中能重离子反应中对称势对熵的影响

Effect of Symmetry Potential on Entropy in Intermediate Energy Heavy Ion Reactions

基于同位旋相关的量子分子动力学模型,研究了对称势、束流能量、对称能强度系数对中能重离子碰撞反应系统的熵的影响。研究发现,对称势对熵有一定影响,且对熵的影响大小与反应系统中质比有关。另外发现在^(40)Ca+^(40)Ca和^(40)Si+^(40)Si反应系统中对称能强度系数对熵也有影响,当对称能强度系数c=32 Me V时,对这两个系统来说其对熵的影响最大。通过实验上对熵的测量可以得到对称势的形式和大小。

Based on the isospin-dependent quantum molecular dynamics model, effects of the symmetry potential, incident beam energy and different symmetry energy strength coefficients on the entropy of reaction system are studied. The results show that the symmetry potential affects the entropy, and the effect changes with the neutron-proton ratio of the reaction system. Besides, in ^40Ca＋^40Ca and ^40Si＋^40Si reaction systems, the symmetry energy strength coefficient also has effect on the entropy when the symmetry energy strength coefficient c = 32 Me V, the effect on the entropy is largest for the two systems. Therefore the form and size of symmetry potential could be obtained by comparison of the model calculation and the experiments on the measurement of entropy.