WorldWideScience

Sample records for baryonium

  1. Baryoniums and related states

    International Nuclear Information System (INIS)

    Hong-Mo, C.

    1978-01-01

    A brief introduction is given to current theoretical ideas on baryonium states with particular emphasis on their interpretation as 'colour molecules'. It is argued that baryonium spectroscopy provides a valuable test for colour as a new degree of freedom. (author)

  2. Quasinuclear baryonium and annihilation

    International Nuclear Information System (INIS)

    Kerbikov, B.O.; Shapiro, I.S.

    1978-01-01

    The properties of the quasinuclear baryonium are considered in the framework of the dynamical coupled channel model. The main principles of the model are reviewed. The energy spectrum of the N anti N system and the problem of the baryonium radius are discussed. A detailed investigation of the problem of baryonium annihilation width and the low energy N anti N annihilation cross section is presented

  3. Exotic baryonium exchanges

    International Nuclear Information System (INIS)

    Nicolescu, B.

    1978-05-01

    The prominent effects supposed to be associated with the exchange of exotic baryonium Regge trajectories are reviewed. The experimental presence of all expected effects leads to suggest that the baryonium exchange mechanism is a correct phenomenological picture and that mesons with isospin 2 or 3/2 or with strangeness 2, strongly coupled to the baryon-antibaryon channels, must be observed

  4. A model for baryonium

    International Nuclear Information System (INIS)

    Hong-Mo, C.

    1977-11-01

    The spectrum of qq anti q anti q hadrons examined in a quark-gluon model yields two types of states both of which have small mesonic widths and may be associated with baryoniums. One type (T-diquonium) has normal hadronic widths into B anti B, while the other (M-diquonium) is narrow and decays into B anti B only reluctantly, preferring if possible to decay by cascade. The experience gained from ordinary hadron spectroscopy plus some new phenomenological observations, allow one to predict the spectrum and properties of both types in considerable detail. The result bears close resemblance to present experiment. The existence of narrow M-diquonium states follows only from hidden colour, and if established would be a major triumph for the concept. It would however be only the first example of a quite general phenomenon which may well develop into a whole new branch of hadron spectroscopy. (author)

  5. Baryoniums - the S-matrix approach

    International Nuclear Information System (INIS)

    Roy, D.P.

    1979-08-01

    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)

  6. Baryonium states: Where do they begin

    International Nuclear Information System (INIS)

    Mitra, A.N.

    1982-01-01

    An investigation of the mass levels of ground and excited qqq-barq-bar (baryonium) states is carried out within a Bethe--Salpeter framework for a four-body system with pairwise q-q-bar and q-q interactions of the h.o. type. The identity of quarks, and separately, of antiquarks, in a qqq-barq-bar system gives rise to a well-defined set of selection rules governing the spin-isospin-orbital structures of T- and M-baryonia. A relativistic mass formula, similar to those derived recently for qq-bar and qqq systems, including spin and momentum dependent effects, is now obtained for the qqq-barq-bar system. The values of the parameters employed for mass prediction for qqq-barq-bar states, viz., the non-strange quark mass (m/sub q/ = 0.28) and the reduced spring constant (omega-bar = 0.15), are the same as those used earlier for a successful description of non-strange qq-bar and qqq spectroscopy in a unified fashion. The main prediction on the mass locations is that the orbitally unexcited qqq-barq-bar states are all in the range 2.5--3.1 GeV, the lowest one (a scalar T-baryonium) being around 2.5 GeV. Possible experimental significance of this result is briefly discussed in the latest context of disappearance of the sharp features of most baryonium states

  7. Baryoniums coupled directly to the photon

    International Nuclear Information System (INIS)

    Hong-Mo, C.

    1978-09-01

    This note is an addendum to a paper recently presented by the author (Hong-Mo. Baryonium Spectroscopy as a Test for Colour Dynamics. IV European Antiproton Symposium. June 1978. CERN preprint TH2540 (1978)). Attention is drawn to a further group of experiments which yield information on the diquonium spectrum, namely e + e - annihilation and diffractive photo-production, which select states with Jsup(PC) = 1 -- . A spectrum of diquoniums with these quantum numbers, in which the splitting due to L . S interactions between the diquark and antidiquark have been included, is shown and discussed. (U.K.)

  8. Proton-antiproton interactions (experimental status of baryonium states)

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, Y.

