Sample records for baryonium

  1. X(1835): A Possible Baryonium

    ZHU Shi-Lin; GAO Chong-Shou


    We point out that the large p(p) coupling of X(1835) and the suppression of the three-body strange final states strongly indicate that X(1835) may be a p(p) baryonium. We also point out that the branching ratio of X(1835) →ηππ should be bigger than that of X(1835) →η′ππ. We suggest BES search X(1835) in the ηππ channel Finally, X(1835)may be used a tetraquark generator if X(1835) is really established as a baryonium state.

  2. Baryoniums - the S-matrix approach

    In this series of lectures the question of how the baryoniums are related to charmoniums and strangoniums is discussed and it is pointed out that in the S-matrix framework, they all follow from the same pair of hypotheses, duality and no exotics. Invoking no underlying quark structure, except that inherent in the assumption of no exotics, it is shown that there are no mesons outside the singlet and octet representation of SU(3) and no baryons outside the singlet, octet and decaplet. In other words all mesons occur within the quantum number of a q-antiq system and all baryons within those of qqq. This seems to be an experimental fact, which has no natural explanation within the S-matrix framework except that it is the minimal non-zero solution to the duality constraints. The approach in the past has been to take it as an experimental input and build up a phenomenological S-matrix framework. Lately it has been realised that the answer may come from the colour dynamics of quarks. If true this would provide an important link between the fundamental but invisible field theory of quarks and gluons and the phenomenological but visible S-matrix theory overlying it. The subject is discussed under the headings; strangonium and charmonium, baryonium, spectroscopy, baryonium resonances, FESR constraint, baryonium exchange, phenomenological estimate of ω - baryonium mixing at t = 0, and models of ω - baryonium mixing. (UK)

  3. Orbital excitation of exotic mesons and the baryonium problem

    The peculiarities of spectrum of orbitally excited q2-q-2 system are discussed in the model of relativistic string with spin-orbit coupling. The meson trajectories q2-q-2 and spin-orbit splitting of different states are considered. The relation between q2-q-2-spectrum, baryonium and NN-bar interaction is also discussed

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

    Chen, Hua-Xing; Chen, Wei; Liu, Xiang; Zhu, Shi-Lin


    We give an explicit QCD sum rule investigation to hidden-charm baryonium states with the quark content $u\\bar u d\\bar d c\\bar c$, spin $J=0/1/2/3$, and of both positive and negative parities. We systematically construct the relevant local hidden-charm baryonium interpolating currents, and find that these currents can couple to various structures, including hidden-charm baryonium states, charmonium states plus two pions, and hidden-charm tetraquark states plus one pion. The masses of the lowest-lying hidden-charm baryonium states with quantum numbers $J^P=2^-/3^-/0^+/1^+/2^+$ are evaluated to be around 5.0 GeV, so we suggest to search for hidden-charm baryonium states in the $D$-wave $J/\\psi \\pi \\pi$ and $S$-wave $J/\\psi \\rho$ and $J/\\psi \\omega$ channels in this energy region.

  5. Multichannel baryonium and some peculiarities of its decay

    A new kind of the baryonium which is a result of baryon-antibaryon-channel coupling and has specific decay properties is studied. The system N anti N-Y ant Y (Y=Σ, Λ) is treated as a physical example. It is shown that narrow resonances may exist in this system between N anti N and Y anti Y thresholds. The peculiarities of these resonances are as follows: N anti N is the only distinguished two-particle decay channel, K-meson modes dominate amongst multimeson channels. Experimental ways to search for these resonances are suggested

  6. Baryonium and non-exotic hadron trajectories from a color dependent potential

    A natural explanation is presented for the apparent increase in Regge slope with number of quarks in a bound state. The framework used is that of a non-relativistic harmonic oscillator potential with a color dependence suggested by quantum chromodynamics. The ratios of modes of orbital excitations in baryonium, baryon and meson states which are in good agreement with experiment are derived, and the modes of excitation within the baryonium states discussed

  7. From baryonium to hexons

    After a short summary of the theoretical status of fermionic and bosonic constituents of hadrons in the topological bootstrap, two distinctive predictions of this approach -narrow-width baryonia and very high-mass hexons- as well as the relevance of the diquark concept are discussed. In particular, the hexons are expected to reveal a new (TeV) scale of strong interactions

  8. X(1859) Baryonium or something else?

    Using a constituent-quark model we study possible bound or resonance N anti N states. The model fits the p anti p and p anti p cross-sections and explains the large 3P0 antiprotonium energy shift. Only a resonance is found in the 3P0 I=0 partial wave. The threshold enhancement in the J/Ψ→γp anti p decay can be explained with FSI effects in S-waves and no N anti N bound state is needed. (orig.)

