arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2002.06386hep-exnucl-ex
收藏

在STAR通过基于角和动量的微分喷流测量约束部分子能量损失

Constraining parton energy loss via angular and momentum based differential jet measurements at STAR

Raghav Kunnawalkam Elayavalli

备注：
Proceedings for XXVIIIth International Conference on Ultrarelativistic Nucleus-Nucleus Collisions (Quark Matter 2019)
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

部分子能量损失是重离子碰撞中夸克-胶子等离子体（QGP）的一个重要特征，因为RHIC最早的测量表明在高的$p_{\rm{T}}$和符合产额下强子谱被抑制。理解这种喷流淬灭现象是通过喷流层析术提取QGP微观特性的要求。STAR最近引入了一种称为喷射几何工程（JGE）的技术，其中我们强制执行特定的选择标准强加于喷射收集，如反冲高$p_{\rm{T}}$强子触发器，以及一个额外的横向动量阈值的事件与背靠背双喷流的喷射成分。通过JGE，我们能够控制从淬火/不平衡到恢复/平衡的双射流的能量损失程度。由于射流淬灭也预计将取决于分辨率/横向长度尺度与射流探针的介质，它是必要的，以执行差分测量与手柄上的动量和角度尺度。为了量化射流内的角度尺度，我们提出了第一次测量的喷气的固有角结构在金$+$金碰撞在$\sqrt{s_{\mathrm{NN}}} = $ 200 GeV通过两个领先的子射流（$θ_{\rm{SJ}}$）之间的开角。我们还测量了di-jet不对称性$A_{\rm{J}}$差分作为$θ_{\rm{SJ}}$的功能，可观察到这些di-jet，并没有发现显着的依赖性的能量损失的反冲射流的开度角。

英文摘要：

Parton energy loss has been established as an essential signature of the Quark-Gluon Plasma (QGP) in heavy ion collisions since the earliest measurements at RHIC indicating suppression of hadron spectra at high $p_{\rm{T}}$ and coincidence yields. Understanding this phenomenon of jet quenching is a requirement for extracting the microscopic properties of the QGP via jet-tomography. STAR has recently introduced a technique called Jet Geometry Engineering (JGE) wherein we enforce particular selection criteria imposed on the jet collection, such as recoiling off a high $p_{\rm{T}}$ hadron trigger along with an additional transverse momentum threshold for jet constituents in events with back-to-back di-jets. With JGE, we are able to control the extent of energy loss ranging from quenched/imbalanced to recovered/balanced di-jets. Since jet quenching is also expected to be dependent on the resolution/transverse-length scales with which the jet probes the medium, it is necessary to perform differential measurements with a handle on both momentum and angular scales. To quantify the angular scale within jets, we present the first measurement of the jet's inherent angular structure in Au$+$Au collisions at $\sqrt{s_{\mathrm{NN}}} = $ 200 GeV via the opening angle between the two leading sub-jets ($θ_{\rm{SJ}}$). We also measure the di-jet asymmetry $A_{\rm{J}}$ differentially as a function of the $θ_{\rm{SJ}}$ observable for these di-jets and find no significant dependence of the energy loss on the opening angle of the recoil jet.

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。

↑