International Nuclear Information System (INIS)
Dominguez, C.A.
1987-02-01
The scalar (0 ++ ) and the tensor (2 ++ ) gluonium spectrum is analyzed in the framework of QCD sum rules. Stable eigenvalue solutions, consistent with duality and low energy theorems, are obtained for the mass and width of these glueballs. (orig.)
In a search for scalar gluonium
International Nuclear Information System (INIS)
Novikov, V.A.; Shifman, M.A.; Vainshtein, A.I.; Zakharov, V.I.
1979-01-01
The problem of a scalar meson coupled strongly to gluons is discussed. Radiative decays of the J/psi are taken as a source of gluons. The aim of the paper is to calculate the GITA(J/psi→σγ) decay width where σ is the presumed scalar luonium. QCD sum rules was used to find both , (where Gsub(μν)sup(a) is the gluon field strength tensor and αsub(s) is the quark-gluon coupling constant) and GITA(J/psi→σγ) in terms of . The final prediction for the width is expected to be valid within a factor of two and gives GITA(J/psi→σγ→ two pions in S wave + γ) approximately equal to 25 eV for Msub(σ)=700 MeV. Nonperturbative QCD naturally explains the observed asymmetry between scalar and pseudoscalar states in the radiative decays of the J/psi. Some general remarks on gluonium in QCD are made
A global fit to determine the pseudoscalar mixing angle and the gluonium content of the η' meson
International Nuclear Information System (INIS)
Ambrosino, F.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bertolucci, S.; Bloise, C.; Bossi, F.; Capon, G.; Capussela, T.; Ciambrone, P.; De Lucia, E.; De Simone, P.; Archilli, F.; Beltrame, P.; Bini, C.; De Santis, A.; De Zorzi, G.; Bocchetta, S.; Ceradini, F.; Branchini, P.
2009-01-01
We update the values of the η-η' mixing angle and of the η' gluonium content by fitting our measurement R φ = BR(φ → η'γ)/BR(φ → ηγ) together with several vector meson radiative decays to pseudoscalars (V → Pγ), pseudoscalar mesons radiative decays to vectors (P → Vγ) and the η' → γγ, π 0 → γγ widths. From the fit we extract a gluonium fraction of Z G 2 = 0.12±0.04, the pseudoscalar mixing angle ψ P = (40.4±0.6) 0 and the φ-ω mixing angle ψ V = (3.32±0.09) 0 . Z G 2 and ψ P are fairly consistent with those previously published. We also evaluate the impact on the η' gluonium content determination of future experimental improvements of the η' branching ratios and decay width.
International Nuclear Information System (INIS)
Heusch, C.A.; California Univ., Santa Cruz, CA
1991-01-01
Quantum chromodynamics predicts the existence of quarkless mesons. The search for these hadrons has been ingenious and persevering. A review is presented of the current status of research that considers all model-dependent theoretical prejudice when searching for specific states. Early hints for candidate states have been investigated in the light of recent data, mostly from the Mark III Collaboration, in radiative charmonium decay. No 'smoking-gun' candidate stands out. (R.P.) 25 refs., 20 figs., 2 tabs
Glueball candidate iota(1460) and quarkonium-gluonium mixing
International Nuclear Information System (INIS)
Basu, S.; Lahiri, A.; Bagchi, B.
1988-01-01
Using infinite-momentum-frame techniques we generalize the Schwinger formula for the pseudoscalar nonets to include the effects of the iota(1460). By seeking consistency with its current rates we estimate the eta-eta'-iota(1460) mixing angles. We also allow the possibility of nonet symmetry breaking in the iota couplings. Our results support a glueball interpretation of the iota with eta,eta' not inconsistent with quarkonium states
Gluonium candidates from hadronic and e+e- interactions
International Nuclear Information System (INIS)
Heusch, C.A.
1985-12-01
The experimental approaches exploited in the search for gluonia that are deemed most promising are briefly described, both in hadron-hadron collisions and heavy quarkonium decay. The presently available evidence is summarized for those states that have been claimed as possible gluonia. Proceeding in the order of lowest-mass expectation, categorization is done only in terms of definitive (or putative) J/sup PC/ assignments. 51 refs., 16 figs., 3 tabs
Quark-gluon mixing in pseudoscalar and tensor mesons
International Nuclear Information System (INIS)
Eremyan, Sh.S.; Nazaryan, A.E.
1986-01-01
A mixing model of quark-antiquark ang gluonium states in η, η', i(1440) pseudoscalar and f, f', Θ(1690) tensor mesons is considered. Description of and predictions for 68 two-particle decays with these particles taking part in them are obtained. It is shown that i(1440) by 85% consists of gluonium and Θ(1690) is a pure gluonic state. The quark-gluon and gluon-gluon couplings in the pseudoscalar sector are obtained to be stronger as compared to the corresponding ones in the tensor case
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.)
