Let there be light from a second light Higgs doublet

TL;DR

This paper shows that a second light Higgs in the type-I two-Higgs-doublet model can explain the CMS 95 GeV di-photon excess and other Higgs anomalies, with future LHC data capable of testing this scenario.

Contribution

It demonstrates a parameter space within the type-I two-Higgs-doublet model that explains multiple Higgs anomalies simultaneously.

Findings

The 95 GeV di-photon excess can be explained by a fermiophobic CP-even Higgs.

The model accommodates Higgs masses between 80 and 350 GeV.

Current constraints are satisfied, future data can test the scenario.

Abstract

In this article, we demonstrate that the unexpected peak at around $95 \, {\rm GeV}$ as seen recently by CMS in the di-photon final state can be explained within the type-I~two-Higgs-doublet model by means of a moderately-to-strongly fermiophobic CP-even Higgs $H$. Depending on the Higgs mass spectrum, the production of such~a~$H$ arises dominantly from vector boson fusion or through a cascade in either $pp \to t \bar t$ with $\overset{(-)}{t} \to H^{\pm} \overset{(-)}{b} \to W^{\pm \, \ast} H \overset{(-)}{b}$ or $pp \to A$ with $A \to W^{\mp} H^{\pm} \to W^{\mp} W^{\pm} H$ or via $pp \to W^{\pm \, \ast} \to H^\pm H$. In this context, we also discuss other Higgs anomalies such as the LEP excess in Higgsstrahlung and the observation of enhanced rates in $t \bar t h$ at both the Tevatron and the LHC, showing that parameters capable of explaining the CMS di-photon signal can address the latter deviations as well. The Higgs spectra that we explore comprise masses between $80 \, {\rm GeV}$ and $350\, {\rm GeV}$. While at present all constraints from direct and indirect searches for spin-0 resonances can be shown to be satisfied for such light Higgses, future LHC data will be able to probe the parameter space that leads to a simultaneous explanation of the discussed anomalies.