The η-meson production in proton-nucleus （pA） collisions near threshold is studied within a rela- tivistic meson-exchange model. The primary production amplitude is presented in the distorted-wave impulse approximation for the nucleus with isospin 0 or 1 by assuming that N^＊（1535） is excited via a meson exchange and then decays into η and nucleon pair（nN）. Taking ISO and 12C nuclei as examples, we evaluate the prouction cross sections as a function of the incident proton energy, and analyze the effects of nuclear medium and various meson-exchange contributions. Finally we discuss implications for further experimental studies at the Cooling Storage Ring （CSR） in Lanzhou.
The spin structure of nucleons is presented in the framework of an extended quark model which in addition to the conventional qqq structure also takes into account qqqq admixtures in the nucleon wave functions, where the qqqq components are in colored quark cluster configurations. The axial vector weak coupling constant and spin distributions for polarized nucleons as well as spin content are obtained for the lowest positive parity qqqq configurations in flavor-spin dependent interaction. In particular, the contributions of the down and strange quarks to the proton spin and the sum rule for polarized neutron are negative, in agreement with recent experiments.
We report on a very recently developed three-dimensional angular momentum projected relativistic mean-field theory with point-coupling interaction (3DAMP+RMF-PC). Using this approach the same effective nucleon-nucleon interaction is adopted to describe both the single-particle and collective motions in nuclei. Collective states with good quantum angular momentum are built projecting out the intrinsic deformed meanfield states. Results for 24Mg are shown as an illustrative application.
Single-particle resonance states of 122Zr are studied in the real stabilization method within the framework of relativistic mean field theory. Two effcient methods are adopted to extract the resonance energy and width of 122Zr. The results are compared with those obtained from the analytic continuation in the coupling approach and scattering phase-shift methods.
Triaxial relativistic mean field (RMF) approaches are used to study the properties of 104Rh. The existence of multiple chiral doublets is suggested for 104Rh based on the triaxial deformations and their corresponding proton and neutron configurations.
