"TChiHH expected + 2 s.d. mass limit curve" 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.

本工作报道了在质心系能量$sqrt{s}=13$ TeV的质子-质子对撞中，针对双希格斯玻色子末态（每个希格斯玻色子均通过$H o boverline{b}$过程衰变）伴随大缺失横动量的超出标准模型物理的搜寻结果，数据来自欧洲核子研究中心（CERN）大型强子对撞机（Large Hadron Collider, LHC）上紧凑型缪子线圈（Compact Muon Solenoid, CMS）实验采集的、对应积分亮度为137 fb⁻¹的数据样本。本次搜寻的理论动机源自超对称模型，该类模型预言了中性微子（neutralinos）——电弱规范玻色子与希格斯玻色子的中性伴子——的产生。研究发现，信号区域内的观测事例产额与标准模型本底预期相符。本结果基于超对称简化模型进行诠释：针对近简并希格斯微子的电弱产生过程，其每条衰变链均会产生一个中性微子$widetilde{chi}^0_1$，该中性微子随后衰变为无质量金斯廷诺与希格斯玻色子，质量介于175 GeV至1025 GeV区间的$widetilde{chi}^0_1$在95%置信度下被排除；对于通过质量略轻的$widetilde{chi}^0_2$衰变至希格斯玻色子与轻中性微子$widetilde{chi}^0_1$的胶微子对强产生过程，质量低于2330 GeV的胶微子被排除。