  9. New variations on two old themes - String Theory and Baryonium

    A trace factor introduced twenty years ago to incorporate internal symmetry into String Theory is generalised to include also string dynamics, while some new spectroscopic data are examined in relation to a ten year old model of exotic qq-q-barq-bar mesons. (author)

  10. A geometrical approcah of the hadrons and the baryonium

    The quarks is defined as a flavour vector state in the C colour space and the antiquark as a vector in the C* dual space. The observables become scalar in the colour-space built even with a vector and a covector (meson) or with a vector and a pseudo-vector (baryon). The pseudo-vector is responsible of the Pauli principle existence and allows a comprehension of the distinction between baryons and mesons. The investigation of the strong interaction as the exchange of gluons leads to a crossing rule in contradiction with the JOZI rule in the general case. The existence and allowed decay of different sort of baryium is then considered

  11. Twisted baryon loop effects in DTU

    Within the framwork of DTU we propose a simple model for mesons, baryons and baryonium which allows use to calculate the effects of inserting non-planar antiBB loops in all possible ways into meson and baryonium propagators. We study the renormalization of the leading non-zero isospin trajectories and the mixing of qantiq and qqantiqantiq states

  12. Multi-jet structure of hadronic final states and trajectory slope

    On the basis of Veneziano's multi-jet view of hadronic final states, trajectory slopes of the pomeron and the baryonium family are calculated in the unit of the rho-trajectory slope. It is shown that an improved treatment of the multi-chain random walk problem in the impact parameter space leads to the result αsub(rho)' : αsub(p)' : αsub(M4J)' : αsub(M2J)' : αsub(M0J)' = 1 : 1/3 : 1 : 1/3 : 3/20, where M sub(2 n)sup( j) stands for N quark-N antiquark baryonium state. (author)

  13. Research in elementary particle physics

    Kirsch, L. E.; Schnitzer, H. J.

    Research in theoretical and experimental properties of elementary particles is described. This includes measurements made at the multiparticle spectrometer facility at Brookhaven, studies of baryonium production, inclusive hyperon production, and E(0) production. Theoretical work included extended field theories, subconstituent models, finite temperature quatum chromodynamics, grad unified theories, and calculational techniques in gauge theories.

  14. Spin physics at LEAR

    The original physics motivation for the existence of broad baryonium resonances in the anti-NN system is reviewed, and information is given on experiment PS172, whose main objective is to measure the two-body channels anti-pp → ππ, KK, and anti-pp, and subsequently to identify such resonances by partial-wave analysis of the final states. The importance of pursuing the study of the anti-NN → anti-NN channel to distinguish baryonium resonances from ordinary qanti-q mesons is stressed, and a program is presented to measure, on a polarized target, the reactions anti-pp → anti-nn and anti-np → anti-np after ACOL construction. 15 refs

  15. GeV partons and TeV hexons from a topological viewpoint

    An elementary TeV topological hadron supermultiplet breaks into GeV-scale mesons, baryons and baryoniums and TeV-scale ''hexons'' (extremely-heavy bosons corresponding to six topological constituents). Phenomena on the GeV scale are described by parton graphs which give meaning to constituent quarks of QCD type. Hexons are responsible -through mixing- for electroweak-bosons masses, may be responsible for cosmic-ray Centauro events, and promise novel TeV accelerator phenomena

  16. Rescattering effects in antiproton deuteron annihilation at intermediate energies

    In this paper higher order corrections to the single scattering term for antiproton deuteron annihilation are evaluated. As dominant corrections the initial state interaction of the antiprotons and the rescattering of pions are considered. For low spectator momenta, these corrections cause a strong modulation of the distribution in the invariant mass of the annihilation pions, which could modify the parameters of the resonant baryonium states

