"Figure 12 bottom right" of "Search for long-lived particles decaying to a pair of muons in proton-proton collisions at $\sqrt{s}$ = 13 TeV"

Comparison of the number of events observed in 2018 data in the TMS-TMS dimuon category with the expected number of background events, in representative $m_{\mu \mu}$ intervals in the $min(d_0 / \sigma_{d_0}) > 20$ bin. The black points with crosses show the number of observed events; the green and yellow components of the stacked histograms represent the estimated numbers of DY and QCD events, respectively. The last bin includes events in the overflow. The uncertainties in the total expected background (shaded area) are statistical only. Signal contributions expected from simulated $H \rightarrow Z_D Z_D$ with $m_{Z_D}$ of 20 and 50 GeV are shown in red and blue, respectively. Their yields are set to the corresponding combined median expected exclusion limits at 95% CL, scaled up as indicated in the legend to improve visibility. The legend also includes the total number of observed events as well as the number of expected background events obtained inclusively, by applying the background evaluation method to the events in all $m_{Z_D}$ and min($d_0 / \sigma_{d_0}$) intervals combined.

本图对比了冲击参数显著性最小值（$min(d_0/sigma_{d_0})$）>20的箱（bin）内，代表性双缪子不变质量（$m_{mumu}$）区间中，2018年TMS-TMS双缪子（dimuon）类别观测到的事例数与预期本底事例数。带叉号的黑色点代表观测事例数；堆叠直方图的绿色与黄色分量分别对应Drell-Yan（DY）过程与量子色动力学（QCD）过程的估算事例数。最后一个箱包含溢出（overflow）事例。总预期本底的不确定度（阴影区域）仅为统计不确定度。通过蒙特卡洛模拟得到的、暗Z玻色子质量（$m_{Z_D}$）分别为20与50 GeV的$H
ightarrow Z_D Z_D$（希格斯玻色子衰变为一对暗Z玻色子）信号贡献，分别以红色与蓝色曲线展示。其产额被设置为对应95%置信度（CL）下的联合中位数预期排除极限，并按图例标注的比例进行缩放以提升可读性。图例同时涵盖总观测事例数，以及将背景评估方法应用于所有$m_{Z_D}$与$min(d_0/sigma_{d_0})$区间内的全部事例后得到的全域预期本底事例数。