相对论重离子碰撞中的热解冻和纵向非均匀集体膨胀流

把非均匀纵向流模型推广到包括横向膨胀流,并计算K介子,Λ和质子的快度分布.这些模型的计算结果能较好地解释CERN/SPS 200A GeV/c能量下S-S碰撞以及158A GeV/c能量下Pb-Pb碰撞的实验结果.并且能够自然地解释实验中出现的中心下凹(centraldip)现象.

Thermal Freeze-Out and Longitudinally Non-uniform Collec tive Expansion Flow in Relativistic Heavy Ion Collisions

The non-uniform longitudinal flow model (NUFM) proposed recently is extended to include also the transverse flow. The resulting longitudinally non-uniform collective expansion model (NUCEM) is applied to the calculation of rapidity distribution of kaons, lambdas and protons in relativistic heavy ion collisions at CERN-SPS energies. The model results are compared with the 200 A GeV/ c S-S and 158 A GeV/ c Pb-Pb collision data. The central dips observed in experiments are reproduced in a natural way. ;It is found that the depth of the central dip depends on the magnitude of the parameter e and the mass of produced particles, i.e. the non-uniformity of the longitudinal flow which is described by the parameter e determines the depth of the central dip for produced particles. Comparing with one-dimensional non-uniform longitudinal flow model, the rapidity distribution of lighter strange particle kaon also shows a dip due to the effect of transverse flow. = =