arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0810.3727nucl-ex
收藏

大横动量强子的测量及对介质不透明度参数的约束

Measurement of Large Transverse Momentum Hadrons and Constraints on Medium Opacity Parameters

D. Winter

摘要:

PHENIX实验测量了金+金碰撞中的{ \piz }s,其能量为sqrt(s_{NN})= 200 GeV,在高达20 GeV/c的横向动量pT下具有良好的统计。发现了五倍的抑制,对于5<pT<20 GeV/c基本上是恒定的。高能p+p碰撞中高pT π介子的产生在微扰QCD的框架中得到了很好的描述,而超相对论性重离子碰撞中的产生涉及到与碰撞中产生的退禁闭介质的不透明度相关的额外自由度。最新测量的不确定性足够小,可以通过应用所提出的统计方法将依赖于模型的不透明度相关参数(例如介质的输运系数qhat或初始胶子密度dN^g/dy)限制在+/-20-25%(一个标准差)的水平。从抑制能级对参与核子数的依赖关系,我们也证实了能量损失随部分子pT的增加而增加。本文介绍了PHENIX关于高横动量强子的最新结果,并详细讨论了碰撞过程中产生的介质的性质。

英文摘要:

The PHENIX experiment has measured {\piz}s in Au+Au collisions at sqrt(s_{NN}) = 200 GeV, with good statistics for transverse momentum, pT, up to 20 GeV/c. A fivefold suppression is found, which is essentially constant for 5<pT<20 GeV/c. While the production of high pT pions in high energy p+p collisions is well described in the framework of perturbative QCD, production in ultra-relativistic heavy ion collisions involves additional degrees of freedom related the opacity of the deconfined medium produced in the collisions. The uncertainties of the latest measurement are small enough to constrain model-dependent opacity-related parameters, such as the transport coefficient of the medium, qhat or initial gluon density dN^g/dy at the level of +/- 20-25% (one standard deviation), by applying a statistical method proposed. From the dependence of the suppression level to the number of participant nucleons, we have also confirmed that the energy loss increases as pT of partons increases. The latest PHENIX result on high transverse momentum hadrons are presented, and the property of the medium created in the collisions is discussed in detail.

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。

↑