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arXiv 0908.2825nucl-th
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核子-核子弹性截面介质修正的动量依赖性探讨

Probing the momentum dependence of medium modifications of the nucleon-nucleon elastic cross sections

Qingfeng Li, Caiwan Shen, M. Di Toro

摘要:

用微观输运理论讨论了介质修正对核子-核子弹性截面的动量依赖性,并用改进的UrQMD微观输运模型进行了数值研究.以束流能量为$E_b=400A$ MeV的半周边Au+Au反应为例进行了计算。结果表明,动量依赖于截面介质修正的不确定性影响了自由核子的产额及其集体流作为其横动量和快度的函数。在这些观测量中,椭圆流对动量依赖的具体形式有着敏感的依赖性,应该引起更多的关注。椭圆流几乎不受中子-中子和质子-质子截面的可能分裂效应的影响,因此人们可以通过研究核子或轻团簇的椭圆流来确定在高束流能量和高核密度下平均场能级的质量分裂效应。

英文摘要:

The momentum dependence of the medium modifications on nucleon-nucleon elastic cross sections is discussed with microscopic transport theories and numerically investigated with an updated UrQMD microscopic transport model. The semi-peripheral Au+Au reaction at beam energy $E_b=400A$ MeV is adopted as an example. It is found that the uncertainties of the momentum dependence on medium modifications of cross sections influence the yields of free nucleons and their collective flows as functions of their transverse momentum and rapidity. Among these observables, the elliptic flow is sensitively dependent on detailed forms of the momentum dependence and more attention should be paid. The elliptic flow is hardly influenced by the probable splitting effect of the neutron-neutron and proton-proton cross sections so that one might pin down the mass splitting effect of the mean-field level at high beam energies and high nuclear densities by exploring the elliptic flow of nucleons or light clusters.

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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