    1980-07-01

    Many experiments have been performed in the last few years to search for the existence of baryonium (baryon-antibaryon bound) states. The current status in this direction is reviewed. Prominent resonances such as the S-meson resonance, broad resonances, narrow resonances and states such as the strange baryonium states, exotic states, antiproton-proton states below threshold, six-quark states are explained. A summary of the experimental data with illustrations is presented in a table.

  9. 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)

    2016-11-15

    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.)

  10. Baryon-antibaryon threshold and ω-baryonium mixing

    International Nuclear Information System (INIS)

    Gavai, R.V.

    1981-01-01

    It is shown that in any dual-topological-unitarization model of ω-baryonium (B) mixing at the cylinder level, in which the production of baryon-antibaryon (bb-bar) pairs can take place only above a certain threshold energy, the phenomenologically relevant ω and B trajectories do not mix below bb-bar threshold. However, their couplings to external particles do get modified. The ω-B mixing angle theta/sub omegahyphenB/, which characterizes these coupling modification effects below bb-bar threshold at t = 0, is estimated in some models. These estimates are found to agree reasonably well with the existing phenomenological bound on theta/sub omegahyphenB/

  11. Investigations on baryonium and other rare pp annihilation modes using high resolution π0 spectrometers (PS 182)

    International Nuclear Information System (INIS)

    Adiels, L.; Backenstoss, G.; Bergstrom, I.; Carius, S.; Charalambous, S.; Cooper, M.; Findeisen, C.; Fransson, K.

    1985-01-01

    In the search for heavy, narrow exotic states such as baryonium or glueballs, carried out so far, various methods of high- and low-energy formation, and e + e - reactions were used. In particular, a search for baryonium states below threshold (M/sub x/ less than or equal to M/sub anti pp/ has shown some evidence for a few states. However, the results of these measurements suffer from poor statistics. Because of the relatively low level of confidence in these results it would be highly desirable to compare them with new measurements of better statistics, now available at the CERN low-energy antiproton ring, LEAR, and with independent measurements based on techniques hitherto not used, which the quality of LEAR now makes feasible

  12. From baryonium to hexons

    International Nuclear Information System (INIS)

    Nicolescu, B.; Poenaru, V.

    1984-10-01

    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

  13. Multiquark exotics (baryonium, dibaryons etc)

    International Nuclear Information System (INIS)

    Kondratyuk, L.A.

    1987-01-01

    The multiquark exotic resonant states q 2 -(anti q) 2 , q 3 -(anti q) 3 , q 6 and q 9 are discussed as systems composed of the few colour clusters. Special attention is devoted to the problem of narrow resonances in channels anti NN, Δanti p+pions, πNN and NN. 42 refs.; 2 figs.; 5 tabs

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

    International Nuclear Information System (INIS)

    Chan Hong-Mo.

    1989-07-01

    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)

  15. Hadron spectroscopy

    International Nuclear Information System (INIS)

    Igi, K.

    1979-01-01

    This paper is related to mini-rapporteur talk on baryonium spectroscopy. First of all, the models of baryonium, namely the diquark model, the string picture, the linear baryonium and the bag model, are described. All of these models so far discussed are highly suggestive. In this paper, discussions are confined to the spectroscopy of the string and the bag models. Because of the color degree of freedom, the bag model has mock diquonium and mock mesonium besides true baryonium. It might be possible that the string model takes into account only a part of them. The constraints among baryonium, baryon and boson trajectories using duality and unitarity were proposed as a guide for classifying various spectra. Inequalities were derived as the modest and reliable constraints on baryonium intercepts from baryon and boson intercepts by imposing unitarity and Regge behaviors on scattering amplitudes. As a consequence of residue factorization and duality, the baryonium slopes were derived. The spin of S (1936) was also obtained. The baryonium containing s or c quarks can also be studied. Topics such as the EXD patterns of baryons, linear baryons, linear Regge trajectories for all Q-anti Q families, and the Al and two Q mesons, are presented in this paper. Comments on di-baryon are described. (Kato, T.)

  16. Summary talk - hadronic interaction session

    International Nuclear Information System (INIS)

    Frautschi, Steven

    1978-01-01

    The recent work on calculating jets and large p sub (T) events by perturbative QCD are reviewed. Special emphasis is placed on the QED origins of the ideas. Prompt lepton pairs and baryonium are also discussed. (author)

  17. New directions in elementary particle physics: p anti p from very low to very high energies

    International Nuclear Information System (INIS)

    Jacob, M.

