesons at LHC energies are in kinetic equilibrium with the formed thermalized matter, but J/ψ mesons are still characterized by early freeze-out.

Isospin-violating mixing in meson nonets

International Nuclear Information System (INIS)

Isgur, N.

1979-01-01

Segregation into ideally mixed nonets results when the OZI-violating interaction which would mix u anti u, d anti d, and s anti s mesons into isospin and SU(3) eigenstates is much weaker than the s anti s-d anti d mass difference. We show that the d anti d-u anti u mass difference can begin to induce a similar segregation into d anti d and anti u mesons which leads to large isospin violations. An experimental example of such large isospin breaking (approx. 30%) which we predict has probably already been seen in f → K anti K. (orig.)

Instanton and tensor-force effects in the strong decays of mesons

International Nuclear Information System (INIS)

Bonnaz, R.; Silvestre-Brac, B.

2001-01-01

The strong decays of mesons are studied in the framework of the 3 P 0 model with a momentum-dependent vertex. The mesons wave functions are obtained from quark-antiquark potentials including a finite quark size, instanton effects, spin-orbit and tensor-force effects. Several prescriptions for treating the decays into three mesons are proposed and analyzed. Comparison to experimental data is presented in detail. (author)

Properties of vector and axial-vector mesons from a generalized Nambu-Jona-Lasinio model

International Nuclear Information System (INIS)

Bernard, V.; Meissner, U.G.; Massachusetts Inst. of Tech., Cambridge; Massachusetts Inst. of Tech., Cambridge

1988-01-01

We construct a generalized Nambu-Jona-Lasinio lagrangian including scalar, pseudoscalar, vector and axial-vector mesons. We specialize to the two-flavor case. The properties of the structured vacuum as well as meson masses and coupling constants are calculated giving an overall agreement within 20% of the experimental data. We investigate the meson properties at finite density. In contrast to the mass of the scalar σ-meson, which decreases sharply with increasing density, the vector meson masses are almost independent of density. Furthermore, the vector-meson-quark coupling constants are also stable against density changes. We point out that these results imply a softening of the nuclear equation of state at high densities. Furthermore, we discuss the breakdown of the KFSR relation on the quark level as well as other deviations from phenomenological concepts such as universality and vector meson dominance. (orig.)

Vector mesons in reactions with colliding electron-positron beams

International Nuclear Information System (INIS)

Rekalo, M.P.; Gakh, G.I.

1980-01-01

Polarization phenomena in the processes of vector meson production in reactions with colliding electron-positron beams e + e - → V+X, where V is a vector meson, X is a nondetected set of particles are investigated. For the one-photon mechanism of the process, where V and X are hadrons, the mutually unambiguous correspondence between the structural functions is found. The dependence of the e + e - → VX differential cross section upon the electron and positron polarizations is calculated using the virtual photon density matrix in the helicity basis. This formalism permits to take explicitly into account the P-invariance consequences for the angular distribution of the V-meson decay products. For the processes e + e - → πA 1 , and e + e - → rho + rho - the structural functions are calculated in terms of the corresponding electromagnetic form factors. It is noted that six functions out ten real structural functions describing the e + e - → VX reaction can be determined by means of investigation of the angular distribution of the V-meson decay products which is produced in collisions of unpolarized leptons. To study the collision of polarized leptons one more structural function can be determined. The formation of the X system with definite values of parity and spin is characterized by seven structural functions, five of which can be found while studying the angular distribution of the V-meson decay products produced in e + e - collisions with unpolarized (polarized) particles. If the spin of the X state is 1, in experiments with polarized beams all structural functions can be determined while investigating the angular distribution of the V-meson decay products

{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.

Heavy Scalar, Vector, and Axial-Vector Mesons in Hot and Dense Nuclear Medium

Directory of Open Access Journals (Sweden)

Arvind Kumar

2014-01-01

Full Text Available In this work we shall investigate the mass modifications of scalar mesons (D0; B0, vector mesons (D*; B*, and axial-vector mesons (D1; B1 at finite density and temperature of the nuclear medium. The above mesons are modified in the nuclear medium through the modification of quark and gluon condensates. We will find the medium modification of quark and gluon condensates within chiral SU(3 model through the medium modification of scalar-isoscalar fields σ and ζ at finite density and temperature. These medium modified quark and gluon condensates will further be used through QCD sum rules for the evaluation of in-medium properties of the above mentioned scalar, vector, and axial vector mesons. We will also discuss the effects of density and temperature of the nuclear medium on the scattering lengths of the above scalar, vector, and axial-vector mesons. The study of the medium modifications of the above mesons may be helpful for understanding their production rates in heavy-ion collision experiments. The results of present investigations of medium modifications of scalar, vector, and axial-vector mesons at finite density and temperature can be verified in the compressed baryonic matter (CBM experiment of FAIR facility at GSI, Germany.

Meson (photo- and) electro-production and the structure of nuclei at short distances

International Nuclear Information System (INIS)

Laget, J.M.

1985-09-01

The present status and the future prospects of the studies of very inelastic electronuclear reaction are reviewed, when both high energy and high momentum are transferred to the nucleus. Real and virtual mesons are tested on the same footing. Real meson production allows us to study the propagation of baryonic and mesonic resonances in nuclei and to put constraints on their interaction with the nucleon. Virtual meson creation is an alternative way to deal with exchange currents. The first lecture deals with the elementary operators, which describe meson photo- and electroproduction on free nucleons. The second one deals with real meson- photo- and electroproduction on few-body systems. Only the main features are discussed here and the last developments are presented. The third lecture deals with the coupling of the electromagnetic probe to the virtual meson in nuclei. The emphasis is put on the few-body systems, since their nuclear wave functions are known and since they are simple enough to allow for elaborate calculations. The case of heavy nuclei is also discussed. In the last lecture, I will try to look for evidence of the limits and the breakdown of the description of nuclei in terms of nucleons and mesons, and to forecast the new developments

D meson hadronic decays at CLEO-c

Energy Technology Data Exchange (ETDEWEB)

Yang, Fan; /Fermilab

2011-01-01

The recent CLEO-c results on hadronic decays of D and D{sub s} mesons are presented. First the absolute branching fractions for D and D{sub s} mesons using a double tag technique are discussed, then are the Cabibbo suppressed decays and doubly Cabibbo suppressed decays. Finally, I present the inclusive and rare decay modes and other measurements from CLEO-c. These decays illuminate a wide range of physics. A brief theoretical introduction is given before the corresponding discussion on measurement.

Peculiarities of the Moon variations of the neutron and meson components of cosmic rays

International Nuclear Information System (INIS)

Naskidashvili, B.D.; Shatashvili, L.Kh.

1979-01-01

Lunar variations of the neutron component of cosmic rays have been investigated individually for groups of stations of the northern hemisphere of the Earth and for groups of stations of the southern hemisphere. A dependence has been found of the amplitude and phase of the first harmonic of lunar variations in the intensity of neutron and meson components of cosmic rays on the geocentric distance of the Moon and on the epoch of solar activity. The amplitudes and phases of lunar variations were determined by the Chapman-Miller method. According to the data on the meson component of cosmic rays obtained by the Nagoya station (Japan), the amplitudes of the first harmonic of lunar daily variations point to the fact that as the Moon approaches the Earth the tidal effects do not exceed the effects of lunar gravitational forces when the Moon is at apogee

Using anti pp annihilation to find exotic mesons

International Nuclear Information System (INIS)

Sharpe, S.R.

1987-10-01

Present data suggests that a number of mesons have been found which cannot be accommodated in standard anti qq multiplets. Theory suggests that such exotic mesons should exist in the spectrum of Quantum Chromodynamics, but provides little guide to their properties. It is argued that a high luminosity, low energy anti pp machine would be a powerful tool with which to search for such exotics

Excited meson spectroscopy with two chirally improved quarks

Science.gov (United States)

Engel, G.; Lang, C. B.; Mohler, D.; Limmer, M.; Schäfer, A.

The excited isovector meson spectrum is explored using two chirally improved dynamical quarks. Seven ensembles, with pion masses down to \\approx 250 MeV are discussed and used for extrapolations to the physical point. Strange mesons are investigated using partially quenched s-quarks. Using the variational method, we extract excited states in several channels and most of the results are in good agreement with experiment.

Meson-induced correlations of nucleons in nuclear Compton scattering

International Nuclear Information System (INIS)

Huett, M.; Milstein, A.I.

1998-01-01

The nonresonant (seagull) contribution to the nuclear Compton amplitude at low energies is strongly influenced by nucleon correlations arising from meson exchange. We study this problem in a modified Fermi gas model, where nuclear correlation functions are obtained with the help of perturbation theory. The dependence of the mesonic seagull amplitude on the nuclear radius is investigated and the influence of a realistic nuclear density on this amplitude is discussed. We found that different form factors appear for the static part (proportional to the enhancement constant κ) of the mesonic seagull amplitude and for the parts, which contain the contribution from electromagnetic polarizabilities. copyright 1998 The American Physical Society

A calculation of the physical mass of sigma meson

International Nuclear Information System (INIS)

Morones-Ibarra, J.R.; Santos-Guevara, Ayax

2007-01-01

We calculate the physical mass and the width of the sigma meson by considering that it couples in vacuum to two virtual pions. The mass is calculated by using the spectral function, and we find that it is about 600 MeV. In addition, we obtained 220 MeV as the value for the width of its spectral function. The value obtained for the mass is in good agreement with that reported in the Particle Data Book for the σ meson, which is also named f 0 (600). This result also shows that σ-meson can be considered as a two-pion resonance. (author)

Measurement of the B+ and B0 meson lifetimes

International Nuclear Information System (INIS)

Abe, F.; Albrow, M.; Amidei, D.; Anway-Wiese, C.; Apollinari, G.; Areti, H.; Auchincloss, P.; Azfar, F.; Azzi, P.; Bacchetta, N.; Badgett, W.; Bailey, M.W.; Bao, J.; de Barbaro, P.; Barbaro-Galtieri, A.; Barnes, V.E.; Barnett, B.A.; Bartalini, P.; Bauer, G.; Baumann, T.; Bedeschi, F.; Behrends, S.; Belforte, S.; Bellettini, G.; Bellinger, J.; Benjamin, D.; Benlloch, J.; Benton, D.; Beretvas, A.; Berge, J.P.; Bertolucci, S.; Bhatti, A.; Biery, K.; Binkley, M.; Bird, F.; Bisello, D.; Blair, R.E.; Blocker, C.; Bodek, A.; Bolognesi, V.; Bortoletto, D.; Boswell, C.; Boulos, T.; Brandenburg, G.; Buckley-Geer, E.; Budd, H.S.; Burkett, K.; Busetto, G.; Byon-Wagner, A.; Byrum, K.L.; Campagnari, C.; Campbell, M.; Caner, A.; Carithers, W.; Carlsmith, D.; Castro, A.; Cen, Y.; Cervelli, F.; Chapman, J.; Chiarelli, G.; Chikamatsu, T.; Cihangir, S.; Clark, A.G.; Cobal, M.; Contreras, M.; Cooper, J.; Cordelli, M.; Coupal, D.P.; Crane, D.; Cunningham, J.D.; Daniels, T.; DeJongh, F.; Dell'Agnello, S.; Dell'Orso, M.; Demortier, L.; Denby, B.; Deninno, M.; Derwent, P.F.; Devlin, T.; Dickson, M.; Donati, S.; Done, J.P.; Drucker, R.B.; Dunn, A.; Einsweiler, K.; Elias, J.E.; Ely, R.; Engels, E. Jr.; Eno, S.; Errede, D.; Errede, S.; Etchegoyen, A.; Fan, Q.; Farhat, B.; Fiori, I.; Flaugher, B.; Foster, G.W.; Franklin, M.; Frautschi, M.; Freeman, J.; Friedman, J.; Frisch, H.; Fry, A.; Fuess, T.A.; Fukui, Y.; Funaki, S.; Gagliardi, G.; Gallinaro, M.; Garfinkel, A.F.; Geer, S.; Gerdes, D.W.; Giannetti, P.; Giokaris, N.; Giromini, P.; Gladney, L.; Glenzinski, D.; Gold, M.; Gonzalez, J.; Gordon, A.; Goshaw, A.T.; Goulianos, K.; Grassmann, H.; Grewal, A.; Grieco, G.; Groer, L.; Grosso-Pilcher, C.; Haber, C.; Hahn, S.R.; Hamilton, R.; Handler, R.; Hans, R.M.; Hara, K.; Harral, B.; Harris, R.M.; Hauger, S.A.; Hauser, J.; Hawk, C.; Heinrich, J.; Hennessy, D.; Hollebeek, R.; Holloway, L.; Hoelscher, A.; Hong, S.; Houk, G.; Hu, P.; Huffman, B.T.; Hughes, R.; Hurst, P.; Huston, J.; Huth, J.

1994-01-01

The lifetimes of the B + and B 0 mesons have been measured using fully reconstructed decays. In a sample of ∼49 600J/ψ→μ + μ - decays recorded with the Collider Detector at Fermilab, 148±16 B + and 121±16B 0 mesons have been reconstructed using the silicon vertex detector. Unbinned likelihood fits to the proper lifetime distributions of these B mesons give τ + =1.61±0.16 (stat)±0.05 (syst) ps, τ 0 =1.57±0.18 (stat) ±0.08 (syst) ps, and τ + /τ 0 =1.02±0.16 (stat) ±0.05 (syst)

Electromagnetic properties and sizes of new vector mesons within the three-triplet model

International Nuclear Information System (INIS)

Govorkov, A.B.

1976-01-01

The new vector mesons psi(3095) and psi'(3684) are treated by analogy with the ω- and PHI-mesons, respectively, within the scheme of three triplets of the integer charge quarks-sakations. Their decay into the lepton pairs is calculated in the model of nonrelativistic harmonic oscillator. It appears that sizes of the new mesons decrease, and the effective mass of constituent quarks increases as compared with the corresponding quantities of the usual mesons. Within the vector meson dominence model the relation between the width of the transition psi → ν+γ and photoproduction cross section on nucleons is established and the estimate for the former is 3 keV

Relativistic mean-field approximation with density-dependent screening meson masses in nuclear matter

International Nuclear Information System (INIS)

Sun, Baoxi; Lu, Xiaofu; Shen, Pengnian; Zhao, Enguang

2003-01-01

The Debye screening masses of the σ, ω and neutral ρ mesons and the photon are calculated in the relativistic mean-field approximation. As the density of the nucleon increases, all the screening masses of mesons increase. A different result with Brown–Rho scaling is shown, which implies a reduction in the mass of all the mesons in the nuclear matter, except the pion. Replacing the masses of the mesons with their corresponding screening masses in the Walecka-1 model, five saturation properties of the nuclear matter are fixed reasonably, and then a density-dependent relativistic mean-field model is proposed without introducing the nonlinear self-coupling terms of mesons. (author)

Techniques in meson spectroscopy

International Nuclear Information System (INIS)

Longacre, R.S.

1991-01-01

This report contains lectures on the following topics: the quark model and beyond using quantum chromodynamics; analysis of formation reactions; energy dependence of the partial wave amplitudes; where the data for the t-matrix analysis comes from; and coupled channel analysis of isoscalar mesons

Modification of the omega-meson lifetime in nuclear matter

NARCIS (Netherlands)

Kotulla, M.; Trnka, D.; Muehlich, P.; Anton, G.; Bacelar, J. C. S.; Bartholomy, O.; Bayadilov, D.; Beloglazov, Y. A.; Bogendoerfer, R.; Castelijns, R.; Crede, V.; Dutz, H.; Ehmanns, A.; Elsner, D.; Ewald, R.; Fabry, I.; Fuchs, M.; Essig, K.; Funke, Ch.; Gothe, R.; Gregor, R.; Gridnev, A. B.; Gutz, E.; Hoeffgen, S.; Hoffmeister, P.; Horn, I.; Hoessl, J.; Jaegle, I.; Junkersfeld, J.; Kalinowsky, H.; Klein, Frank; Klein, Fritz; Klempt, E.; Konrad, M.; Kopf, B.; Krusche, B.; Langheinrich, J.; Loehner, H.; Lopatin, I. V.; Lotz, J.; Lugert, S.; Menze, D.; Messchendorp, J. G.; Mertens, T.; Metag, V.; Mosel, U.; Nanova, M.; Novotny, R.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Roy, A.; Radkov, A.; Schadmand, S.; Schmidt, Ch.; Schmieden, H.; Schoch, B.; Shende, S.; Suft, G.; Sumachev, V. V.; Szczepanek, T.; Suele, A.; Thoma, U.; Varma, R.; Walther, D.; Weinheimer, Ch.; Wendel, Ch.

2008-01-01

Information on hadron properties in the nuclear medium has been derived from the photoproduction of omega mesons on the nuclei C, Ca, Nb, and Pb using the Crystal Barrel/TAPS detector at the ELSA tagged photon facility in Bonn. The dependence of the omega-meson cross section on the nuclear mass

πη pair hard electroproduction and exotic hybrid mesons

International Nuclear Information System (INIS)

Anikin, I.V.; Pire, B.; Szymanowski, L.; Teryaev, O.V.; Wallon, S.

2005-01-01

We show that hard electroproduction is a promising way to study exotic hybrid mesons, in particular through the hybrid decay channel H->πη. We discuss the πη generalized distribution amplitude, calculate the production amplitude and propose a forward-backward asymmetry as a signal for the hybrid meson production

{pi}{eta} pair hard electroproduction and exotic hybrid mesons

Energy Technology Data Exchange (ETDEWEB)

Anikin, I.V. [LPT, Universite Paris-Sud, 91405-Orsay, France, UMR 8627 du CNRS (France); BLTP, JINR, 141980 Dubna (Russian Federation); CPHT, Ecole Polytechnique, 91128 Palaiseau, France, UMR 7644 du CNRS (France); Pire, B. [CPHT, Ecole Polytechnique, 91128 Palaiseau, France, UMR 7644 du CNRS (France); Szymanowski, L. [Soltan Institute for Nuclear Studies, Warsaw (Poland) and Univ. de Liege, B-4000 Liege (Belgium); Teryaev, O.V. [BLTP, JINR, 141980 Dubna (Russian Federation); Wallon, S. [LPT, Universite Paris-Sud, 91405-Orsay, France, UMR 8627 du CNRS (France)

2005-06-13

We show that hard electroproduction is a promising way to study exotic hybrid mesons, in particular through the hybrid decay channel H->{pi}{eta}. We discuss the {pi}{eta} generalized distribution amplitude, calculate the production amplitude and propose a forward-backward asymmetry as a signal for the hybrid meson production.

Mesonic Form Factors

Energy Technology Data Exchange (ETDEWEB)

Frederic D. R. Bonnet; Robert G. Edwards; George T. Fleming; Randal Lewis; David Richards

2003-07-22

We have started a program to compute the electromagnetic form factors of mesons. We discuss the techniques used to compute the pion form factor and present preliminary results computed with domain wall valence fermions on MILC asqtad lattices, as well as Wilson fermions on quenched lattices. These methods can easily be extended to rho-to-gamma-pi transition form factors.

Decays of open charmed mesons in the extended Linear Sigma Model

Directory of Open Access Journals (Sweden)

Eshraim Walaa I.

2014-01-01

Full Text Available We enlarge the so-called extended linear Sigma model (eLSM by including the charm quark according to the global U(4r × U(4l chiral symmetry. In the eLSM, besides scalar and pseudoscalar mesons, also vector and axial-vector mesons are present. Almost all the parameters of the model were fixed in a previous study of mesons below 2 GeV. In the extension to the four-flavor case, only three additional parameters (all of them related to the bare mass of the charm quark appear.We compute the (OZI dominant strong decays of open charmed mesons. The results are compatible with the experimental data, although the theoretical uncertainties are still large.

Spectroscopy of pseudoscalar and vector mesons and their electroweak decays

International Nuclear Information System (INIS)

Ablakulov, Kh.

1997-01-01

Proceeding from the effective action of QCD for bilocal meson fields the formula for the action describing the spectroscopy of mesons and their electroweak decays is obtained. The numerical solutions of the Salpeter equation (SE) for the qq-bound state and the Schwinger-Dyson equation (SDE) for the quark phase function are obtained with potential as sum of the oscillator and Coulomb terms. It is shown that for the oscillator potential and current quark mass m 0 0 → γγ) are 3-4 times smaller than their experimentations. This discrepancy was not removed even choosing other shapes of the potential. In order to resolve this problem the modification of the SDE, which consists in introducing the additional terms that do not change asymptotical properties of solutions of this equation is proposed. Using such modification both constant fπ and Γ(π 0 → γγ) are reproduced on a good quantitative level. The new SE for vector mesons is proposed and its solution with potential mentioned above gives the mass spectra of these mesons. Considering the τ → ρν decay the representation for leptonic decay constant of ρ meson f π , which expresses via solutions of the SDE and the proposed SE with a given potential is obtained. It is shown that the proposed SE allows to describe both the spectroscopy of vector mesons and their leptonic decay constants on a satisfactory level in comparison with the experimental values. (author)

Hybrid mesons (Q anti Qg) in N anti N annihilation

International Nuclear Information System (INIS)

Dover, C.B.; Gutsche, T.; Faessler, A.

1993-09-01

N anti N annihilation reactions provide exciting possibilities to study mesonic resonances beyond the usual Q anti Q spectrum. Particularly the search for Q anti Qg mesons containing an explicit dynamical excitation of the gluon field is not promising, since hybrids are predicted to display unique features: exotic quantum numbers (J πC ) and dynamical selection rules for their decay modes. The authors have investigated the possibility of producing hybrids from p anti p atomic states in reactions of the type N anti N(L= 0,1) → π + Q anti Qg. Production rates for hybrid mesons are found to display a strong dependence on the quantum numbers and kinematical factors associated with the transition. The dependence on the orbital angular momentum L of the p anti p atomic state, accessible in p anti p annihilation at rest, would provide a striking signature for the production of hybrids. In estimating branching ratios for the formation of Q anti Qg hybrid mesons in N anti N annihilation reactions at rest, the authors have employed a microscopic model with constituent quarks and gluons in analogy to the annihilation model for the production of Q anti Q mesons

Improved measurement of the B 0 and B + meson lifetimes

Science.gov (United States)

Buskulic, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J. P.; Lucotte, A.; Minard, M. N.; Odier, P.; Pietrzyk, B.; Casado, M. P.; Chmeissani, M.; Crespo, J. M.; Delfino, M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, L.; Juste, A.; Martinez, M.; Orteu, S.; Pacheco, A.; Padilla, C.; Pascual, A.; Perlas, J. A.; Riu, I.; Sanchez, F.; Teubert, F.; Colaleo, A.; Creanza, D.; de Palma, M.; Gelao, G.; Girone, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Marinelli, N.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Alemany, R.; Bazarko, A. O.; Bonvicini, G.; Cattaneo, M.; Comas, P.; Coyle, P.; Drevermann, H.; Forty, R. W.; Frank, M.; Hagelberg, R.; Harvey, J.; Janot, P.; Jost, B.; Kneringer, E.; Knobloch, J.; Lehraus, I.; Martin, E. B.; Mato, P.; Minten, A.; Miquel, R.; Mir, Ll. M.; Moneta, L.; Oest, T.; Palla, F.; Pater, J. R.; Pusztaszeri, J. F.; Ranjard, F.; Rensing, P.; Rolandi, L.; Schlatter, D.; Schmelling, M.; Schneider, O.; Tejessy, W.; Tomalin, I. R.; Venturi, A.; Wachsmuth, H.; Wagner, A.; Wildish, T.; Ajaltouni, Z.; Barrès, A.; Boyer, C.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Rossignol, J. M.; Fearnley, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Nilsson, B. S.; Wäänänen, A.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, P.; Rougé, A.; Rumpf, M.; Valassi, A.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Focardi, E.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Jaffe, D. E.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Casper, D.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Curtis, L.; Dorris, S. J.; Halley, A. W.; Knowles, I. G.; Lynch, J. G.; O'Shea, V.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Thompson, A. S.; Thomson, F.; Thorn, S.; Turnbull, R. M.; Becker, U.; Geweniger, C.; Graefe, G.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E. E.; Putzer, A.; Rensch, B.; Schmidt, M.; Sommer, J.; Stenzel, H.; Tittel, K.; Werner, S.; Wunsch, M.; Abbaneo, D.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Dornan, P. J.; Moutoussi, A.; Nash, J.; Sedgbeer, J. K.; Stacey, A. M.; Williams, M. D.; Dissertori, G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Betteridge, A. P.; Bowdery, C. K.; Colrain, P.; Crawford, G.; Finch, A. J.; Foster, F.; Hughes, G.; Sloan, T.; Williams, M. I.; Galla, A.; Greene, A. M.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H. G.; van Gemmeren, P.; Zeitnitz, C.; Aubert, J. J.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Diaconu, C.; Etienne, F.; Konstantinidis, N.; Payre, P.; Rousseau, D.; Talby, M.; Sadouki, A.; Thulasidas, M.; Trabelsi, K.; Aleppo, M.; Ragusa, F.; Abt, I.; Assmann, R.; Bauer, C.; Blum, W.; Dietl, H.; Dydak, F.; Ganis, G.; Gotzhein, C.; Jakobs, K.; Kroha, H.; Lütjens, G.; Lutz, G.; Männer, W.; Moser, H. G.; Richter, R.; Rosado-Schlosser, A.; Schael, S.; Settles, R.; Seywerd, H.; St. Denis, R.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J. F.; Heusse, Ph.; Jacquet, M.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A. M.; Nikolic, I.; Park, H. J.; Park, I. C.; Schune, M. H.; Simion, S.; Veillet, J. J.; Videau, I.; Azzurri, P.; Bagliesi, G.; Batignani, G.; Bettarini, S.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Ciulli, V.; Dell'Orso, R.; Fantechi, R.; Ferrante, I.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Marrocchesi, P. S.; Messineo, A.; Rizzo, G.; Sanguinetti, G.; Sciabà, A.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Vannini, C.; Verdini, P. G.; Walsh, J.; Blair, G. A.; Bryant, L. M.; Cerutti, F.; Chambers, J. T.; Gao, Y.; Green, M. G.; Medcalf, T.; Perrodo, P.; Strong, J. A.; von Wimmersperg-Toeller, J. H.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Maley, P.; Norton, P. R.; Thompson, J. C.; Wright, A. E.; Bloch-Devaux, B.; Colas, P.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J. F.; Roussarie, A.; Schuller, J. P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Black, S. N.; Dann, J. H.; Johnson, R. P.; Kim, H. Y.; Litke, A. M.; McNeil, M. A.; Taylor, G.; Booth, C. N.; Boswell, R.; Brew, C. A. J.; Cartwright, S.; Combley, F.; Koksal, A.; Letho, M.; Newton, W. M.; Reeve, J.; Thompson, L. F.; Böhrer, A.; Brandt, S.; Büscher, V.; Cowan, G.; Grupen, C.; Lutters, G.; Minguet-Rodriguez, J.; Rivera, F.; Saraiva, P.; Smolik, L.; Stephan, F.; Apollonio, M.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Musolino, G.; Rothberg, J.; Wasserbaech, S.; Armstrong, S. R.; Bellantoni, L.; Elmer, P.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; González, S.; Grahl, J.; Greening, T. C.; Harton, J. L.; Hayes, O. J.; Hu, H.; McNamara, P. A.; Nachtman, J. M.; Orejudos, W.; Pan, Y. B.; Saadi, Y.; Schmitt, M.; Scott, I. J.; Sharma, V.; Walsh, A. M.; Wu, Sau Lan; Wu, X.; Yamartino, J. M.; Zheng, M.; Zobernig, G.