  17. Elementary particle physics. Progress report covering the five year period November 1, 1974 to October 31, 1979

    Experimental and theoretical research in high energy physics is summarized. Preparations and proposals for future experiments include high mass states decaying into phiπ+-, phiπ+-γ and phiphi produced centrally in 300 GeV/c π-p interactions, search for baryonium and for hyperonium, exotic states and charm decays, and dilepton production by neutrinos. A list of publications is included

  18. Research in elementary particle physics. Technical progress report, May 1, 1979-May 29, 1980

    Experimental research during the period involved use of the BNL multiparticle spectrometer to study S=-2 production and charm and baryonium production. Comments on the program are offered, along with a brief discussion of work on particle detectors. Theoretical research concentrated on topics in effective field theories, quantum chromodynamics, supersymmetry, and Regge behavior in gauge theories. This report is administrative in nature, with no data. A publications list is included

  19. Hadron physics

    Is all hadronic physics ultimately describable by QCD. Certainly, many disparate phenomena can be understood within the QCD framework. Also certainly, there are important questions which are open, both theoretically (little guidance, as yet) and experimentally, regarding confinement. Are there dibaryons, baryonium, glueballs. In addition, there are experimental results which at present do not have an explanation. This talk, after a short section on QCD successes and difficulties, will emphasize two experimental topics which have recent results - glueball spectroscopy and exclusive reactions at large momentum transfer. Both are experimentally accessible in the AGS/LAMPF II/AGS II/TRIUMF II/SIN II energy domain

  20. A search for structure in charged meson spectra from proton-antiproton annihilations at rest

    The charged meson momentum spectra from anti pp annihilation at rest have been measured with high statistics. A search is made for structures between 150 and 300 MeV/c which might indicate narrow baryonium states. We find four narrow lines which are identified with the absorption and decay processes of kaons stopping in the target. No other narrow structure are seen, giving limits of 2-6x10-4/anti p (90% CL) for the yield of a narrow state in the mass range 1510-1660 MeV. (orig.)

  1. A search for narrow lines in gamma spectra from proton-antiproton annihilations at rest

    The gamma ray spectrum from anti pp annihilation at rest has been measured with good energy resolution and high statistics using a magnetic pair spectrometer. No narrow lines with widths comparable to the spectrometer resolution are found. Upper limits (90% CL) are obtained on the yield of narrow baryonium states of 2-5x10-4/anti p for states below 1700 MeV, and 5-10x10-4/anti p for states between 1700 and 1800 MeV. These results are inconsistent with narrow lines observed in an earlier experiment. (orig.)

  2. Quasinuclear states in baryon-antibaryon systems

    A review of modern state of physics of quasinuclear baryon-antibarion systems (''baryonium'') is presented. The comparison between the theory predictions and recent experimental data is carried out. Discrete γ - spectrum from the anti pp annihilation, annihilation and elastic widths for N anti N resonances from experiments with hydrogen and deuterium targets, proton form factor and e+e- annihilation in the vicinity of N anti N threshold are considered. The most important future experiments on antiproton annihilation in nuclear targers are discussed. Experiments which may reveal the existences of 2B anti B and 2B anti 2B systems are predicted

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


    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.

  4. On the production of narrow q2antiq2

    A rather detailed prediction of the mass spectrum and decay modes of Baryonium (or alternatively - diquonium) states has been proposed. The Baryonium in this approach is pictured as a diquark and an antidiquark bound by a short range force but separated by high angular momentum (L approximately or >1). Color plays a crucial role in the procedure, leading to the emergence of two distinct types of qq anti q anti q resonances. One kind has the qq (anti q anti q) pair in colour anti 3 (3) representation and hence consists of broad states decaying primarily into anti B B (T(True)-diquonium). The other type arises when the relevant color representation is 6(anti 6) which means that decay into anti B B must be suppressed if color is to be confined (M(Mock)-diquonium). Both qq anti q anti q classes are expected to decay only reluctantly into mesons as a result of the angular momentum barrier, an argument which derives its main support from the Dual Unitarisation scheme. Experimentally, this means that M-diquoniums should be rather easily detectable objects as they are distinguished by their narrowness on the one hand and their cascade decay mode on the other. The primary aim here is to elaborate on the production mechanisms for the various trajectories, using these to get some estimates of the cross-sections involved. (author)

