"Figure 2-24" of "In-medium modification of dijets in PbPb collisions at $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV"

Modifications to the distribution of charged particles with respect to high transverse momentum $(p_{\mathrm{T}})$ jets passing through a quark-gluon plasma are explored using the CMS detector. Back-to-back dijets are analyzed in lead-lead and proton-proton collisions at $\sqrt{s_{\mathrm{NN}}} = 5.02$ TeV via correlations of charged particles in bins of relative pseudorapidity and angular distance from the leading and subleading jet axes. In comparing the lead-lead and proton-proton collision results, modifications to the charged-particle relative distance distribution and to the momentum distributions around the jet axis are found to depend on the dijet momentum balance $x_{j}$, which is the ratio between the subleading and leading jet $p_{\mathrm{T}}$. For events with $x_{j} \approx 1$, these modifications are observed for both the leading and subleading jets. However, while subleading jets show significant modifications for events with a larger dijet momentum imbalance, much smaller modifications are found for the leading jets in these events.

本研究利用CMS探测器(CMS)，探究了穿过夸克-胶子等离子体(quark-gluon plasma)的高横动量(p_T)喷注对应的带电粒子分布的修正效应。我们针对√(s_NN)=5.02 TeV的铅-铅碰撞与质子-质子碰撞中的背对背双喷注展开分析，通过对相对赝快度分箱内的带电粒子，以及与领头喷注、次领头喷注轴线的角距离进行关联研究。对比两类碰撞的结果，我们发现带电粒子相对距离分布与喷注轴周围的动量分布的修正效应，依赖于双喷注动量平衡x_j——即次领头喷注与领头喷注的p_T比值。对于x_j≈1的事件，领头喷注与次领头喷注均观测到此类修正。而当双喷注动量失衡程度更高时，次领头喷注会呈现显著的修正效应，但此类事件中的领头喷注仅存在极微小的修正。