arXiv 1104.00462011-04nucl-ex

RHIC最小偏置喷流系统学述评

Review of minimum-bias jet systematics at RHIC

Duncan Prindle

备注：: Proceedings for the Workshop on Critical Examination of RHIC Paradigms April 14, 2010 Austin, Texas, U.S.A

摘要：

在RHIC和LHC的A-A碰撞中研究喷流，目的是了解它们如何受到介质的影响以及它们如何影响介质。人们普遍认为，硬散射部分子在强子化之前通过介质传播时会损失能量。失去足够能量的部分子甚至可能无法以可识别的喷流的形式离开介质（尽管动量将在发射的任何粒子之间共享）。“全”喷注重建试图确定部分子能量损失以及喷注形状的可能变化。重离子碰撞通常会在喷流“锥”内产生许多不相关的粒子，而减去此背景会引入显著的不确定性。使用高$p_t$粒子的各种技术，假设是来自射流破碎的领先粒子，寻找射流的消失和相对于反应平面的射流的衰减，以及介质的修改，如马赫锥。这些技术由于减去$v_2$而具有相当大的不确定性。在本文中，我们讨论了在RHIC使用两粒子关联观测到的最小偏压喷流。我们发现在p-p碰撞中产生的喷流具有一些有趣的性质。外围的A-A碰撞看起来像p-p碰撞。当我们选择更多的中心碰撞，射流的数量增加后，二元碰撞缩放，直到在一个系统依赖的中心，与射流相关联的粒子的数量增加大大超过这个缩放。在这个过渡中心附近的喷流的纵横比-细长横向于光束方向的低能量喷流产生的p-p碰撞-成为高度细长沿光束方向在A-A碰撞。

英文摘要：

Jets are studied in A-A collisions at RHIC and LHC with the goal to understand how they are affected by the medium and how they affect the medium. It is widely believed that hard-scattered partons lose energy when propagating through a medium before hadronizing. Partons losing enough energy may not even make it out of the medium as identifiable jets (although the momentum will be shared among whatever particles are emitted). "Full" jet reconstruction attempts to determine the partonic energy loss as well as possible changes in jet shape. Heavy ion collisions typically produce many unrelated particles within the jet "cone," and subtraction of this background introduces significant uncertainties. A variety of techniques using high-$p_t$ particles, assumed to be leading particles from jet fragmentation, look for disappearance of jets and attenuation of jets relative to the reaction plane, as well as medium modifications such as Mach cones. Those techniques have considerable uncertainty due to subtraction of $v_2$. In this paper we discuss minimum-bias jets observed at RHIC using two-particle correlations. We find that jets produced in p-p collisions have interesting properties. Peripheral A-A collisions look like p-p collision. As we select more central collisions the number of jets increases following binary collision scaling until at a system-dependent centrality the number of particles associated with jets increases substantially above this scaling. Near this transition centrality the jet aspect ratio---elongated transverse to the beam direction for low-energy jets produced in p-p collisions---becomes highly elongated along the beam direction in A-A collisions.

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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英文摘要：

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