1996-03-01

The lifetimes of the B 0 and B + mesons have been measured with the Aleph detector at LEP, using approximately 3 million hadronic Z decays collected in the period 1991 1994. In the first of three methods, semileptonic decays of B 0 and B + mesons were partially reconstructed by identifying events containing a lepton with an associated D*- orbar D^0 meson. The second method used fully reconstructed B 0 and B + mesons. The third method, used to measure the B 0 lifetime, employed a partial reconstruction technique to identify B 0→ D*- π + X decays. The combined results are begin{gathered} tau _0 = 1.55 ± 0.06 ± 0.03 ps, \\ tau _ + = 1.58 ± 0.09 ± 0.03 ps, \\ tfrac{{tau _ + }}{{tau _0 }} = 1.03 ± 0.08 ± 0.02. \\ .

Heavy quarks fragmentation in charmed mesons in DELPHI experiment at LEP

International Nuclear Information System (INIS)

Levy, J.M.

1994-04-01

With the big statistics expected at LEP, the electroweak sector of the Standard Model can be tested as well as the theory of strong interactions. Quantum Chromo-Dynamics is indeed predictive for quarks properties, but does not explain how quarks fragment into hadrons. So far the hadronization can only be described with phenomenological models. The work presented in this thesis was performed on the DELPHI experiment at LEP and concerns the production and the fragmentation of heavy quarks into charmed mesons D , D* and D**. With the whole statistics of 1991 and 1992 (1 013 300 hadronic decays of the Z), more than 4500 charmed mesons decays have been reconstructed in the channels D 0 → K - π + , D + → K - π + π+ and D * +→ D 0 π + followed by D 0 → K - π + . Using also 1993 data and the channel D 0 → K - π + π + π - , evidence for D** production is presented. For the first time, the production rate is measured for each D meson separately for cc and bb contributions. In fact, D mesons can be produced either directly from the fragmentation of c quark or un-directly from the fragmentation of b quark into B mesons which decay into D mesons. (authors). 120 refs

Effects of renormalizing the chiral SU(2) quark-meson model

Science.gov (United States)

Zacchi, Andreas; Schaffner-Bielich, Jürgen

2018-04-01

We investigate the restoration of chiral symmetry at finite temperature in the SU(2) quark-meson model, where the mean field approximation is compared to the renormalized version for quarks and mesons. In a combined approach at finite temperature, all the renormalized versions show a crossover transition. The inclusion of different renormalization scales leave the order parameter and the mass spectra nearly untouched but strongly influence the thermodynamics at low temperatures and around the phase transition. We find unphysical results for the renormalized version of mesons and the combined one.

Chiral symmetry breaking and the spin content of the ρ and ρ‧ mesons

Science.gov (United States)

Glozman, L. Ya.; Lang, C. B.; Limmer, M.

2011-11-01

Using interpolators with different SU(2)L × SU(2)R transformation properties we study the chiral symmetry and spin contents of the ρ and ρ‧ mesons in lattice simulations with dynamical quarks. A ratio of couplings of the qbarγi τq and qbarσ0i τq interpolators to a given meson state at different resolution scales tells one about the degree of chiral symmetry breaking in the meson wave function at these scales. Using a Gaussian gauge invariant smearing of the quark fields in the interpolators, we are able to extract the chiral content of mesons up to the infrared resolution of ∼ 1 fm. In the ground state ρ meson the chiral symmetry is strongly broken with comparable contributions of both the (0 , 1) + (1 , 0) and (1 / 2 , 1 / 2) b chiral representations with the former being the leading contribution. In contrast, in the ρ‧ meson the degree of chiral symmetry breaking is manifestly smaller and the leading representation is (1 / 2 , 1 / 2) b. Using a unitary transformation from the chiral basis to the LJ2S+1 basis, we are able to define and measure the angular momentum content of mesons in the rest frame. This definition is different from the traditional one which uses parton distributions in the infinite momentum frame. The ρ meson is practically a 3S1 state with no obvious trace of a "spin crisis". The ρ‧ meson has a sizeable contribution of the 3D1 wave, which implies that the ρ‧ meson cannot be considered as a pure radial excitation of the ρ meson.

D mesons in asymmetric nuclear matter

International Nuclear Information System (INIS)

Mishra, Amruta; Mazumdar, Arindam

2009-01-01

We calculate the in-medium D and D meson masses in isospin-asymmetric nuclear matter in an effective chiral model. The D and D mass modifications arising from their interactions with the nucleons and the scalar mesons in the effective hadronic model are seen to be appreciable at high densities and have a strong isospin dependence. These mass modifications can open the channels of the decay of the charmonium states (Ψ ' ,χ c ,J/Ψ) to DD pairs in dense hadronic matter. The isospin asymmetry in the doublet D=(D 0 ,D + ) is seen to be particularly appreciable at high densities and should show in observables such as their production and flow in asymmetric heavy-ion collisions in the compressed baryonic matter experiments in the future facility of FAIR, GSI. The results of the present work are compared to calculations of the D(D) in-medium masses in the literature using the QCD sum rule approach, quark meson coupling model, and coupled channel approach as well as to those from studies of quarkonium dissociation using heavy-quark potentials from lattice QCD at finite temperatures

Reproductive cyst and operculum formation in the Cambrian-Ordovician galeate-plexus microfossils

DEFF Research Database (Denmark)

Agic, Heda; Moczydlowska, Malgorzata; Canfield, Donald Eugene

2016-01-01

Unicellular organic-walled microfossils from the Cambrian-Ordovician transition in Estonia (ca. 490-480million years ago) exhibit rare characters reflecting their function as reproductive algal cysts. The studied assemblages record the evolutionary history of phytoplankton in the early Palaeozoic...... alga Acetabularia (Chlorophyta), which possesses an intrinsic lid-forming apparatus used during the organism's reproductive stage. Based on the observations on the fossil material and studies on the Acetabularia lid formation, we propose a model of operculum formation in the galeate plexus micro-organisms...

Perturbative QCD effects in heavy meson decays

International Nuclear Information System (INIS)

Szezepaniak, A.; Henley, E.M.

1991-01-01

The amplitude for the exclusive nonleptonic decay of a heavy meson into two light pseudoscalar mesons is analyzed using the factorization formalism of perturbative QCD for exclusive reactions at large momentum transfer. We calculate the form factor b → u transition and compare it to the old quark model calculation and the new one based on the light cone formulation of the full quark model wave function. The new results we obtain are smaller by a factor of 2 - 3 as compared to the old value. (orig.)

B-meson factories: Physics, machines and detectors

International Nuclear Information System (INIS)

Kolanoski, H.

1990-10-01

This report gives a short survey of the present status of B-meson factory plans and discussions at different laboratories. The physics motivation for an e + e - machine running with the highest possible luminosity in the Γ(4S) energy region is outlined emphasizing the possibility to observe CP violation in the B-meson system. The technical concepts for such machines together with the basic luminosity limitations are discussed. Finally, the requirements on a detector which is able to cover the rich physics program are presented. (orig.)

The static-light meson spectrum from twisted mass lattice QCD

International Nuclear Information System (INIS)

Jansen, Karl; Michael, Chris; Shindler, Andrea; Wagner, Marc

2008-10-01

We compute the static-light meson spectrum with N f =2 flavours of sea quarks using Wilson twisted mass lattice QCD. We consider five different values for the light quark mass corresponding to 300 MeV PS s mesons. (orig.)

Radiative transitions in mesons within a non relativistic quark model

International Nuclear Information System (INIS)

Bonnaz, R.; Silvestre-Brac, B.; Gignoux, C.

2002-01-01

An exhaustive study of radiative transitions in mesons is performed in a non relativistic quark model. Three different types of mesons wave functions are tested. The effect of some usual approximations is commented. Overall agreement with experimental data is obtained

Meson radiobiology and therapy

International Nuclear Information System (INIS)

Kilgerman, M.M.

1975-08-01

High-linear energy transfer radiation (neutrons, heavy ions, and pions) have a greater relative biological effectiveness than low-linear energy transfer radiation by depositing a high density of ionization in irradiated cells. This overcomes the protective effect of oxygen; decreases the variation in sensitivity among the several stages of the cell cycles; and, inhibits the repair of sublethal damage as compared to x-rays, gamma rays, electrons and protons. Negative pi mesons (pions), appear particularly suited for radiation therapy as their penetration and depth-dose profiles lend themselves to shaping the high dose area to the tumor size and location. Preliminary biological experiments with pions produced at the Los Alamos Meson Physics Facility studied cell survival at various radiation depths and cell cycle sensitivity. Histologic study of data from the first human experiments indicated severe tumor cell destruction by pions as compared to x-rays in treating malignant melanoma skin nodules, without increased effects on dermal elements. (U.S.)

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

Production of charmed mesons in γγ interactions

International Nuclear Information System (INIS)

Braunschweig, W.; Gerhards, R.; Kirschfink, F.J.; Martyn, H.U.; Kolanoski, H.; Hart, J.C.; Saxon, D.H.; Brandt, S.; Holder, M.; Muller, D.; Ritz, S.; Strom, D.; Takashima, M.; Wu Saulan; Zobernig, G.

1990-01-01

Production of charmed mesons in γγ-interactions at PETRA energies has been observed in the TASSO detector. Cross sections for inclusive D *± and D 0 anti D 0 production have been measured. Neutral and charged meson pairs are estimated to be produced with comparable cross sections, and their sum to account for a sizeable function of σ tot (γγ→hadrons) near the canti c threshold. (orig.)

On meson resonances and chiral symmetry

International Nuclear Information System (INIS)

Lutz, M.F.M.

2003-07-01

We study meson resonances with quantum numbers J P = 1 + in terms of the chiral SU(3) Lagrangian. At leading order a parameter-free prediction is obtained for the scattering of Goldstone bosons off vector mesons with J P = 1 - once we insist on approximate crossing symmetry of the unitarized scattering amplitude. A resonance spectrum arises that is remarkably close to the empirical pattern. In particular, we find that the strangeness-zero resonances h 1 (1380), f 1 (1285) and b 1 (1235) are formed due to strong K anti K μ and K K μ channels. This leads to large coupling constants of those resonances to the latter states. (orig.)

Dipole moments of the rho meson

International Nuclear Information System (INIS)

Hecht, M.B.; McKellar, B.H.P.

1997-04-01

The electric and magnetic dipole moments (EDM) of the rho meson are calculated using the propagators and vertices derived from the quantum chromodynamics Dyson-Schwinger equations. Results obtained from using the Bethe-Salpeter amplitude studied by Chappell, Mitchell et. al., and Pichowsky and Lee, are compared. The rho meson EDM is generated through the inclusion of a quark electric dipole moment, which is left as a free variable. These results are compared to the perturbative results to obtain a measure of the effects of quark interactions and confinement. The two dipole moments are also calculated using the phenomenological MIT bag model to provide a further basis for comparison

Quarks and mesons in nuclei

International Nuclear Information System (INIS)

Rho, M.

1981-01-01

Quantum chromodynamics is believed to be candidate theory for the strong interactions and contains as its ingredients spinor quark fields and vector gluons, none of which can perhaps be ever liberated and detected in laboratories. A nucleus consists of nucleons bound by nuclear force which are however separately observable and which seem to preserve their identities even under extreme conditions. An intriguing question is: when compressed to high densities or heated to high temperature, at what point does a nuclear matter cease to be describable in terms of nucleon and meson degrees of freedom, but become a plasma of quarks and gluons; and how does this transition occur. This is not an idle question. If quarks and gluons are never to be observed isolated, then it may be that at low energies (or at low densities) they are not the right variables to do physics with. Instead hadrons must be. On the other hand, asymptotic freedom - the unique property of non-abelian gauge theories to which QCD belongs that quark-gluon and gluon-gluon interactions get weaker at short distances - tells us that at some large matter density the matter must necessarily be in the form of quark gas interacting only weakly. This means that a change in degrees of freedom must take place. We would like to know where this occurs and how. In this talk, I would like to address to this question by discussing first the large success we have had in understanding the role that mesons play in finite nuclei and nuclear matter and then attempting to correlate nucleon and meson degrees of freedom to quark-gluon degrees of freedom. In my opinion we are now at a stage where we feel fairly confident in our understanding of nucleon-meson structure of nuclei and nuclear matter and any further progress in deeper understanding of nuclear dynamics - and strong interactions - must come from QCD or its effective version, bags or strings. (orig.)

Pan African Collisional Tectonics Along the Moroccan West African Craton Continued to Ediacaran-Cambrian Boundary

Science.gov (United States)

Hefferan, K. P.; Samson, S. D.; Rice, K.; Soulaimani, A.

2016-12-01

Precision geochronologic dating and field mapping in the Anti-Atlas Mountains of Morocco document a Neoproterozoic Pan African orogenic cycle consisting of three distinct orogenic events: Iriri-Tichibanine orogeny (760-700 Ma), Bou Azzer orogeny (680-640 Ma) and the WACadomian orogeny (620 Ma to either 555 or 544 Ma). The Iriri-Tichibanine and Bou Azzer orogenies involved northward directed subduction beneath island arc volcanic terranes. These orogenic events generated calc-alkaline magmatism and supra-subduction zone ophiolites exposed in the Bou Azzer and Siroua erosional inliers. The WACadomian orogeny involved subduction and collision of the Cadomia arc complex with the West African Craton and generation of clastic sedimentary basins. The termination of the WACadomian orogeny has been the subject of debate as calc-alkaline to high K magmatism and folding continued to 544 Ma: Was 620-544 Ma calc-alkaline to high K magmatism and clastic basin development due to a) continental rift basin tectonics or b) southward directed subduction and collisional tectonics with associated back arc basin tectonism? We present field and geochemical data supporting the continuation of subduction-collisional tectonics to the Ediacaran-Cambrian boundary 544 Ma. Field mapping in the Central Anti-Atlas (Agadir Melloul) clearly documents an angular unconformity between Ouarzazate Group and Adoudounian limestones (N 30°31'28.91", W07°48'29.12"). Volcaniclastic rocks of Ouarzazate Group (615-545 Ma) are clearly folded and unconformably overlain by Adoudou Formation (541-529 Ma) limestones to the north. Geochemical discrimination diagrams on Latest Neoproterozoic calc-alkaline to high K igneous rocks throughout the Anti-Atlas plot in subduction and collisional arc magma domains. Back arc basin tectonism is likely responsible for localized extensional basins but continental rift tectonics and passive margin sedimentation did not begin in the Anti-Atlas Mountains until Early

Brookhaven: Hunting for unusual mesons

Energy Technology Data Exchange (ETDEWEB)

Dzierba, Alex R.

1990-12-15

After the overwhelming experimental evidence for the quark model came the notions of colour and confinement which explained why quarks should prefer to bind in 'colourless' systems - quark-antiquark (mesons) and three quarks (baryons)

Measurement of Charm Meson Lifetimes

International Nuclear Information System (INIS)

Bonvicini, G.; Cinabro, D.; Greene, R.; Perera, L.P.; Zhou, G.J.; Chan, S.; Eigen, G.; Lipeles, E.; Schmidtler, M.; Shapiro, A.; Sun, W.M.; Urheim, J.; Weinstein, A.J.; Wuerthwein, F.; Jaffe, D.E.; Masek, G.; Paar, H.P.; Potter, E.M.; Prell, S.; Sharma, V.; Asner, D.M.; Eppich, A.; Gronberg, J.; Hill, T.S.; Korte, C.M.; Lange, D.J.; Morrison, R.J.; Nelson, H.N.; Nelson, T.K.; Roberts, D.; Tajima, H.; Behrens, B.H.; Ford, W.T.; Gritsan, A.; Krieg, H.; Roy, J.; Smith, J.G.; Alexander, J.P.; Baker, R.; Bebek, C.; Berger, B.E.; Berkelman, K.; Boisvert, V.; Cassel, D.G.; Crowcroft, D.S.; Dickson, M.; Dombrowski, S. von; Drell, P.S.; Dumas, D.J.; Ecklund, K.M.; Ehrlich, R.; Foland, A.D.; Gaidarev, P.; Gibbons, L.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Henderson, S.; Hopman, P.I.; Katayama, N.; Kreinick, D.L.; Lee, T.; Liu, Y.; Meyer, T.O.; Mistry, N.B.; Ng, C.R.; Nordberg, E.; Ogg, M.; Patterson, J.R.; Peterson, D.; Riley, D.; Soffer, A.; Thayer, J.G.; Thies, P.G.; Valant-Spaight, B.; Warburton, A.; Ward, C.; Athanas, M.; Avery, P.; Jones, C.D.; Lohner, M.; Prescott, C.; Rubiera, A.I.; Yelton, J.; Zheng, J.; Brandenburg, G.; Briere, R.A.; Ershov, A.; Gao, Y.S.; Kim, D.Y.; Wilson, R.; Browder, T.E.; Li, Y.; Rodriguez, J.L.; Yamamoto, H.; Bergfeld, T.; Eisenstein, B.I.; Ernst, J.; Gladding, G.E.; Gollin, G.D

1999-01-01

We report measurements of the D 0 , D + , and D + s meson lifetimes using 3.7 fb -1 of e + e - annihilation data collected near the Υ(4S) resonance with the CLEO detector. The measured lifetimes of the D 0 , D + , and D + s mesons are 408.5±4.1 +3.5 -3.4 fs , 1033.6±22.1 +9.9 -12.7 fs , and 486.3±15.0 +4.9 -5.1 fs . The precision of these lifetimes are comparable to those of the best previous measurements, and the systematic errors are very different. In a single experiment we find that the ratio of the D + s and D 0 lifetimes is 1.19±0.04 . copyright 1999 The American Physical Society

Nucleon and meson beams of the JINR phasotron for fundamental and applied investigations

International Nuclear Information System (INIS)

Abazov, V.M.; Andreev, G.A.; Bragin, A.N.

1990-01-01

The paper throughly describes the medical beam lines and reports the results obtained in measurement of the physical and dosimetric characteristics of high energy neutron, meson and proton beams obtained at the JINR phasotron in the last three years. It is pointed out that for the present intensity of the extracted proton beam of the JINR phasotron 2.0-2.5 μA the meson beam intensities 10 3 s- 1 (π + -mesons) and 3x10 7 s -1 (π - -mesons) have been achieved with a wide-angle magnetic lens. These values correspond to the designed parameters of the facility 'F' meson beams for the extracted proton beam intensity planned to be 25 μA. Besides, a beam of so-called 'surface μ-muons (energy about 4 MeV) with the intensity 10 4 s -1 has been obtained. The achieved meason beam intensities make the possibilities of the JINR phasotron as high as those of small meson factories with the equivalent extracted proton beam current 20-25 μA and ensures progress both in meson physics studies and in fulfilment of some applied tasks. 20 refs.; 7 figs.; 8 tabs

Meson production in two-photon interactions at LHC energies

Energy Technology Data Exchange (ETDEWEB)

Da Silva, D. T.; Goncalves, V. P.; Sauter, W. K. [Instituto de Fisica e Matematica, Universidade Federal de Pelotas, Campus Universitario UFPel, CP 354, 96010-900, Capao do Leao-RS (Brazil)

2013-03-25

The LHC opens a new kinematical regime at high energy, where several questions related to the description of the high-energy regime of the Quantum Chromodynamics (QCD) remain without satisfactory answers. Some open questions are the search for non-q-bar q resonances, the determination of the spectrum of q-bar q states and the identification of states with anomalous {gamma}{gamma} couplings. A possible way to study these problems is the study of meson production in two-photon interactions. In this contribution we calculate the meson production in two-photon interactions at LHC energies considering proton - proton collisions and estimate the total cross section for the production of the mesons {pi}, a, f, {eta} and {chi}.

Study of D(1285) → K+K-π0 decay and D(1285)- and E(1420)-mesons production in exclusive reactions, induced by π-- and K--mesons at 32.5 GeV/c

International Nuclear Information System (INIS)

Bitukov, S.I.; Viktorov, V.A.; Golovkin, S.V.

