Identifying a light charged Higgs boson at the LHC Run II

Abdesslam Arhrib,Rachid Benbrik,Rikard Enberg,William Klemm,Stefano Moretti,Shoaib Munir

doi:10.1016/j.physletb.2017.10.006

Abstract

We analyse the phenomenological implications of a light Higgs boson, h, within the CP-conserving 2-Higgs Doublet Model (2HDM) Type-I, for the detection prospects of the charged H± state at Run II of the Large Hadron Collider (LHC), assuming s=13 TeV as energy and O(100 fb−1) as luminosity. When sufficiently light, this h state can open up the bosonic decay channel H±→W±(⁎)h, which may have a branching ratio significantly exceeding those of the H±→τν and H±→cs channels. We perform a broad scan of the 2HDM Type-I parameter space, assuming the heavier of the two CP-even Higgs bosons, H, to be the observed SM-like state with a mass near 125 GeV. Through these scans we highlight regions in which mH±<mt+mb that are still consistent with the most recent limits from experimental searches. We find in these regions that, when the H±→W±(⁎)h decay mode is the dominant one, the h can be highly fermiophobic, with a considerably large decay rate in the γγ channel. This can result in the total cross section of the σ(pp→H±h→W±(⁎)+4γ) process reaching up to O(100 fb). We therefore investigate the possibility of observing this spectacular signal at the LHC Run II.

Highlights

The discovery of a resonance around 125 GeV at the Large Hadron Collider (LHC) [1,2] triggered plenty of activity in the particle physics community
The possibility that the Hobs could belong to a model with an extended Higgs sector, such as the SM with an extra singlet, doublet and/or triplet has not been ruled out. Amongst such higher Higgs representations, those with an extra doublet or triplet contain one or more charged Higgs bosons in their scalar spectrum. The discovery of such charged Higgs bosons would be an eminent signal of an extended Higgs sector and clear evidence of physics Beyond the SM (BSM)
Through the minimisation conditions of the potential, m211 and m222 can be traded for v1 and v2 and the tree-level mass relations allow the quartic couplings λ1–5 to be substituted by the four physical Higgs boson masses and the neutral sector mixing term sin(β − α), where β is defined through tan β = v2/v1, and α is the mixing angle between the CP-even interaction states

Summary

Introduction

The discovery of a resonance around 125 GeV at the Large Hadron Collider (LHC) [1,2] triggered plenty of activity in the particle physics community. The measured signal rates of this scalar particle, Hobs, in its dominant decay channels, agree with those predicted for the SM Higgs boson at the 2σ level [3]. The possibility that the Hobs could belong to a model with an extended Higgs sector, such as the SM with an extra singlet, doublet and/or triplet has not been ruled out Amongst such higher Higgs representations, those with an extra doublet or triplet contain one or more charged Higgs bosons in their scalar spectrum. Two other important features of the relevant parameter space were noted there: i) for consistency with the EW precision measurements, such light h and A are accompanied by an H± not much heavier than the Z boson, and ii) the h can be extremely fermiophobic, so that its decays into SM fermions are highly suppressed, which can in turn result in a very large.

Types of the 2HDM

Fermiophobic h in the 2HDM-I

Discovery potential

Conclusions