"Table 52" of "Correlations between jets and charged particles in PbPb and pp collisions at sqrt(s[NN])= 2.76 TeV"

CERN-LHC. The quark-gluon plasma is studied via medium-induced changes to correlations between jets and charged particles in PbPb collisions compared to pp reference data. This analysis uses data sets from PbPb and pp collisions with integrated luminosities of 166 inverse microbarns and 5.3 inverse picobarns, respectively, collected at sqrt(s[NN]) = 2.76 TeV. The angular distributions of charged particles are studied as a function of relative pseudorapidity (Delta eta) and relative azimuthal angle (Delta phi) with respect to reconstructed jet directions. Charged particles are correlated with all jets with transverse momentum (pT) above 120 GeV, and with the leading and subleading jets (the highest and second-highest in pT, respectively) in a selection of back-to-back dijet events. Modifications in PbPb data relative to pp reference data are characterized as a function of PbPb collision centrality and charged particle pT. A centrality-dependent excess of low-pT particles is present for all jets studied, and is most pronounced in the most central events. This excess of low-pT particles follows a Gaussian-like distribution around the jet axis, and extends to large relative angles of Delta eta ~ 1 and Delta phi ~1.

欧洲核子研究中心大型强子对撞机（CERN-LHC）：本研究通过对比质子-质子（pp）参考数据，分析铅-铅（PbPb）碰撞中介质诱导的喷注与带电粒子间关联的变化，以此研究夸克-胶子等离子体（quark-gluon plasma）。本分析使用了在核子-核子质心系能量√(s_NN)=2.76 TeV下采集的铅-铅与质子-质子碰撞数据集，二者的积分亮度分别为166逆微靶恩与5.3逆皮靶恩。研究以重建喷注方向为参照，分析带电粒子的角分布随相对赝快度（Δη，relative pseudorapidity）与相对方位角（Δφ，relative azimuthal angle）的变化规律。研究将带电粒子与所有横向动量（p_T，transverse momentum）大于120 GeV的喷注进行关联，并在筛选得到的背对背双喷注事件中，进一步将带电粒子与领头喷注及次领头喷注（分别为横向动量最高与第二高的喷注）建立关联。相较于质子-质子参考数据，铅-铅碰撞数据中的关联修正特征以碰撞中心度（collision centrality）与带电粒子横向动量为变量进行表征。在所研究的全部喷注样本中，均存在与碰撞中心度相关的低横向动量（low-p_T）粒子超额现象，且该现象在最中心的碰撞事件中最为显著。这类低横向动量粒子的超额分布在喷注轴附近呈类高斯形态，并可延伸至Δη~1与Δφ~1的较大相对角区间。