1985-01-01

D(1285) and E(1420)-mesons production in charge-exchange reactions induced by π - and K - -mesons at 32.5 GeV/c has been studied. The measured cross sections allowed one to derive limitations for the mixing angle in the axial-vector meson nonet. This means that E(1420)-meson consists mainly of strange quarks. The invariant mass distribution for the kaon pair in D(1285) → K + K - π 0 decay with statistics by an order of magnitude higher than the available data was obtained. The differential spectrum dN/dmsub(Ksup(+)Ksub(-)) analysis carried out in the delta-dominance model shows that delta(980)-meson cannot be described as a Breit-Wigner resonance with small width. The effective width for delta-meson at the point of √s=1 GeV/c 2 GITAsub(delta) is greater than 180 MeV/c 2 . It points to a strong coupling of delta-meson to hadrons

Measurement of the $\\bar{B}^{0}$ and $B^{-}$ Meson Lifetimes

CERN Document Server

Barate, R.; Ghez, Philippe; Goy, C.; Lees, J.P.; Merle, E.; Minard, M.N.; Pietrzyk, B.; Bravo, S.; Casado, M.P.; Chmeissani, M.; Crespo, J.M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Grauges, E.; Martinez, M.; Merino, G.; Miquel, R.; Mir, Ll.M.; Pacheco, A.; Ruiz, H.; Colaleo, A.; Creanza, D.; de Palma, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Boix, G.; Buchmuller, O.; Cattaneo, M.; Cerutti, F.; Dissertori, G.; Drevermann, H.; Forty, R.W.; Frank, M.; Greening, T.C.; Hansen, J.B.; Harvey, John; Janot, P.; Jost, B.; Lehraus, I.; Mato, P.; Minten, A.; Moutoussi, A.; Ranjard, F.; Rolandi, Gigi; Schlatter, D.; Schmitt, M.; Schneider, O.; Spagnolo, P.; Tejessy, W.; Teubert, F.; Tournefier, E.; Wright, A.E.; Ajaltouni, Z.; Badaud, F.; Chazelle, G.; Deschamps, O.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Monteil, S.; Montret, J.C.; Pallin, D.; Perret, P.; Podlyski, F.; Hansen, J.D.; Hansen, J.R.; Hansen, P.H.; Nilsson, B.S.; Waananen, A.; Daskalakis, G.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Vayaki, A.; Blondel, A.; Bonneaud, G.; Brient, J.C.; Rouge, A.; Rumpf, M.; Swynghedauw, M.; Verderi, M.; Videau, H.; Focardi, E.; Parrini, G.; Zachariadou, K.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Chiarella, V.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G.P.; Passalacqua, L.; Pepe-Altarelli, M.; Halley, A.W.; Lynch, J.G.; Negus, P.; O'Shea, V.; Raine, C.; Teixeira-Dias, P.; Thompson, A.S.; Cavanaugh, R.; Dhamotharan, S.; Geweniger, C.; Hanke, P.; Hansper, G.; Hepp, V.; Kluge, E.E.; Putzer, A.; Sommer, J.; Tittel, K.; Werner, S.; Wunsch, M.; Beuselinck, R.; Binnie, D.M.; Cameron, W.; Dornan, P.J.; Girone, M.; Marinelli, N.; Sedgbeer, J.K.; Thompson, J.C.; Thomson, Evelyn J.; Ghete, V.M.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bowdery, C.K.; Buck, P.G.; Finch, A.J.; Foster, F.; Hughes, G.; Jones, R.W.L.; Robertson, N.A.; Giehl, I.; Jakobs, K.; Kleinknecht, K.; Quast, G.; Renk, B.; Rohne, E.; Sander, H.G.; Wachsmuth, H.; Zeitnitz, C.; Bonissent, A.; Carr, J.; Coyle, P.; Leroy, O.; Payre, P.; Rousseau, D.; Talby, M.; Aleppo, M.; Ragusa, F.; Dietl, H.; Ganis, G.; Heister, A.; Huttmann, K.; Lutjens, G.; Mannert, C.; Manner, W.; Moser, H.G.; Schael, S.; Settles, R.; Stenzel, H.; Wiedenmann, W.; Wolf, G.; Azzurri, P.; Boucrot, J.; Callot, O.; Chen, S.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.F.; Heusse, Ph.; Jacholkowska, A.; Le Diberder, F.; Lefrancois, J.; Lutz, A.M.; Schune, M.H.; Veillet, J.J.; Videau, I.; Yuan, C.; Zerwas, D.; Bagliesi, Giuseppe; Boccali, T.; Calderini, G.; Ciulli, V.; Foa, L.; Giassi, A.; Ligabue, F.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Sciaba, A.; Sguazzoni, G.; Tenchini, R.; Venturi, A.; Verdini, P.G.; Blair, G.A.; Cowan, G.; Green, M.G.; Medcalf, T.; Strong, J.A.; von Wimmersperg-Toeller, J.H.; Clifft, R.W.; Edgecock, T.R.; Norton, P.R.; Tomalin, I.R.; Bloch-Devaux, Brigitte; Colas, P.; Emery, S.; Kozanecki, W.; Lancon, E.; Lemaire, M.C.; Locci, E.; Perez, P.; Rander, J.; Renardy, J.F.; Roussarie, A.; Schuller, J.P.; Schwindling, J.; Trabelsi, A.; Vallage, B.; Black, S.N.; Dann, J.H.; Johnson, R.P.; Kim, H.Y.; Konstantinidis, N.; Litke, A.M.; McNeil, M.A.; Taylor, G.; Booth, C.N.; Cartwright, S.; Combley, F.; Lehto, M.; Thompson, L.F.; Affholderbach, K.; Boehrer, Armin; Brandt, S.; Grupen, C.; Misiejuk, A.; Prange, G.; Sieler, U.; Giannini, G.; Gobbo, B.; Rothberg, J.; Wasserbaech, S.; Armstrong, S.R.; Cranmer, K.; Elmer, P.; Ferguson, D.P.S.; Gao, Y.; Gonzalez, S.; Hayes, O.J.; Hu, H.; Jin, S.; Kile, J.; McNamara, P.A., III; Nielsen, J.; Orejudos, W.; Pan, Y.B.; Saadi, Y.; Scott, I.J.; Walsh, J.; Wu, Sau Lan; Wu, X.; Zobernig, G.

2000-01-01

The lifetimes of the B0 and B- mesons are measured using a sample of about four million hadronic Z decays collected from 1991 to 19 95 with the ALEPH detector at LEP. The data sample has been recently reprocessed, achieving a substantial improvement in the tracking performance. Semileptonic decays of B0 and B- mesons are partially reconstructed by identifying events containing a lepton with an associated D* or D0 meson. The proper time of the B meson is estimated from the measured decay length and the momentum of the D-lepton system. A fit to the proper time of 1880 D* l- and 2856 D0 l- candidates yields the following results: tau B0 = 1.518 +- 0.053 +- 0.034 ps, tau B- = 1.648 +- 0.049 +- 0.035 ps, tau B- / tau B0 = 1.085 +- 0.059 +- 0.018.

Angular Momentum Content of the ρ Meson in Lattice QCD

International Nuclear Information System (INIS)

Glozman, Leonid Ya.; Lang, C. B.; Limmer, Markus

2009-01-01

The variational method allows one to study the mixing of interpolators with different chiral transformation properties in the nonperturbatively determined physical state. It is then possible to define and calculate in a gauge-invariant manner the chiral as well as the partial wave content of the quark-antiquark component of a meson in the infrared, where mass is generated. Using a unitary transformation from the chiral basis to the 2S+1 L J basis one may extract a partial wave content of a meson. We present results for the ground state of the ρ meson using quenched simulations as well as simulations with n f =2 dynamical quarks, all for lattice spacings close to 0.15 fm. We point out that these results indicate a simple 3 S 1 -wave composition of the ρ meson in the infrared, like in the SU(6) flavor-spin quark model.

Angular Momentum Content of the ρ Meson in Lattice QCD

Science.gov (United States)

Glozman, Leonid Ya.; Lang, C. B.; Limmer, Markus

2009-09-01

The variational method allows one to study the mixing of interpolators with different chiral transformation properties in the nonperturbatively determined physical state. It is then possible to define and calculate in a gauge-invariant manner the chiral as well as the partial wave content of the quark-antiquark component of a meson in the infrared, where mass is generated. Using a unitary transformation from the chiral basis to the LJ2S+1 basis one may extract a partial wave content of a meson. We present results for the ground state of the ρ meson using quenched simulations as well as simulations with nf=2 dynamical quarks, all for lattice spacings close to 0.15 fm. We point out that these results indicate a simple S13-wave composition of the ρ meson in the infrared, like in the SU(6) flavor-spin quark model.

On the spin-parity of a E(1420) meson

International Nuclear Information System (INIS)

Asatryan, G.M.; Zaslavskij, A.N.

1977-01-01

The phenomenological analysis of data on the E(1420)-meson decay is carried out. The Adair distribution are constructed for the decays E→deltaπ, K* anti K(antiK*K), K anti K π, νππ in different reactions: the correlations in which the spin of E-meson is most explicitely manifested are marked

Covariant, chirally symmetric, confining model of mesons

International Nuclear Information System (INIS)

Gross, F.; Milana, J.

1991-01-01

We introduce a new model of mesons as quark-antiquark bound states. The model is covariant, confining, and chirally symmetric. Our equations give an analytic solution for a zero-mass pseudoscalar bound state in the case of exact chiral symmetry, and also reduce to the familiar, highly successful nonrelativistic linear potential models in the limit of heavy-quark mass and lightly bound systems. In this fashion we are constructing a unified description of all the mesons from the π through the Υ. Numerical solutions for other cases are also presented

Mesons from (non) Abelian T-dual backgrounds

Energy Technology Data Exchange (ETDEWEB)

Itsios, Georgios [Instituto de Física Teórica, UNESP-Universidade Estadual Paulista, R. Dr. Bento T. Ferraz 271, Bl. II, Sao Paulo 01140-070, SP (Brazil); Department of Physics, University of Oviedo,Avda. Calvo Sotelo 18, 33007 Oviedo (Spain); Núñez, Carlos [Department of Physics, Swansea University,Swansea SA2 8PP (United Kingdom); Zoakos, Dimitrios [Centro de Física do Porto, Universidade do Porto,Rua do Campo Alegre 687, 4169-007 Porto (Portugal)

2017-01-03

In this work we study mesonic excitations in a Quantum Field Theory dual to the non Abelian T-dual of AdS{sub 5}×S{sup 5}, using a D6 brane probe on the Sfetsos-Thompson background. Before and after the duality, we observe interesting differences between the spectra and interpret them. The spectrum of masses and the interactions between mesonic excitations teach valuable lessons about the character of non-Abelian T-duality and its implications for Holography. The case of Abelian T-duality is also studied.

Meson wave functions in 2-dim QCD

International Nuclear Information System (INIS)

Hildebrandt, S.; Visnjic, V.

1977-07-01

We consider the eigenvalue problem of 't Hooft for the meson spectrum in 2-dim QCD by defining some alternative formulations whose equivalence we prove. Hence we are able to prove that the spectrum is discrete and of finite multiplicity and to derive bounds (upper and lower) for the eigenvalues (ground state, with state and n → infinitely state). We prove that the functions are analytic and use this to carry out explicit numerical calculations of the wave functions for various values of the quark masses and to recalculate the meson spectrum. (orig.) [de

Brookhaven: Hunting for unusual mesons

International Nuclear Information System (INIS)

Dzierba, Alex R.

1990-01-01

After the overwhelming experimental evidence for the quark model came the notions of colour and confinement which explained why quarks should prefer to bind in 'colourless' systems - quark-antiquark (mesons) and three quarks (baryons)

DS Mesons in Asymmetric Hot and Dense Hadronic Matter

Directory of Open Access Journals (Sweden)

Divakar Pathak

2015-01-01

Full Text Available The in-medium properties of DS mesons are investigated within the framework of an effective hadronic model, which is a generalization of a chiral SU(3 model, to SU(4, in order to study the interactions of the charmed hadrons. In the present work, the DS mesons are observed to experience net attractive interactions in a dense hadronic medium, hence reducing the masses of the DS+ and DS- mesons from the vacuum values. While this conclusion holds in both nuclear and hyperonic media, the magnitude of the mass drop is observed to intensify with the inclusion of strangeness in the medium. Additionally, in hyperonic medium, the mass degeneracy of the DS mesons is observed to be broken, due to opposite signs of the Weinberg-Tomozawa interaction term in the Lagrangian density. Along with the magnitude of the mass drops, the mass splitting between DS+ and DS- mesons is also observed to grow with an increase in baryonic density and strangeness content of the medium. However, all medium effects analyzed are found to be weakly dependent on isospin asymmetry and temperature. We discuss the possible implications emanating from this analysis, which are all expected to make a significant difference to observables in heavy ion collision experiments, especially the upcoming Compressed Baryonic Matter (CBM experiment at the future Facility for Antiproton and Ion Research (FAIR, GSI, where matter at high baryonic densities is planned to be produced.

Decay of heavy mesons into possible spin 3/2 leptons

International Nuclear Information System (INIS)

Carvalho, H.F. de; Antunes, A.C.B.

1982-01-01

The recent interest in the study of possible spin 3/2 leptons motivated our calculation of the decay rate of heavy mesons into these leptons. The mesons be upsilon UPSILON particles (bb sup(-) systems) or any other system of the qq sup(-) (quark-antiquark) kind with mass larger than those of the upsilon particles, for example, tt sup(-) bound states (not yet detected). The decay rate of these mesons is calculated as a function of the mass of the spin 3/2 leptons. The results obtained are compared with those of the spin 1/2 leptons. (Author) [pt

Scattering phaseshift formulas for mesons and baryons in elongated boxes

Science.gov (United States)

Lee, Frank X.; Alexandru, Andrei

2018-03-01

We derive Lüscher phaseshift formulas for two-particle states in boxes elongated in one of the dimensions. Such boxes offer a cost-effective way of varying the relative momentum of the particles. Boosted states in the elongated direction, which allow wider access to energies, are also considered. The formulas for the various scenarios (moving and zero-momentum states in cubic and elongated boxes) are compared and relations between them are clarified. The results are applicable to a wide set of meson-meson and meson-baryon elastic scattering processes, with the two-particle system having equal or unequal masses.

Recent results on D meson decays from the MARK III

International Nuclear Information System (INIS)

Coward, D.H.

1985-10-01

The MARK III Collaboration recently completed the analysis of a number of decay modes of charged and neutral D mesons produced in electron-positron collisions near the peak of the psi(3770) resonance at SLAC's SPEAR storage ring. The mesons were produced nearly at rest in pairs, either D + D - or D 0 anti D 0 , at a center-of-mass energy below the threshold for DD production. The unique kinematics of the production allow us to isolate the charmed meson signal clearly and unambiguously. The data were collected with the MARK III Spectrometer, a large solid angle magnetic detector. Our data sample corresponds to an integrated luminosity of approximately 9.3 inverse picobarns. New results will be presented on the absolute branching ratios of D mesons into hadronic final states, branching ratios for three body decays via pseudoscalar-vector intermediate states, and branching ratios for Cabibbo allowed and Cabibbo suppressed decays. Inclusive and exclusive branching ratios for the semi-leptonic decays of D mesons will be presented, as well as the first measurement of the vector form factor in the decay D 0 → K - e + nu, evidence for interference in D + decays, and new information on the contributions of W exchange diagrams to D 0 decays

New data on the Lower Cambrian trilobites of Cortijos de Malagon (Spain

Directory of Open Access Journals (Sweden)

Jago, J. B.

1989-04-01

Full Text Available A Small trilobite fauna from the late Lower Cambrian Sanstones from Los Cortijos de Malagon of Southem Spain is described herein. This fauna ineludes the following taxa: Realaspis (? sp.; Kingaspis (? sp.; cf. Latoucheia sp. and Lusatiops afI. ribotanusd, Richter and Richter, 1948.En este trabajo se describe la fauna de trilobites del Cámbrico inferior de las areniscas de los Cortijos de Malagón en el SE español. Comprende Realaspis (? sp., Kingaspis (? sp.; cf. Latoucheia sp. y Lusatiops afI. ribotanus. Richter y Richter, 1948.

Semileptonic decays of strange beauty mesons at Belle

International Nuclear Information System (INIS)

Oswald, Christian

2015-01-01

Semileptonic decays of b-flavoured mesons are an important tool for the determination of the CKM matrix element vertical stroke V cb vertical stroke. In this thesis, measurements of semileptonic B s meson decays are presented. They provide complementary information to the precision measurements of B meson decays and serve as a test of QCD-calculations predicting SU(3) flavour symmetry for the partial decay widths and form factors. The semi-inclusive and inclusive analyses of semileptonic B s decays are based on the 121.4 fb -1 dataset collected by the Belle detector at the KEKB asymmetric-energy e + e - collider in Tsukuba, Japan. The sample recorded at a centre-of-mass energy √(s)=10.86 GeV, which corresponds to the Y(5S) resonance, contains (7.1±1.3) million B s pair events. To measure the semi-inclusive B s → D s Xlν and B s → D s * Xlν branching fractions, D s and D s * candidates are reconstructed and are paired with an oppositely charged lepton, l + =e + ,μ + . The yields of correctly reconstructed D s and D s * mesons are determined by fits to their respective invariant mass distributions. The signal yield and the yields of the remaining backgrounds are extracted using kinematic distributions of the reconstructed decay products and the constraint from the known initial state of the e + e - collision. The measured branching fractions are: B(B s → D s Xlν)=(8.2±0.2(stat)±0.6(syst)±1.4(ext)) % and B(B s → D s * lν)=(5.4±0.4(stat)±0.4(syst)±0.9 (ext)) %, where the first two uncertainties are the statistical and systematic uncertainties of the measurement and the last uncertainty is due to external parameters. Making an assumption about the B s → D s Xlν branching fraction, the measurement of the B s → D s Xlν yield is also used to obtain the current best estimate of the B s pair production cross-section at a centre-of-mass energy √(s)=10.86 GeV: σ(e + e - → B s pairs)=(57.1±1.5(stat)±4.3(syst)±4.2(ext)) pb. The semi

SU(N)-QCD2 meson equation in next-to-leading order

International Nuclear Information System (INIS)

Durgut, M.; Pak, N.K.

1982-08-01

We compute the 1/N corrections to the meson equation in the regular cut-off scheme. We illustrate that although the quark and gluon self energy and vertex corrections do not vanish explicitly as in the singular cut-off scheme, their contributions to the meson Bethe-Salpeter equation get cancelled within the whole set of contributing diagrams. We also argue that 0(1/N) corrections to the meson equation remove the massless boson from the spectrum in accordance with the Coleman theorem. (author)

Heavy quarks fragmentation in charmed mesons in DELPHI experiment at LEP; Etude de la fragmentation des quarks lourds en mesons charmes dans l`experience Delphi au LEP

Energy Technology Data Exchange (ETDEWEB)

Levy, J.M.

1994-04-01

With the big statistics expected at LEP, the electroweak sector of the Standard Model can be tested as well as the theory of strong interactions. Quantum Chromo-Dynamics is indeed predictive for quarks properties, but does not explain how quarks fragment into hadrons. So far the hadronization can only be described with phenomenological models. The work presented in this thesis was performed on the DELPHI experiment at LEP and concerns the production and the fragmentation of heavy quarks into charmed mesons D , D* and D**. With the whole statistics of 1991 and 1992 (1 013 300 hadronic decays of the Z), more than 4500 charmed mesons decays have been reconstructed in the channels D{sup 0}{yields} K{sup -} {pi}{sup +} , D{sup +}{yields} K{sup -} {pi}{sup +}{pi}+ and D{sup *}+{yields} D{sup 0}{pi}{sup +} followed by D{sup 0}{yields} K{sup -}{pi}{sup +} . Using also 1993 data and the channel D{sup 0}{yields} K{sup -}{pi}{sup +}{pi}{sup +}{pi}{sup -} , evidence for D** production is presented. For the first time, the production rate is measured for each D meson separately for cc and bb contributions. In fact, D mesons can be produced either directly from the fragmentation of c quark or un-directly from the fragmentation of b quark into B mesons which decay into D mesons. (authors). 120 refs.

On a low energy, strong interaction model, unifying mesons and baryons

International Nuclear Information System (INIS)

Kalafatis, D.

1993-03-01

This thesis is concerned with the study of a unified theory of mesons and baryons. An effective Lagrangian with the low mass mesons, generalizing the Skyrme model, is constructed. The vector meson fields are introduced as gauge fields in the linear sigma model instead of the non linear sigma model. Topological soliton solutions of the model are examined and the nucleon-nucleon interaction in the product approximation is investigated. The leading correction to the classical skyrmion mass, the Casimir energy, is evaluated. The problem of the stability of topological solitons when vector fields enter the chiral Lagrangian is also studied. It is shown that the soliton is stable in very much the same way as with the ωmeson and that peculiar classical doublet solutions do not exist

Neutron stars in relativistic mean field theory with isovector scalar meson

International Nuclear Information System (INIS)

Kubis, S.; Kutschera, M.; Stachniewicz, S.

1998-01-01

We study the equation of state (EOS) of β-stable dense matter and models of neutron stars in the relativistic mean field (RMF) theory with the isovector scalar mean field corresponding to the δ-meson (a 0 (980)). A range of values of the δ-meson coupling compatible with the Bonn potentials is explored. Parameters of the model in the isovector sector are constrained to fit the nuclear symmetry energy, E s ∼30 MeV. We find that the quantity most sensitive to the δ-meson coupling is the proton fraction of neutron star matter. It increases significantly in the presence of the δ-field. The energy per baryon also increases but the effect is smaller. The EOS becomes slightly stiffer and the maximum neutron star mass increases for stronger δ-meson coupling. (author)

Improved measurement of the $\\overline{B}^{0}$ and B$^{-}$ meson lifetimes

CERN Document Server

Buskulic, Damir; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Casado, M P; Chmeissani, M; Crespo, J M; Delfino, M C; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Nuzzo, S; Ranieri, A; Raso, G; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Alemany, R; Bazarko, A O; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Mir, L M; Moneta, L; Oest, T; Palla, Fabrizio; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wagner, A; Wildish, T; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Wäänänen, A; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Casper, David William; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Geweniger, C; Graefe, G; Hanke, P; Hansper, G; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Abbaneo, D; Beuselinck, R; Binnie, David M; Cameron, W; Dornan, Peter J; Moutoussi, A; Nash, J; Sedgbeer, J K; Stacey, A M; Williams, M D; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Betteridge, A P; Bowdery, C K; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Konstantinidis, N P; Payre, P; Rousseau, D; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Aleppo, M; Ragusa, F; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Verdini, P G; Walsh, J; Blair, G A; Bryant, L M; Cerutti, F; Chambers, J T; Gao, Y; Green, M G; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Maley, P; Norton, P R; Thompson, J C; Wright, A E; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Black, S N; Dann, J H; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Booth, C N; Boswell, R; Brew, C A J; Cartwright, S L; Combley, F; Köksal, A; Letho, M; Newton, W M; Reeve, J; Thompson, L F; Böhrer, A; Brandt, S; Büscher, V; Cowan, G D; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Greening, T C; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

1996-01-01

The lifetimes of the \\b0 \\ and \\bp\\ mesons have been measured with the \\aleph\\ detector at LEP, using approximately 3 million hadronic Z decays collected in the period 1991--1994. In the first of three methods, semileptonic decays of \\b0 \\ and \\bp\\ mesons were partially reconstructed by identifying events containing a lepton with an associated \\ds\\ or \\d0 \\ meson. The second method used fully reconstructed \\bz\\ and \\bp\\ mesons. The third method, used to measure the \\bz\\ lifetime, employed a partial reconstruction technique to identify \\bz\\to D^{*+}\\pi^- X decays. The combined results are \\begin{eqnarray*} \\t0 & = & 1.55\\pm 0.06\\pm 0.03 \\mathrm{\\ ps}, \\\\ \\tp & = & 1.58\\pm 0.09\\pm 0.03 \\mathrm{\\ ps}, \\\\ \\trat & = & 1.03\\pm 0.08\\pm 0.02.

Meson form factors and covariant three-dimensional formulation of composite model

International Nuclear Information System (INIS)

Skachkov, N.B.; Solovtsov, I.L.

1978-01-01

An approach is developed which is applied in the framework of the relativistic quark model to obtain explicit expressions for meson form factors in terms of covariant wave functions of the two-quark system. These wave functions obey the two-particle quasipotential equation in which the relative motion of quarks is singled out in a covariant way. The exact form of the wave functions is found using the transition to the relativistic configurational representation with the help of the harmonic analysis on the Lorentz group instead of the usual Fourier expansion and then solving the relativistic difference equation thus obtained. The expressions found for form factors are transformed into the three-dimensional covariant form which is a direct geometrical relativistic generalization of analogous expressions of the nonrelativistic quantum mechanics and provides the decrease of the meson form factor by the Fsub(π)(t) approximately t -1 law as -t infinity, in the Coulomb field

Observation of the weak time’s arrow in B mesons

CERN Multimedia

CERN. Geneva

2012-01-01

The mechanism of CP violation in weak interactions, as arising from the single physical phase in the CKM matrix, has been validated by more than a decade of intense experimental work probing CP violation, particularly with studies with B mesons. Since the Standard Model theory is CPT invariant, it predicts a “weak arrow of time” matching the large observed matter-antimatter asymmetry in B mesons. However, until recently there has been no direct observation of the expected, large time reversal (T) asymmetry. In this seminar we shall discuss how the BABAR experiment at SLAC has conducted a new data analysis where the decays of entangled neutral B mesons allow comparisons between the rates of four different transitions and their inverse, as a function of the time evolution of the B meson. The results lead to the first high significance, direct observation of T non-invariance through the exchange of initial and final states in transitions that can only be connected by a T symmetry transformation.

