"Figure 1-12" 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.

本研究借助紧凑型μ子线圈探测器（CMS, Compact Muon Solenoid），探究了穿过夸克-胶子等离子体的高横动量$(p_mathrm{T})$喷注相关带电粒子分布的修正效应。针对$sqrt{s_{mathrm{NN}}}=5.02$ TeV的铅核-铅核与质子-质子碰撞事件中的背对背双喷注，本研究通过带电粒子在相对赝快度分箱内的关联特性，以及其与领头喷注、次领头喷注轴线的角距离展开分析。通过对比两类碰撞的实验结果，本研究发现：带电粒子相对角距离分布以及喷注轴线附近的动量分布的修正效应，依赖于双喷注动量平衡量$x_j$——即次领头喷注与领头喷注的横动量之比。当$x_j approx 1$时，领头喷注与次领头喷注均观测到此类修正效应。然而，对于双喷注动量失衡程度更大的事件，次领头喷注呈现出显著的修正效应，而此类事件中的领头喷注仅存在极微弱的修正。