"Figure 2-1" 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CMS探测器，探究了穿过夸克-胶子等离子体（quark-gluon plasma）的高横动量（transverse momentum，$p_mathrm{T}$）喷流对带电粒子分布的修正效应。通过在相对赝快度分箱以及相对于领头喷流与次领头喷流轴线的角距离分箱内对带电粒子开展关联分析，我们对$sqrt{s_{mathrm{NN}}}=5.02$太电子伏特（TeV）下铅核-铅核与质子-质子碰撞中的背对背双喷流进行了分析。对比铅核-铅核与质子-质子碰撞的实验结果后发现，带电粒子相对距离分布以及喷流轴周边动量分布的修正效应，取决于双喷行动量平衡量$x_j$——该量定义为次领头喷流与领头喷流的横动量之比。对于$x_japprox1$的物理事例，领头喷流与次领头喷流均观测到了此类修正；而当双喷行动量失衡程度更高时，次领头喷流会呈现显著的修正效应，但此类事件中的领头喷流仅表现出极微弱的修正。