在$\sqrt{s}$ = 13 TeV质子-质子碰撞中搜索末态包含增强缪子对和陶子对的轻赝标量希格斯玻色子
Search for a light pseudoscalar Higgs boson in final states with boosted muon pairs and tau lepton pairs in proton-proton collisions at $\sqrt{s}$ = 13 TeV
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中文总结 AI 辅助
利用CMS实验138 fb$^{-1}$数据搜索轻赝标量希格斯玻色子，通过H→aa→μμττ过程，开发深度神经网络双陶子重建技术，未发现超出，设置95%置信水平上限，首次覆盖至1 TeV标量质量。
中文摘要 AI 辅助
本文报道了一项利用CMS实验在2016至2018年间收集的$\sqrt{s}$ = 13 TeV LHC质子-质子数据（对应积分亮度为138 fb$^{-1}$）对轻赝标量希格斯玻色子a的搜索。该分析针对H $\to$ aa $\to \mu\mu\tau\tau$过程，其中标量H可以是125 GeV希格斯玻色子或更重的态。由于H与a之间质量差较大，两个陶子受到高度洛伦兹增强并准直，常常无法通过CMS标准陶子重建。为此，开发了包括深度神经网络在内的专用双陶子重建技术，以提高至少一个陶子强子衰变事例的效率。未观察到相对于标准模型（SM）背景的显著超出。在95%置信水平上，设置了希格斯玻色子产生截面与分支比乘积除以SM截面的模型无关上限。对于质量$m_\mathrm{H}$等于125 GeV的希格斯玻色子，在赝标量质量3.6至21 GeV范围内，这些上限介于5$\times$10$^{-5}$至2.7$\times$10$^{-4}$之间。利用LHC数据，首次在含陶子末态中获得了质量高达1 TeV的假设标量玻色子的上限。对于$m_\mathrm{H}$ = 1 TeV，在赝标量质量3.6至50 GeV范围内，上限介于3.5$\times$10$^{-4}$至1.5$\times$10$^{-3}$之间。此外，对于$m_\mathrm{H}$ = 125 GeV的双希格斯二重态加单态模型SM扩展，也设置了限制，扩展了此前LHC的结果。
英文摘要
A search is presented for a light pseudoscalar Higgs boson, a, using LHC proton-proton data at $\sqrt{s}$ = 13 TeV collected by the CMS experiment from 2016 to 2018, corresponding to an integrated luminosity of 138 fb$^{-1}$. The analysis targets the process H $\to$ aa $\to μμττ$, where the scalar H can be either the 125 GeV Higgs boson or a heavier state. Because of the large mass difference between H and a, the two tau leptons are highly Lorentz boosted and collimated, often failing standard CMS tau lepton reconstruction. To address this, dedicated ditau reconstruction techniques, including a deep neural network, are developed to improve the efficiency for events in which at least one tau lepton decays to hadrons. No significant excess over the standard model (SM) background is observed. Model-independent upper limits at the 95% confidence level are set on the product of the Higgs boson production cross section and branching fraction, divided by the SM cross section. For a Higgs boson mass ($m_\mathrm{H}$) equal to 125 GeV, these limits range from 5$\times$10$^{-5}$ to 2.7$\times$10$^{-4}$ for pseudoscalar masses between 3.6 and 21 GeV. For the first time using LHC data, upper limits are also obtained in final states with tau leptons for a hypothetical scalar boson with a mass up to 1 TeV. For $m_\mathrm{H}$ = 1 TeV, the limits range from 3.5$\times$10$^{-4}$ to 1.5$\times$10$^{-3}$ for pseudoscalar masses between 3.6 and 50 GeV. In addition, limits are set for SM extensions involving two-Higgs-doublet plus singlet models for $m_\mathrm{H}$ = 125 GeV, extending previous LHC results.
