热核物质液气相变的临界温度和三体核力效应  

Critical Temperature of Liquid-Gas Phase Transition for Hot Nuclear Matter and Three-Body Force Effect

作　　者：左维[1] 陆广成[1] 李增花[1] 罗培燕[1] 

机构地区：[1]中国科学院近代物理研究所,兰州730000

出　　处：《高能物理与核物理》2005年第11期1061-1066,共6页High Energy Physics and Nuclear Physics

基　　金：中国科学院知识创新工程重要方向性项目(KJCX2-SW-N02);国家重点基础研究发展规划项目(G2000077400);国家自然科学重点基金(10235030;10175082;国家科技部重大前期研究专项基金(2002CCB00200)~~

摘　　要：通过引入微观三体核力,扩展了有限温度Brueckner-Hartree-Fock方法。利用这一扩展的理论模型,研究了热核物质的状态方程和液气相变现象并计算了临界温度,讨论了三体核力对液气相变临界点性质的影响并与Dirac-Brueckner-Hartree-Fock方法的理论预言进行了比较。结果表明:三体核力对热核物质状态方程提供一个随密度和温度增大而增强的排斥贡献,而且三体核力的排斥效应导致热核物质液气相变的临界温度明显降低。The finite temperature Brueckner-Hartree-Fock （FTBHF） approach is extended by introducing a microscopic three-body force. Within the extended approach, the three-body force effects on the equation of state of hot nuclear matter and its temperature dependence have been investigated. The critical properties of the liquid-gas phase transition of hot nuclear matter have been calculated. It is shown that the three-body force provides a repulsive contribution to the equation of state of hot nuclear matter. The repulsive effect of the three-body force becomes more pronounced as the density and temperature increase and consequently inclusion of the three-body force contribution in the calculation reduces the predicted critical temperature from about 16MeV to about 13MeV. By separating the contribution originated from the 2σ-exchange process coupled to the virtual excitation of a nucleon-antinucleon pair from the full three-body force, the connection between the three-body force effect and the relativistic correction from the Dirac-Brueckner- Hartree-Fock has been explored. It turns out that the contribution of the 2σ-NN^- part is more repulsive than that of the full three-body force and the calculated critical temperature is about llMeV if only the 2a-NN^- component of the three-body force is included which is lower than the value obtained in the case of including the full three-body force and is close to the value predicted by the Dirac-Brueckner-Hartree-Fock （DBHF） approach. Our result provides a reasonable explanation for the discrepancy between the values of critical temperature predicted from the FTBHF approach including the three-body force and the DBHF approach.

关 键 词：微观三体核力 有限温度BHF方法 核物质 液气相变 临界温度 三体核力效应 热核物质 HARTREE-FOCK 核物质状态方程 相变临界点 

分 类 号：O572.2[理学—粒子物理与原子核物理]