J/psi and Υ radiative and hadronic decays
International Nuclear Information System (INIS)
Bloom, E.D.
1987-07-01
The search for gluonium at the J/psi and Υ is discussed, as well as the search for exotics at the Υ. Reactions discussed include radiative and hadronic decays of the J/psi and the search for radiative decays of the Υ. Future perspectives are also briefly considered. 45 refs., 27 figs
International Nuclear Information System (INIS)
Roy, P.
1980-03-01
The issue of the existence and of the mass values of a new type of unstable hadron composed only of glue, called glueballs (or gluonium), is discussed. Suggested models which could indicate their existence are considered and possible production mechanisms in hadron-hadron collisions and in the decay of heavy quarkonia examined. (UK)
The tau-charm factory: Experimental perspectives
International Nuclear Information System (INIS)
Perl, M.L.; Schindler, R.H.
1991-09-01
This report discusses the Tau-Charm Factory Concept; D and D S Physics at the Tau-Charm Factory; τ and ν τ Physics at the Tau-Charm Factory; and Charmonium, Gluonium and Light Quark Spectroscopy at the Tau-Charm Factory
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
Recent status and results from BES
International Nuclear Information System (INIS)
Wang, P.
1994-01-01
Recent results on the τ leptonic mass by the analysis of several one prong decay channels, the search of gluonium state near J/ψ which was proposed to explain the so-called ρπ puzzle, and some preliminary results of D s meson from BES (Beijing Electron Spectrometer) are reported. Future plans of upgrading BEPC (Beijing Electron-Positron Collider) and BES are also described. (author). 3 refs., 1 fig., 1 tab
Search for a vector glueball by a scan of the J/ψ resonance
International Nuclear Information System (INIS)
Bai, J.Z.; Bardon, O.; Blum, I.; Breakstone, A.; Burnett, T.; Chen, G.P.; Chen, H.F.; Chen, J.; Chen, S.M.; Chen, Y.; Chen, Y.B.; Chen, Y.Q.; Cheng, B.S.; Cowan, R.F.; Cui, X.Z.; Ding, H.L.; Du, Z.Z.; Dunwoodie, W.; Fan, X.L.; Fang, J.; Fero, M.; Gao, C.S.; Gao, M.L.; Gao, S.Q.; Gratton, P.; Gu, J.H.; Gu, S.D.; Gu, W.X.; Gu, Y.F.; Guo, Y.N.; Han, S.W.; Han, Y.; Harris, F.A.; Hatanaka, M.; He, J.; He, M.; Hitlin, D.G.; Hu, G.Y.; Hu, T.; Hu, X.Q.; Huang, D.Q.; Huang, Y.Z.; Izen, J.M.; Jia, Q.P.; Jiang, C.H.; Jin, S.; Jin, Y.; Jones, L.; Kang, S.H.; Ke, Z.J.; Kelsey, M.H.; Kim, B.K.; Kong, D.; Lai, Y.F.; Lan, H.B.; Lang, P.F.; Lankford, A.; Li, F.; Li, J.; Li, P.Q.; Li, Q.; Li, R.B.; Li, W.; Li, W.D.; Li, W.G.; Li, X.H.; Li, X.N.; Lin, S.Z.; Liu, H.M.; Liu, J.; Liu, J.H.; Liu, Q.; Liu, R.G.; Liu, Y.; Liu, Z.A.; Lou, X.C.; Lowery, B.; Lu, J.G.; Luo, S.Q.; Luo, Y.; Ma, A.M.; Ma, E.C.; Ma, J.M.; Mao, H.S.; Mao, Z.P.; Malchow, R.; Mandelkern, M.; Meng, X.C.; Ni, H.L.; Nie, J.; Olsen, S.L.; Oyang, J.; Paluselli, D.; Pan, L.J.; Panetta, J.; Porter, F.; Prabhakar, E.; Qi, N.D.; Que, Y.K.; Quigley, J.; Rong, G.; Schernau, M.; Schmid, B.; Schultz, J.; Shao, Y.Y.; Shen, B.W.; Shen, D.L.; Shen, H.; Shen, X.Y.; Sheng, H.Y.; Shi, H.Z.; Shi, X.R.; Smith, A.; Soderstrom, E.; Song, X.F.; Standifird, J.; Stoker, D.; Sun, F.; Sun, H.S.; Sun, S.J.; Synodinos, J.; Tan, Y.P.; Tang, S.Q.; Toki, W.; Tong, G.L.; Torrence, E.; Wang, F.; Wang, L.S.; Wang, L.Z.; Wang, M.; Wang, P.; Wang, P.L.; Wang, S.M.; Wang, T.J.; Wang, Y.Y.; Wei, C.L.; Whittaker, S.; Wilson, R.; Wisniewski, W.J.; Xi, D.M.; Xia, X.M.; Xie, P.P.; Xiong, W.J.; Xu, D.Z.; Xu, R.S.; Xu, Z.Q.; Xue, S.T.; Yamamoto, R.; Yan, J.; Yan, W.G.; Yang, C.M.; Yang, C.Y.; Yang, J.; Yang, W.; Ye, M.H.; Ye, S.W.; Ye, S.Z.; Young, K.; Yu, C.S.; Yu, C.X.; Yu, Z.Q.; Yuan, C.Z.; Zhang, B.Y.; Zhang, C.C.; Zhang, D.H.; Zhang, H.L.; Zhang, J.; Zhang, J.W.; Zhang, L.S.; Zhang, S.Q.; Zhang, Y.; Zhang, Y.Y.; Zhao, D.X.; Zhao, H.W.; Zhao, J.W.
