Nuclear Matter in a Chiral SU(3) Quark Mean-Field Model

A quark meson coupling model based on SU(3)_L×SU(3)_R symmetry and scale invariance is proposed. The quarks and mesons get masses through symmetry broken. We apply this SU(3) chiral constituent quark model to investigating the nuclear matter at finite temperature and density. The effective baryon masses, compression modulus and hyperon potentials are all reasonable. The critical temperature of liquid-gas phase transition is also calculated in this model.     

Antiproton-Nucleus Scattering in a Hybrid Quark-Hadron Model

A hybrid quark-hadron model is used to describe high energy antiproton-nucleus scattering. The parameters for the quark regime are determined by fitting antiproton-proton elastic scattering data.     

Ω＋Ω→（ΩΩ）Jπ=0＋＋X Cross section Calculation

The cross sections of Ω+Ω→(ΩΩ)_J^π=0⁺+X are studied by using an effective Hamiltonian method. The results are σ_{Ω+Ω→(ΩΩ)0⁺+γ}=0.03～0.16×10^-29 cm² for p_Ω=100～400 MeV, and the cross sections of η production are about 10^-28 cm² for p_Ω > 880 MeV.     

Confining Potential Mode in Baryons Spectrum

Based on the flux tube model, the effects of the confining potentials of different configurations, namely the △-type and the Y-type, on the spectra of baryons are studied on SUSF（6） basis. The baryon spectra are obtained in a unified manner. Our result shows that by employing either the △-mode or the Y-mode confining potential, one can achieve reasonable baryon spectra. The △-mode may be mostly effective for the short- and medium-distances, while the Y-mode may offer more contributions to the spectra for long-distances. Although the binding energies in baryon spectra may deviate by a few to several tens MeV for different modes, it is hard to determine either one to be dominant by simply evaluating the baryon spectra. One may need to invoke the baryon decay process to make further judgement.     

Effects of R-Parity Violating Supersymmetry in Top Pair Production at Linear Colliders with Polarized Beams

In the minimal supersymmetric standard model with R-parity violation, the lepton number violating top quark interactions can contribute to the top pair production at a linear collider via tree-level u-channel squark exchange diagrams. We calculate such contributions and find that in the allowed range of these R-violating couplings, the top pair production rate as well as the top quark polarization and the forward-backward asymmetry can be significantly altered. By comparing the unpolarized beams with the polarized beams, we find that the polarized beams are more powerful in probing such new physics.     

非定域夸克真空的结构和Kisslinger函数

夸克的真空凝聚是量子色动力学(QCD)研究中一个非常重要的问题.用完全穿衣服的夸克传播子研究了QCD真空性质和夸克的真空结构.计算了定域夸克的真空凝聚值,预言了夸克的真空结构.其结果与文献中的经验值相符合,也与Dyson-Schwinger方程解一致.说明参数化的夸克传播子是成功和可靠的.     

兰州冷却储存环上可开展的强子物理研究

介绍了当前强子物理的研究现状和兰州冷却储存环的能量特点,以及国内强子物理专家的分析和建议。在兰州冷却储存环上,可利用中能轻离子束核反应产生强子激发态研究强子内部夸克态的结构和性质、强子性质随核环境的变化和手征对称破缺与部分恢复。尤其是通过兰州冷却储存环上限能区附近的P＋P反应,研究奇异夸克的不对称性和形状因子,寻找超子激发态和pentaquark的实验证据,发现双重子态的实验事例。 According to both the development on badrons physics and the aspect of Lanzhou cooling storage ring （CSR） and based on the analysis and propositions given by experts in China, we propose some hadrons physics program at CSR. The hadron spectroscopy produced in light nucleus collisions at CSR used to probe the quark and gluon structure of hadrons, to study the modification of the hadron properties in nuclear matter and to investigate the spontaneous breaking of the chiral symmetry and its partial restoration. Especially, the proton-proton collisions at beam energies per proton below 2.8 GeV at CSR should be used to measure the strangeness asymmetry and strange form lector, to probe the existence of hyperon and pentaquarks and to find the evidence for the existence of dibaryon.     

多夸克态研究概况

介绍了多夸克态研究的重要性,侧重介绍了最近发现的5夸克态的实验和理论研究现况.