"Figure 43 aux" of "Search for long-lived particles using out-of-time trackless jets in proton-proton collisions at $\sqrt{s}$ = 13 TeV"

A search for long-lived particles decaying in the outer regions of the CMS silicon tracker or in the calorimeters is presented. The search is based on a data sample of proton-proton collisions at $\sqrt{s} = 13$ TeV recorded with the CMS detector at the LHC in 2016-2018, corresponding to an integrated luminosity of 138 $\text{fb}^{-1}$. A novel technique, using trackless and out-of-time jet information combined in a deep neural network discriminator, is employed to identify decays of long-lived particles. The results are interpreted in a simplified model of chargino-neutralino production, where the neutralino is the next-to-lightest supersymmetric particle, is long-lived, and decays to a gravitino and either a Higgs or $Z$ boson.This search is most sensitive to neutralino proper decay lengths of approximately 0.5 m, for which masses up to 1.18 TeV are excluded at 95% confidence level. The current search is the best result to date in the mass range from the kinematic limit imposed by the Higgs mass up to 1.8 TeV.

本文报道了一项针对在紧凑型μ子线圈（CMS）探测器的硅径迹外层区域或量能器内发生衰变的长寿命粒子的搜寻分析。本分析基于2016至2018年大型强子对撞机（LHC）上的CMS探测器采集的质心系能量√s=13 TeV的质子-质子碰撞数据样本，对应积分亮度为138 fb⁻¹。本分析采用了一种新颖方法：将无径迹粒子与时序外喷注信息相结合，输入深度神经网络判别器，以识别长寿命粒子的衰变信号。本分析结果在荷微子（chargino）与中性微子（neutralino）产生的简化模型框架下展开解释：该模型中中性微子为次轻超对称粒子，寿命较长，且会衰变为引力微子（gravitino）与希格斯（Higgs）玻色子或Z玻色子。本搜寻实验对固有衰变长度约0.5米的中性微子具有最高灵敏度，在此参数区间内，质量不超过1.18 TeV的中性微子在95%置信水平下被排除。在由希格斯粒子质量限定的运动学上限至1.8 TeV的质量范围内，本分析是目前为止灵敏度最优的搜寻结果。