1996-01-01
The cross section for e + e - →ρπ has been measured by the BES detector at BEPC at center-of-mass energies covering a 40 MeV interval spanning the J/ψ resonance. The data are used to search for the vector gluonium state hypothesized by Brodsky, Lepage, and Tuan as an explanation of the ρπ puzzle in charmonium physics. The shape of the ρπ cross section is compatible with that of the total hadronic cross section. No distortions indicating the presence of a vector glueball are seen. copyright 1996 The American Physical Society
Glueballs--some selected theoretical topics
International Nuclear Information System (INIS)
Carlson, C.E.
1983-01-01
Elementary considerations of how glueballs may be found--by oddballs (abnormal -c /SUB n/ states), by overpopulation, and by decay democracy--are given. Two glueball candidates iota 1440 and theta 1640 are considered. It is stated that iota 1440 can be accommodated as a radically excited pseudoscalar, not as a glueball. Theta 1640 has decay properties uncharacteristic of glueballs, but of a state made from quarks. Finally, the worry that glueballs may mix with quark states with the same quantum number (gluonium-quarkonium mixing) is examined
Absence of even-integer ζ-function values in Euclidean physical quantities in QCD
Jamin, Matthias; Miravitllas, Ramon
2018-04-01
At order αs4 in perturbative quantum chromodynamics, even-integer ζ-function values are present in Euclidean physical correlation functions like the scalar quark correlation function or the scalar gluonium correlator. We demonstrate that these contributions cancel when the perturbative expansion is expressed in terms of the so-called C-scheme coupling αˆs which has recently been introduced in Ref. [1]. It is furthermore conjectured that a ζ4 term should arise in the Adler function at order αs5 in the MS ‾-scheme, and that this term is expected to disappear in the C-scheme as well.
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)
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)
SVZ⊕1/q{sup 2}-expansion versus some QCD holographic models
Energy Technology Data Exchange (ETDEWEB)
Jugeau, F., E-mail: frederic.jugeau@if.ufrj.br [Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, RJ 21941-972, Rio de Janeiro (Brazil); Narison, S., E-mail: snarison@yahoo.fr [Laboratoire Particules et Univers de Montpellier, CNRS-IN2P3, Case 070, Place Eugène Bataillon, 34095 Montpellier (France); Ratsimbarison, H., E-mail: herysedra@yahoo.fr [Institute of High-Energy Physics of Madagascar (iHEP-MAD), University of Antananarivo (Madagascar)
2013-05-13
Considering the classical two-point correlators built from (axial-) vector, scalar q{sup ¯}q and gluonium currents, we confront results obtained using the SVZ⊕1/q{sup 2}-expansion to the ones from some QCD holographic models in the Euclidean region and with negative dilaton Φ{sub i}(z)=−|c{sub i}{sup 2}|z{sup 2}. We conclude that the presence of the 1/q{sup 2}-term in the SVZ-expansion due to a tachyonic gluon mass appears naturally in the Minimum Soft-Wall (MSW) and the Gauge/String Dual (GSD) models which can also reproduce semi-quantitatively some of the higher dimension condensate contributions appearing in the OPE. The Hard-Wall model shows a large departure from the SVZ⊕1/q{sup 2}-expansion in the vector, scalar and gluonium channels due to the absence of any power corrections. The equivalence of the MSW and GSD models is manifest in the vector channel through the relation of the dilaton parameter with the tachyonic gluon mass. For approximately reproducing the phenomenological values of the dimension d=4,6 condensates, the holographic models require a tachyonic gluon mass (α{sub s}/π)λ{sup 2}≈−(0.12–0.14) GeV{sup 2}, which is about twice the fitted phenomenological value from e{sup +}e{sup −} data. The relation of the inverse length parameter c{sub i} to the tachyonic gluon mass also shows that c{sub i} is channel dependent but not universal for a given holographic model. Using the MSW model and M{sub ρ}=0.78 GeV as input, we predict a scalar q{sup ¯}q mass M{sub S}≈(0.95–1.10) GeV and a scalar gluonium mass M{sub G}≈(1.1–1.3) GeV.