    1979-01-01

    The review covers low energy anti pp physics including annihilation processes, the spectroscopy of baryonium states, quasinuclear states and their relation to baryonium, the spectroscopy of protonium, and access to the whole charmonium family. High energy anti pp physics is reviewed covering total cross section rise, the common shape of cross sections, real part of forward amplitude, particle production, quantum number excitation, high transverse momentum, and high mass lepton pair. Also reviewed are the search for the weak bosons, hadron physics at collider energies, and the anti pp collider program. 47 references

  18. Progress report 1977-1978

    International Nuclear Information System (INIS)

    1978-01-01

    This annual report surveys briefly the studies for the year 1977-78 in Corpuscular Physics Laboratory. The results of different experiments made in collaboration with other laboratories are reported: long range hadron interactions, baryonium states put into evidence by baryon exchange, two-body interactions, excited baryons, quark transverse momentum, quark annihilations [fr

  19. Topics in gauge theories and unification of elementary particle interactions: Progress report for period April 1, 1986-June 30, 1987

    International Nuclear Information System (INIS)

    Srivastava, Y.N.; Vaughn, M.T.

    1987-06-01

    Work is reported on: minjets and the rise of the total cross-section in QCD; quantum electrodynamic effects in macroscopic circuits; experimental search for electroweak effects in circuits; baryonium states with heavy quarks; E 6 superpotentials and heterotic string phenomenology; and computer graphic representations of solutions to classical field equations

  20. Annual report 1979-1980

    International Nuclear Information System (INIS)

    Experiments have been performed at CERN in collaboration with scientists from other laboratories: search of new narrow resonant structures, baryonium, dibaryons, hadrons structure studied with the 'Lezard' spectrometer, flavour... The participation to the UA1 experiment continued and developed a very important technical cooperation [fr

  1. NantiN forces and annihilation in the potential approach

    International Nuclear Information System (INIS)

    Vinh Mau, R.

    1982-05-01

    The future experimental program of LEAR justifies the necessity for a careful theoretical study of the nucleon-antinucleon interaction. The question is whether the baryonium states exist and if so, whether they can the described as NantiN bound states or resonances

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

    International Nuclear Information System (INIS)

    1979-01-01

    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

  3. A four-body potential in multiquark states

    International Nuclear Information System (INIS)

    Warner, R.C.; Joshi, G.C.

    1980-01-01

    A detailed analysis is presented of the first member of a previously derived hierarchy of instanton generated many-body potentials for multiquark states. Comparison with two-body instanton generated potential in the heavy quark framework is made in the T-baryonium system

  4. Research in elementary particle physics. Technical progress report, May 1, 1980-April 30, 1981

    International Nuclear Information System (INIS)

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

    1981-01-01

    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. Theroetical work included extended field theories, subconstituent models, finite temperature QCD, grand unified theories, and calculational techniques in gauge theories

  5. Note on the narrow 3.1 GeV (Λ p-bar + pions)

    International Nuclear Information System (INIS)

    Chan Hongmo; Tsou Sheungtsun

    1987-02-01

    It is pointed out that the narrow exotic U(3.105) (Λ p-bar + pions) state reported at CERN and Serpukhov and its companion at 3.410 GeV, fall neatly on top of the spectrum predicted nine years ago for 'M-baryoniums' and agree with the expected decay characteristics. Further, when so interpreted, their spacing gives a direct measure of the colour Casimir factor in the string tension. (author)

  6. A scheme for the hadron spectrum

    International Nuclear Information System (INIS)

    Hoyer, P.

    1978-03-01

    A theoretically self-consistent dual scheme is proposed for the hadron spectrum, which follows naturally from basic requirements and phenomenology. All resonance properties and couplings are calculable in terms of a limited number of input parameters. A first application to ππ→ππ explains the linear trajectory and small daughter couplings. The Zweig rule and the decoupling of baryonium from mesons are expected to be consequences of the scheme. (Auth.)

  7. Elementary particle physics. Progress report covering the five year period November 1, 1974 to October 31, 1979. [Summaries of research activities at Florida State Univ

    Energy Technology Data Exchange (ETDEWEB)

    1979-01-01

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

  8. Why explicit gluonic components are needed in multiquark wave functions

    International Nuclear Information System (INIS)

    Lipkin, H.J.

