123240421
Strange hadronic matter in a modified quark-meson coupling model
Strange hadronic matter with nucleons,Lambda-hyperons and Xi-hyperons is studied by using a modified quark-meson coupling (MQMC) model in a mean-field approximation. The density dependence of the effective baryon masses as well as the saturation properties and stabilities of the strange hadronic matter are discussed. (C) 1999 Published by Elsevier Science B.V. All rights reserved.
117796835
Static three-body potential in baryons
The first principle of quantum chromodynamics is used to calculate the static perturbative three-body potential between three valence quarks in baryons, which is gauge invariant and flavor-dependent, and of magnitude of the same order as the next non-leading static q-q potential. Its effect on an S-state baryon composed of three valence quarks of equal mass may be viewed as a slight increase of the constituent quark masses with respect to those in mesons.
118632293
Nucleon magnetic form factors with non-local chiral effective Lagrangian
Chiral perturbation theory is a useful method to investigate the hadron properties. We apply the non-local chiral effective Lagrangian to study the nucleon magnetic form factors. The octet and decuplet intermediate states are included in the one-loop calculation. With the modified propagators and non-local interaction, the loop integral is convergent. The obtained proton and neutron magnetic form factors are both reasonable up to relatively large Q2.
121124456
An Extended Chiral SU(3) Quark Model
The chiral SU(3) quark model is extended by including the vector meson exchanges to describe the short range interactions. The phase shifts of NN scattering are studied in this model. Compared with the results of the chiral SU(3) quark model in which only the pseudo-scalar and scalar chiral fields are considered, the phase shifts of 1S0 wave are obviously improved.
121034531
Strange hadronic matter in a chiral model
The strange hadronic matter with nucleon, Λ-hyperon and Ξ-hyperon is studied by using a chiral symmetry model in a mean-field approximation. The saturation properties and stabilities of the strange hadronic matter are discussed. The result indicates a quite large strangeness fraction (fS) region where the strange hadronic matter is stable against particle emission. In the large fS region, the Ξ component dominates, resulting in a deep minimum in the curve of the binding energy per baryon EB versus the strangeness fraction fS with (EB, fS) (-26.0 MeV, 1.23).
123370023
Chiral symmetry restoration of nuclear matter
The phase transition of chiral symmetry restoration of nuclear matter is studied in the chiral SU(3) quark mean field model. For some kinds of confining potentials, there exists a critical density ρc. When the baryon density is larger than ρc, nuclear matter will be in the phase of chiral symmetry restoration. At critical density, the physical quantities change discontinuously. The critical density will become larger when the vector part of the confining potential increases.
118698175
Measurement of $e^+ e^- \to \omega \pi^0$, $K^{\ast}(892)\bar{K}$ and $K_2^{\ast}(1430)\bar{K}$ at $\sqrt{s}$ near 10.6 GeV
Using data samples of 89 fb$^{-1}$, 703 fb$^{-1}$, and 121 fb$^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider at center-of-mass energies 10.52 GeV, 10.58 GeV, and 10.876 GeV, respectively, we study the exclusive reactions $e^+e^- \to \omega\pi^0$, $K^{\ast}(892)\bar{K}$, and $K_2^{\ast}(1430)\bar{K}$ (Charge-conjugate modes are included implicitly). Significant signals of $\omega\pi^0$, $K^{\ast}(892)^0\bar{K}^0$, and $K_2^{\ast}(1430)^-K^+$ are observed for the first time at these energies, and the energy dependencies of the cross sections are presented. On the other hand, no significant excesses for $K^{\ast}(892)^-K^+$ and $K_2^{\ast}(1430)^0 \bar{K}^0$ are found, and we set limits on the cross section ratios $R_{\rm VP} = \frac{\sigma_B(e^+e^-\to K^{\ast}(892)^0\bar K^0)} {\sigma_B(e^+e^-\to K^{\ast}(892)^-K^+)}>$ 4.3, 20.0, and 5.4, and $R_{\rm TP} = \frac{\sigma_B(e^+e^-\to K_2^{\ast}(1430)^0\bar K^0)} {\sigma_B(e^+e^-\to K_2^{\ast}(1430)^-K^+)}<$ 1.1, 0.4, and 0.6, for center-of-mass energies of 10.52 GeV, 10.58 GeV, and 10.876 GeV, respectively, at the 90% C.L.
121984352
The BES detector
Abstract The Beijing Spectrometer (BES) is a general purpose solenoidal detector at the Beijing Electron Positron Collider (BEPC). It is designed to study exclusive final states in e + e − annihilations at the center of mass energy from 3.0 to 5.6 GeV. This requires large solid angle coverage combined with good charged particle momentum resolution, good particle identification and high photon detection efficiency at low energies. In this paper we describe the construction and the performance of BES detector.
119717624
Asymmetric nuclear matter at finite temperature and density
Asymmetric nuclear matter is studied by using an effective nuclear model in a mean-field approximation. The density, temperature, and asymmetric parameter dependence of the effective baryon mass is discussed. The liquid-gas phase transition of a system with two independent conserved charges (baryon number and isospin) is studied using the stability conditions on the free energy and Gibbs conditions for phase equilibrium. The critical temperature is calculated with and without $\ensuremath{\rho}$ meson contribution, respectively.
122907449
Baryon-antibaryon nonets
The baryon-antibaryon SU(3) nonets are proposed as a scheme to classify the increased number of experimentally observed enhancements near the baryon antibaryon mass threshold. The scheme is similar to the Fermi-Yang-Sakata model, which was put forth about fifty years ago in explaining the mesons observed at that time. According to the present scheme, many new baryon-antibaryon bound states are predicted, and their possible productions in quarkonium decays and B decays are suggested for experimental search. (c) 2005 Elsevier B.V. All rights reserved.
123878919
Partial wave analysis of J/psi ---> p anti-p pi0
Using a sample of 58 million J/{psi} events collected with the BESII detector at the BEPC, more than 100 000 J/{psi}{yields}pp{pi}{sup 0} events are selected, and a detailed partial wave analysis is performed. The branching fraction is determined to be Br(J/{psi}{yields}pp{pi}{sup 0})=(1.33{+-}0.02{+-}0.11)x10{sup -3}. A long-sought missing N*, first observed in J/{psi}{yields}pn{pi}{sup -}, is observed in this decay too, with mass and width of 2040{sub -4}{sup +3}{+-}25 MeV/c{sup 2} and 230{sub -8}{sup +8}{+-}52 MeV/c{sup 2}, respectively. Its spin-parity favors (3/2){sup +}. The masses, widths, and spin parities of other N* states are obtained as well.