Could the LHC two-photon signal correspond to the heavier scalar in two-Higgs-doublet models?

TL;DR

This paper investigates whether the 125 GeV two-photon signal at the LHC could be due to the heavier scalar in two-Higgs-doublet models, considering various decay channels and model types.

Contribution

It explores the possibility that the heavier scalar is responsible for the observed signal, analyzing parameter constraints and decay scenarios in different two-Higgs-doublet models.

Findings

The heavier scalar can explain the 125 GeV signal under certain parameter conditions.

The non-observation of the lighter scalar at LEP constrains the models significantly.

Decay channels like H --> h h are crucial in understanding the signal interpretation.

Abstract

LHC has reported tantalizing hints for a Higgs boson of mass 125 GeV decaying into two photons. We focus on two-Higgs-doublet Models, and study the interesting possibility that the heavier scalar (H) has been seen, with the lightest scalar (h) having thus far escaped detection. Non-observation of h at LEP severely constrains the parameter-space of two-Higgs-doublet models. We analyze cases where the decay H --> h h is kinematically allowed, and cases where it is not, in the context of type I, type II, lepton-specific, and flipped models.