Let there be light from a second light Higgs doublet

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.