Measurement of the overlineB0 and B- meson lifetimes

Science.gov (United States)

Buskulic, D.; Decamp, D.; Goy, C.; Lees, J.-P.; Minard, M.-N.; Mours, B.; Pietrzyk, B.; Alemany, R.; Ariztizabal, F.; Comas, P.; Crespo, J. M.; Delfino, M.; Fernandez, E.; Fernandez-Bosman, M.; Gaitan, V.; Garrido, Ll.; Mattison, T.; Pacheco, A.; Padilla, C.; Pascual, A.; Creanza, D.; de Palma, M.; Farilla, A.; Iaselli, G.; Maggi, G.; Maggi, M.; Natali, S.; Nuzzo, S.; Quattromini, M.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Chai, Y.; Hu, H.; Huang, D.; Huang, X.; Lin, J.; Wang, T.; Xie, Y.; Xu, D.; Xu, R.; Zhang, J.; Zhang, L.; Zhao, W.; Bauerdick, L. A. T.; Blucher, E.; Bonvicini, G.; Boudreau, J.; Casper, D.; Drevermann, H.; Forty, R. W.; Ganis, G.; Gay, C.; Hagelberg, R.; Harvey, J.; Haywood, S.; Hilgart, J.; Jacobsen, R.; Jost, B.; Knobloch, J.; Lehraus, I.; Lohse, T.; Lusiani, A.; Martinez, M.; Mato, P.; Meinhard, H.; Minten, A.; Miotto, A.; Miquel, R.; Moser, H.-G.; Palazzi, P.; Perlas, J. A.; Pusztaszeri, J.-F.; Ranjard, F.; Redlinger, G.; Rolandi, L.; Rothberg, J.; Ruan, T.; Saich, M.; Schlatter, D.; Schmelling, M.; Sefkow, F.; Tejessy, W.; Wachsmuth, H.; Wiedenmann, W.; Wildish, T.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; Badaud, F.; Bardadin-Otwinowska, M.; El Fellous, R.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Prulhière, F.; Saadi, F.; Fearnley, T.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Møllerud, R.; Nilsson, B. S.; Efthymiopoulos, I.; Kyriakis, A.; Simopoulou, E.; Vayaki, A.; Zachariadou, K.; Badier, J.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Fouque, G.; Orteu, S.; Rougé, A.; Rumpf, M.; Tanaka, R.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Veitch, E.; Moneta, L.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Ikeda, M.; Lannutti, J.; Levinthal, D.; Mermikides, M.; Sawyer, L.; Wasserbaech, S.; Antonelli, A.; Baldini, R.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Cerutti, F.; Chiarella, V.; D'Ettorre-Piazzoli, B.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Picchi, P.; Colrain, P.; Ten Have, I.; Lynch, J. G.; Maitland, W.; Morton, W. T.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Smith, M. G.; Thompson, A. S.; Turnbull, R. M.; Brandl, B.; Braun, O.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E. E.; Maumary, Y.; Putzer, A.; Rensch, B.; Stahl, A.; Tittel, K.; Wunsch, M.; Belk, A. T.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Cattaneo, M.; Colling, D. J.; Dornan, P. J.; Dugeay, S.; Greene, A. M.; Hassard, J. F.; Lieske, N. M.; Nash, J.; Payne, D. G.; Phillips, M. J.; Sedgbeer, J. K.; Tomalin, I. R.; Wright, A. G.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bowdery, C. K.; Brodbeck, T. J.; Finch, A. J.; Foster, F.; Hughes, G.; Jackson, D.; Keemer, N. R.; Nuttall, M.; Patel, A.; Sloan, T.; Snow, S. W.; Whelan, E. P.; Kleinknecht, K.; Raab, J.; Renk, B.; Sander, H.-G.; Schmidt, H.; Steeg, F.; Walther, S. M.; Wanke, R.; Wolf, B.; Aubert, J.-J.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Carr, J.; Coyle, P.; Drinkard, J.; Etienne, F.; Nicod, D.; Papalexiou, S.; Payre, P.; Roos, L.; Rousseau, D.; Schwemling, P.; Talby, M.; Adlung, S.; Assmann, R.; Bauer, C.; Blum, W.; Brown, D.; Cattaneo, P.; Dehning, B.; Dietl, H.; Dydak, F.; Frank, M.; Halley, A. W.; Lauber, J.; Lütjens, G.; Lutz, G.; Männer, W.; Richter, R.; Rotscheidt, H.; Schröder, J.; Schwarz, A. S.; Settles, R.; Seywerd, H.; Stierlin, U.; Stiegler, U.; Denis, R. St.; Wolf, G.; Boucrot, J.; Callot, O.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Jaffe, D. E.; Janot, P.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Schune, M.-H.; Veillet, J.-J.; Videau, I.; Zhang, Z.; Abbaneo, D.; Bagliesi, G.; Batignani, G.; Bosisio, L.; Bottigli, U.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Dell'Orso, R.; Ferrante, I.; Fidecaro, F.; Foà, L.; Focardi, E.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Mannelli, E. B.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Vannini, C.; Venturi, A.; Verdini, P. G.; Walsh, J.; Betteridge, A. P.; Carter, J. M.; Green, M. G.; March, P. V.; Mir, Ll. M.; Medcalf, T.; Quazi, I. S.; Strong, J. A.; West, L. R.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Edwards, M.; Fisher, S. M.; Jones, T. J.; Norton, P. R.; Salmon, D. P.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Duarte, H.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Perez, P.; Perrier, F.; Rander, J.; Renardy, J.-F.; Rosowsky, A.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Si Mohand, D.; Vallage, B.; Johnson, R. P.; Litke, A. M.; Taylor, G.; Wear, J.; Ashman, J. G.; Babbage, W.; Booth, C. N.; Buttar, C.; Carney, R. E.; Cartwright, S.; Combley, F.; Hatfield, F.; Thompson, L. F.; Barberio, E.; Böhrer, A.; Brandt, S.; Cowan, G.; Grupen, C.; Lutters, G.; Rivera, F.; Schäfer, U.; Smolik, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Ragusa, F.; Bellantoni, L.; Chen, W.; Cinabro, D.; Conway, J. S.; Cowen, D. F.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; Grahl, J.; Harton, J. L.; Jared, R. C.; Leclaire, B. W.; Lishka, C.; Pan, Y. B.; Pater, J. R.; Saadi, Y.; Sharma, V.; Schmitt, M.; Shi, Z. H.; Walsh, A. M.; Weber, F. V.; Sau Lan Wu; Wu, X.; Zheng, M.; Zobernig, G.; Aleph Collaboration

1993-06-01

The lifetimes of the overlineB0 and B- mesons have been measured with the ALEPH detector at LEP. Semileptonic decays of overlineB0 and B- mesons were partially reconstructed by identifying events containing a lepton with an associated D ∗+or D 0 meson. The proper time of the B meson was estimated from the measured decay length and the momentum and mass of the D-lepton system. A fit to the proper time of 77 D ∗+ℓ - and 77 D0ℓ - candidates, combined with a constraint on the lifetime ratio ( {τ -}/{τ 0}) arising from the relative rates of observed D ∗+ℓ - and D0ℓ - events, yielded the following lifetimes: τ 0=1.52 -0.18+0.20( stat.) -0.13+0.07( syst.) ps, τ - = 1.47 -0.19+0.22( stat.) -0.14+0.15( syst.) ps, {τ -}/{τ 0} = 0.96 -0.15+0.19( stat.) -0.12+0.18( syst.) .

Effective mass of omega meson and NNω interaction at finite temperature and density

International Nuclear Information System (INIS)

Gao, S.; Su, R.; Yu, P.K.N.

1994-01-01

By means of the thermofield dynamical theory, the effective mass of omega meson is calculated by summing the bubble diagrams. It is found that the formula for the effective mass of the ρ meson can also be used to describe the ω meson in the low density region, but the parameter n and the critical temperature T c depend on the density. The temperature and density dependence of one omega exchage potential of nucleon-nucleon interaction are given. The conjecture of Brown and Rho about the effective masses of mesons is discussed

Microbial involvement in the formation of Cambrian sea-floor silica-iron oxide deposits, Australia

Science.gov (United States)

Duhig, Nathan C.; Davidson, Garry J.; Stolz, Joe

1992-06-01

The Cambrian-Ordovician Mount Windsor volcanic belt in northern Australia is host to stratiform lenses of massive ferruginous chert that are spatially associated with volcanogenic massive sulfide occurrences, in particular the Thalanga zinc-lead-copper-silver deposit. The rocks are composed principally of Fe2O3 and SiO2, with very low concentrations of alkalic elements, and lithogenous elements such as Al, Zr, and Ti; they are interpreted as nearly pure chemical sediments. Textural evidence is documented of the integral role of filamentous bacteria (and/or fungi) in depositing iron from hydrothermal fluids, and of the inorganic precipitation of silica-iron-oxyhydroxide gels that subsequently matured to subcrystalline and crystalline silica forms. At least three distinct iron-accumulating microbial forms are distinguished: networks of septate filaments, nonseptate filament networks, and extremely coarse branching filaments that do not reconnect. Values for δ34S in disseminated pyrite are up to 50‰ lighter than those of contemporaneous Cambrian seawater, suggesting postdepositional colonization of some ironstones by sulfur-reducing bacteria. The site not only preserves the textural interplay of biological and inorganic depositional processes in exhalites, but also extends the oldest known instance of microbial mediation in vent-proximal hydrothermal iron precipitation to at least 500 Ma.

Beauty vector meson decay constants from QCD sum rules

Energy Technology Data Exchange (ETDEWEB)

Lucha, Wolfgang [Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); Melikhov, Dmitri [Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); D. V. Skobeltsyn Institute of Nuclear Physics, M. V. Lomonosov Moscow State University, 119991, Moscow (Russian Federation); Simula, Silvano [Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, Via della Vasca Navale 84, I-00146, Roma (Italy)

2016-01-22

We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity.

Meson exchange and neutral weak currents

Energy Technology Data Exchange (ETDEWEB)

Beck, D.H. [Univ. of Illinois, Urbana, IL (United States)

1994-04-01

Measurements of parity-violating electron scattering asymmetries to determine weak neutral currents in nuclei will be effected by the presence of meson exchange currents. Present low momentum transfer calculations, based on a flavor independent framework, show these effects to be small. In general, however, as the momentum transfer increases to values typical of deep-inelastic scattering, fragmentation functions show a clear flavor dependence. It is suggested that a good experimental starting point for understanding the flavor dependence of meson production and exchange currents is the Q{sup 2} dependence of parity-violating asymmetry in inclusive single pion electroproduction. A CEBAF facility with doubled energy is necessary to approach momentum transfers where this process begins to scale.

A phenomenological analysis of non-resonant charm meson decays

International Nuclear Information System (INIS)

Bediaga, I.; Goebel, C.; Mendez-Galain, R.

1997-07-01

We analyse the consequences of the usual assumption of a constant function to fit non-resonant decays from experimental Dalitz plot describing charmed meson decays. We first show, using the D + -> K 0 π + π 0 decay channel as an example, how an inadequate extraction of the non-resonant contribution could yield incorrect measurements for the resonant channels. We analyse how the correct study of this decay will provide a test for the validity of factorization in D meson decays. Finally, we show how form factors that can be measured from the D + s -> π - π + π + decay. We emphasize its relevance for the study of the decay τ -> v t 3π and the extraction of the α 1 meson width. (author)

General characteristics of Bc-mesons. Production mechanisms and decays

International Nuclear Information System (INIS)

Gershtein, S.S.; Likhoded, A.K.; Slabospitsky, S.R.

1989-01-01

Using Martin potential, independent of b- and c-quark flavour, the mass spectrum of B c (bc-bar)-mesons and widths of electromagnetic transition between them are calculated. The estimations of the production cross section at e + e - colliders, in hadronic and neutrino interactions are obtained. A real possibility to observed B c mesons at LEP and also at hadron colliders (σ(B c )/σ(bb-bar)∼10 -3 ) has been pointed out. The importance of observing the annihilation decay channels of B c -mesons: B c →τν τ (Br(B c →τν τ )=1.5-2%), and B c →ΦD s , B C →DK etc, has been emphasized. 25 refs.; 16 figs.; 5 tabs

Summary of Meson'98 Workshop

International Nuclear Information System (INIS)

Henley, E.M.

1998-01-01

One never quite knows what to say in a summary. If you were at the sessions, you heard the same talks I did. Perhaps the purpose is to summarize the parallel sessions, but like you, I can only attend one of these sessions. In addition, the time is short, so that this cannot be a real summary. What I will present are impressions of the past two days, and these will certainly be colored by my own views. Thus at the outset, let me apologize for any and all omissions and distortions. I will cover primarily the plenary session talks, but will organize this summary along the following lines: 1. vector (V) mesons; 2. pseudoscalar mesons, and 3. other subjects, notably with electrons. This afternoon's talks are so close in time to this summary that I shall omit them. (author)

Doubly charmed exotic mesons: A gift of nature?

Energy Technology Data Exchange (ETDEWEB)

Carames, T.F. [Departamento de Fisica Fundamental, Universidad de Salamanca, E-37008 Salamanca (Spain); Valcarce, A., E-mail: valcarce@usal.e [Departamento de Fisica Fundamental, Universidad de Salamanca, E-37008 Salamanca (Spain); Vijande, J. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Valencia (UV) and IFIC (UV-CSIC), Valencia (Spain)

2011-05-16

We study doubly charmed exotic states by solving the scattering problem of two D mesons. Our results point to the existence of a stable isoscalar doubly charmed meson with quantum numbers (I)J{sup P}=(0)1{sup +}. We perform a thorough comparison to the results obtained within the hyperspherical harmonic formalism. Such exotic states could be measured at LHC and RHIC. Their experimental observation would, for the first time, confirm the contribution of multiquark structures to hadron spectroscopy.

About absence of oscillations at CP violation and presence of interference between KS-, KL-meson states in the system of K0 mesons

International Nuclear Information System (INIS)

Beshtoev, Kh.M.

2014-01-01

Two approaches to the description of K 0 -, K 0 -bar-meson transitions into K 1 0 mesons at CP violation in weak interactions are considered. The first approach uses the standard theory of oscillations and the second approach supposes that (K S , K L ) states which arise at CP violation are normalized but not orthogonal state functions, then there arise interferences between these states but not oscillations. It is necessary to remark that the available experimental data are in good agreement with the second approach. So, we come to the conclusion that oscillations do not arise at CP violation in weak interactions in the system of K 0 mesons. Only interference between K S and K L states takes place here.

SU(3) properties of semileptonic and nonleptonic decays of mesons

International Nuclear Information System (INIS)

Montvay, I.

1977-11-01

The recent discovery of charmed D and F mesons led to an accumulation of a lot of information on the weak decays of these particles. The facts known at present are generally consistent with the Glashow-Iliopoulos-Maiami scheme for the weak currents, which are predicted the fourth flavour of quarks, the charm. The weak decays of the charmed mesons are governed by SU(3) rules analogous to the Okubo-Zweig-Iizuka rule for strong decays. Such Su(3) rules are given for semileptonic and nonleptonic decays of strange and charmed mesons. These relations depend on the colour structure of currents in the nonleptonic case. (D.P.)

The meson spectroscopy program with CLAS12 at Jefferson Laboratory

Energy Technology Data Exchange (ETDEWEB)

Rizzo, Alessandro [Univ. of Rome Tor Vergata (Italy)

2016-06-01

The study of the hadronic spectrum is one of the most powerful tools to investigate the mechanism at the basis of quark confinement within hadrons. A precise determination of the spectrum allows not only to assess the properties of the hadrons in their fundamental and excited states, but also to investigate the existence of states resulting from alternative configurations of quarks and gluons, such as the glue-balls, hybrid hadrons and many-quarks configurations. The study of the mesonic part of the spectrum can play a central role in this investigation thanks to the strong signature that the hybrid mesons are expected to have: the presence of explicit gluonic degrees of freedom in such states may result in JPC configurations not allowed for the standard q ¯ q states. From the experimental side the expected high-multiplicity decays of the hybrid mesons require an apparatus with high performances in terms of rate-capability, resolution and acceptance. The CLAS12 experiment (formally MesonEx) is one of new-generation experiments at Thomas Jefferson National Laboratory (JLAB) for which an unprecedented statistics of events, with fully reconstructed kinematics for large particle multiplicity decays, will be available. A wide scientific program that will start in 2016 has been deployed for meson spectrum investigation with the CLAS12 apparatus in Hall B at energies up to 11 GeV. One of the main parts of the program is based on the use of the Forward Tagger apparatus, which will allow CLAS12 experiment to extend the study of meson electro-production to the quasi-real photo-production kinematical region (very low Q2), where the production of hybrid mesons is expected to be favoured. The data analysis which is required to extract the signal from hybrid states should go beyond the standard partial wave analysis techniques and a new analysis framework is being set up through the international network Haspect. The Haspect Network gathers people involved into theoretical and

Charged-particle multiplicities in B-meson decay

International Nuclear Information System (INIS)

Alam, M.S.; Csorna, S.E.; Fridman, A.; Hicks, R.G.; Panvini, R.S.; Andrews, D.; Avery, P.; Berkelman, K.; Cabenda, R.; Cassel, D.G.; DeWire, J.W.; Ehrlich, R.; Ferguson, T.; Gilchriese, M.G.D.; Gittelman, B.; Hartill, D.L.; Herrup, D.; Herzlinger, M.; Holzner, S.; Kandaswamy, J.; Kreinick, D.L.; Mistry, N.B.; Morrow, F.; Nordberg, E.; Perchonok, R.; Plunkett, R.; Silverman, A.; Stein, P.C.; Stone, S.; Weber, D.; Wilcke, R.; Sadoff, A.J.; Bebek, C.; Haggerty, J.; Hempstead, M.; Izen, J.M.; Loomis, W.A.; MacKay, W.W.; Pipkin, F.M.; Rohlf, J.; Tanenbaum, W.; Wilson, R.; Chadwick, K.; Chauveau, J.; Ganci, P.; Gentile, T.; Kagan, H.; Kass, R.; Melissinos, A.C.; Olsen, S.L.; Poling, R.; Rosenfeld, C.; Rucinski, G.; Thorndike, E.H.; Green, J.; Sannes, F.; Skubic, P.; Snyder, A.; Stone, R.; Brody, A.; Chen, A.; Goldberg, M.; Horwitz, N.; Lipari, P.; Kooy, H.; Moneti, G.C.; Pistilli, P.

1982-01-01

The charged multiplicity has been measured at the UPSILON(4S) and a value of 5.75 +- 0.1 +- 0.2 has been obtained for the mean charged multiplicity in B-meson decay. Combining this result with the measurement of prompt letpons from B decay, the values 4.1 +- 0.35 +- 0.2 and 6.3 +- 0.2 +- 0.2 are found for the semileptonic and nonleptonic charged multiplicities, respectively. If b→c dominance is assumed for the weak decay of the B meson, then the semileptonic multiplicity is consistent with the recoil mass determined from the lepton momentum spectrum

Are the gluon distributions different in π- and K-mesons?

International Nuclear Information System (INIS)

Batunin, A.V.; Likhoded, A.K.; Kiselev, V.V.

1988-01-01

The experimental data an excess of D-meson production in K - -beam as compared with π - one (NA32 collaboration) is discussed. Such a situation is shown to be possible at larger total number of gluons in K-meson only. However, this is in a disagreemtn with other charm production experiments

Excited meson radiative transitions from lattice QCD using variationally optimized operators

Energy Technology Data Exchange (ETDEWEB)

Shultz, Christian J. [Old Dominion Univ., Norfolk, VA (United States); Dudek, Jozef J. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Old Dominion Univ., Norfolk, VA (United States); Edwards, Robert G. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2015-06-02

We explore the use of 'optimized' operators, designed to interpolate only a single meson eigenstate, in three-point correlation functions with a vector-current insertion. These operators are constructed as linear combinations in a large basis of meson interpolating fields using a variational analysis of matrices of two-point correlation functions. After performing such a determination at both zero and non-zero momentum, we compute three-point functions and are able to study radiative transition matrix elements featuring excited state mesons. The required two- and three-point correlation functions are efficiently computed using the distillation framework in which there is a factorization between quark propagation and operator construction, allowing for a large number of meson operators of definite momentum to be considered. We illustrate the method with a calculation using anisotopic lattices having three flavors of dynamical quark all tuned to the physical strange quark mass, considering form-factors and transitions of pseudoscalar and vector meson excitations. In conclusion, the dependence on photon virtuality for a number of form-factors and transitions is extracted and some discussion of excited-state phenomenology is presented.

Neutron stars in relativistic mean field theory with isovector scalar meson

Energy Technology Data Exchange (ETDEWEB)

Kubis, S.; Kutschera, M.; Stachniewicz, S. [H. Niewodniczanski Institute of Nuclear Physics, Cracow (Poland)

1998-03-01

We study the equation of state (EOS) of {beta}-stable dense matter and models of neutron stars in the relativistic mean field (RMF) theory with the isovector scalar mean field corresponding to the {delta}-meson (a{sub 0}(980)). A range of values of the {delta}-meson coupling compatible with the Bonn potentials is explored. Parameters of the model in the isovector sector are constrained to fit the nuclear symmetry energy, E{sub s}{approx}30 MeV. We find that the quantity most sensitive to the {delta}-meson coupling is the proton fraction of neutron star matter. It increases significantly in the presence of the {delta}-field. The energy per baryon also increases but the effect is smaller. The EOS becomes slightly stiffer and the maximum neutron star mass increases for stronger {delta}-meson coupling. (author) 8 refs, 6 figs, 2 tabs

Measurement of the lifetimes of the neutral and charged D mesons

International Nuclear Information System (INIS)

Gladney, L.D.

1985-03-01

Results are presented on the use of a high-resolution drift chamber in the Mark II Detector at PEP to measure the lifetimes of D 0 and D +- mesons produced in e + e - annihilations at 29 GeV. Based on a sample of 74 events for the D 0 mesons and 23 events for the D +- mesons, the lifetimes are found to be tau/sub D 0 = 4.7/sub -0.8//sup +0.9/ +- 0.5 x 10 -13 s; tau/sub D +- / = 8.9/sub -2.7//sup +3.8/ +- 1.3 x 10 -13 s. The ratio of these lifetimes, tau/sub D 0 //tau/sub D +- / = 1.9/sub -0.7//sup +0.9/ +- 0.3, indicates that the decays of these mesons cannot be explained by the simple spectator model of charmed particle decay

Meson Spectroscopy at COMPASS

CERN Document Server

Grube, Boris

2015-01-01

The COmmon Muon and Proton Apparatus for Structure and Spectroscopy (COMPASS) is a multi-purpose fixed-target experiment at the CERN Super Proton Synchrotron (SPS) aimed at studying the structure and spectrum of hadrons. The two-stage spectrometer has a good acceptance for charged as well as neutral particles over a wide kinematic range and thus allows to access a wide range of reactions. Light mesons are studied with negative (mostly $\\pi^-$) and positive ($p$, $\\pi^+$) hadron beams with a momentum of 190 GeV/$c$. The spectrum of light mesons is investigated in various final states produced in diffractive dissociation reactions at squared four-momentum transfers to the target between 0.1 and 1.0 $(\\text{GeV}/c)^2$. The flagship channel is the $\\pi^-\\pi^+\\pi^-$ final state, for which COMPASS has recorded the currently largest data sample. These data not only allow to measure the properties of known resonances with high precision, but also to search for new states. Among these is a new resonance-like signal, t...

Meson Spectroscopy at COMPASS

CERN Document Server

Grube, Boris

2016-11-29

The goal of the COMPASS experiment at CERN is to study the structure and dynamics of hadrons. The two-stage spectrometer used by the experiment has large acceptance and covers a wide kinematic range for charged as well as neutral particles and can therefore measure a wide range of reactions. The spectroscopy of light mesons is performed with negative (mostly $\\pi^-$) and positive ($p$, $\\pi^+$) hadron beams with a momentum of 190 GeV/$c$. The light-meson spectrum is measured in different final states produced in diffractive dissociation reactions with squared four-momentum transfer $t$ to the target between 0.1 and 1.0 $(\\text{GeV}/c)^2$. The flagship channel is the $\\pi^-\\pi^-\\pi^+$ final state, for which COMPASS has recorded the currently world's largest data sample. These data not only allow to measure the properties of known resonances with high precision, but also to observe new states. Among these is a new axial-vector signal, the $a_1(1420)$, with unusual properties. Novel analysis techniques have been...

Direct production of anti D0 mesons in neutrino-nucleon collisions

International Nuclear Information System (INIS)

Onipchuk, A.B.; Choban, E.A.

1992-01-01

The inclusive production of anti D 0 mesons in neutrino-nucleon collisions is studied from the viewpoint of the quasiparton mechanism. The ratio R anti D 0 υ = σ(υ μ N → μ - X)/σ(υ μ N → μ - X), the kinematic distributions averaged over the υ μ spectrum, and the average kinematic characteristics of the final μ - and anti D 0 mesons are calculated. The number of events with anti D 0 -meson production is estimated as a function of the number of inclusive events

Electroweak production of hybrid mesons in a flux-tube simulation of lattice QCD

International Nuclear Information System (INIS)

Close, F.E.; Dudek, J.J.

2003-01-01

We make the first calculation of the electroweak couplings of hybrid mesons to conventional mesons appropriate to photoproduction and to the decays of B or D mesons. E1 amplitudes are found to be large and may contribute in charge exchange γp→nH + allowing production of (among others) the charged 1 -+ exotic hybrid off a 2 exchange. Axial hybrid meson photoproduction is predicted to be large courtesy of π exchange, and its strange hybrid counterpart is predicted in B→ψK H (1 + ) with branching ratio B∼10 -4 . Higher multipoles and some implications for hybrid charmonium are briefly discussed

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.

Hadronic and leptonic decay widths of D and Ds mesons using Dirac formalism

International Nuclear Information System (INIS)

Vinodkumar, P.C.; Shah, Manan; Patel, Bhavin

2014-01-01

The decay of charged meson is important annihilation channel through the exchange of the virtual W boson. Though this annihilation process is rare, they have clear experimental signatures due to the presence of highly energetic leptons, hadrons in the final state. There exist experimental observations of the hadronic and leptonic decays of D and Ds mesons. The decays of mesons entail an appropriate representation of the initial state of the decaying mesons in terms of the constituent quark and antiquark with their respective momenta and spin. Thus, it is appropriate to compute the branching ratio here

Inclusive weak decays of charmed mesons

International Nuclear Information System (INIS)

Matthews, C.G.

