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arXiv 0901.4653nucl-th
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相对论重离子碰撞早期各向异性等离子体动力学

Dynamics of anisotropic plasma at the early stages of relativistic heavy-ion collisions

W. Florkowski, R. Ryblewski

摘要:

讨论了相对论性重离子碰撞早期可能产生的各向异性增强不变夸克-胶子等离子体的演化。我们的考虑是基于最近提出的形式主义,这是相对论完美流体流体力学的扩展。我们分析了由各向异性相空间分布函数描述的纯部分子系统和与局域磁场相互作用的部分子系统。第二个分析是一个简化的尝试,包括颜色场对粒子动力学的影响。我们的模型结果进行了讨论的背景下,早期热化和各向同性。在粒子,能量和动量守恒的一般假设下,我们表明,对于大的演化时间的纯部分子系统的纵向和横向压力的比率趋于零。因此,系统的初始动量分布沿束轴拉长总是通过各向同性阶段,在横向和纵向压力是相等的。在这种情况下,包含磁场对纵向压力产生负贡献,因此,取决于磁场的强度,可以更早地达到总纵向压力和横向压力变得相等的瞬态阶段。

英文摘要:

We discuss the evolution of anisotropic boost-invariant quark-gluon plasma possibly created at the early stages of relativistic heavy-ion collisions. Our considerations are based on the recently proposed formalism that is an extension of the relativistic perfect-fluid hydrodynamics. We analyze i) the pure partonic system described by the anisotropic phase-space distribution function and ii) the system of partons interacting with the local magnetic fields. The second analysis is a simplified attempt to include the effects of color fields on the particle dynamics. Our model results are discussed in the context of early thermalization and isotropization. Under general assumptions of the particle, energy, and momentum conservations we show that for large evolution times the ratio of the longitudinal and transverse pressures of the pure partonic system tends to zero. Hence, the system with the initial momentum distribution elongated along the beam axis always passes through the isotropic stage where the transverse and longitudinal pressures are equal. The inclusion of the magnetic field in this case gives negative contribution to the longitudinal pressure, hence the transient stage when the total longitudinal and transverse pressures become equal may be reached earlier, depending on the strength of the field.

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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