Selected results on J/PSI hadronic decays from DM2 and Mark III
International Nuclear Information System (INIS)
Augustin, J.E.
1985-01-01
Results from the high statistics experiments Mark III and DM2 on J/PSI hadronic decays are reviewed. Special interest is given to SU3 violating decays into two pseudoscalars and baryon-antibaryon, especially the first observation of J/PSI → Ksub(S)sup(o)Ksub(L)sup(o). The complete measurement of the vector + pseudoscalar modes allows a new determination of the eta and eta' mixing parameters, indicating the presence of a new component in the eta' wave function. The iota(1440) and theta(1700) gluonium candidates have been searched for in hadronic decays, and the Mark III experiment observes a signal in J/PSI → ω iota (or ωE)
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.)
High energy physics: V. 1 and 2. Proceedings
International Nuclear Information System (INIS)
Bussey, P.J.; Knowles, I.G.
1995-01-01
The 27th International Conference on High Energy Physics attracted 950 abstracts eventually materialising as 613 full papers. These were made accessible on the World Wide Web and formed the basis of 22 plenary session talks and 274 parallel session talks. The plenary session talks are reproduced in Volume 1 of the Proceedings and most of the parallel session talks in Volume 2. The main topics covered were: top quark searches; electroweak interactions; low x physics; deep inelastic scattering and structure functions; beyond the Standard Model; searches for new particles; non-perturbative methods; lattice gauge theory; weak and rare decays; CP violation and BB-bar mixing; developments in field and string theory; light quark and gluonium spectroscopy; QCD and jet physics; flavour production on hadronic targets; non-accelerator experiments; neutrino masses; mixing and oscillations; new detectors and experimental techniques; low Q 2 and soft phenomena; particle astrophysics and cosmology; heavy quark physics; heavy ion collisions; future accelerators. (UK)
Energy Technology Data Exchange (ETDEWEB)
Castro, Antonio Soares de
1990-05-01
A potential which incorporates the concepts of confinement and asymptotic freedom, previously utilized in the description of the spectroscopy of mesons and baryons, is extended to the gluon sector. The mass spectroscopy of glueballs and hybrids is analyzed considering only pairwise potentials and massive constituent gluons. The mass spectrum of the color octet two-gluon system is adopted as a suitable description of the intermediate states of hadronic transitions, within the framework of the multipole expansion for quantum chromodynamics. The spin-dependent effects in the gluonium spectrum, associated with the Coulombian potential, are calculated through the inverted first Born approximation for the gluon-gluon scattering. (author). 102 refs, 1 fig, 13 tabs.
Bound states of quarks and gluons and hadronic transitions
International Nuclear Information System (INIS)
Castro, Antonio Soares de.
1990-05-01
A potential which incorporates the concepts of confinement and asymptotic freedom, previously utilized in the description of the spectroscopy of mesons and baryons, is extended to the gluon sector. The mass spectroscopy of glueballs and hybrids is analyzed considering only pairwise potentials and massive constituent gluons. The mass spectrum of the color octet two-gluon system is adopted as a suitable description of the intermediate states of hadronic transitions, within the framework of the multipole expansion for quantum chromodynamics. The spin-dependent effects in the gluonium spectrum, associated with the Coulombian potential, are calculated through the inverted first Born approximation for the gluon-gluon scattering. (author). 102 refs, 1 fig, 13 tabs
Nonperturbative QCD effects in physical cross sections
International Nuclear Information System (INIS)
Dubovikov, M.S.; Smilga, A.V.