1993-01-01

Inclusive analysis provide a different insight into the understanding of weak decay physics. This thesis experimentally determines inclusive decay predictions of charmed D mesons. Exclusive decay predictions are also used from a variety of theoretical models to make predictions about inclusive properties. Both experimental and theoretical realms benefit from the new techniques presented in this thesis. Inclusive properties derived are the multiplicity distributions, average multiplicities and inclusive branching ratios of charged particles, charged and neutral kaons, and charged pions. The center-of-mass momentum spectra of charged and neutral kaons are also obtained. Additionally, in the theoretical realm only, the inclusive properties of neutral pions, and the center-of-mass momentum spectra of charged and neutral pions are determined. The experimental analysis, which uses data from the mark II experiment at the Stanford Linear Accelerator Center, employs an unfold technique utilizing fold matrices to obtain the charged particle and kaon properties. A new enhanced unfold technique involving fold tensors obtains the first-ever results for the inclusive charged pion properties. The average strange quark contents and the average charged lepton multiplicities of the D + , D 0 and D + 8 are also presented. In the theoretical analysis, the exclusive decay mode predictions from the factorization model for Bauer, Stech and Wirbel; the quark diagram scheme of Chau and Cheng; and the QCD sum rules model of Block and Shifman are processed to determine inclusive predictions will lead to a better understanding of the model. The thesis also derives inclusive predictions from the D meson exclusive branching ratios compiled by the Particle Data Group

Meson-baryon four-body reaction amplitudes in exact SU(4)

International Nuclear Information System (INIS)

Liede, I.; Maalampi, J.; Roos, M.

1976-01-01

Fully SU(4) symmetric meson-baryon four body reaction amplitudes are presented in terms of SU(4) eigenamplitudes. The mesons and baryons considered belong to the SU(4) representations 15 and 20, respectively. Using these reletions, the cross-sections for the production of charmed particles can be predicted from known uncharmed reactions. (author)

Paleoecologic Implications of Ichnofossils Associated with Slightly Skeletonized Body Fossils, Middle Cambrian of the Barrandian Area, Czech Republic

Czech Academy of Sciences Publication Activity Database

Mikuláš, Radek; Fatka, O.; Szabad, M.

2012-01-01

Roč. 19, č. 4 (2012), s. 199-210 ISSN 1042-0940 R&D Projects: GA ČR GA205/09/1521 Institutional support: RVO:67985831 Keywords : Middle Cambrian * ichnofossils * slightly skeletonized fauna * Barrandian area Subject RIV: DB - Geology ; Mineralogy Impact factor: 0.727, year: 2012

On exotic hybrid meson production in γ*γ collisions

International Nuclear Information System (INIS)

Anikin, I.V.; Teryaev, O.V.; Pire, B.; Szymanowski, L.; Universite de Liege; Paris-11 Univ., 91 - Orsay; Wallon, S.

2006-01-01

We present a theoretical study of exotic hybrid meson (J PC =1 -+ ) production in photon-photon collisions where one of the photons is deeply virtual, including twist two and twist three contributions. We calculate the cross section of this process, which turns out to be large enough to imply sizeable counting rates in the present high luminosity electron-positron colliders. We emphasize the importance of the πη decay channel for the detection of the hybrid meson candidate π 1 (1400) and calculate the cross section and the angular distribution for πη pair production in the unpolarized case. This angular distribution is a useful tool for disentangling the hybrid meson signal from the background. Finally, we calculate the single spin asymmetry associated with one initial longitudinally polarized lepton. (orig.)

Relative rates of B meson decays into psi(2S) and J/psi mesons

OpenAIRE

Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T.; Aguilo, E.; Ahn, S. H.; Ahsan, M.; Alexeev, G. D.; Alkhazov, G.; Alton, A.; Alverson, G.; Alves, G. A.; Anastasoaie, M.

2009-01-01

We report on a study of the relative rates of B meson decays into ψ(2S) and J/ψ mesons using 1.3  fb-1 of pp̅ collisions at √s=1.96  TeV recorded by the D0 detector operating at the Fermilab Tevatron Collider. We observe the channels Bs0→ψ(2S)ϕ, Bs0→J/ψϕ, B±→ψ(2S)K±, and B±→J/ψK± and we measure the relative branching fractions for these channels to be B(Bs0→ψ(2S)ϕ)/B(Bs0→J/ψϕ)=0.53±0.10(stat)±0.07(syst)±0.06(B), B(B±→ψ(2S)K±)/B(B±→J/ψK±)=0.63±0.05(stat)±0.03(syst)±0.07(B),where the final erro...

Chiral symmetry breaking and the spin content of the {rho} and {rho}{sup '} mesons

Energy Technology Data Exchange (ETDEWEB)

Glozman, L.Ya., E-mail: leonid.glozman@uni-graz.at [Institut fuer Physik, FB Theoretische Physik, Universitaet Graz, A-8010 Graz (Austria); Lang, C.B., E-mail: christian.lang@uni-graz.at [Institut fuer Physik, FB Theoretische Physik, Universitaet Graz, A-8010 Graz (Austria); Limmer, M., E-mail: markus.limmer@uni-graz.at [Institut fuer Physik, FB Theoretische Physik, Universitaet Graz, A-8010 Graz (Austria)

2011-11-03

Using interpolators with different SU(2){sub L}xSU(2){sub R} transformation properties we study the chiral symmetry and spin contents of the {rho} and {rho}{sup '} mesons in lattice simulations with dynamical quarks. A ratio of couplings of the q-bar {gamma}{sup i}{tau}q and q-bar {sigma}{sup 0}i{tau}q interpolators to a given meson state at different resolution scales tells one about the degree of chiral symmetry breaking in the meson wave function at these scales. Using a Gaussian gauge invariant smearing of the quark fields in the interpolators, we are able to extract the chiral content of mesons up to the infrared resolution of {approx}1 fm. In the ground state {rho} meson the chiral symmetry is strongly broken with comparable contributions of both the (0,1)+(1,0) and (1/2,1/2){sub b} chiral representations with the former being the leading contribution. In contrast, in the {rho}{sup '} meson the degree of chiral symmetry breaking is manifestly smaller and the leading representation is (1/2,1/2){sub b}. Using a unitary transformation from the chiral basis to the {sup 2S+1}L{sub J} basis, we are able to define and measure the angular momentum content of mesons in the rest frame. This definition is different from the traditional one which uses parton distributions in the infinite momentum frame. The {rho} meson is practically a {sup 3}S{sub 1} state with no obvious trace of a 'spin crisis'. The {rho}{sup '} meson has a sizeable contribution of the {sup 3}D{sub 1} wave, which implies that the {rho}{sup '} meson cannot be considered as a pure radial excitation of the {rho} meson.

The anatomy, taphonomy, taxonomy and systematic affinity of Markuelia: Early Cambrian to Early Ordovician scalidophorans

Science.gov (United States)

Dong, X.-P.; Bengtson, S.; Gostling, N.J.; Cunningham, J.A.; Harvey, T.H.P.; Kouchinsky, A.; Val'Kov, A.K.; Repetski, J.E.; Stampanoni, M.; Marone, F.; Donoghue, P.C.J.

2010-01-01

Markuelia is a vermiform, annulated introvertan animal known as embryonic fossils from the Lower Cambrian to Lower Ordovician. Analysis of an expanded and revised dataset for Introverta shows that the precise position of Markuelia within this clade is dependent on the taxa included. As a result, Markuelia is assigned to the scalidophoran total group to reflect uncertainty as to whether it is a stem-scalidophoran or a stem-priapulid. The taxonomy of the genus is revised to provide an improved taxonomic framework for material assigned to Markuelia. Five species are recognized: M. secunda Val'kov, M. hunanensis Dong and Donoghue, M. lauriei Haug et al., M. spinulifera sp. nov. and M. waloszeki sp. nov. Finally, the preservation of Markuelia is evaluated in the light of both the taphonomy of the fossil embryos themselves and the experimental taphonomy of the priapulid Priapulus caudatus, which has been proposed as both a close relative and an anatomical analogue of Markuelia. ?? The Palaeontological Association.

Semileptonic decays of the B{sub c} meson

Energy Technology Data Exchange (ETDEWEB)

Barik, N [Department of Physics, Utkal University, Bhubaneswar-751004 (India); Naimuddin, Sk [Department of Physics, Maharishi College of Natural Law, Bhubaneswar-751007 (India); Dash, P C [Department of Physics, Prananath Autonomous College, Khurda-752057 (India); Kar, Susmita [Department of Physics, North Orissa University, Baripada-757003 (India)

2009-10-01

We study the semileptonic transitions B{sub c}{yields}{eta}{sub c},J/{psi},D,D*,B,B*,B{sub s},B{sub s}* in the leading order in the framework of a relativistic independent quark model based on a confining potential in the equally mixed scalar-vector harmonic form. We compute relevant weak form factors as overlap integrals of the meson-wave functions obtained in the relativistic independent quark model in the whole accessible kinematical range. We predict that the semileptonic transitions of the B{sub c} meson are mostly dominated by two Cabibbo-Kobayashi-Maskawa (CKM)-favored modes, B{sub c}{yields}B{sub s}(B{sub s}*)e{nu}, contributing about 77% of the total decay width, and its decays to vector meson final states take place in the predominantly transverse mode. Our predicted values for the total decay rates, branching ratios, polarization ratios, the forward-backward asymmetry factor, etc., are broadly in agreement with other model predictions.

Mesonic and baryonic Regge trajectories with quantized masses

International Nuclear Information System (INIS)

Hothi, N.; Bisht, S.

2011-01-01

We have constructed some Regge trajectories for mesons and baryons by taking the 70 MeV spinless mass quanta as the ultimate building block for the light hadrons. In order to make masses integral multiples of seventy, small changes in masses has been made with due explanation. We have shown how a linear relationship between J and M 2 is maintained by considering quantized hadron masses, which is a direct consequence of the string model and gives a strong clue for quark confinement. It has also been established that mesons and baryons have different slopes and the slopes of baryons is less than the slope of the mesons. This clearly defies the concept of universality of slopes (α ≅ 1.1 GeV 2 ) of hadrons, which can only be achieved if the strings joining the quarks have constant string tension α 1/(2πω) (where ω is the string tension). (author)

Light Scalar Mesons in Central Production at COMPASS

CERN Document Server

Austregesilo, A.

2016-01-01

COMPASS is a fixed-target experiment at the CERN SPS that studies the spectrum of light-quark hadrons. In 2009, it collected a large dataset using a $190\\,$GeV$/c$ positive hadron beam impinging on a liquid-hydrogen target in order to measure the central exclusive production of light scalar mesons. One of the goals is the search for so-called glueballs, which are hypothetical meson-like objects without valence-quark content. We study the decay of neutral resonances by selecting centrally produced pion pairs from the COMPASS dataset. The angular distributions of the two pseudoscalar mesons are decomposed in terms of partial waves, where particular attention is paid to the inherent mathematical ambiguities. The large dataset allows us to perform a detailed analysis in bins of the two squared four-momentum transfers carried by the exchange particles in the reaction. Possible parameterisations of the mass dependence of the partial-wave amplitudes in terms of resonances are also discussed.

Microscopic nuclear structure calculations with modern meson-exchange potentials

International Nuclear Information System (INIS)

Hjort-Jensen, M.; Osnes, E.; Muether, H.; Schmid, K.W.; Kuo, T.T.S.

1990-07-01

The report presents the results of microscopic nuclear shell-model calculations using three different nucleon-nucleon potentials. These are the phenomenological Reid-Soft-Core potential and the meson-exchange potentials of the Paris and the Bonn groups. It is found that the Bonn potential yields sd-shell matrix elements which are more attractive than those obtained with the Reid or the Paris potentials. The harmonic-oscillator matrix elements of the Bonn potential are also in better agreement with the empirically derived matrix elements of Wildenthal. The implications are discussed. 27 refs., 4 figs., 1 tab

Exclusive meson production at COMPASS

CERN Document Server

Pochodzalla, Josef; Moinester, Murray; Piller, Gunther; Sandacz, Andrzej; Vanderhaeghen, Marc; Pochodzalla, Josef; Mankiewicz, Lech; Moinester, Murray; Piller, Gunther; Sandacz, Andrzej; Vanderhaeghen, Marc

1999-01-01

We explore the feasibility to study exclusive meson production (EMP) in hard muon-proton scattering at the COMPASS experiment. These measurements constrain the off-forward parton distributions (OFPD's) of the proton, which are related to the quark orbital contribution to the proton spin.

Kodymirus and the case for convergence of raptorial appendages in Cambrian arthropods.

Science.gov (United States)

Lamsdell, James C; Stein, Martin; Selden, Paul A

2013-09-01

Kodymirus vagans Chlupáč and Havlíček in Sb Geol Ved Paleontol 6:7-20, 1965 is redescribed as an aglaspidid-like arthropod bearing a single pair of enlarged raptorial appendages, which are shown to be the second cephalic appendage. A number of early Palaeozoic arthropods, recognized from predominantly Cambrian Konservat-Lagerstätten, are known to have borne single pairs of large raptorial appendages. They are well established for the iconic yet problematic anomalocarids, the common megacheirans, and the ubiquitous bivalved Isoxys. Further taxa, such as fuxianhuiids and Branchiocaris, have been reported to have single pairs of specialized cephalic appendages, i.e., appendages differentiated from a largely homonomous limbs series, members of which act in metachronal motion. The homology of these raptorial appendages across these Cambrian arthropods has often been assumed, despite differences in morphology. Thus, anomalocaridids, for instance, have long multiarticulate "frontal appendages" consisting of many articles bearing an armature of paired serial spines, while megacheirans and Isoxys have short "great appendages" consisting of few articles with well-developed endites or elongate fingers. Homology of these appendages would require them to belong to the same cephalic segment. We argue based on morphological evidence that, to the contrary, the raptorial appendages of some of these taxa can be shown to belong to different cephalic segments and are the result of convergence in life habits. K. vagans is yet another important example for this, representing an instance for this morphology from a marginal marine environment.

The decays Psub(c) -> VP in the group theoretical and quark diagrammatic approaches

International Nuclear Information System (INIS)

Tuan, S.F.; Xiaoyuan Li.

1983-08-01

Decays of charmed meson into one vector meson and one pseudoscalar meson Psub(c) -> VP in both the group theoretical and quark diagrammatic approaches are considered. A complete decay amplitude analysis is given. The present available experimental data can be accomodated if the contributions from exotic final states and exotic piece of weak Hamiltonian are also taken into account. (orig.)

Investigation of Semileptonic {ital B} Meson Decays to {ital p} -Wave Charm Mesons

Energy Technology Data Exchange (ETDEWEB)

Anastassov, A.; Duboscq, J.E.; Fujino, D.; Gan, K.K.; Hart, T.; Honscheid, K.; Kagan, H.; Kass, R.; Lee, J.; Spencer, M.B.; Sung, M.; Undrus, A.; Wanke, R.; Wolf, A.; Zoeller, M.M. [Ohio State University, Columbus, Ohio 43210 (United States); Nemati, B.; Richichi, S.J.; Ross, W.R.; Skubic, P. [University of Oklahoma, Norman, Oklahoma 73019 (United States); Bishai, M.; Fast, J.; Hinson, J.W.; Menon, N.; Miller, D.H.; Shibata, E.I.; Shipsey, I.P.; Yurko, M. [Purdue University, West Lafayette, Indiana 47907 (United States); Glenn, S.; Johnson, S.D.; Kwon, Y.; Roberts, S.; Thorndike, E.H. [University of Rochester, Rochester, New York 14627 (United States); Jessop, C.P.; Lingel, K.; Marsiske, H.; Perl, M.L.; Savinov, V.; Ugolini, D.; Wang, R.; Zhou, X. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States); Coan, T.E.; Fadeyev, V.; Korolkov, I.; Maravin, Y.; Narsky, I.; Shelkov, V.; Staeck, J.; Stroynowski, R.; Volobouev, I.; Ye, J. [Southern Methodist University, Dallas, Texas 75275 (United States); Artuso, M.; Efimov, A.; Goldberg, M.; He, D.; Kopp, S.; Moneti, G.C.; Mountain, R.; Schuh, S.; Skwarnicki, T.; Stone, S.; Viehhauser, G.; Xing, X. [Syracuse University, Syracuse, New York 13244 (United States); Bartelt, J.; Csorna, S.E.; Jain, V.; McLean, K.W.; Marka, S. [Vanderbilt University, Nashville, Tennessee 37235 (United States); Godang, R.; Kinoshita, K.; Lai, I.C.; Pomianowski, P.; Schrenk, S. [Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 (United States); Bonvicini, G.; Cinabro, D.; Greene, R.; Perera, L.P.; Zhou, G.J. [Wayne State University, Detroit, Michigan 48202 (United States); Barish, B.; Chadha, M.; Chan, S.; Eigen, G.; Miller, J.S.; OGrady, C.; Schmidtler, M.; Urheim, J.; Weinstein, A.J.; Wuerthwein, F. [California Institute of Technology, Pasadena, California 91125 (United States); Bliss, D.W.; Masek, G.; Paar, H.P.; Prell, S.; Sharma, V. and others

1998-05-01

We have studied semileptonic B meson decays with a p -wave charm meson in the final state using 3.29{times}10{sup 6} B{ovr B} events collected with the CLEOII detector at the Cornell Electron-Positron Storage Ring. We find a value for the exclusive semileptonic product branching fraction B(B{sup {minus}}{r_arrow}D{sup 0}{sub 1} {ell}{sup {minus}}{ovr {nu}}{sub {ell}}) B(D{sup 0}{sub 1}{r_arrow}D{sup {asterisk}+} {pi}{sup {minus}})=(0.373{plus_minus}0.085{plus_minus} 0.052{plus_minus}0.024){percent} and an upper limit for B(B{sup {minus}}{r_arrow}D{sup {asterisk}0}{sub 2} {ell}{sup {minus}}{ovr {nu}}{sub {ell}}) B(D{sup {asterisk}0}{sub 2}{r_arrow}D{sup {asterisk}+ }{pi}{sup {minus}}){lt}0.16{percent} (90{percent} C.L.). Furthermore, we present the first measurement of the q{sup 2} spectrum for B{sup {minus}}{r_arrow}D{sup 0}{sub 1}{ell}{sup {minus}} {ovr {nu}}{sub {ell}} . {copyright} {ital 1998} {ital The American Physical Society}

Strange Meson Radiative Capture on the Proton in Low Energy QCD Lagrangian

Institute of Scientific and Technical Information of China (English)

ZHOU Li-Juan; MA Wei-Xing

2002-01-01

Based on our low energy QCD Lagrangian description of strange meson photoproduction off the protonand the crossing symmetry, the strange meson radiative capture on the proton, K- + p →γ + A, is investigated in the[SUsF (6) O(3)]sym. SUc (3) quark model of baryon structure with the same input parameter, the only strong couplingconstant aM, as that in the strange meson photoproduction off the proton γ + p → K+ + A, a crossing channel of thecapture reaction. A good agreement on the branching ratio between the predictions and data is obtained successfully.This excellent fit indicates that our low energy QCD Lagrangian theory with only one free parameter is an advancedand unified description of strange meson photoproduction and its associated radiative capture.

Holographic estimate of the meson cloud contribution to nucleon axial form factor

Science.gov (United States)

Ramalho, G.

2018-04-01

We use light-front holography to estimate the valence quark and the meson cloud contributions to the nucleon axial form factor. The free couplings of the holographic model are determined by the empirical data and by the information extracted from lattice QCD. The holographic model provides a good description of the empirical data when we consider a meson cloud mixture of about 30% in the physical nucleon state. The estimate of the valence quark contribution to the nucleon axial form factor compares well with the lattice QCD data for small pion masses. Our estimate of the meson cloud contribution to the nucleon axial form factor has a slower falloff with the square momentum transfer compared to typical estimates from quark models with meson cloud dressing.

Universal Behavior in Excited Heavy-Light and Light-Light Mesons

OpenAIRE

Olsson, M. G.

1996-01-01

A common pattern of large orbital and radial excitations in heavy-light and light-light mesons is demonstrated. Within a general potential model the Regge slopes of the light degrees of freedom for these mesons are shown to be in the ratio of two. The possibility of ``tower'' degeneracy occurs only with pure scalar confinement.

Calculation of excited vector meson electron widths using QCD sum rules

International Nuclear Information System (INIS)

Geshkenbein, B.V.

1984-01-01

The sum rules are suggested which allow one to calculate the electron widths of excited vector mesons of the PSI, UPSILON, rho meson family assuming the values of their masses to be known. The calculated values of the electron widths agree with experiment

Unitary eikonal formalism for multiproduction of isovector mesons at high energy

CERN Document Server

Redei, L B

1973-01-01

Unitary eikonal models for multiproduction of isovector mesons are discussed in general terms. A closed analytic expression is derived for the partial production cross sections and for the meson multiplicity moments. A simple class of models is discussed in more detail. (11 refs).

Asymmetries in heavy meson production from light quark fragmentation

International Nuclear Information System (INIS)

Dias de Deus, J.; Duraes, F.

2000-01-01

We discuss the possibility of the asymmetry in D - /D + production from π - beams, being a direct consequence of the properties of the light quark fragmentation function into heavy mesons. The main features of the asymmetry, as a function of x F , are easily described. An integrated sum rule for the D - , D + multiplicity difference is presented. Predictions for the asymmetry in B meson production are given. (orig.)

Tetraquark and two-meson states at large N{sub c}

Energy Technology Data Exchange (ETDEWEB)

Lucha, Wolfgang [Austrian Academy of Sciences, Institute for High Energy Physics, Vienna (Austria); Melikhov, Dmitri [Austrian Academy of Sciences, Institute for High Energy Physics, Vienna (Austria); M.V. Lomonosov Moscow State University, D.V. Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); University of Vienna, Faculty of Physics, Vienna (Austria); Sazdjian, Hagop [IPNO, Universite Paris-Sud, CNRS-IN2P3, Universite Paris-Saclay, Orsay (France)

2017-12-15

Considering four-point correlation functions of color-singlet quark bilinears, we investigate, in the large-N{sub c} limit of QCD, the subleading diagrams that involve, in the s-channel of meson-meson scattering amplitudes, two-quark-two-antiquark intermediate states. The latter contribute, together with gluon exchanges, to the formation, at the hadronic level, of two-meson and tetraquark intermediate states. It is shown that the two-meson contributions, which are predictable, in general, from leading-order N{sub c}-behaviors, consistently satisfy the constraints resulting from the 1/N{sub c} expansion procedure and thus provide a firm basis for the extraction of tetraquark properties from N{sub c}-subleading diagrams. We find that, in general, tetraquarks, if they exist in compact form, should have narrow decay widths, of the order of N{sub c}{sup -2}. For the particular case of exotic tetraquarks, involving four different quark flavors, two different types of tetraquark are needed, each having a preferred decay channel, to satisfy the consistency constraints. (orig.)

Meson thermalization by baryon injection in D4/D6 model

Science.gov (United States)

Rezaei, Z.

2016-12-01

We study meson thermalization in a strongly coupled plasma of quarks and gluons using AdS/CFT duality technique. Four dimensional large-Nc QCD is considered as a theory governing this quark-gluon plasma (QGP) and D4/D6-brane model is chosen to be its holographic dual theory. In order to investigate meson thermalization, we consider a time-dependent change of baryon number chemical potential. Thermalization in gauge theory side corresponds to horizon formation on the probe flavor brane in the gravity side. The gravitational dual theory is compactified on a circle that the inverse of its radius is proportional to energy scale of dual gauge theory. It is seen that increase of this energy scale results in thermalization time dilation. In addition we study the effect of magnetic field on meson thermalization. It will be seen that magnetic field also prolongs thermalization process by making mesons more stable.

Electromagnetic Transition Form Factor of the η meson with WASA-at-COSY

Science.gov (United States)

Goswami, A.

2016-11-01

In this work we present a study of the Dalitz decay η → γe+e-. The aim of this work is to measure the transition form factor of the η meson. The transition form factor of the η meson describes the electromagnetic structure of the meson. The study of the Dalitz decay helps to calculate the transition form factor of the η meson. When a particle is point-like it's decay rate can be calculated within QED. However, the complex structure of the meson modifies its decay rate. The transition form factor is determined by comparing the lepton-antilepton invariant mass distribution with QED. For this study data on proton-proton reaction at a beam energy of 1.4 GeV has been collected with WASA-at-COSY detector at Forschungszentrum Juelich, Germany. In the higher invariant mass region recent theoretical calculations slightly deviate from the fit to the data. We expect better results in the higher invariant mass region than previous measurements. The preliminary results of the analysis will be presented.

