Sample records for baryonium

  1. Searching for hidden-charm baryonium signals in QCD sum rules

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Hua-Xing; Zhou, Dan [Beihang University, School of Physics, Beijing Key Laboratory of Advanced Nuclear Materials and Physics, Beijing (China); Chen, Wei [University of Saskatchewan, Department of Physics and Engineering Physics, Saskatoon, SK (Canada); Liu, Xiang [Lanzhou University, School of Physical Science and Technology, Lanzhou (China); Lanzhou University, Research Center for Hadron and CSR Physics, Institute of Modern Physics of CAS, Lanzhou (China); Zhu, Shi-Lin [Peking University, School of Physics, State Key Laboratory of Nuclear Physics and Technology, Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China); Peking University, Center of High Energy Physics, Beijing (China)


    We give an explicit QCD sum rule investigation for hidden-charm baryonium states with the quark content u anti ud anti dc anti c, spin J = 0/1/2/3, and of both positive and negative parities. We systematically construct the relevant local hidden-charm baryonium interpolating currents, which can actually couple to various structures, including hidden-charm baryonium states, charmonium states plus two pions, and hidden-charm tetraquark states plus one pion, etc. We do not know which structure these currents couple to at the beginning, but after sum rule analyses we can obtain some information. We find some of them can couple to hidden-charm baryonium states, using which we evaluate the masses of the lowest-lying hidden-charm baryonium states with quantum numbers J{sup P} = 2{sup -}/3{sup -}/0{sup +}/1{sup +}/2{sup +} to be around 5.0 GeV. We suggest to search for hidden-charm baryonium states, especially the one of J = 3{sup -}, in the D-wave J/ψππ and P-wave J/ψρ and J/ψω channels in this energy region. (orig.)

  2. Search for baryonium and the physics at FAIR

    Directory of Open Access Journals (Sweden)

    Wycech S.


    Full Text Available The existence of nucleon-antinucleon quasi-bound state is indicated in two decay modes of the J/ψ meson studied by BES. We discuss an explanation in a fairly traditional Paris-potential model of the NN̄ interactions. A broad, S-wave and a narrow P-wave quasi-bound states are predicted by this model. Some existing experimental evidence and possible verifications in the future are indicated.

  3. Search for baryonium and the physics at FAIR

    CERN Document Server

    Wycech, Slawomir; Loiseau, Benoit


    The existence of nucleon-antinucleon quasi-bound state is indicated in two decay modes of the J/psi meson studied by BES. We discuss an explanation in a fairly traditional Paris-potential model of the nucleon-antinucleon interactions. A broad, S-wave and a narrow P-wave quasi-bound states are predicted by this model. Some existing experimental evidence and possible verifications in the future are indicated.

  4. The WA56 Experiment at CERN: How Does It Look in the Unified Picture for Hadron Spectra?

    CERN Document Server

    Arkhipov, A A


    In this note we demonstrate how the experimental material taken from WA56 Experiment at CERN looks in the recently developed unified picture for hadron spectra. Our analysis shows that baryonium states observed in the WA56 Experiment are the states living in the corresponding KK tower built in according to the earlier established general, physical law.

  5. Measurements of the Ratio Between Double and Single Ionization of Helium for Antiprotons

    CERN Multimedia


    The inclusive spectra of @p|0's and @h's associated with @*p annihilation at rest are measured. Peaks in these spectra can be identified either with so far not explicitly observed two mesonic final states such as @p|0@w, @p|0@h, @h@h or @p|0@g, or with production of exotic mesonlike states such as baryonium. The apparatus is also suitable for searching for baryonium through some of its particular decay channels. As a by-product we expect information on direct @g production in @*p annihilations at rest.\\\\ \\\\ The apparatus consists of two modular BGO spectrometers and one array of leadglas detectors. The BGO spectrometers are adjustable in angle relative to each other and to the leadglas matrix, thus allowing to cover an angular range from 9|0 to 180|0, corresponding to momenta of zero to more than 1~GeV/c. The apparatus is designed such as to utilize the full potential of LEAR.