1982-01-01
The physical phenomena arising from the presence of singularities of polarization operators of colourless currents in the complex X-plane are discussed. The singularities of PI(X 2 ) at the nonzero points yield exponentially falling terms to the Fourier image PI tilde (q 2 ) in the deep Euclidean region g 2 → - infinity. However, these singularities give rise to significant contributions to the imaginary part of PI tilde (q 2 ) in the physical region q 2 > 0. These contributions iscillate and die out slowly wiht the energy increase. Under the simplest assumptions on the analytical structure of PIsub(μμ)(Xsup(2)) in the vector channel is gotten the analytical expression for R(S) in the resonance range. The parameters are fixed by a condition that R(S) thus obtained must satisfy SVZ sum rules and the requirement R(0)=0. Model expression for R(s) gives reasonable qualitative description of experimental data. The scalar gluonic channel is also discussed. A very broad structure is observed in the energy range 2-3 GeV. The problem of existing of a well defined resonance scalar gluonium state remains open
A study of the phi phi system in hadronic interactions
International Nuclear Information System (INIS)
Thompson, I.R.M.
1984-05-01
The thesis presents a study of the phi phi system in hadronic interactions. Data were collected from the reaction π - Be → phi phiX, at 85 GeV/c, using the CERN OMEGA Spectrometer. The phi phi system was of interest because it has been suggested that the hadronic production of the Jsup(p)=O - hidden charm state etac(2980) may be observed through the decay to two phi mesons, and because it is expected that gluonium states exist in the mass range 2.0 to 2.5 GeV/c 2 , and these should decay to two phi mesons. Experimental details and data analysis of the experiment are given. The phi phi mass resolution was determined from the errors on the track parameters of the particles and from the examination of the observed phi and K 0 signals. The mass resolution was used in an examination of the phi phi mass spectrum for narrow resonances and in the estimation of the upper limits of the cross-section for a narrow resonance. (U.K.)
A Study of Large Transverse Momentum Phenomena
2002-01-01
This experiment studies the structure of those p-p and @*-p collisions which are characterized by a very high transverse momentum flow in the central region. Some specific items studied are:\\\\ \\\\ \\item -~~Structure of events, where the high transverse momentum is shared by charged and neutral hadron (``jets''). Transverse momentum distribution, correlations and momentum balance for such events. \\item -~~Structure of events, where the high transverse momentum is mostly carried by one identified particle. Quantum number dependence and quantum number correlations of the high transverse momentum events. \\item -~~Structure of events containing large transverse momentum leptons or lepton pairs or direct photons. \\end{enumerate}.sk -~~Study of low momentum electrons and photons. -~~Search for gluonium states. -~~Search for new and rare particles. \\\\ \\\\ A conventional C-type magnet with a 0.5 T field in the direction of the beams together with a 42-layer cylindrical drift chamber detector is used for momentum analysi...
2002-01-01
The aim of this experiment is to study the properties of 2K|+2K|- systems and to search for new states produced centrally in the @p|-p collisions at 85 GeV/c. The experiment makes use of the high data rate capability of the upgraded @W' MWPC system and the large forward acceptance of the two hodoscoping Cerenkov counters. \\\\ \\\\ A sample of 20 M events was recorded using a selective trigger on 4 charged kaons with X~@$>$~0. Amongst the topics to be explored are : \\item a) Study of the @F@F(C=+1) and @F@F@p@+ mass spectrum including a search for the n^c; \\item b) Search for gluonium states decaying to K|+K|-, @F@F, @Ff', f'f'; \\item c) Study of @F production as a function of (X(F), p^t) and whether it prefers to be produced singly or in association with another @F; \\item d) Study of the KK@p, and KK@p@p systems including (i) a search for low-lying crypto exotic mesons (usds) predicted to decay to K|+K|-@p@+ or @F@p@+; (ii) a search for charmed-strange exotic mesons (udcs) predicted to decay into two kaons of th...
Experimental and theoretical high energy physics. Progress report 1 Oct 1979 to 30 Sep 1980
International Nuclear Information System (INIS)
Research performed in theoretical high energy physics includes: nonabelian Stokes theorem; connection between asymptotic behavior and bound states in QCD; classical solutions for gauge fields interacting with Higgs mesons; neutrino oscillations; relativistic wave equation and mass spectrum of gluonium; dynamical structures of the pion; convergence of reflectionless approximations to confining potentials; degeneracy in one-dimensional quantum mechanics; review of heavy quarks and new particles; semiclassical results on normalization of bound state wave functions; proton lifetime; quark magnetic moments and E1 radiative transitions in charmonium; lectures on quark models; inverse scattering and the upsilon family; and magnetic moments of quarks in baryons and mesons. In experimental high energy physics, the emphasis has been on strong interactions but also includes several crucial tests of the currently most important theories of elementary particle interactions. Experiments described include: electromagnetic couplings of vector mesons; direct photon production at large transverse momentum; hyperon experiments; spin effects in strong interactions; a dense detector for proton decay; and exclusive processes at large transverse momenta
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
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.)