Electromagnetic Transition Form Factor of the η meson with WASA-at-COSY

Directory of Open Access Journals (Sweden)

Goswami A.

2016-01-01

Full Text Available In this work we present a study of the Dalitz decay η → γe+e−. The aim of this work is to measure the transition form factor of the η meson. The transition form factor of the η meson describes the electromagnetic structure of the meson. The study of the Dalitz decay helps to calculate the transition form factor of the η meson. When a particle is point-like it’s decay rate can be calculated within QED. However, the complex structure of the meson modifies its decay rate. The transition form factor is determined by comparing the lepton-antilepton invariant mass distribution with QED. For this study data on proton-proton reaction at a beam energy of 1.4 GeV has been collected with WASA-at-COSY detector at Forschungszentrum Juelich, Germany. In the higher invariant mass region recent theoretical calculations slightly deviate from the fit to the data. We expect better results in the higher invariant mass region than previous measurements. The preliminary results of the analysis will be presented.

QCD sum-rules analysis of vector (1-) heavy quarkonium meson-hybrid mixing

Science.gov (United States)

Palameta, A.; Ho, J.; Harnett, D.; Steele, T. G.

2018-02-01

We use QCD Laplace sum rules to study meson-hybrid mixing in vector (1-) heavy quarkonium. We compute the QCD cross-correlator between a heavy meson current and a heavy hybrid current within the operator product expansion. In addition to leading-order perturbation theory, we include four- and six-dimensional gluon condensate contributions as well as a six-dimensional quark condensate contribution. We construct several single and multiresonance models that take known hadron masses as inputs. We investigate which resonances couple to both currents and so exhibit meson-hybrid mixing. Compared to single resonance models that include only the ground state, we find that models that also include excited states lead to significantly improved agreement between QCD and experiment. In the charmonium sector, we find that meson-hybrid mixing is consistent with a two-resonance model consisting of the J /ψ and a 4.3 GeV resonance. In the bottomonium sector, we find evidence for meson-hybrid mixing in the ϒ (1 S ) , ϒ (2 S ), ϒ (3 S ), and ϒ (4 S ).

Study of temporal quantum correlations in decohering B and K meson systems

Science.gov (United States)

Naikoo, Javid; Alok, Ashutosh Kumar; Banerjee, Subhashish

2018-03-01

In this work we study temporal quantum correlations, quantified by Leggett-Garg (LG) and LG-type inequalities, in the B and K meson systems. We use the tools of open quantum systems to incorporate the effect of decoherence which is quantified by a single phenomenological parameter. The effect of C P violation is also included in our analysis. We find that the LG inequality is violated for both B and K meson systems, the violation being most prominent in the case of K mesons and least for Bs system. Since the systems with no coherence do not violate LGI, incorporating decoherence is expected to decrease the extent of violation of LGI and is clearly brought out in our results. We show that the expression for the LG functions depends upon an additional term, apart from the experimentally measurable meson transition probabilities. This term vanishes in the limit of zero decoherence. On the other hand, the LG-type parameter can be directly expressed in terms of transition probabilities, making it a more appropriate observable for studying temporal quantum correlations in neutral meson systems.

Production of excited charm and charm-strange mesons at HERA

International Nuclear Information System (INIS)

Chekanov, S.; Derrick, M.; Magill, S.; Musgrave, B.; Nicholass, D.; Repond, J.; Yoshida, R.; Mattingly, M.C.K.; Antonioli, P.; Bari, G.; Bellagamba, L.; Boscherini, D.; Bruni, A.; Bruni, G.; Cindolo, F.; Corradi, M.; Iacobucci, G.; Margotti, A.; Nania, R.; Polini, A.; Antonelli, S.; Basile, M.; Bindi, M.; Cifarelli, L.; Contin, A.; De Pasquale, S.; Sartorelli, G.; Zichichi, A.; Bartsch, D.; Brock, I.; Hartmann, H.; Hilger, E.; Jakob, H.P.; Juengst, M.; Nuncio-Quiroz, A.E.; Paul, E.; Samson, U.; Schoenberg, V.; Shehzadi, R.; Wlasenko, M.; Brook, N.H.; Heath, G.P.; Morris, J.D.; Capua, M.; Fazio, S.; Mastroberardino, A.; Schioppa, M.; Susinno, G.; Tassi, E.; Kim, J.Y.; Ibrahim, Z.A.; Kamaluddin, B.; Wan Abdullah, W.A.T.; Ning, Y.; Ren, Z.; Sciulli, F.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Galas, A.; Gil, M.; Olkiewicz, K.; Stopa, P.; Zawiejski, L.; Adamczyk, L.; Bold, T.; Grabowska-Bold, I.; Kisielewska, D.; Lukasik, J.; Przybycien, M.; Suszycki, L.; Kotanski, A.; Slominski, W.; Behrens, U.; Blohm, C.; Bonato, A.; Borras, K.; Ciesielski, R.; Coppola, N.; Fang, S.; Fourletova, J.; Geiser, A.; Goettlicher, P.; Grebenyuk, J.; Gregor, I.; Haas, T.; Hain, W.; Huettmann, A.; Januschek, F.; Kahle, B.; Katkov, I.I.; Klein, U.; Koetz, U.; Kowalski, H.; Lobodzinska, E.; Loehr, B.; Mankel, R.; Melzer-Pellmann, I.A.; Miglioranzi, S.; Montanari, A.; Namsoo, T.; Notz, D.; Parenti, A.; Rinaldi, L.; Roloff, P.; Rubinsky, I.; Santamarta, R.; Schneekloth, U.; Spiridonov, A.; Szuba, D.; Szuba, J.; Theedt, T.; Wolf, G.; Wrona, K.; Yaguees Molina, A.G.; Youngman, C.; Zeuner, W.; Drugakov, V.; Lohmann, W.; Schlenstedt, S.; Barbagli, G.; Gallo, E.; Pelfer, P.G.; Bamberger, A.; Dobur, D.; Karstens, F.; Vlasov, N.N.; Bussey, P.J.; Doyle, A.T.; Dunne, W.; Forrest, M.; Rosin, M.; Saxon, D.H.; Skillicorn, I.O.; Gialas, I.; Papageorgiu, K.; Holm, U.; Klanner, R.; Lohrmann, E.; Schleper, P.; Schoerner-Sadenius, T.; Sztuk, J.; Stadie, H.; Turcato, M.; Foudas, C.; Fry, C.; Long, K.R.; Tapper, A.D.; Matsumoto, T.; Nagano, K.; Tokushuku, K.; Yamada, S.; Yamazaki, Y.; Barakbaev, A.N.; Boos, E.G.; Pokrovskiy, N.S.; Zhautykov, B.O.; Aushev, V.; Bachynska, O.; Borodin, M.; Kadenko, I.; Kozulia, A.; Libov, V.; Lisovyi, M.; Lontkovskyi, D.; Makarenko, I.; Sorokin, I.; Verbytskyi, A.; Volynets, O.; Son, D.; Favereau, J. de; Piotrzkowski, K.; Barreiro, F.; Glasman, C.; Jimenez, M.; Labarga, L.; Peso, J. del; Ron, E.; Soares, M.; Terron, J.; Zambrana, M.; Corriveau, F.; Liu, C.; Schwartz, J.; Walsh, R.; Zhou, C.; Tsurugai, T.; Antonov, A.; Dolgoshein, B.A.; Gladkov, D.; Sosnovtsev, V.; Stifutkin, A.; Suchkov, S.; Dementiev, R.K.; Ermolov, P.F.; Gladilin, L.K.; Golubkov, Yu.A.; Khein, L.A.; Korzhavina, I.A.; Kuzmin, V.A.; Levchenko, B.B.; Lukina, O.Yu.; Proskuryakov, A.S.; Shcheglova, L.M.; Zotkin, D.S.; Abt, I.; Caldwell, A.; Kollar, D.; Reisert, B.; Schmidke, W.B.; Grigorescu, G.; Keramidas, A.; Koffeman, E.; Kooijman, P.; Pellegrino, A.; Tiecke, H.; Vazquez, M.; Wiggers, L.; Bruemmer, N.; Bylsma, B.; Durkin, L.S.; Lee, A.; Ling, T.Y.; Allfrey, P.D.; Bell, M.A.; Cooper-Sarkar, A.M.; Devenish, R.C.E.; Ferrando, J.; Foster, B.; Korcsak-Gorzo, K.; Oliver, K.; Robertson, A.; Uribe-Estrada, C.; Walczak, R.; Bertolin, A.; Dal Corso, F.; Dusini, S.; Longhin, A.; Stanco, L.; Bellan, P.; Brugnera, R.; Carlin, R.; Garfagnini, A.; Limentani, S.; Oh, B.Y.; Raval, A.; Ukleja, J.; Whitmore, J.J.; Iga, Y.; D'Agostini, G.; Marini, G.; Nigro, A.; Cole, J.E.; Hart, J.C.

2009-01-01

The production of excited charm, D 1 (2420) 0 and D 2 * (2460) 0 , and charm-strange, D s 1(2536) ± , mesons in ep collisions was measured with the ZEUS detector at HERA using an integrated luminosity of 126 pb -1 . Masses, widths and helicity parameters were determined. The measured yields were converted to the rates of c quarks hadronising as a given excited charm meson and to the ratios of the dominant D 2 * (2460) 0 and D s1 (2536) ± branching fractions. A search for the radially excited charm meson, D *' (2640) ± , was also performed. The results are compared with those measured previously and with theoretical expectations. (orig.)

The Chiral and Angular Momentum Content of the ρ-Meson

Science.gov (United States)

Glozman, L. Ya.; Lang, C. B.; Limmer, M.

2010-01-01

It is possible to define and calculate in a gauge-invariant manner the chiral as well as the partial wave content of the quark-antiquark Fock component of a meson in the infrared, where mass is generated. Using the variational method and a set of interpolators that span a complete chiral basis we extract in a lattice QCD Monte Carlo simulation with n f = 2 dynamical light quarks the orbital angular momentum and spin content of the ρ-meson. We obtain in the infrared a simple 3 S 1 component as a leading component of the ρ-meson with a small admixture of the 3 D 1 partial wave, in agreement with the SU(6) flavor-spin symmetry.

Non-leptonic weak decay rate of explicitly flavored heavy mesons

International Nuclear Information System (INIS)

Suzuki, M.; California Univ., Berkeley

1981-01-01

It is argued quantitatively that a large difference between the D 0 and D + lifetimes is mainly due to non-perturbative long-distance effects. The total non-leptonic weak decay rates are related to the soft limit of short-distance processes. Scaling laws for the decay rates of heavy mesons with respect to mass are inferred from the QCD analysis of the soft limit of fragmentation. It is found that the decay rates are not determined by the disconnected spectator diagrams alone even in the limit of the heavy quark mass M Going to infinity ( 5 exp √ c log M. Some numerical discussion is made for the decay of B mesons and T mesons. (orig.)

Production of excited charm and charm-strange mesons at HERA

International Nuclear Information System (INIS)

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

2008-07-01

The production of excited charm, D 1 (2420) 0 and D * 2 (2460) 0 , and charm-strange, D s1 (2536) ± , mesons in ep collisions was measured with the ZEUS detector at HERA using an integrated luminosity of 126 pb -1 . Masses, widths and helicity parameters were determined. The measured yields were converted to the rates of c quarks hadronising as a given excited charm meson and to the ratios of the dominant D * 2 (2460) 0 and D s1 (2536) ± branching fractions. A search for the radially excited charm meson, D *' (2640) ± , was also performed. The results are compared with those measured previously and with theoretical expectations. (orig.)

Baryon and meson phenomenology in the extended Linear Sigma Model

Energy Technology Data Exchange (ETDEWEB)

Giacosa, Francesco; Habersetzer, Anja; Teilab, Khaled; Eshraim, Walaa; Divotgey, Florian; Olbrich, Lisa; Gallas, Susanna; Wolkanowski, Thomas; Janowski, Stanislaus; Heinz, Achim; Deinet, Werner; Rischke, Dirk H. [Institute for Theoretical Physics, J. W. Goethe University, Max-von-Laue-Str. 1, 60438 Frankfurt am Main (Germany); Kovacs, Peter; Wolf, Gyuri [Institute for Particle and Nuclear Physics, Wigner Research Center for Physics, Hungarian Academy of Sciences, H-1525 Budapest (Hungary); Parganlija, Denis [Institute for Theoretical Physics, Vienna University of Technology, Wiedner Hauptstr. 8-10, A-1040 Vienna (Austria)

2014-07-01

The vacuum phenomenology obtained within the so-called extended Linear Sigma Model (eLSM) is presented. The eLSM Lagrangian is constructed by including from the very beginning vector and axial-vector d.o.f., and by requiring dilatation invariance and chiral symmetry. After a general introduction of the approach, particular attention is devoted to the latest results. In the mesonic sector the strong decays of the scalar and the pseudoscalar glueballs, the weak decays of the tau lepton into vector and axial-vector mesons, and the description of masses and decays of charmed mesons are shown. In the baryonic sector the omega production in proton-proton scattering and the inclusion of baryons with strangeness are described.

Lack of inhibiting effect of oil emplacement on quartz cementation: Evidence from Cambrian reservoir sandstones, Paleozoic Baltic Basin

DEFF Research Database (Denmark)

Molenaar, Nicolaas; Cyziene, Jolanta; Sliaupa, Saulius

2008-01-01

Currently, the question of whether or not the presence of oil in sandstone inhibits quartz cementation and preserves porosity is still debated. Data from a number of Cambrian sandstone oil fields and dry fields have been studied to determine the effects of oil emplacement on quartz cementation. T...

Effective meson lagrangian with chiral and heavy quark symmetries from quark flavor dynamics

International Nuclear Information System (INIS)

Ebert, D.; Feldmann, T.; Friedrich, R.; Reinhardt, H.

1994-06-01

By bosonization of an extended NJL model we derive an effective meson theory which describes the interplay between chiral symmetry and heavy quark dynamics. This effective theory is worked out in the low-energy regime using the gradient expansion. The resulting effective lagrangian describes strong and weak interactions of heavy B and D mesons with pseudoscalar Goldstone bosons and light vector and axial-vector mesons. Heavy meson weak decay constants, coupling constants and the Isgur-Wise function are predicted in terms of the model parameters partially fixed from the light quark sector. Explicit SU(3) F symmetry breaking effects are estimated and, if possible, confronted with experiment. (orig.)

Decay of the Bottom mesons

International Nuclear Information System (INIS)

Duong Van Phi; Duong Anh Duc

1992-12-01

The channels of the decay of Bottom mesons are deduced from a selection rule and the Lagrangians which are formed on the LxO(4) invariance and the principle of minimal structure. The estimation of the corresponding decay probabilities are considered. (author). 21 refs

Distribution amplitudes of vector mesons

Energy Technology Data Exchange (ETDEWEB)

Braun, V.M. [Regensburg Univ. (Germany). Inst. fuer Theoretische Physik; Broemmel, D. [Deutsches Elektronen-Synchrotron, Hamburg (Germany); Goeckeler, M. [Regensburg Univ. (DE). Inst. fuer Theoretische Physik] (and others)

2007-11-15

Results are presented for the lowest moment of the distribution amplitude for the K{sup *} vector meson. Both longitudinal and transverse moments are investigated. We use two flavours of O(a) improved Wilson fermions, together with a non-perturbative renormalisation of the matrix element. (orig.)

Spontaneous symmetry breaking and vector-meson dominance

International Nuclear Information System (INIS)

Caldi, D.G.; Pagels, H.

1977-01-01

This article is a continuation of our previous work on the rho-π puzzle. It examines further consequences of the unification of partial conservation of axial-vector current (PCAC) and vector-meson dominance (VMD) in which the pion is a Goldstone state and the rho is a ''dormant'' Goldstone state. Our new picture of the vector mesons does not require an A 1 meson although such a state is not ruled out. The Weinberg sum rules which provide the raison d'etre for the A 1 are reexamined. The first Weinberg sum rule can be accommodated without a narrow A 1 state although some enhancement seems required. Examining the J/sup P C/ = 1 +- nonet we conclude that a new state, the isoscalar octet partner of the B (1235) should exist around 1.7 GeV assuming ideal mixing. Without a detailed assumption on the mixing angle, its mass should be in the range 1.4 to 1.7 GeV. We also discuss the photon-rho interactions. In the standard VMD picture the predicted rate for rho → π + γ fails by five standard deviations, while in our picture this undesired result is averted

Search for Neutrinoless τ Decays Involving π0 or η Mesons

International Nuclear Information System (INIS)

Bonvicini, G.; Cinabro, D.; Greene, R.; Perera, L.P.; Zhou, G.J.; Barish, B.; Chadha, M.; Chan, S.; Eigen, G.; Miller, J.S.; OGrady, C.; Schmidtler, M.; Urheim, J.; Weinstein, A.J.; Wuerthwein, F.; Asner, D.M.; Bliss, D.W.; Brower, W.S.; Masek, G.; Paar, H.P.; Prell, S.; Sharma, V.; Gronberg, J.; Hill, T.S.; Kutschke, R.; Lange, D.J.; Menary, S.; Morrison, R.J.; Nelson, H.N.; Nelson, T.K.; Qiao, C.; Richman, J.D.; Roberts, D.; Ryd, A.; Witherell, M.S.; Balest, R.; Behrens, B.H.; Cho, K.; Ford, W.T.; Park, H.; Rankin, P.; Roy, J.; Smith, J.G.; Alexander, J.P.; Bebek, C.; Berger, B.E.; Berkelman, K.; Bloom, K.; Cassel, D.G.; Cho, H.A.; Coffman, D.M.; Crowcroft, D.S.; Dickson, M.; Drell, P.S.; Ecklund, K.M.; Ehrlich, R.; Elia, R.; Foland, A.D.; Gaidarev, P.; Galik, R.S.; Gittelman, B.; Gray, S.W.; Hartill, D.L.; Heltsley, B.K.; Hopman, P.I.; Kandaswamy, J.; Kim, P.C.; Kreinick, D.L.; Lee, T.; Liu, Y.; Ludwig, G.S.; Masui, J.; Mevissen, J.; Mistry, N.B.; Ng, C.R.; Nordberg, E.; Ogg, M.; Patterson, J.R.; Peterson, D.; Riley, D.; Soffer, A.; Valant-Spaight, B.; Ward, C.; Athanas, M.; Avery, P.; Jones, C.D.; Lohner, M.; Prescott, C.; Yelton, J.; Zheng, J.; Brandenburg, G.; Briere, R.A.; Gao, Y.S.; Kim, D.Y.; Wilson, R.; Yamamoto, H.; Browder, T.E.; Li, F.; Li, Y.; Rodriguez, J.L.; Bergfeld, T.; Eisenstein, B.I.; Ernst, J.

1997-01-01

We have searched for lepton flavor violating decays of the τ lepton using final states with an electron or a muon and one or two π 0 or η mesons but no neutrinos. The data used in the search were collected with the CLEO II detector at the Cornell Electron Storage Ring (CESR) and correspond to an integrated luminosity of 4.68 fb -1 . No evidence for signals was found, resulting in much improved limits on the branching fractions for the one-meson modes and the first upper limits for the two-meson modes. copyright 1997 The American Physical Society

Subtracted Dispersion Relations for In-medium Meson Correlators in QCD Sum Rules

Energy Technology Data Exchange (ETDEWEB)

Florkowski, W; Broniowski, W [The H. Niewodniczanski Institute of Nuclear Physics, Cracow (Poland)

1999-01-01

We analyze subtracted dispersion relations for meson correlators at finite baryon density and temperature. Such relations are needed for QCD sum rules. We point out that importance of scattering terms, as well as finite, well-defined subtraction constants. Both are necessary for consistency, in particular for the equality of the longitudinal and transverse correlators in the limit of the vanishing three-momentum of mesons relative to the medium. We present detailed calculations in various mesonic channels of the Fermi gas of nucleons. (author)

Exclusive semileptonic decays of charmed and b-flavored mesons

International Nuclear Information System (INIS)

Barik, N.; Tripathy, S.K.; Kar, S.; Dash, P.C.

1997-01-01

We investigate the exclusive semileptonic decays of (B,B s ;D,D s ) mesons into less heavy as well as light mesons in a field-theoretic framework based on the independent quark model with a confining potential in scalar-vector-harmonic form. With the recoil effect properly taken into account, the present model describes consistently the semileptonic decays of charmed and b-flavored mesons, agreeing well with the experimental data. The transition form factors in the heavy to heavy decays, in particular, comply with the heavy quark symmetry relations expected from HQET. The CKM parameters extracted in this formalism are close to the existing data. The model prediction also satisfies the Isgur-Wise relation connecting the form factors of the semileptonic (B→ρeν) and that of rare radiative decay (B→ργ). copyright 1997 The American Physical Society

A phenomenological analysis of non-resonant charm meson decays

Energy Technology Data Exchange (ETDEWEB)

Bediaga, I.; Goebel, C. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Mendez-Galain, R. [Montevideo Univ. (Uruguay). Facultad de Ingenieria

1997-07-01

We analyse the consequences of the usual assumption of a constant function to fit non-resonant decays from experimental Dalitz plot describing charmed meson decays. We first show, using the D{sup +} -> K{sup 0} {pi}{sup +} {pi}{sup 0} decay channel as an example, how an inadequate extraction of the non-resonant contribution could yield incorrect measurements for the resonant channels. We analyse how the correct study of this decay will provide a test for the validity of factorization in D meson decays. Finally, we show how form factors that can be measured from the D{sup +}{sub s} -> {pi}{sup -} {pi}{sup +} {pi}{sup +} decay. We emphasize its relevance for the study of the decay {tau} -> v{sub t} 3{pi} and the extraction of the {alpha}{sub 1} meson width. (author) 26 refs., 6 figs.

High statistics inclusive phi-meson production at SPS energies

International Nuclear Information System (INIS)

Dijkstra, H.B.

1985-01-01

This thesis describes an experiment studying the inclusive reaction hadron + Be → phi + anything → K + + K - + anything in 100 GeV/c, 120 GeV/c and 200 GeV/c hadron interactions. A total of 8x10 6 events were recorded using both positively and negatively charged unseparated hadron beams supplied by the CERN SPS. The experiment made use of an intelligent on-line event selection system based on micro-processors (FAMPs) in conjunction with a system of large MWPCs to increase the number of phi-events recorded per unit time. In 32 days of data taking over 600,000 phi-mesons were recorded onto magnetic tape. The physics motivation for collecting a large statistics sample of inclusive phi-mesons was the investigation of the inclusive phi-meson production mechanism and phi-spectroscopy. (Auth.)

Charmless decays of the B-meson in perturbative QCD

International Nuclear Information System (INIS)

Libo Guo; Dongsheng Du; Lianshou Liu

1999-01-01

Using the perturbative QCD method and Chau's six-quark-graph scheme, we report a theoretical calculation of exclusive nonleptonic decays of the B meson into two light pseudoscalar mesons in the context of the low-energy effective Hamiltonian. The contributions from both tree-level and one-loop diagrams are taken into account. Under the approximation of neglecting light quark and light meson masses, we find that (i) within perturbative QCD there is no singularity which exists in the computation of spacelike penguin diagrams when the BSW model is used; (ii) the contributions from spacelike-type (W-annihilation, W-exchange, spacelike penguin and penguin-annihilation) graphs are strongly suppressed relative to those from timelike-type (external W-emission, internal W-emission and timelike penguin) ones; (iii) our results are well below the experimental upper limits but lower than the BSW ones. (author)

Current status of high energy nucleon-meson transport code

Energy Technology Data Exchange (ETDEWEB)

Takada, Hiroshi; Sasa, Toshinobu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1998-03-01

Current status of design code of accelerator (NMTC/JAERI code), outline of physical model and evaluation of accuracy of code were reported. To evaluate the nuclear performance of accelerator and strong spallation neutron origin, the nuclear reaction between high energy proton and target nuclide and behaviors of various produced particles are necessary. The nuclear design of spallation neutron system used a calculation code system connected the high energy nucleon{center_dot}meson transport code and the neutron{center_dot}photon transport code. NMTC/JAERI is described by the particle evaporation process under consideration of competition reaction of intranuclear cascade and fission process. Particle transport calculation was carried out for proton, neutron, {pi}- and {mu}-meson. To verify and improve accuracy of high energy nucleon-meson transport code, data of spallation and spallation neutron fragment by the integral experiment were collected. (S.Y.)

