"Covariance matrix" of "Search for higgsinos decaying to two Higgs bosons and missing transverse momentum in proton-proton collisions at $\sqrt{s}$ = 13 TeV"

Results are presented from a search for physics beyond the standard model in proton-proton collisions at $\sqrt{s}=13$ TeV in channels with two Higgs bosons, each decaying via the process H$\to b\overline{b}$, and large missing transverse momentum. The search uses a data sample corresponding to an integrated luminosity of 137 fb$^{-1}$ collected by the CMS experiment at the CERN LHC. The search is motivated by models of supersymmetry that predict the production of neutralinos, the neutral partners of the electroweak gauge and Higgs bosons. The observed event yields in the signal regions are found to be consistent with the standard model background expectations. The results are interpreted using simplified models of supersymmetry. For the electroweak production of nearly degenerate higgsinos, each of whose decay chains yields a neutralino ($\widetilde{\chi}^0_1$) that in turn decays to a massless goldstino and a Higgs boson, $\widetilde{\chi}^0_1$ masses in the range 175 to 1025 GeV are excluded at 95\% confidence level. For the strong production of gluino pairs decaying via a slightly lighter $\widetilde{\chi}^0_2$ to H and a light $\widetilde{\chi}^0_1$, gluino masses below 2330 GeV are excluded.本研究报道了在质心系能量$sqrt{s}=13$ TeV的质子-质子碰撞中，针对双希格斯玻色子（Higgs bosons）衰变道（每个希格斯玻色子均通过$mathrm{H} o boverline{b}$过程衰变）且伴随大横向缺失动量的超出标准模型（Standard Model）物理现象的搜寻结果。本次搜寻使用了欧洲核子研究中心（CERN）大型强子对撞机（LHC）上的紧凑缪子线圈（CMS，Compact Muon Solenoid）实验采集的、积分亮度为137 fb⁻¹的数据样本。本次搜寻的理论动机来自超对称（supersymmetry）模型，该类模型预言了中性伴子（neutralino）的产生——中性伴子是电弱规范玻色子与希格斯玻色子的中性伴随粒子。信号区域内观测到的事例产额与标准模型背景预期相符。研究结果基于简化超对称模型进行诠释：对于近简并希格斯微子（higgsino）的电弱产生过程，其每个衰变链均会产生一个中性伴子$widetilde{chi}^0_1$，该中性伴子进一步衰变为无质量金斯廷诺（goldstino）与希格斯玻色子，此时175 GeV至1025 GeV范围内的$widetilde{chi}^0_1$质量在95%置信度下被排除。对于通过稍轻的$widetilde{chi}^0_2$衰变为希格斯玻色子与轻中性伴子$widetilde{chi}^0_1$的胶微子（gluino）对强产生过程，质量低于2330 GeV的胶微子在95%置信度下被排除。