  5. Stability of D brane-anti D brane systems in confining gauge theories

    Ghoroku, Kazuo [Fukuoka Institute of Technology, Fukuoka (Japan); Nakamura, Akihiro [Kagoshima University, Department of Physics, Kagoshima (Japan); Toyoda, Fumihiko [Kinki University, School of Humanity-Oriented Science and Engineering, Iizuka (Japan)


    We study the stability of a special form of D brane embedding which is regarded as a bound state of D{sub n} and anti-D{sub n} brane embedded in a 10D supergravity background which is dual to a confining gauge theory. For D5 branes with U(1) flux, their bound-state configuration can be regarded as the baryonium vertex. For D branes of n=6 and 8 without the U(1) flux, their bound states have been used to introduce flavor quarks in the dual supersymmetric Yang-Mills theory. In any case, it would be important to ensure that they are free from tachyon instability. For all these cases, we could show their stability with respect to this point. (orig.)

  6. Stability of D brane-anti D brane systems in confining gauge theories

    Ghoroku, Kazuo; Nakamura, Akihiro; Toyoda, Fumihiko


    We study the stability of a special form of D brane embedding which is regarded as a bound state of D n and anti-D n brane embedded in a 10D supergravity background which is dual to a confining gauge theory. For D5 branes with U(1) flux, their bound-state configuration can be regarded as the baryonium vertex. For D branes of n=6 and 8 without the U(1) flux, their bound states have been used to introduce flavor quarks in the dual supersymmetric Yang-Mills theory. In any case, it would be important to ensure that they are free from tachyon instability. For all these cases, we could show their stability with respect to this point.

  7. Research in elementary particle physics: Technical progress report, June 1, 1986-May 31, 1987

    Work is reported in the areas of: design, construction, and testing of components of the CDF, including shower counters, electronics, and electron identification algorithms; contributions to the design and construction of the Brookhaven MultiParticle Spectrometer; search for charm and K*'s and baryonium; measurement of differential cross section and polarization in the Lambda-antiLambda channel; a study of Xi states which measured the Xi asymmetry parameter; and dibaryon searches using the Brookhaven Hypernuclear Spectrometer. Theoretical efforts are reported in the areas of string theory, the Skyrme model applied to elementary particle phenomenology, quantum field theory, cosmology, galaxy formation, supernova 187A, field theory in curved space-times, and spin-glasses

  8. Proceedings of the meeting on few-body problems in high and medium energy physics

    The study meeting on few-body problems in high and medium energy physics was held from October 3 to 5, 1985, at National Laboratory for High Energy Physics. Two meetings were held already concerning few body physics, but most of the participants were theorists. In this meeting, high priority was put on the attendance of experimental physicists. As a bridge between particle and nuclear physics, the few body physics in an intermediate energy region has become important recently. The topics in this meeting were meson spectroscopy, baryonium, kaon physics, muonic fusion, dibaryon, φNN system, quarks and skyrmions, NN correlation, and symmetry test in few-body system. The gists of the papers presented are collected in this book. (Kako, I.)

  9. Common Problems and Ideas of Modern Physics - Proceedings of the 6th Winter School on Hadronic Physics

    Bressani, T.; Minetti, B.; Zenoni, A.


    The Table of Contents for the full book PDF is as follows: * Preface * I. COHERENCE PHENOMENA * Coherence in QCD and QED * Quantum theory of scattering for tightly coupled scatterers * Gravitational radiation antenna cross sections * The EMC effect * The Mössbauer effect * II. SUBNUCLEAR PHYSICS * Heavy quarkonium spectroscopy * Baryonium phenomenology * Physics at DAΦNE * The "Darmstadt effect" * III. NUCLEAR PHYSICS * Frontiers and Perspectives in Nuclear Physics * Nuclear physics at DAΦNE * Intermediate energy antiproton-nucleus reactions to test quantum chromodynamics * Boundary condition approach to multiple scattering off composite systems * An updated survey of experimental work on nuclear cold fusion * IV. EXPERIMENTAL TECHNIQUES AND PARTICLE ACCELERATORS * The Frascati Φ-factory project * The Obelix central detector * New trends in gas drift chambers * Multi-level triggers in modem experiments * List of Participants * Subject Index * Author Index