Lifetime of rho meson in correlation with magnetic-dimensional reduction

Energy Technology Data Exchange (ETDEWEB)

Kawaguchi, Mamiya [Nagoya University, Department of Physics, Nagoya (Japan); Matsuzaki, Shinya [Nagoya University, Department of Physics, Nagoya (Japan); Nagoya University, Institute for Advanced Research, Nagoya (Japan)

2017-04-15

It is naively expected that in a strong magnetic configuration, the Landau quantization ceases the neutral rho meson to decay to the charged pion pair, so the neutral rho meson will be long-lived. To closely access this naive observation, we explicitly compute the charged pion loop in the magnetic field at the one-loop level, to evaluate the magnetic dependence of the lifetime for the neutral rho meson as well as its mass. Due to the dimensional reduction induced by the magnetic field (violation of the Lorentz invariance), the polarization (spin s{sub z} = 0, ±1) modes of the rho meson, as well as the corresponding pole mass and width, are decomposed in a nontrivial manner compared to the vacuum case. To see the significance of the reduction effect, we simply take the lowest Landau level approximation to analyze the spin-dependent rho masses and widths. We find that the ''fate'' of the rho meson may be more complicated because of the magnetic-dimensional reduction: as the magnetic field increases, the rho width for the spin s{sub z} = 0 starts to develop, reaches a peak, then vanishes at the critical magnetic field to which the folklore refers. On the other side, the decay rates of the other rhos for s{sub z} = ±1 monotonically increase as the magnetic field develops. The correlation between the polarization dependence and the Landau level truncation is also addressed. (orig.)

Measurement of the production of K{sup +} mesons by protons in nuclei (1960); Mesure de la production des mesons K{sup +} par des protons dans les noyaux (1960)

Energy Technology Data Exchange (ETDEWEB)

Teiger, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1960-07-01

K{sup +} mesons produced by the internal proton beam of Saturne have been identified by means of scintillation and Cerenkov counters. The production cross sections are given per target nucleus measured at a laboratory angle of 35 deg. as well as the cross section relative to {pi}{sup +} mesons of the same momentum for: - incident protons of kinetic energy between 1.3 and 2.8 GeV, - targets of C, Cu and Pb, - K{sup +} produced with kinetic energies between 0.45 and 0.65 GeV. From these results we have tried to deduce the importance of indirect production by intermediate {pi} mesons with respect to direct production by proton-nucleon collisions. (author) [French] Au moyen de detecteurs a scintillations et a rayonnement Cerenkov, on a identifie les mesons lourds K{sup +} produits par les protons du faisceau interne de 'Saturne'. On donne les sections efficaces de production, par noyau cible, mesurees a 35 deg. dans le laboratoire, ainsi que les sections efficaces relatives par rapport aux mesons {pi}{sup +} de meme impulsion pour: - des protons incidents d'energie cinetique entre 1,3 GeV et 2,8 GeV, - des cibles de C, de Cu et de Pb, - des K{sup +} produits avec des energies cinetiques entre 0,45 et 0,65 GeV. De ces resultats, on a essaye de deduire l'importance de la production indirecte, par mesons {pi} intermediaires, par rapport a la production directe dans un choc proton-nucleon. (auteur)

Semileptonic decays of strange beauty mesons at Belle

Energy Technology Data Exchange (ETDEWEB)

Oswald, Christian

2015-06-19

Semileptonic decays of b-flavoured mesons are an important tool for the determination of the CKM matrix element vertical stroke V{sub cb} vertical stroke. In this thesis, measurements of semileptonic B{sub s} meson decays are presented. They provide complementary information to the precision measurements of B meson decays and serve as a test of QCD-calculations predicting SU(3) flavour symmetry for the partial decay widths and form factors. The semi-inclusive and inclusive analyses of semileptonic B{sub s} decays are based on the 121.4 fb{sup -1} dataset collected by the Belle detector at the KEKB asymmetric-energy e{sup +}e{sup -} collider in Tsukuba, Japan. The sample recorded at a centre-of-mass energy √(s)=10.86 GeV, which corresponds to the Y(5S) resonance, contains (7.1±1.3) million B{sub s} pair events. To measure the semi-inclusive B{sub s} → D{sub s}Xlν and B{sub s} → D{sub s}{sup *}Xlν branching fractions, D{sub s} and D{sub s}{sup *} candidates are reconstructed and are paired with an oppositely charged lepton, l{sup +}=e{sup +},μ{sup +}. The yields of correctly reconstructed D{sub s} and D{sub s}{sup *} mesons are determined by fits to their respective invariant mass distributions. The signal yield and the yields of the remaining backgrounds are extracted using kinematic distributions of the reconstructed decay products and the constraint from the known initial state of the e{sup +}e{sup -} collision. The measured branching fractions are: B(B{sub s} → D{sub s}Xlν)=(8.2±0.2(stat)±0.6(syst)±1.4(ext)) % and B(B{sub s} → D{sub s}{sup *}lν)=(5.4±0.4(stat)±0.4(syst)±0.9 (ext)) %, where the first two uncertainties are the statistical and systematic uncertainties of the measurement and the last uncertainty is due to external parameters. Making an assumption about the B{sub s} → D{sub s}Xlν branching fraction, the measurement of the B{sub s} → D{sub s}Xlν yield is also used to obtain the current best estimate of the B{sub s} pair

Strange Meson Radiative Capture on the Proton in Low Energy QCD Lagrangian

Institute of Scientific and Technical Information of China (English)

ZHOULi－Juan; MAWei－Xing; 等

2002-01-01

Based on our low energy QCD Lagrangian description of strange meson photoproduction off the proton and the crossing symmetry,the strange meson radiative capture on the proton,K-+p→γ+A,is investigated in the [SU SF(6)×O(3)]sym,SUc(3) quark model of baryon structure with the same input parameter,the only strong coupling constant αM,as that in the strange meson photoproduction off the proton γ+p-→K+ Α，a crossing channel of the capture reaction,A good agreement on the branching ratio between the predictions and data is obtained successfully.This excellent fit indicates that our low energy QCD Lagrangian theory with only one free parameter is an advanced and unified description of strange meson photoproduction and its associated radiative capture.

Heavy quark fragmentation functions for D-wave quarkonium and charmed beauty mesons

International Nuclear Information System (INIS)

Cheung, K.; Yuan, T.C.

1995-09-01

At the large transverse momentum region, the production of heavy-heavy bound-states such as charmonium, bottomonium, and anti bc mesons in high energy e + e - and hadronic collisions is dominated by parton fragmentation. The authors calculate the heavy quark fragmentation functions into the D-wave quarkonium and anti bc mesons to leading order in the strong coupling constant and in the non-relativistic expansion. In the anti bc meson case, one set of its D-wave states is expected to lie below the open flavor threshold. The total fragmentation probability for a anti b antiquark to split into the D-wave anti bc mesons is about 2 x 10 -5 , which implies that only 2% of the total pseudo-scalar ground state B c comes from the cascades of these orbitally excited states

Meson-baryon coupling constants from a chiral-invariant SU(3) Lagrangian and application to NN scattering

International Nuclear Information System (INIS)

Stoks, V.G.J.

1997-01-01

We present a chiral-invariant meson-baryon Lagrangian which describes the interactions of the baryon octet with the lowest-mass meson nonets. The nonlinear realization of the chiral symmetry generates pair-meson interaction vertices. The corresponding pair-meson coupling constants can all be expressed in terms of the meson-nucleon-nucleon pseudovector, scalar, and vector coupling constants, and their corresponding F/(F+D) ratios, and for which empirical estimates are given. We show that it is possible to construct an NN potential of reasonable quality satisfying these theoretical and empirical constraints. (orig.)

Mass shift of σ-meson in nuclear matter

International Nuclear Information System (INIS)

Morones-Ibarra, J.R.; Maciel, Mónica Menchaca; Padilla, Felipe Robledo; Santos-Guevara, Ayax

2013-01-01

The propagation of σ-meson in nuclear matter is studied in the Walecka model, by assuming that sigma couples to a pair of nucleon-antinucleon states to particle-hole states. The in-medium effect of σ-ω mixing is also studied. For completeness, the coupling of sigma to two virtual pions was also considered. It is found that the σ-meson mass decreases with respect to its value in vacuum and that the contribution of the σ-ω mixing effect on the mass shift is relatively small. (author)

Radiative decays of the Upsilon(1S) meson

International Nuclear Information System (INIS)

Besson, D.Z.

1986-01-01

Using the CLEO detector at the Cornell Electron Storage Ring, the author is able to measure the QCD scaling parameter Λ/sub MS/ as well as the strong coupling constant α/sub s/ through a measurement of the direct photon energy spectrum resulting from decays of the Upsilon(1S) meson. The author finds fair agreement with previous work. In addition, the author sets limits on exclusive two-body radiative decays of the Upsilon(1S) meson and see no evidence for the type of such two-body decays which are observed in psi decays

Meson thermalization by baryon injection in D4/D6 model

Energy Technology Data Exchange (ETDEWEB)

Rezaei, Z., E-mail: z.rezaei@aut.ac.ir [Department of Physics, Tafresh University, Tafresh 39518 79611 (Iran, Islamic Republic of); School of Particles and Accelerators, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of)

2016-12-15

We study meson thermalization in a strongly coupled plasma of quarks and gluons using AdS/CFT duality technique. Four dimensional large-N{sub c} QCD is considered as a theory governing this quark–gluon plasma (QGP) and D4/D6-brane model is chosen to be its holographic dual theory. In order to investigate meson thermalization, we consider a time-dependent change of baryon number chemical potential. Thermalization in gauge theory side corresponds to horizon formation on the probe flavor brane in the gravity side. The gravitational dual theory is compactified on a circle that the inverse of its radius is proportional to energy scale of dual gauge theory. It is seen that increase of this energy scale results in thermalization time dilation. In addition we study the effect of magnetic field on meson thermalization. It will be seen that magnetic field also prolongs thermalization process by making mesons more stable.

Meson thermalization by baryon injection in D4/D6 model

International Nuclear Information System (INIS)

Rezaei, Z.

2016-01-01

We study meson thermalization in a strongly coupled plasma of quarks and gluons using AdS/CFT duality technique. Four dimensional large-N_c QCD is considered as a theory governing this quark–gluon plasma (QGP) and D4/D6-brane model is chosen to be its holographic dual theory. In order to investigate meson thermalization, we consider a time-dependent change of baryon number chemical potential. Thermalization in gauge theory side corresponds to horizon formation on the probe flavor brane in the gravity side. The gravitational dual theory is compactified on a circle that the inverse of its radius is proportional to energy scale of dual gauge theory. It is seen that increase of this energy scale results in thermalization time dilation. In addition we study the effect of magnetic field on meson thermalization. It will be seen that magnetic field also prolongs thermalization process by making mesons more stable.

In-medium properties of pseudoscalar D_s and B_s mesons

Science.gov (United States)

Chhabra, Rahul; Kumar, Arvind

2017-11-01

We calculate the shift in the masses and decay constants of D_s(1968) and B_s(5370) mesons in hot and dense asymmetric strange hadronic matter using QCD sum rules and chiral SU(3) model. In-medium strange quark condensates _{ρ _B}, and gluon condensates _{ρ _B}, to be used in the QCD sum rules for pseudoscalar D_s and B_s mesons, are calculated using a chiral SU(3) model. As an application of our present work, we calculate the in-medium decay widths of the excited (c\\bar{s}) states D_s^*(2715) and D_s^*(2860) decaying to (D_s(1968),η ) mesons. The medium effects in their decay widths are incorporated through the mass modification of the D_s(1968) and η mesons. The results of the present investigation may be helpful in understanding the possible outcomes of the future experiments like CBM and PANDA under the FAIR facility.

Pseudoscalar Meson Electroproduction and Transversity

International Nuclear Information System (INIS)

Goldstein, G.; Liuti, S.

2011-01-01

Exclusive meson leptoproduction from nucleons in the deeply virtual exchanged boson limit can be described by generalized parton distributions (GPDs). Including spin dependence in the description requires 8 independent quark-parton and gluon-parton functions. The chiral even subset of 4 quark-nucleon GPDs are related to nucleon form factors and to parton distribution functions. The chiral odd set of 4 quark-nucleon GPDs are related to transversity, the tensor charge, and other quantities related to transversity. Different meson or photon production processes access different combinations of GPDs. This is analyzed in terms of t-channel exchange quantum numbers, J PC and it is shown that pseudoscalar production can isolate chiral odd GPDs. There is a sensitive dependence in various cross sections and asymmetries on the tensor charge of the nucleon and other transversity parameters. In a second section, analyticity and completeness are shown to limit the partonic interpret ation of the GPDs in the ERBL region.

Decay properties of charm and bottom mesons in a quantum isotonic nonlinear oscillator potential model

Energy Technology Data Exchange (ETDEWEB)

Rahmani, S.; Hassanabadi, H. [Shahrood University of Technology, Physics Department, Shahrood (Iran, Islamic Republic of)

2017-09-15

Employing generalized quantum isotonic oscillator potential we determine wave function for mesonic system in nonrelativistic formalism. Then we investigate branching ratios of leptonic decays for heavy-light mesons including a charm quark. Next, by applying the Isgur-Wise function we obtain branching ratios of semileptonic decays for mesons including a bottom quark. The weak decay of the B{sub c} meson is also analyzed to study the life time. Comparison with other available theoretical approaches is presented. (orig.)

Thermal Properties of Light Tensor Mesons via QCD Sum Rules

Directory of Open Access Journals (Sweden)

K. Azizi

2015-01-01

Full Text Available The thermal properties of f2(1270, a2(1320, and K2*(1430 light tensor mesons are investigated in the framework of QCD sum rules at finite temperature. In particular, the masses and decay constants of the light tensor mesons are calculated taking into account the new operators appearing at finite temperature. The numerical results show that, at the point at which the temperature-dependent continuum threshold vanishes, the decay constants decrease with amount of (70–85% compared to their vacuum values, while the masses diminish about (60–72% depending on the kinds of the mesons under consideration. The results obtained at zero temperature are in good consistency with the experimental data as well as the existing theoretical predictions.

Production of excited charm and charm-strange mesons at HERA

Energy Technology Data Exchange (ETDEWEB)

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

2008-07-15

The production of excited charm, D{sub 1}(2420){sup 0} and D{sup *}{sub 2}(2460){sup 0}, and charm-strange, D{sub s1}(2536){sup {+-}}, mesons in ep collisions was measured with the ZEUS detector at HERA using an integrated luminosity of 126 pb{sup -1}. Masses, widths and helicity parameters were determined. The measured yields were converted to the rates of c quarks hadronising as a given excited charm meson and to the ratios of the dominant D{sup *}{sub 2}(2460){sup 0} and D{sub s1}(2536){sup {+-}} branching fractions. A search for the radially excited charm meson, D{sup *'}(2640){sup {+-}}, was also performed. The results are compared with those measured previously and with theoretical expectations. (orig.)

Photoproduction of vector mesons in proton-proton ultraperipheral collisions at the CERN Large Hadron Collider

Science.gov (United States)

Xie, Ya-Ping; Chen, Xurong

2018-05-01

Photoproduction of vector mesons is computed with dipole model in proton-proton ultraperipheral collisions (UPCs) at the CERN Large Hadron Collider (LHC). The dipole model framework is employed in the calculations of vector mesons production in diffractive processes. Parameters of the bCGC model are refitted with the latest inclusive deep inelastic scattering experimental data. Employing the bCGC model and boosted Gaussian light-cone wave function for vector mesons, we obtain the prediction of rapidity distributions of J/ψ and ψ(2s) mesons in proton-proton ultraperipheral collisions at the LHC. The predictions give a good description of the experimental data of LHCb. Predictions of ϕ and ω mesons are also evaluated in this paper.

Proposal to measure the D meson decay constant F/sub D/

Energy Technology Data Exchange (ETDEWEB)

Deshpande, N.G.; Iskandar, D.

1978-08-01

Because the branching ratios of the purely leptonic modes of D meson are small compared to the semileptonic decays, it is suggested that the decay D ..-->.. K + l + ..nu.. might be used to deduce the value of F/sub D/, the weak decay constant of D meson. 17 references.

Remarks on semileptonic B and D decays into orbitally excited mesons

Energy Technology Data Exchange (ETDEWEB)

Mayorga, H B; Briceno, A Moreno; Munoz, J H [Departamento de Fisica, Universidad del Tolima, A. A. 546, Ibague (Colombia)

2003-09-01

We have obtained the differential decay rate and calculated the branching ratios of the exclusive semileptonic decays B(D) {yields} Xl{nu}, where X is a p-wave meson, using the nonrelativistic ISGW quark model. Our results are compared with the predictions of the ISGW2 model. We have computed some branching ratios that were not reported or were reported with 0.00 in this model. For example, we find that Br(B{sub c}{sup -} {yields} B-bar{sub s2}*{sup 0}l{sup -}{nu}-bar ) 4.03 x 10{sup -5}, Br(B{sub c}{sup -} {yields} B-bar{yields}{sub 2}*{sup 0}l{sup -} {nu}-bar ) = 3.65 x 10{sup -6} and Br(D{sup +}{sub s} {yields} f{sub 2}l{sup +}{nu}) = 2.7 x 10{sup -5}, which seem to be within the reach of forthcoming experiments. Furthermore, we have classified the B{sub u,d,s} {yields} Tl{nu} decays into two groups and compared the semileptonic and nonleptonic decays including a tensor meson in the final state.

New results on Coulomb effects in meson production in relativistic heavy ion collisions

Directory of Open Access Journals (Sweden)

Rybicki Andrzej

2014-01-01

Full Text Available We propose a new method of investigating the space-time evolution of meson production in heavy ion collisions, by making use of spectator-induced electromagnetic (“Coulomb” effects. The presence of two nuclear remnants (“spectator systems” in the non-central collision generates a strong Coulomb field, which modifies the trajectories of charged final state hadrons. This results in charge-dependent azimuthal anisotropies in final state meson emission. In our approach, this effect can be computed numerically by means of a high-statistics Monte Carlo simulation, using the distance between the meson formation zone and the spectator system as free parameter. Our simulation correctly describes the electromagnetic effect on azimuthal anisotropies observed for π+ and π−mesons in Au+Au collisions at lower RHIC energy, known from data recently reported by the STAR Collaboration. Similarly to our earlier studies of spectator-induced electromagnetic effects, also in the present study we find that these effects offer sensitivity to the position of the meson formation zone with respect to the spectator system. Therefore, we conclude that they can serve as a new tool to investigate the space-time evolution of meson production, and the dynamics of the heavy ion collision.

On the mass spectra of the pseudoscalar mesons in the relativistic independent quark model

International Nuclear Information System (INIS)

Khrushchev, V.V.; Semenov, S.V.

2002-01-01

In the framework of the relativistic independent quark model with the QCD-motivated static potential, the masses of the ground states of pseudoscalar mesons and their radial excitations are calculated for both observed mesons and unobserved ones. The strength of the spin-spin interaction and the magnitude of the mean field contribution are estimated for both the light and heavy 0 -+ mesons. The calculated masses are in agreement with experimental values within an accuracy of 30 - 40 MeV, and the predictions are obtained for the mass values of a number of unobserved yet radial excitations of pseudoscalar mesons

Nucleon quark structure and strong meson-nucleon form factors

International Nuclear Information System (INIS)

Efimov, G.V.; Ivanov, M.A.

1987-01-01

The nucleon is considered as a three-quark system in virton-quark model. The main statistic properties of proton and neutron are calculated: magnetic moments, electromagnetic radii, G A /G V ratio in weak neutron decay. Strong meson-nucleon form factors which determine nucleon-nucleon potential are obtained as a function of squared transfer momentum of mesons. The results are compared with phenomenological form factors used for description of phases of NN-scattering in the one-boson-, exchange model

Application of heavy-light methods to B meson physics

International Nuclear Information System (INIS)

Eichten, E.; Hockney, G.; Thacker, H.B.

1989-01-01

The heavy-light method is applied to the study of the B meson spectrum, the pseudoscalar decay constant f B , the mixing (B) parameter, and exclusive semileptonic B meson decays. Preliminary results are discussed for f B and the B parameter at β = 5.7 and κ = 0.165 on a 12 3 x 24 lattice and at β = 5.9 and κ = 0.158 on a 16 3 x 32 lattice. 9 refs., 2 figs., 2 tabs

What Can We Learn from Hadronic and Radiative Decays of Light Mesons?

Science.gov (United States)

Kubis, Bastian

2013-04-01

Chiral perturbation theory offers a powerful tool for the investigation of light pseudoscalar mesons. It incorporates the fundamental symmetries of QCD, interrelates various processes, and allows to link these to the light quark masses. Its shortcomings lie in a limited energy range: the radius of convergence of the chiral expansion is confined to below resonance scales. Furthermore, the strongest consequences of chiral symmetry are manifest for pseudoscalars (pions, kaons, eta) only: vector mesons, e.g., have a severe impact in particular for reactions involving photons. In this talk, I advocate dispersions relations as another model-independent tool to extend the applicability range of chiral perturbation theory. They even allow to tackle the physics of vector mesons in a rigorous way. It will be shown how dispersive methods can be used to resum large rescattering effects, and to provide model-independent links between hadronic and radiative decay modes. Examples to be discussed will include decays of the eta meson, giving access to light-quark-mass ratios or allowing to test the chiral anomaly; and meson transition form factors, which have an important impact on the hadronic light-by-light-scattering contribution to the anomalous magnetic moment of the muon.

Holographic picture of heavy vector meson melting

Energy Technology Data Exchange (ETDEWEB)

Braga, Nelson R.F.; Diles, Saulo [Universidade Federal do Rio de Janeiro, Instituto de Fisica, Rio de Janeiro, RJ (Brazil); Martin Contreras, Miguel Angel [Universidad de los Andes, High Energy Group, Department of Physics, Bogota (Colombia)

2016-11-15

The fraction of heavy vector mesons produced in a heavy ion collision, as compared to a proton-proton collision, serves as an important indication of the formation of a thermal medium, the quark-gluon plasma. This sort of analysis strongly depends on understanding the thermal effects of a medium like the plasma on the states of heavy mesons. In particular, it is crucial to know the temperature ranges where they undergo a thermal dissociation, or melting. AdS/QCD models are know to provide an important tool for the calculation of hadronic masses, but in general are not consistent with the observation that decay constants of heavy vector mesons decrease with excitation level. It has recently been shown that this problem can be overcome using a soft wall background and introducing an extra energy parameter, through the calculation of correlation functions at a finite position of anti-de Sitter space. This approach leads to the evaluation of masses and decay constants of S wave quarkonium states with just one flavor dependent and one flavor independent parameter. Here we extend this more realistic model to finite temperatures and analyze the thermal behavior of the states 1S, 2S and 3S of bottomonium and charmonium. The corresponding spectral function exhibits a consistent picture for the melting of the states where, for each flavor, the higher excitations melt at lower temperatures. We estimate for these six states the energy ranges in which the heavy vector mesons undergo a transition from a well-defined peak in the spectral function to complete melting in the thermal medium. A very clear distinction between the heavy flavors emerges, with the bottomonium state Υ(1S) surviving a deconfinement transition at temperatures much larger than the critical deconfinement temperature of the medium. (orig.)

Topics on CP violation in B-meson decays

International Nuclear Information System (INIS)

Soares, J.M.

1993-01-01

In this work several independent topics on CP violation in the B-meson decays are addressed. To begin with, the present constraints on the parameters of the Cabibbo-Kobayashi-Maskawa (CKM) matrix are discussed. Then, I calculate the CP-violating asymmetry in the radiative decays of the charged B-mesons: it only appears at the 2-loop level, but it can be large in the b → dγ decays. At this point, the possibility of using these decays to measure the CKM entry |V td | will be studied. I also consider the decays of the neutral B-mesons: the strong correlation between the asymmetries in B 0 → ΨK S and the B 0 → π + π - is suggested as a powerful test of the standard model (a simple extension of the model is given where the correlation disappears). Finally, I address the question of observing direct CP violation in comparing these two asymmetries. An ambiguity that may arise is resolved due to the role that is played by penguin diagram contributions to the decay amplitudes

Modified quark-meson coupling model for nuclear matter

International Nuclear Information System (INIS)

Jin, X.; Jennings, B.K.

1996-01-01

The quark-meson coupling model for nuclear matter, which describes nuclear matter as nonoverlapping MIT bags bound by the self-consistent exchange of scalar and vector mesons, is modified by introducing medium modification of the bag constant. We model the density dependence of the bag constant in two different ways: One invokes a direct coupling of the bag constant to the scalar meson field, and the other relates the bag constant to the in-medium nucleon mass. Both models feature a decreasing bag constant with increasing density. We find that when the bag constant is significantly reduced in nuclear medium with respect to its free-space value, large canceling isoscalar Lorentz scalar and vector potentials for the nucleon in nuclear matter emerge naturally. Such potentials are comparable to those suggested by relativistic nuclear phenomenology and finite-density QCD sum rules. This suggests that the reduction of bag constant in nuclear medium may play an important role in low- and medium-energy nuclear physics. copyright 1996 The American Physical Society

Production and interaction of the η meson with nucleons and nuclei

Directory of Open Access Journals (Sweden)

Krzemień Wojciech

2016-01-01

Full Text Available We report on the status of the search for η-mesic nuclei and the studies of the interaction of the η meson with nucleons. Recently we have completed the analysis of the newWASA-at-COSY data on the production of the η meson with polarized proton beam. New results on the analyzing power for the p̄p → ppη reaction with more than an order of magnitude improved precision shed a new light on the production mechanism of the η meson in nucleon-nucleon collisions. Also, the latest results of the search for η-mesic nuclei are discussed.

