"Figure 2-7" 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（CMS detector），对穿过夸克-胶子等离子体（quark-gluon plasma）的高横动量$(p_{mathrm{T}})$喷注对应的带电粒子分布修正效应展开探究。针对$sqrt{s_{mathrm{NN}}} = 5.02$ TeV下的铅-铅碰撞与质子-质子碰撞事件，通过相对赝快度分箱内的带电粒子关联，以及相对于领头喷注、次领头喷注轴的角距离，对背对背双喷注开展分析。对比铅-铅与质子-质子碰撞的实验结果，研究发现带电粒子相对距离分布以及喷注轴周围动量分布的修正效应，取决于双喷行动量平衡$x_j$——即次领头喷注与领头喷注的$p_{mathrm{T}}$比值。对于$x_j approx 1$的事件，领头喷注与次领头喷注均观测到了此类分布修正。不过，当双喷行动量失衡程度更高时，次领头喷注会呈现显著的分布修正；而此类事件中的领头喷注仅表现出极微弱的分布修正。