  10. Search for narrow meson production in antipN interactions at 6 and 9 GeV

    The experiment described in this report was carried out with the SLAC hybrid bubble chamber. Evidence was found for a narrow peak of mass M approximately 2.02 GeV and width GAMMA +π-π- at 6 GeV and antipp → πsub(f)sub(+)(antipn)π+π- at GeV, with an observed cross section of about 1 μb in both cases. The total statistical significance of these signals is better that 7 σ; the production mechanisms of this NantiN resonance which could be an isovector baryonium seem very complex. More classical resonances such as the ω(1670) detected in the reaction antipp → π+π+π-π-π0 in its π+π-π0 decay mode were otherwise analysed

  11. Narrow baryonia with open hidden strangeness

    A search for baryonia with open and hidden strangeness decaying into strange particles has been carried out in a neutron beam with a mean momentum of 40 GeV/c with the BIS-2 spectrometer at the Serpukhov accelerator. There is a strong indication of the existence of baryonia with negative (Ms) and positive (M-bars) strangeness, decaying respectively into Λp-bar + pions and Λ-barp + pions. The isotopic spin of the strange baryonia is ≥ 3/2. Their mean mass is (3060 ±5 (st.) ± 20 (syst.)) MeV/c2. There is an indication of the existence of narrow baryonium with hidden strangeness (Mφ), decaying into Λp-barK+(+π±), Λ-barpK-(+π±) and K0spp-barK±. The mean value of its mass is (3260 ±5 (st.) ±20 (syst.)) MeV/c2. The widths of the searched baryonia are (35 ± 5) MeV/c. The production cross-sections the baryonia in the kinematic region XF ≥0.2 and Pt ≤ 1 GeV/c, are (0.3 - 1.0) μb/per nucleon (90% C.L.). 33 refs.; 9 figs.; 4 tabs

  12. Particle spectroscopy

    During the last years, particle spectroscopy has evolved into the spectroscopy of leptons and quarks. This era was initiated in 1974 by the discovery of J/psi mesons, quickly followed by new lepton Tau and finally Ypsilon mesons. In this report, talk is concentrated on one specific old hadrons, namely exotics. The main part is then devoted to the new quarks charm and beauty. As for the exotics, baryonium in its broad and narrow states, dibaryons, and exotic quantum numbers are described. There is no firm evidence for exotic quantum numbers so far. Consequently, both experiments and theory have to be improved. Next, new quark spectroscopy is described on quark charge, charm (charmonium, charm particles, F mesons), and beauty. Description of the beauty is further divided into Ypsilon parameters, event topology, quark jets, change of topology at the Ypsilon, other properties of events in the Ypsilon region, Ypsilon summary, and Ypsilon prime. As seen above, in addition to the charm quark, there is now ample evidence for the existence of a new heavy quark which is most probably of the 'beauty' type. To answer the question whether a 6th quark t would constitute perfect symmetry between leptons and quarks, again the answer can now only be: PETRA works and CESR and PEP will follow soon. (Wakatsuki, Y.)

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


    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...

  14. High accuracy measurement of the total cross section and of the real part of the scattering amplitude π+p from 2 to 14 GeV/c

    This thesis presents the results of the experiment PS 157 which has been carried out at the CERN in 1980; the total cross section of π+p for 4000 values of energy was measured with an accuracy of 5%. The density of the measurements allows the exploration of a new region of the plane (width, elasticity) for narrow baryon resonances of which the mass is between 2 and 5,5 GeV/c2. The total cross section of K-p has also been measured between 4,6 and 4,9 GeV/c for 80 momentum values; the measurement quality allows to exclude any narrow resonance of which the partial elastic width is below 10 kw/c2 and to clarify the confused situation of the Δ resonances. The principles of the measurements are first given. The experimental results of the researches of narrow baryon resonances are presented; the main results of baryonium physics are recalled as also the most important theoretical models which are applied to mesobaryons. Then, one deals with the normalization process, the efficiency of the transmission detectors, and the determination of the total cross section. Finally, the total cross sections of π+p and π-p are compared, and one studies the forward elastic differential cross sections, to determinate on one side ''the slope'' of the nuclear differential cross section, and on the other side the real part of the scattering amplitude, by means of the measurement of the interference term between the Coulomb and nuclear amplitudes. 33 refs

  15. Study of B Meson Decays to ppbarh Final States

    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