arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0903.3734nucl-th
收藏

重离子碰撞中初态扰动的命运

The Fate of the Initial State Perturbations in Heavy Ion Collisions

Edward Shuryak

摘要:

RHIC中的重离子碰撞可用(接近理想的)流体力学来描述。在本文中,我们研究的传播引起的扰动的移动电荷(射流)上的膨胀火球,使用流体力学和(双重)磁流体力学。在大- $p_t$触发条件下,在双强子关联函数中发现了两种实验观测到的结构,称为“锥”和“硬脊”,而“软脊”是在没有硬触发条件下观察到的类似结构。所有这三个都可以被看作是物质中移动电荷在整体膨胀之上留下的痕迹。令人困惑的是,为什么这些扰动在火球冻结时显然保存得相当完好。我们研究了两种可能的解决方案:(i)“分波”声学选项和(ii)“亚稳态电通量管”。在第一种情况下,我们表明,快速可变的声速在一定条件下导致二次声波,这是在冻结时间更接近原来的位置,并具有更大的强度比第一波。在后一种情况下,我们依靠(双)磁流体力学,它也预测两个圆锥或圆柱体的波。我们还简要地讨论了亚稳态电通量管在近$T_c$阶段和它们的关系,聚类数据。

英文摘要:

Heavy ion collisions at RHIC are well described by the (nearly ideal) hydrodynamics. In the present paper we study propagation of perturbations induced by moving charges (jets) on top of the expanding fireball, using hydrodynamics and (dual) magnetohydrodynamics. Two experimentally observed structures, called a "cone" and a "hard ridge", have been discovered in dihadron correlation function with large-$p_t$ trigger, while "soft ridge" is a similar structure seen without hard trigger. All three can be viewed as traces left by a moving charge in matter, on top of overall expansion. A puzzle is why those perturbations are apparently rather well preserved at the time of the fireball freezeout. We study two possible solutions to it: (i) a "wave-splitting" acoustic option and (ii) a "metastable electric flux tubes". In the first case we show that rapidly variable speed of sound under certain conditions leads to secondary sound waves, which are at freezeout time closer to the original location and have larger intensities than the first wave. In the latter case we rely on (dual) magnetohydrodynamics, which also predicts two cones or cylinders of the waves. We also briefly discuss metastable electric flux tubes in the near-$T_c$ phase and their relation to clustering data.

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。

↑