Direct production of light scalars in the type-I two-Higgs-doublet model at the lifetime frontier of the LHC

Abstract

A light pseudoscalar A in the sufficient large tanβ region of type-I two-Higgs-doublet model can be naturally a long-lived particle. We focus on H±A, HA, and AA pair productions via the electroweak processes mediated by the bosons at the LHC, including pp→W±/Z→H±/HA and pp→h→AA at the 14 TeV LHC. The possibility of probing A as a LLP at the FASER-2, FACET, MoEDAL-MAPP-2, and MATHUSLA is discussed. We find that FASER-2 fails to probe any parameter space within 0.2 GeV<mA<10 GeV for all the considered processes. For 130<mH±=mH<400 GeV, FACET, MoEDAL-MAPP-2, and MATHUSLA can probe tanβ≲104−6 for mA≲3 GeV, and tanβ≲106−8 for 3 GeV≲mA<10 GeV from pp→W±/Z→H±/ZA processes. And pp→h→AA process covers similar parameter space. All processes can surpass the current limits. Published by the American Physical Society 2024