Long-lived charged Higgs at LHC as a probe of scalar Dark Matter

TL;DR

This paper investigates the production and decay of long-lived charged Higgs bosons at the LHC within a scalar dark matter model, highlighting their potential for discovery through displaced vertices and decay chain reconstruction.

Contribution

It introduces a detailed analysis of inert charged Higgs bosons in a constrained scalar dark matter model, emphasizing their long-lived nature and experimental signatures at the LHC.

Findings

Long-lived $H^\pm$ can produce detectable displaced vertices.

Cross sections for $pp o H^+H^-, H^\pm S_i^0$ are computed.

Benchmark points for LHC studies are proposed.

Abstract

We study inert charged Higgs boson $H^\pm$ production and decays at LHC experiments in the context of constrained scalar dark matter model (CSDMM). In the CSDMM the inert doublet and singlet scalar's mass spectrum is predicted from the GUT scale initial conditions via RGE evolution. We compute the cross sections of processes $pp\to H^+H^-,\, H^\pm S_i^0$ at the LHC and show that for light $H^\pm$ the first one is dominated by top quark mediated 1-loop diagram with Higgs boson in s-channel. In a significant fraction of the parameter space $H^\pm$ are long-lived because their decays to predominantly singlet scalar dark matter (DM) and next-to-lightest (NL) scalar, $H^\pm\to S_{\text{DM, NL}} ff',$ are suppressed by the small singlet-doublet mixing angle and by the moderate mass difference $ \Delta M=M_{H^+}-M_{\text{DM}} .$ The experimentally measurable displaced vertex in $H^\pm$ decays to leptons and/or jets and missing energy allows one to discover the $H^+H^-$ signal over the huge $W^+W^-$ background. We propose benchmark points for studies of this scenario at the LHC. If, however, $H^\pm$ are short-lived, the subsequent decays $S_{\text{NL}}\to S_{\text{DM}} f\bar f$ necessarily produce additional displaced vertices that allow to reconstruct the full $H^\pm$ decay chain.