arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2004.11737nucl-th
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微观输运模型在中能重离子碰撞核物质状态方程研究中的应用

Application of microscopic transport model in the study of nuclear equation of state from heavy ion collisions at intermediate energies

Yongjia Wang, Qingfeng Li

摘要:

核物质的状态方程(EOS),即,核子结合能与温度、密度以及同位旋不对称性之间的热力学关系一直是核物理和天体物理研究的热点。核物态方程的知识对于研究核的性质、中子星的结构、重离子碰撞动力学以及中子星合并等都是必不可少的。HIC提供了一种在地面实验室中产生高密度和同位旋不对称性的核物质的独特方法,但所形成的致密核物质只存在很短的时间,无法在实验中直接测量核物态方程。在实际应用中,输运模型通常包含唯象势作为输入,通过与实验室测量的观测值的比较来推导状态方程。超相对论量子分子动力学(UrQMD)模型已被广泛用于研究从费米能(40 MeV/核子)到CERN大型强子对撞机能(TeV)的HIC。通过对UrQMD模型的核平均场势项、碰撞项和团簇识别项的进一步改进,可以再现FOPI合作组新测得的轻带电粒子集体流和核停止数据。本文介绍了我们在UrQMD模型下对核物态方程和核对称能的研究结果。讨论了从输运模型和HIC实验中提取核状态方程的新机遇和挑战。

英文摘要:

The equation of state (EOS) of nuclear matter, i.e., the thermodynamic relationship between the binding energy per nucleon, temperature, density, as well as the isospin asymmetry, has been a hot topic in nuclear physics and astrophysics for a long time. The knowledge of the nuclear EOS is essential for studying the properties of nuclei, the structure of neutron stars, the dynamics of heavy ion collision (HIC), as well as neutron star mergers. HIC offers a unique way to create nuclear matter with high density and isospin asymmetry in terrestrial laboratory, but the formed dense nuclear matter exists only for a very short period, one cannot measure the nuclear EOS directly in experiments. Practically, transport models which often incorporate phenomenological potentials as an input are utilized to deduce the EOS from the comparison with the observables measured in laboratory. The ultrarelativistic quantum molecular dynamics (UrQMD) model has been widely employed for investigating HIC from the Fermi energy (40 MeV per nucleon) up to the CERN Large Hadron Collider energies (TeV). With further improvement in the nuclear mean-field potential term, the collision term, and the cluster recognition term of the UrQMD model, the newly measured collective flow and nuclear stopping data of light charged particles by the FOPI Collaboration can be reproduced. In this article we highlight our recent results on the studies of the nuclear EOS and the nuclear symmetry energy with the UrQMD model. New opportunities and challenges in the extraction of the nuclear EOS from transport models and HIC experiments are discussed.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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