    1982-03-01

    Constituent quark models with nontrivial correlations between color and space and no explicit description of the gluon degrees of freedom are inconsistent with local color gauge invariance. The screening by gluons of local color density in the quark sector must be included in treatments of long range forces in multiquark states. Neglect of gauge invariance and screening leads to erroneous predictions like unobserved Van der Weals forces and unobserved ''baryonium'' states with localized color. (author)

  9. GeV partons and TeV hexons from a topological viewpoint

    International Nuclear Information System (INIS)

    Chew, G.F.; Issler, D.; Nicolescu, B.; Poenaru, V.

    1984-04-01

    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 describable by parton graphs which give meaning to constituent quarks of QCD type. Hexons are responsible - through mixing - for electroweak-boson masses, may be responsible for cosmic-ray Centauro events, and promise novel TeV accelerator phenomena. 25 references

  10. GeV partons and TeV hexons from a topological viewpoint

    International Nuclear Information System (INIS)

    Chew, G.F.; Issler, D.; Nicolescu, B.; Poenaru, V.

    1984-04-01

    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

  11. The colour and flavour 1/N expansions

    International Nuclear Information System (INIS)

    Veneziano, G.

    General ideas about the colour and flavour 1/N expansions are presented in a non-specialized fashion according to both: a unified approach to meson dynamics (the basic logical scheme, lepton-hadron interactions, hadronic processes in lowest order, higher order effects and the Reggeon calculus); and a possible extension to baryons (difficulties with baryons in dual and gauge theories, possible definition of dual baryons in quantum chromodynamics, lowest order B anti-B and BB scattering: baryonium, Reggeon calculus for processes involving baryons)

  12. Hadron physics

    International Nuclear Information System (INIS)

    Bunce, G.

    1984-01-01

    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

  13. Some open issues in nucleon-antinucleon interaction

    International Nuclear Information System (INIS)

    Richard, J.M.

    1990-01-01

    The conventional picture of the NN-bar (nucleon-antinucleon) interaction at low energy relies on the superposition of a long-range elastic potential and a short-range absorption. The meson-exchange model, which has been successful until the opening of LEAR, is not likely to survive the LEAR-ACOL era. Recent data on spin observables contradict the predictions of potential models. Annihilation and long-range forces are discussed as well as quasi-bound baryonium states. (K.A.) 11 refs

  14. The NN and NantiN interactions

    International Nuclear Information System (INIS)

    Vinh Mau, R.

    1981-01-01

    The present status of the low and medium energy NN interaction and of the low energy NantiN interaction is reviewed. Careful confrontation of theoretical predictions with the most recent results on experimental observables is emphasized. The question of the dibaryon resonances is discussed. For the NantiN interaction, in view of the problem of the existence of baryonium states as bound states or resonant states of the NantiN system and of their properties, tests of different types of annihilation potentials against the existing experimental data are examined. Implications for the future experimental program at LEAR are discussed

  15. LEAR

    International Nuclear Information System (INIS)

    Lefevre, P.

    1984-01-01

    In general LEAR provides a precise experimental tool which: opens the domain of low energy quark dynamics (chemistry of quarks by carrying experiments connected to baryonium, gluonium, etc..), using nuclear targets it allows to tackle the nuclear physics aspects in a completely new fashion, permits many exciting applications to future options due to the further improvements on statistical precision and energy resolution (Δp/p): internal targets, H - anti p co-rotating beams (protonium formation in flight), panti p collider and ultra low energy domain (down to 20 MeV/c.). (orig./HSI)

  16. One interpretation for recent BES observation

    International Nuclear Information System (INIS)

    Hao Gang; Qiao Congfeng; Zhang Ailin

    2007-01-01

    Motivated by the recent BES observation of the p(p-bar) enhancement near threshold in radiative J/ψ decays, X(1860) and X(1835), we choose the 0 -+ trigluonium state as a possible candidate and calculate its mass with QCD sum rules, which is found to be approximately in the region between 1.9GeV and 2.7GeV with some theoretical uncertainties. With the fact that the new BES resonance exhibits the behavior of this trigluon state, our analyses favor the baryonium-gluonium mixing picture for the BES observation. (authors)

  17. Search for narrow signals in the γ-spectrum from panti p annihilation at rest

    International Nuclear Information System (INIS)

    Adiels, L.; Bergstroem, I.; Backenstoss, G.; Findeisen, C.; Repond, J.; Tauscher, L.; Williams, M.C.S.; Charalambous, S.; Hatzifotiadou, D.; Zioutas, K.; Cooper, M.D.; Kerek, A.; Pavlopoulos, P.; Troester, D.

