"Figure 8 (lower right)" of "Measurement of Differential ZZ+Jets Production Cross Sections in pp Collisions at $\sqrt{s}$ = 13 TeV"

Diboson production in association with jets is studied in the fully leptonic final states, $\textrm{pp} \to (\textrm{Z}/\gamma^*)(\textrm{Z}/\gamma^*)+\textrm{jets} \to 2\ell2\ell'+\textrm{jets}$, ($\ell,\ell' = \textrm{e}$ or $\mu$) in proton-proton collisions at a center-of-mass energy of 13 TeV. The data sample corresponds to an integrated luminosity of 138 fb$^{-1}$ collected with the CMS detector at the LHC. Differential distributions and normalized differential cross sections are measured as a function of jet multiplicity, transverse momentum $p_\textrm{T}$, pseudorapidity $\eta$, invariant mass and $\Delta\eta$ of the highest-$p_\textrm{T}$ and second-highest-$p_\textrm{T}$ jets, and as a function of invariant mass of the four-lepton system for events with various jet multiplicities. These differential cross sections are compared with theoretical predictions that mostly agree with the experimental data. However, in a few regions we observe discrepancies between the predicted and measured values. Further improvement of the predictions is required to describe the ZZ+jets production in the whole phase space.

本研究针对质心系能量为13 TeV的质子-质子碰撞中伴随喷注的双玻色子产生过程的全轻子末态展开分析，其反应过程为$ extrm{pp} o ( extrm{Z}/gamma^*)( extrm{Z}/gamma^*)+ extrm{jets} o 2ell2ell'+ extrm{jets}$，其中$ell、ell'$代表电子（e）或μ子（μ）。本次分析使用大型强子对撞机（Large Hadron Collider, LHC）上的紧凑型μ子线圈探测器（Compact Muon Solenoid, CMS）采集的积分亮度为138 fb$^{-1}$的数据样本。针对不同喷注多重度的事件，我们测量了多项微分分布与归一化微分截面，这些观测量分别以喷注多重度、最高横向动量$p_ extrm{T}$喷注与次高横向动量喷注的横向动量、赝快度$eta$、不变质量以及二者的赝快度差$Deltaeta$为自变量，同时也以四轻子系统的不变质量为自变量。我们将上述微分截面与理论预言进行比对，多数情况下理论预言与实验测量结果吻合良好，但在少数相空间区域中观测到预言值与测量值之间存在偏差。为完整描述ZZ+喷注产生过程在全相空间内的行为，仍需对理论预言作出进一步优化。