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arXiv 1111.2406hep-ph
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一个新的排除体积模型对热重强子气体性质的描述

Description of Hot and Dense Hadron Gas Properties in a New Excluded-Volume model

S. K. Tiwari, P. K. Srivastava, C. P. Singh

摘要:

本文在排斥体积修正的热力学相容公式中考虑了重子有限的硬核尺寸,得到了一个新的热密强子气体的物态方程。我们的模型不同于其他现有的方法在以下几点。我们只给每个重子和介子分配一个硬核体积,尽管它们的体积很小,但它们可以相互融合和渗透。使用的全量子统计是在获得巨正则配分函数排除体积校正已被纳入明确整合体积。因此,我们发现,新模型的作品,即使是极端的温度和/或密度的情况下,大多数其他方法失败。即使在极端密度下,该模型也不违反因果关系。各种物理量,如压力、重子密度、熵和能量密度对温度和密度的依赖性与其它微观HG模型的结果比较好。经过适当的参数化的质心能量的温度和重子化学势,我们探索了一些新的冻结出的标准,表现出完全独立的碰撞能量和碰撞核的结构。我们进一步证明了我们的模型在解释各种粒子及其反粒子的多重比的各种实验结果中的适用性。最后,我们使用我们的排除体积模型,以获得热和/或密集HG的输运行为,如剪切粘度熵比,声速等,并与早期的计算结果进行比较。

英文摘要:

A new equation of state for a hot and dense hadron gas (HG) is obtained where the finite hard-core size of baryons has been incorporated in a thermodynamically consistent formulation of excluded volume correction. Our model differs from other existing approaches on the following points. We assign a hard-core volume only to each baryon and mesons though possess a small volume but they can fuse and interpenetrate into one another. Use of the full quantum statistics is made in obtaining the grand canonical partition function where excluded-volume correction has been incorporated by explicitly integrating over volume. We thus find that the new model works even for the cases of extreme temperatures and/or densities where most of other approaches fail. The model does not violate causality even at extreme densities. The temperature and density dependence of various thermodynamical quantities, e.g. pressure, baryon density, entropy and energy density compare well with the results of other microscopic HG models. After suitable parametrization of the centre-of-mass energy in terms of temperature and baryon chemical potential, we explore some new freeze-out criteria which exhibit full independence of the collision energy and of the structures of the colliding nuclei. We further demonstrate the suitability of our model in explaining various experimental results of the multiplicity-ratios of various particles and their antiparticles. Finally, we use our excluded-volume model to obtain the transport behaviour of the hot and/or dense HG such as shear viscosity to entropy ratio, speed of sound etc. and compare the results with earlier calculations.

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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