    1986-01-01

    The γ-spectrum originating from panti p annihilations at rest in liquid hydrogen was measured with two BGO spectrometers. A total of 24x10 6 γ's were accumulated. No narrow peaks indicating exotic states such as baryonium were observed. The upper limit for the branching ratio panti p→γ+X with 1040≤m x ≤1770 MeV/c 2 and with Γ x ≤25 MeV/c 2 is less than 10 -3 with more than 99.96% confidence. (orig.)

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

    CERN Multimedia

    2002-01-01

    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.

  19. Session A5: hadron spectroscopy, experimental

    International Nuclear Information System (INIS)

    Ozaki, S.

    1978-01-01

    Reports 55 contubutions made by mini-rapporteurs and individual contributors are assembled. It is clear, from the contributions made to this session, that there has been steady progress in solving the problem of the hadron spectroscopy of the old style. The picture on the scalar mesons has become clearer. Among the vector meson group, we started to understand Q mesons, though the situation with A 1 is still not clear. Mesons with higher spin have been found and, in some cases, confirmed. In a sense, the jigsaw puzzle on the mesons is gradually being completed while more complex features are found. The same can be said on the baryons. An active study is in progress in the experiment on the exotic states such as narrow baryonium and dibaryon states. However, owing to the difficulty of such experiments and interpretation of the data, a definitive result is yet to come. 94 references

  20. Colour isomers in multiquark systems

    International Nuclear Information System (INIS)

    Hoegaasen, H.

    1979-01-01

    If we select configurations where a high angular momentum separates coloured groups of quarks the states can be sufficiently stable to show up as resonances. The kind of states I shall talk about are mesons of the following kind (C=6,7), (C=3 bar,3) and baryons: (C=8,8), (C=6 bar,6). In each state the quarks on each end of the colourelectric flux tube are taken to be in relative s-waves. Models for baryonium and of narrow mesobaryonium states have been proposed on the basis of these configurations. The theoretical input in these models is an extrapolation of what is known about quark-quark interactions from ordinary q anti q and qqq spectroscopy. (author)

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

    International Nuclear Information System (INIS)

    Kirsch, L.E.; Schnitzer, H.J.; Abbott, L.F.; Bensinger, J.R.; Blocker, C.A.

    1987-01-01

    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

  2. The quark bag model

    International Nuclear Information System (INIS)

    Hasenfratz, P.; Kuti, J.

    1978-01-01

    The quark bag model is reviewed here with particular emphasis on spectroscopic applications and the discussion of exotic objects as baryonium, gluonium, and the quark phase of matter. The physical vacuum is pictured in the model as a two-phase medium. In normal phase of the vacuum, outside hadrons, the propagation of quark and gluon fields is forbidden. When small bubbles in a second phase are created in the medium of the normal phase with a characteristic size of one fermi, the hadron constituent fields may propagate inside the bubbles in normal manner. The bubble (bag) is stabilized against the pressure of the confined hadron constituent fields by vacuum pressure and surface tension. Inside the bag the colored quarks and gluons are governed by the equations of quantum chromodynamics. (Auth.)

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

    International Nuclear Information System (INIS)

    Yukawa, T.

    1985-12-01

    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.)

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

    International Nuclear Information System (INIS)

    Vilanova, D.

    1984-02-01

    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 - π 0 in its π + π - π 0 decay mode were otherwise analysed [fr

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

    CERN Document Server

    Van De Walle, R T

    1980-01-01

    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...

  6. Duality, exchange-degeneracy breaking, and exotic states

    International Nuclear Information System (INIS)

    Goldstein, G.R.; Haridas, P.

