Probing a long-lived pseudoscalar in type-I 2HDM with displaced vertices and jets at the LHC
摘要
In the type-I two-Higgs-doublet model, the pseudoscalar A can act as a long-lived particle (LLP) for sufficiently large values of tan β. At the LHC, the A particles are predominantly produced in pairs through pp → W∗/Z∗ → H±/H A, with subsequent decays H±/H → W±/Z A. For the mass range of our interest, 10 GeV ≲ mA ≲ 100 GeV, the pseudoscalar A typically decays into a pair of bottom quarks after traveling a macroscopic distance from its production point, giving rise to displaced-vertex (DV) signatures inside the inner detector. We perform Monte Carlo simulations of signal events with DVs plus jets, and assess the discovery prospects of A as an LLP at the ATLAS and CMS experiments. Our findings show that a substantial portion of the parameter space with mA > 10 GeV has already been excluded by LHC Run-2 data, while the high-luminosity LHC will be able to probe broader regions.