Non-self-conjugate mesons in a potential model with vacuum-polarization corrections

International Nuclear Information System (INIS)

Barik, N.; Jena, S.N.

1980-01-01

We present a unified approach to the study of non-self-conjugate mesons including both light and heavy mesons in the framework of the vacuum-polarization-corrected flavor-independent potential. We have found that the quark-confining potential in the form of an almost equal admixture of vector and scalar parts successfully explains the S-wave hyperfine levels of the observed light and heavy mesons. Finally we calculate the electromagnetic mass differences of the heavy-quark mesons and obtain (K-bar* 0 -K* - )=3.79 MeV, (K-bar 0 -K - )=6 MeV, (D* + /sub c/-D* 0 /sub c/)=2.4 MeV, (D + /sub c/-D 0 /sub c/)=5.8 MeV, (D* 0 /sub b/-D* - /sub b/)=3.547 MeV, and (D 0 /sub b/-D - /sub b/)=3.558 MeV

A Review on ϕ Meson Production in Heavy-Ion Collision

Directory of Open Access Journals (Sweden)

Md. Nasim

2015-01-01

Full Text Available The main aim of the relativistic heavy-ion experiment is to create extremely hot and dense matter and study the QCD phase structure. With this motivation, experimental program started in the early 1990s at the Brookhaven Alternating Gradient Synchrotron (AGS and the CERN Super Proton Synchrotron (SPS followed by Relativistic Heavy Ion Collider (RHIC at Brookhaven and recently at Large Hadron Collider (LHC at CERN. These experiments allowed us to study the QCD matter from center-of-mass energies (sNN 4.75 GeV to 2.76 TeV. The ϕ meson, due to its unique properties, is considered as a good probe to study the QCD matter created in relativistic collisions. In this paper we present a review on the measurements of ϕ meson production in heavy-ion experiments. Mainly, we discuss the energy dependence of ϕ meson invariant yield and the production mechanism, strangeness enhancement, parton energy loss, and partonic collectivity in nucleus-nucleus collisions. Effect of later stage hadronic rescattering on elliptic flow (v2 of proton is also discussed relative to corresponding effect on ϕ meson v2.

Proposal to measure the D meson decay constant F/sub D/

International Nuclear Information System (INIS)

Deshpande, N.G.; Iskandar, D.

1978-08-01

Because the branching ratios of the purely leptonic modes of D meson are small compared to the semileptonic decays, it is suggested that the decay D → K + l + ν might be used to deduce the value of F/sub D/, the weak decay constant of D meson. 17 references

Meson decays in a quark model

International Nuclear Information System (INIS)

Roberts, W.; Silvestre-Brac, B.

1998-01-01

A recent model of hadron states is extended to include meson decays. We find that the overall success of the model is quite good. Possible improvements to the model are suggested. copyright 1997 The American Physical Society

New physics effects from meson decays

Indian Academy of Sciences (India)

beyond the Standard Model from -meson decays, taking К-parity conserving and violating super- symmetry .... particular choice of the parameter space, can be much higher than the SM ones. .... CLEO has already given some food for thought.

Inclusive vector meson production and hadron structure

International Nuclear Information System (INIS)

Boeckmann, K.

1977-08-01

It is shown that J/PSI production in hadronic interactions is dominated by central production from sea quarks even at beam momenta as low as 40 GeV/c. All known experimental data on inclusive vector meson production support the hypothesis that cross sections obtained from meson-nucleon and nucleon-nucleon interactions have to be compared in the quark C.M. system. With the distinction of sea quark and valence quark interactions in the additive quark model a consistent description of inclusive rho, K*, PHI and J/PSI production in hadronic interactions. A natural connection of inclusive rho 0 production cross sections in anti pp, pp and πp interactions is obtained. (orig.) [de

A transverse lattice QCD model for mesons

Energy Technology Data Exchange (ETDEWEB)

Patel, Apoorva D.; Ratabole, Raghunath

2004-03-01

QCD is analysed with two light-front continuum dimensions and two transverse lattice dimensions. In the limit of large number of colours and strong transverse gauge coupling, the contributions of light-front and transverse directions factorise in the dynamics, and the theory can be analytically solved in a closed form. An integral equation is obtained, describing the properties of mesons, which generalises the 't Hooft equation by including spin degrees of freedom. The meson spectrum, light-front wavefunctions and form factors can be obtained by solving this equation numerically. These results would be a good starting point to model QCD observables which only weakly depend on transverse directions, e.g. deep inelastic scattering structure functions.

Charmed meson production by e+e- annihilation

International Nuclear Information System (INIS)

Wiss, J.E.

1977-08-01

Compelling evidence is presented for the production of the lying (D 0 , D + ) isodoublet of charmed mesons by e + e - annihilation. A study of the recoil mass spectra against these mesons reveals the presence of more massive charmed states, the D* 0 and D* + , produced in association with the D isodoublet. Mass values and upper limits on the width of the D and D* are established, and the branching fractions for several D* decay modes are obtained. An analysis of the production and decay angular distributions shows that the D is probably a pseudoscalar state and the D* is probably a vector. Finally, upper limits are obtained for D 0 -antiD 0 mixing

Observation of orbitally excited B(s) mesons.

Science.gov (United States)

Aaltonen, T; Abulencia, A; Adelman, J; Akimoto, T; Albrow, M G; Alvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Apresyan, A; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzi-Bacchetta, P; Azzurri, P; Bacchetta, N; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Baroiant, S; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Bednar, P; Behari, S; Bellettini, G; Bellinger, J; Belloni, A; Benjamin, D; Beretvas, A; Beringer, J; Berry, T; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bolshov, A; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Compostella, G; Convery, M E; Conway, J; Cooper, B; Copic, K; Cordelli, M; Cortiana, G; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Cully, J C; Dagenhart, D; Datta, M; Davies, T; de Barbaro, P; De Cecco, S; Deisher, A; De Lentdecker, G; De Lorenzo, G; Dell'orso, M; Demortier, L; Deng, J; Deninno, M; De Pedis, D; Derwent, P F; Di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Forrester, S; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garberson, F; Garcia, J E; Garfinkel, A F; Gerberich, H; Gerdes, D; Giagu, S; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C M; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Hamilton, A; Han, B-Y; Han, J Y; Handler, R; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hauser, J; Hays, C; Heck, M; Heijboer, A; Heinemann, B; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hewamanage, S; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; Iyutin, B; James, E; Jayatilaka, B; Jeans, D; Jeon, E J; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Kar, D; Karchin, P E; Kato, Y; Kephart, R; Kerzel, U; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Klute, M; Knuteson, B; Ko, B R; Koay, S A; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kraus, J; Kreps, M; Kroll, J; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhlmann, S E; Kuhr, T; Kulkarni, N P; Kusakabe, Y; Kwang, S; Laasanen, A T; Lai, S; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecompte, T; Lee, J; Lee, J; Lee, Y J; Lee, S W; Lefèvre, R; Leonardo, N; Leone, S; Levy, S; Lewis, J D; Lin, C; Lin, C S; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lovas, L; Lu, R-S; Lucchesi, D; Lueck, J; Luci, C; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Lytken, E; Mack, P; Macqueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis, A; Margaroli, F; Marino, C; Marino, C P; Martin, A; Martin, M; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Mattson, M E; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzemer, S; Menzione, A; Merkel, P; Mesropian, C; Messina, A; Miao, T; Miladinovic, N; Miles, J; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyake, H; Moed, S; Moggi, N; Moon, C S; Moore, R; Morello, M; Movilla Fernandez, P; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Neu, C; Neubauer, M S; Nielsen, J; Nodulman, L; Norman, M; Norniella, O; Nurse, E; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Oldeman, R; Orava, R; Osterberg, K; Pagan Griso, S; Pagliarone, C; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Piedra, J; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Portell, X; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Reisert, B; Rekovic, V; Renton, P; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Saarikko, H; Safonov, A; Sakumoto, W K; Salamanna, G; Saltó, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savard, P; Savoy-Navarro, A; Scheidle, T; Schlabach, P; Schmidt, E E; Schmidt, M A; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scott, A L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sfyrla, A; Shalhout, S Z; Shapiro, M D; Shears, T; Shepard, P F; Sherman, D; Shimojima, M; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soderberg, M; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spinella, F; Spreitzer, T; Squillacioti, P; Stanitzki, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Stuart, D; Suh, J S; Sukhanov, A; Sun, H; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thompson, G A; Thomson, E; Tipton, P; Tiwari, V; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Tourneur, S; Trischuk, W; Tu, Y; Turini, N; Ukegawa, F; Uozumi, S; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Vellidis, C; Veszpremi, V; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vogel, M; Volobouev, I; Volpi, G; Würthwein, F; Wagner, P; Wagner, R G; Wagner, R L; Wagner, J; Wagner, W; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Wynne, S M; Yagil, A; Yamamoto, K; Yamaoka, J; Yamashita, T; Yang, C; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zaw, I; Zhang, X; Zheng, Y; Zucchelli, S

2008-02-29

We report the observation of two narrow resonances consistent with states of orbitally excited (L=1) B_(s) mesons using 1 fb;(-1) of pp[over ] collisions at sqrt[s]=1.96 TeV collected with the Collider Detector at Fermilab II detector at the Fermilab Tevatron. We use two-body decays into K- and B+ mesons reconstructed as B(+)-->J/psiK(+), J/psi-->mu(+)mu(-) or B(+)-->D[over ](0)pi(+), D[over ](0)-->K(+)pi(-). We deduce the masses of the two states to be m(B_(s1))=5829.4+/-0.7 MeV/c(2) and m(B_(s2);(*))=5839.6+/-0.7 MeV/c;(2).

Universal behavior in excited heavy-light and light-light mesons

International Nuclear Information System (INIS)

Olsson, M.G.

1997-01-01

A common pattern of large orbital and radial excitations in heavy-light and light-light mesons is demonstrated. For a general potential model with linear confinement the Regge slopes of the light degrees of freedom for these mesons are shown to be in the ratio of 2. The possibility of 'tower' degeneracy occurs only with pure scalar confinement. copyright 1997 The American Physical Society

Pion physics at the meson factories

International Nuclear Information System (INIS)

Nagle, D.E.; Johnson, M.B.; Measday, D.F.

1987-01-01

Pi meson probes have contributed much to our ideas about how neutrons and protons are distributed and move relative to each other in nuclei, and along with other probes, to our understanding of basic symmetries in particle physics

Two-body spectra of pseudoscalar mesons with an O(a2)-improved lattice action using Wilson fermions

International Nuclear Information System (INIS)

Fiebig, H.R.; Mihaly, A.; Woloshyn, R.M.

1998-01-01

We extend our calculations with the second-order tree-level and tadpole improved next-nearest-neighbor action to meson-meson systems. Correlation matrices built from interpolating fields representing two pseudoscalar mesons (π-π) with relative momenta vector-p are diagonalized, and the mass spectrum is extracted. Link variable fuzzing and operator smearing at both sinks and sources is employed. Calculations are presented for two values of the hopping parameter. The spectrum is used to discuss the residual interaction in the meson-meson system. (orig.)

Search for Bc+ decays to two charm mesons

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R. Aaij

2018-05-01

Full Text Available A search for decays of Bc+ mesons to two charm mesons is performed for the first time using data corresponding to an integrated luminosity of 3.0fb−1, collected by the LHCb experiment in pp collisions at centre-of-mass energies of 7 and 8 TeV. The decays considered are Bc+→D(s(⁎+D‾(⁎0 and Bc+→D(s(⁎+D(⁎0, which are normalised to high-yield B+→D(s+D‾0 decays. No evidence for a signal is found and limits are set on twelve Bc+ decay modes.

Studies of phi meson radiative decays with KLOE

International Nuclear Information System (INIS)

Aloisio, A.; Ambrosino, F.; Antonelli, A.; Antonelli, M.; Bacci, C.; Bencivenni, G.; Bertolucci, S.; Bini, C.; Bloise, C.; Bocci, V.; Bossi, F.; Branchini, P.; Bulychjov, S.A.; Caloi, R.; Campana, P.; Capon, G.; Carboni, G.; Casarsa, M.; Casavola, V.; Cataldi, G.; Ceradini, F.; Cervelli, F.; Cevenini, F.; Chiefari, G.; Ciambrone, P.; Conetti, S.; De Lucia, E.; De Robertis, G.; De Simone, P.; De Zorzi, G.; Dell'Agnello, S.; Denig, A.; Di Domenico, A.; Di Donato, C.; Di Falco, S.; Doria, A.; Dreucci, M.; Erriquez, O.; Farilla, A.; Felici, G.; Ferrari, A.; Ferrer, M.L.; Finocchiaro, G.; Forti, C.; Franceschi, A.; Franzini, P.; Gatt, C.; Gauzzi, P.; Giovannella, S.; Gorini, E.; Grancagnolo, F.; Graziani, E.; Han, S.W.; Incagli, M.; Ingrosso, L.; Kluge, W.; Kuo, C.; Kulikov, V.; Lacava, F.; Lanfranchi, G.; Lee-Franzini, J.; Leone, D.; Lu, F.; Martemianov, M.; Matsyuk, M.; Mei, W.; Merola, L.; Messi, R.; Miscetti, S.; Moulson, M.; Mueller, S.; Murtas, F.; Napolitano, M.; Nedosekin, A.; Nguyen, F.; Palutan, M.; Pasqualucci, E.; Passalacqua, L.; Passeri, A.; Patera, V.; Petrolo, E.; Pontecorvo, L.; Primavera, M.; Ruggieri, F.; Santangelo, P.; Santovetti, E.; Saracino, G.; Schamberger, R.D.; Sciascia, B.; Sciubba, A.; Scuri, F.; Sfiligoi, I.; Spadaro, T.; Spiriti, E.; Tong, G.L.; Tortora, L.; Valente, E.; Valente, P.; Valeriani, B.; Vernanzoni, G.; Veneziano, S.; Ventura, A.; Xu, G.; Yu, G.W.

2003-01-01

A sample of 5.3 x 10 7 phi mesons, produced at the Frascati phi-factory DAPHINE, has been used by the KLOE Collaboration to study the phi radiative decays. The decays phi → ηπ 0 γ and phi → π o π o γ have been exploited to study the scalar mesons a o (980) and f o (980). Furthermore a new determination of the η - η' mixing angle has been obtained from the measurement of the ratio of the decay rates of phi → η'γ to phi → ηγ to phi → ηγ

A Dependence of Charmed Meson Production

Energy Technology Data Exchange (ETDEWEB)

Alves, Gilvan Augusto [Rio de Janeiro, CBPF

1992-03-01

One report is presented of a recent direct measurement of the nucleon number (A) dependence of the production cross sections for the charmed mesons $D^0$ and $D^+$ using $\\pi^+_{-}$ and $K^+_{-}$ beams incident on a segmented target of Be, Al, Cu and W. The data derive from the experiment E769 - Hadroproductlon of Charm at Fermilab. The experimental apparatus is described together with the following analysis. Starting from a sample of -1500 D mesons in the range of $O< x_{f} <1$, the data are found to be well described by the parameterization $\\sigma_{A}$ = $\\sigma_{O}$ , with $\\alpha = 0.99 \\pm 0.03$. The $x_f$ dependence of $\\alpha$ is examined and the results obtained are compared with those of other .experiments and wl th -theoretical expectations based on perturbatlve QCD and on an EMC like model of nuclear shadowing

Exclusive vector meson production at HERA

International Nuclear Information System (INIS)

Szuba, Dorota

2013-01-01

The exclusive photoproduction of Υ has been studied with the ZEUS detector in ep collisions at HERA. The exponential slope, b, of the |t|-dependence of the cross section, where t is the squared four-momentum transfer at the proton vertex, has been measured. This constitutes the first measurement of the |t|-dependence of the γp→Υp cross section. The differential crosssections as a function of t at lower energies of γp centre-of-mass has been studied in exclusive diffractive photoproduction of J/ψ mesons with the H1 detector. The exclusive electroproduction of two pions has been measured by the ZEUS experiment. The two-pion invariant-mass distribution is interpreted in terms of the pion electromagnetic form factor, assuming that the studied mass range includes the contributions of the ρ, ρ′ and . ρ'' vector-meson states.

Meson Spectroscopy from QCD - Project Results

Energy Technology Data Exchange (ETDEWEB)

Dudek, Jozef [Old Dominion Univ., Norfolk, VA (United States)

2017-04-17

Highlights of the research include: the determination of the form of the lowest energy gluonic excitation within QCD and the spectrum of hybrid hadrons which follows; the first calculation of the spectrum of hybrid baryons within a first-principles approach to QCD; a detailed mapping out of the phase-shift of elastic ππ scattering featuring the ρ resonance at two values of the light quark mass within lattice QCD; the first (and to date, only) determinations of coupled-channel meson-meson scattering within first-principles QCD; the first (and to date, only) determinations of the radiative coupling of a resonant state, the ρ appearing in πγ→ππ; the first (and to date, only) determination of the properties of the broad σ resonance in elastic ππ scattering within QCD without unjustified approximations.

Experimental Status of Exotic Mesons and the GlueX Experiment

Energy Technology Data Exchange (ETDEWEB)

Daniel Carman

2006-10-22

One of the unanswered and most fundamental questions in physics regards the nature of the confinement mechanism of quarks and gluons in QCD. Exotic hybrid mesons manifest gluonic degrees of freedom and their spectroscopy will provide the data necessary to test assumptions in lattice QCD and the specific phenomenology leading to confinement. Within the past two decades a number of experiments have put forth tantalizing evidence for the existence of exotic hybrid mesons in the mass range below 2 GeV. This talk represents an overview of the available data and what has been learned. In looking toward the future, the GlueX experiment at Jefferson Laboratory represents a new initiative that will perform detailed spectroscopy of the light-quark meson spectrum. This experiment and its capabilities will be reviewed.

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.

On exotic hybrid meson production in {gamma}{sup *}{gamma} collisions

Energy Technology Data Exchange (ETDEWEB)

Anikin, I.V.; Teryaev, O.V. [Bogoliubov Laboratory of Theoretical Physics, Dubna (Russian Federation); Pire, B. [Ecole Polytechnique, 91 - Palaiseau (France). CPHT; Szymanowski, L. [Soltan Inst. for Nuclear Studies, Warsaw (Poland); Universite de Liege (Belgium); Paris-11 Univ., 91 - Orsay (France). LPT; Wallon, S. [Paris-11 Univ., 91 - Orsay (France). LPT

2006-07-15

We present a theoretical study of exotic hybrid meson (J{sup PC}=1{sup -+}) production in photon-photon collisions where one of the photons is deeply virtual, including twist two and twist three contributions. We calculate the cross section of this process, which turns out to be large enough to imply sizeable counting rates in the present high luminosity electron-positron colliders. We emphasize the importance of the {pi}{eta} decay channel for the detection of the hybrid meson candidate {pi}{sub 1}(1400) and calculate the cross section and the angular distribution for {pi}{eta} pair production in the unpolarized case. This angular distribution is a useful tool for disentangling the hybrid meson signal from the background. Finally, we calculate the single spin asymmetry associated with one initial longitudinally polarized lepton. (orig.)

B meson physics with polarized electron beams at the SLC

International Nuclear Information System (INIS)

Atwood, W.B.

1988-09-01

The expected large cross-section for e + e - → Z 0 and subsequent decay to b/bar b/ quarks makes the Z 0 an attractive place to pursue B meson physics. In addition, the big Electroweak asymmetries, thought to exist in Z 0 decays to b/bar b/ quarks with polarized electron beams, provide an outstanding handle for observation of such effects as B 0 -/bar B/ 0 mixing. In this paper, the feasibility of such measurements is investigated and, with relatively small samples of Z 0 's (a few hundred thousand), both B/sub d/ and B/sub s/ meson mixing are shown to be measurable. The subject of CP violation in neutral B mesons is discussed last, but presently such measurements seem to be out of reach. 7 refs., 6 figs., 3 tabs

Characterization of the Lower Cambrian sandstone aquifer in the Swedish Baltic Sea area - assessment regarding its potential suitability for storage of CO2

Science.gov (United States)

Erlström, M.; Sivhed, U.

2012-04-01

In the Baltic region the Cambrian sandstone is considered to have great economic value concerning its aquifer and reservoir properties. Its potential as petroleum reservoir is well known, especially from the Polish, Lithuanian and Russian sectors of the Baltic Sea where oil and gas has been found in anticline traps in the sandstone sequence. Offshore exploration in the Swedish sector has so far not encountered any significant findings of oil and gas. However, the extensive exploration has generated data, which is now being used for assessing the overall properties regarding suitability for storage of CO2. The Swedish primary industry has a great interest in finding potential sites for storage of CO2. A suitable site in the Baltic Sea would be a most favourable alternative in comparison to more remote alternatives such as deep saline aquifers in the North Sea. The Lower Cambrian is in the Swedish sector of the Baltic Sea composed of three main sandstone units varying in thickness between 5 and 50 m occurring within an up to 250 m thick Cambrian sequence dominated by fine-grained terriclastic sediments. The limit of Lower Palaeozoic sequence in the Baltic area is today defined by erosional truncation because of the gently dipping Lower Palaeozoic sequence. To the north and northwest, the limit is found in the Pre-Quaternary, whereas the erosional limit is deeply buried beneath Permian and Mesozoic sediments to the south. Here the Lower Palaeozoic limit is buried to depths reaching more than 2 km. The Cambrian sequence in the distal parts of the Swedish sector occurs at depths of c. 1300 m while it constitutes the bedrock surface in a narrow zone trending from Öland to the north of of Gotland. Sandstone beds constitute 40-60% of the total Cambrian sequence. The main sandstone units have a regional distribution of several thousands of square kilometres. The up to 50 m thick Faludden sandstone member exhibits the best reservoir properties including porosities in the

Exotic nature of scalar G(1590) meson and possibilities for its further experimental study

International Nuclear Information System (INIS)

Gershtejn, S.S.

1987-01-01

It is pointed out that exotic properties of the scalar G(1590)-meson (an enchancement of the G → η'η decay probability as compared with G → ηη and of the GG → ηη decay probability as compared with G → ππ, KK) may be explained if an account is made of the strong coupling between two gluons with η'(η)-mesons in the framework of two different models, I.E. a) G-meson is a glueball, b) G-meson is a hybrid state (an eight component of the SU(3) f octet). Experimental predictions of both models are discussed

Disc-shaped fossils resembling porpitids or eldonids from the early Cambrian (Series 2: Stage 4 of western USA

Directory of Open Access Journals (Sweden)

Bruce S. Lieberman

2017-06-01

Full Text Available The morphology and affinities of newly discovered disc-shaped, soft-bodied fossils from the early Cambrian (Series 2: Stage 4, Dyeran Carrara Formation are discussed. These specimens show some similarity to the Ordovician Discophyllum Hall, 1847; traditionally this taxon had been treated as a fossil porpitid. However, recently it has instead been referred to as another clade, the eldonids, which includes the enigmatic Eldonia Walcott, 1911 that was originally described from the Cambrian Burgess Shale. The status of various Proterozoic and Phanerozoic taxa previously referred to porpitids and eldonids is also briefly considered. To help ascertain that the specimens were not dubio- or pseudofossils, elemental mapping using energy dispersive X-ray spectroscopy (EDS was conducted. This, in conjunction with the morphology of the specimens, indicated that the fossils were not hematite, iron sulfide, pyrolusite, or other abiologic mineral precipitates. Instead, their status as biologic structures and thus actual fossils is supported. Enrichment in the element carbon, and also possibly to some extent the elements magnesium and iron, seems to be playing some role in the preservation process.

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.

The effect of vector meson decays on di-hadron fragmentation functions

International Nuclear Information System (INIS)

Matevosyan, H.H.; Thomas, A.W.; Bentz, W.

2014-01-01

Di-hadron Fragmentation Functions (DFF) provide a vast amount of information on the intricate details of the parton hadronization process. Moreover, they provide a unique access to the 'clean' extraction of nucleon transversity parton distribution functions in semi inclusive deep inelastic two hadron production process with a transversely polarised target. On the example of the u → π + π - we analyse the properties of unpolarized DFFs using their probabilistic interpretation. We use both the NJL-jet hadronization model and PYTHIA 8.1 event generator to explore the effect of the strong decays of the vector mesons produced in the quark hadronization process on the pseudoscalar DFFs. Our study shows that, even though it is less probable to produce vector mesons in the hadronization process than pseudo scalar mesons of the same charge, the products of their strong decays drastically affect the DFFs for pions because of the large combinatorial factors. Thus, an accurate description of both vector meson production and decays are crucial for theoretical understanding of DFFs. (authors)