  6. Summary of the most significant results reported in this session

    CERN Document Server

    Van De Walle, R T


    In the following a summary is presented of five parallel sessions on light quark had- ron spectroscopy. In general all topics which were discussed in the plenary sessions, and for which the proceedings contain separate (invited) papers, will be left out; only occa- sionally (and for reasons of completeness) will we make a reference to these presentations. Several other restrictions can be made. Nearly all papers submitted to the (parallel) hadron spectroscopy sessions were experimenta1 1 ), the only exceptions being a series of four theoretical papers on the baryonium problem. Furthermore, there was virtually no new information concerning the 'classical' baryons. In particular, no new facts were submitted on the problem of the possible existence of baryon states outside the so-called minimal spectrum, i.e. outside {56,L+ } and {70,L-dd}, the existence of the {ZO}'s, and the exis- even o tence of (baryon) exotic states. There was one contribution on a 'possible' new:".* 2 ), and a report on the final measureme...

  7. Measurement of Antiproton-proton Cross-Sections at Low Antiproton Momenta

    CERN Multimedia


    The experiment is designed to measure four different cross sections in the momentum range 150~MeV/c to 600~MeV/c: 1)~~~~the differential elastic \\\\ \\\\ 2)~~~~the differential charge exchange\\\\ \\\\ 3)~~~~the annihilation into charged and neutral pions\\\\ \\\\ 4)~~~~and the total cross section via the optical theorem. \\\\ \\\\ The experiment allows one to search once again and with good precision for baryonium. Of special interest is the existence of the S-meson, for which a signal of about 20~MeV-mb was found in a 1981 experiment (performed in the East Hall).\\\\ \\\\ A second point of special interest is the momentum region below 300~MeV/c because the cross sections are basically unknown. We will be able to explore the momentum dependence of this region for the first time.\\\\ \\\\ The elastic cross section is measured by a cylindrical multiwire proportional chamber and a scintillator hodoscope placed around a scattering chamber under vacuum. The charge exchange cross section is measured by a ring of 32~anti-neutron detector...

  8. p(-p) final state interaction in J/Ψ→γp(-p)

    Institute of Scientific and Technical Information of China (English)

    ZENG Zhuo-Quan; GUO Xin-Heng; SHEN Peng-Nian; DING Yi-Bing


    The phenomenon of the near p(-p)-threshold enhancement observed in the J/Ψ → γp(-p) decay is studied by using the enhancement factor method with a simpler one-pion-exchange potential between p and (-p).The Jost function caused by the mentioned potential is perturbatively calculated in the zero-th order approximation,and the corresponding enhancement factor is obtained.It is found that such a final state interaction offers an important contribution to the decay width near the p(-p)-threshold,although it is not large enough.To explain the decay data,a pheuomenological factor G(p) with the form of 285500/(m2/π +p2) should be introduced.A further calculation including the p-dependent bare T-matrix,a more realistic N(-N) potential and the contribution from the higher-order wave functions would provide a better understanding of the decay data and even the existence of the baryonium p(-p).The near p(-p)-threshold behavior of the decay width in the J/Ψ →π0p(-p) process is also discussed.

  9. Implications of a DK Molecule at 2.32 GeV

    CERN Document Server

    Barnes, T; Lipkin, H J


    We discuss the implications of a possible quasinuclear DK bound state at 2.32 GeV. Evidence for such a state was recently reported in D_s^+pi^o by the BaBar Collaboration. We first note that a conventional quark model c-sbar assignment is implausible, and then consider other options involving multiquark systems. An I=0 c sbar n nbar baryonium assignment is one possibility. We instead favor a DK meson molecule assignment, which can account for the mass and quantum numbers of this state. The higher-mass scalar c-sbar state expected at 2.48 GeV is predicted to have a very large DK coupling, which would encourage formation of an I=0 DK molecule. Isospin mixing is expected in hadron molecules, and a dominantly I=0 DK state with some I=1 admixture could explain both the narrow total width of the 2.32 GeV state as well as the observed decay to D_s^+ pi^o. Additional measurements that can be used to test this and related scenarios are discussed.

