On the 750 GeV di-photon excess

TL;DR

This paper investigates various perturbative models, including scalar singlets and two Higgs doublet models, to explain the 750 GeV di-photon excess observed in experiments, analyzing their feasibility and parameter space constraints.

Contribution

It compares different theoretical scenarios for the 750 GeV excess, highlighting the conditions under which each can produce the observed signal.

Findings

Scalar singlet models fit the excess more naturally than doublets.

Gluon fusion and vector boson fusion can produce sufficient di-photon rates.

Heavy resonance decays can explain the excess without contradicting 8 TeV data.

Abstract

We explore several perturbative scenarios in which the di-photon excess at 750 GeV can potentially be explained: a scalar singlet, a two Higgs doublet model (2HDM), a 2HDM with an extra singlet, and the decays of heavier resonances, both vector and scalar. We draw the following conclusions: (i) due to gauge invariance a 750 GeV scalar singlet can accommodate the observed excess more readily than a scalar SU(2)_L doublet; (ii) scalar singlet production via gluon fusion is one option, however, vector boson fusion can also provide a large enough rate, (iii) 2HDMs with an extra singlet and no extra fermions can only give a signal in a severely tuned region of the parameter space; (iv) decays of heavier resonances can give a large enough di-photon signal at 750 GeV, while simultaneously explaining the absence of a signal at 8 TeV.