We calculate the meson mass spectra in a quark potential model by using the complete Fermi-Breit potential including the terms of orbit-orbit interaction, spin-orbit coupling, and tensor force interaction. We find that these terms give nontrivial contributions to the calculated meson spectra. The orbit-orbit coupling term may lead to an instability of the solution of the Schrdinger equation and should be regularized.
We examine the two-pion Hanbury-Brown-Twiss(HBT) interferometry for the particle-emitting source produced in heavy ion collisions at HIRFL-CSR energy.The source evolution is described by relativistic hydrodynamics with three kinds of equations of state for chemical equilibrium(CE),chemical freeze-out(CFO),and partial chemical equilibrium(PCE) models,respectively.We investigate the effects of particle decay,multiple scattering,and source collective expansion on the two-pion interferometry results.We find that the HBT radii of the evolution source for the CFO and PCE models are smaller than that for the CE model.The HBT lifetime for the CFO model is smaller than those for the PCE and CE models.The particle decay increases the HBT radius and lifetime while the source expansion decreases the HBT radius.The multiple scattering effect on the HBT results can be neglected based on our model calculations.
We give the formulas of two-pion Hanbury-Brown-Twiss (HBT) correlation function for a partially coherent evolution pion-emitting source,using quantum probability amplitudes in a path-integral formalism. The multiple scattering of the particles in the source is taken into consideration based on Glauber scattering theory.Two-pion interferometry with effects of the multiple scattering and source collective expansion is exam- ined for a partially coherent source of hadronic gas with a finite baryon density and evolving hydrodynamically. We do not find observable effect of either the multiple scattering or the source collective expansion on HBT chaotic parameter.
This paper evaluates the interaction potential between a hydrogen and an antihydrogen using the second-order perturbation theory within the framework of the four-body system in a separable two-body basis. It finds that the H– H interaction potential possesses the peculiar features of a shallow local minimum located around interatomic separations of r ～ 6 a.u. and a barrier rising at r■ 5 a.u.