  10. A possible description of baryon dynamics in dual and gauge theories

    CERN Document Server

    Rossi, G C


    The authors generalize to baryons a framework recently proposed in order to unify gauge, dual and Regge-Gribov theories of mesons. They depart from the 1/N/sub colour/ expansion of quantum chromodynamics (QCD) and replace it by a more general definition of a 'dual' approximation of QCD, based on the zero-width limit. Theoretical and phenomenological consequences of the scheme are derived. For N/sub colour/=3, the baryon resembles a Y shaped string; three families of new 'baryonium' bound states are predicted and rough estimates of intercepts and slopes of the associated Regge trajectories are given. A new type of Zweig-like selection rule is found to hold in leading order and its violations through higher-order topologies are discussed. Duality diagrams for baryons are ambiguous unless implemented with extra lines indicating the flow of certain colour indices. Duality between scattering and annihilation channels is found in BB scattering and its consequences are discussed. Some justification is given for the ...

  11. High energy physics at Tufts University. Progress report. [Summaries of research activities at Tufts University

    Energy Technology Data Exchange (ETDEWEB)


    During the year a final paper was produced on XI* production from 2.9 GeV/c K/sup -/p interactions, and a paper on the ..sigma../sup -/..pi../sup -/..pi../sup +/ (..pi../sup 0/) final state from 2.9 GeV/c K/sup -/d interactions is on the verge of completion. From our 14.75 GeV/c anti pp experiment results have been prepared for publication on three topics: the charm search, V/sup 0/ inclusive production, and ..pi../sup 0/ production. Further analysis of data is continuing. In the 300 GeV/c pp experiment, investigations are completed or underway in three areas: neutral and charged pion correlations, inclusive ..gamma.. and V/sup 0/ production, and inclusive resonance production. Further data on inclusive V/sup 0/ distributions from 6.5 GeV/c K/sup -/p interactions has been obtained and analysis is nearing completion. A good deal of effort went into the development of proposals for new physics. These new directions may be represented by three approved experiments at three different laboratories: Neutrino-deuterium interactions at Fermilab (an approved and a proposed experiment); Search for new states decaying into anti ..lambda lambda.. and K/sup 0//sub s/K/sup 0//sub s/ using the Multiparticle Spectrometer at B.N.L. (approved in May, 1977); Search for baryonium using the SLAC hybrid bubble chamber system, which won approval in September with a recommendation for prompt running from the Program Advisory Committee. A list of publications is included.

  12. Study of B Meson Decays to ppbarh Final States

    Energy Technology Data Exchange (ETDEWEB)

    Hryn' ova, Tetiana B.; /SLAC


    B mesons are unique among well-established non-quarkonium mesons in their ability to decay into baryons. Baryonic B decays offer a wide range of interesting areas of study: they can be used to test our theoretical understanding of rare decay processes involving baryons, search for direct CP violation and study low-energy QCD. This thesis presents measurements of branching fractions and a study of the decay dynamics of the charmless three-body decays of B meson into p{bar p}h final states, where h = {pi}{sup +}, K{sup +}, K{sub S}{sup 0}, K*{sup 0} or K*{sup +}. With a sample of 232 million {Upsilon}(4S) {yields} B{bar B} events collected with the BaBar detector, we report the first observation of the B {yields} p{bar p}K*{sup 0} decay, and provide improved measurements of branching fractions of the other modes. The distribution of the three final-state particles is of particular interest since it provides dynamical information on the possible presence of exotic intermediate states such as the hypothetical pentaquark states {Theta}*{sup ++} and {Theta}{sup +}in the m{sub pK{sup +}} and m{sub pK{sub S}{sup 0}} spectra, respectively, or glueball states (such as the tensor glueball f{sub J}(2220)) in the m{sub p{bar p}} spectrum. No evidence for exotic states is found and upper limits on the branching fractions are set. An enhancement at low p{bar p} mass is observed in all the B {yields} p{bar p}h modes, and its shape is compared between the decay modes and with the shape of the time-like proton form factor. A Dalitz plot asymmetry in B {yields} p{bar p}K{sup +} mode suggests dominance of the penguin amplitude in this decay and disfavors the possibility that the low mass p{bar p} enhancement originates from the presence of a resonance below threshold (such as the recently seen baryonium candidate at 1835 MeV/c{sup 2}). We also identify decays of the type B {yields} X{sub c{bar c}}h {yields} p{bar p}h, where h = K{sup +}, K{sub S}{sup 0}, K*{sup 0} or K*{sup +}, and X