RHIC能量扫描中逐事件净质子数分布的高阶矩实验研究

项目名称： RHIC能量扫描中逐事件净质子数分布的高阶矩实验研究

项目编号： No.11205067

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 物理学II

项目作者： 罗晓峰

作者单位： 华中师范大学

项目金额： 28万元

中文摘要： 美国布鲁克海汶国家实验室(BNL)中相对论重离子对撞机(RHIC)上进行的能量扫描计划的主要目的之一就是通过改变金核金核碰撞质心能量来探索更大范围的QCD物质相图区域，这为实验研究强相互作用物质的相变结构提供了一种有效的途径。理论研究表明，高能重离子碰撞实验中可观测的逐事件净质子数（质子数减去反质子数）分布的高阶矩对系统的关联长度非常灵敏并且与系统重子数的热力学感应率有直接的关联。这为研究QCD物质性质以及相变结构提供了很好的实验探针。本项目旨在利用从RHIC上的STAR探测器采集到的能量扫描实验数据，对逐事件净质子数分布的高阶矩进行系统的测量和分析，并将所得实验结果应用到寻找QCD相变临界点的研究。

中文关键词： 临界点；QCD相图；重离子碰撞；夸克胶子等离子体；能量扫描

英文摘要： The phase structure of nuclear matter, described by strong interaction, can be demonstrated by QCD phase diagram, which is two dimensional diagram with parameters temperature and baryon chemical potential. A new form of matter-Quark Gluon Plasma (QGP) dominated by quark and gluon degree of freedom is believed to exist in the early Universe after few tens microseconds of Big Bang, when the energy density and temperature is extremely high. Finite temperature Lattice QCD calculations predict a smooth cross-over transition from hadronic phase to the QGP phase at high temperature and small baryon chemical potential region, and a first order phase transition at large baryon chemical potential region. The end point of the first order phase boundary toward the cross-over region is the so called QCD Critical Point (CP). Although many efforts have been made by theorist and experimentalist to locate the CP, its location or even existence is still not confirmed yet. In the year 2010, The Relativistic Heavy Ion Collider (RHIC) in BNL, USA has started its Beam Energy Scan (BES) program and tuned the Au+Au collision energy from 39 down to 7.7 GeV. This allows us to access and probe broad region of the QCD phase diagram and provides us an ideal experimental tool to explore the phase structure of nuclear matter and study the pr

英文关键词： Critical Point；QCD Phase Diagram；heavy-ion collisions；Quark-gluon plasma；Beam Energy Scan