    1979-01-01

    We study the connection between exchange-degeneracy breaking and multiquark states within the framework of a highly constrained dual approach. We show that M 4 (baryonium) states emerge at the daughter trajectory level as a consequence of small exchange-degeneracy breaking in the meson-meson system (approx.delta) and larger exchange-degeneracy breaking of the baryon trajectories in the meson-baryon system (approx.epsilon). The M 4 states are coupled weakly to external mesons in proportion to the breaking parameter delta. Assuming M 4 couplings to B-barB channels are strong, as determined by duality with normal mesons in the B-barB system, consistency requires epsilon approx. √delta-bar, thereby relating the larger breaking of baryon trajectories to the violation of the Okubo-Zweig-Iizuka-type rule for M 4 . It is shown that exotic baryon states, B 5 , also emerge from this scheme at the daughter level and that dibaryons will appear at the second daughter level

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

    CERN Document Server

    Rossi, G C

    1977-01-01

    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 ...

  8. High energy physics at Tufts University. Progress report

    International Nuclear Information System (INIS)

    1977-09-01

    During the year a final paper was produced on XI* production from 2.9 GeV/c K - p interactions, and a paper on the Σ - π - π + (π 0 ) final state from 2.9 GeV/c K - 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 0 inclusive production, and π 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 γ and V 0 production, and inclusive resonance production. Further data on inclusive V 0 distributions from 6.5 GeV/c K - 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 ΛΛ and K 0 /sub s/K 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

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

    CERN Multimedia

    2002-01-01

    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...

  10. The Okubo-Zweig-Iizuka rule and dual unitarization

    International Nuclear Information System (INIS)

    Ninomiya, Kansuke; Toyoda, Fumihiko.

    1978-01-01

    The Okubo-Zweig-Iizuka (OZI) rule carries an important role in the constituent rearrangement and interest in the rule has been increased by the discovery of the J/psi particle. An example of phenomenological analysis related to the OZI rule is introduced. The decays of psi particles can be explained consistently by an existence of the disconnected type of a constituent rearrangement diagram (CRD) with comparable strength to that of the connected one. A survey of an outline of the dual unitarization scheme and discussion of the OZI rule with the scheme and other related theory are presented. The method of dual unitarization starts with the unitarity relation. In the estimation of multiparticle production amplitude in the unitarity sum, dominant nondiffractive production component is taken as a first approximation and the amplitude is described by the multiperipheral model of Reggeon exchange. Here, a case of meson-meson scattering in flavor of SU(N) scheme is considered. A survey of the mechanism of the planar bootstrap and Pomeron generation in the dual unitarization is made. The nonplanar CR diagrams give breaking of various features at the planar level. The reaction with the disconnected CRD could occur in the nonperipheral region through the hard collision of constituent and appears at large momentum transfers in comparable order with a connected one. Baryon and baryoniums with the scheme of the dual unitarization are examined. (Kato, T.)

  11. Protonium spectrosopy and identification of P-wave and S-wave initial states of p-p annihilations at rest with the ASTERIX experiment at LEAR

    International Nuclear Information System (INIS)

    Gastaldi, U.; Ahmad, S.; Amsler, C.

    1984-01-01

    This chapter discusses an experiment designed to study the general features of p - p interactions at rest, to extend work done in the spectroscopy of light mesons produced in p - p annihilations at rest, and to search with high sensitivity for gluonium, qq - qq baryonium structures and NN states bound by strong interactions. The effect of using a gas target and a large acceptance X-ray detector is examined. The rate and the signature of antiprotons stopping in the gas target are investigated. Topics covered include the protonium cascade and spectroscopy; a comparison of S-wave and P-wave p - p annihilations at rest; - p stop and the formation of p - p atoms; the x-ray detector (projection chamber, electronics, tests); and examples of estimations of signal and background (protonium spectroscopy, search of resonances in P-wave annihilations, search of resonances in S-wave annihilations). The distinctive features of the ASTERIX experiment are the use of a gaseous H 2 target instead of a conventional liquid H 2 one; an X-ray detector of large overall detection efficiency, low energy threshold and low background rate that enables identification of P-wave and S-wave annihilation events from 2P and 1S levels of protonium; a detection system for the products of p - p annihilations; and a trigger system that enables filtration of the acquisition of events by means of two independent chains of processors working in parallel

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

    Energy Technology Data Exchange (ETDEWEB)

    1977-09-01

    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.

  13. Study of B Meson Decays to ppbarh Final States

    Energy Technology Data Exchange (ETDEWEB)

    Hryn' ova, Tetiana B.; /SLAC

    2006-03-22

    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