A Promising Interpretation of Diphoton Resonance at 750 GeV

TL;DR

This paper proposes a simple extension of the Standard Model with an extra doublet Higgs and a singlet to explain the 750 GeV diphoton resonance observed at the LHC, showing it can produce the observed signals while satisfying experimental constraints.

Contribution

The paper introduces a minimal model extension with a new Higgs doublet and a light singlet to interpret the 750 GeV diphoton excess as a resonance decaying into collimated photons.

Findings

Diphoton cross section from 3 to 13 fb

Decay width of 30 to 60 GeV for the resonance

Model satisfies current experimental constraints

Abstract

Recently, an excess of events in diphoton channel with invariant mass of about 750 GeV has been reported by the ATLAS and CMS Collaborations. Considering it as a tantalizing hint for new physics beyond the Standard Model (SM), we propose a simple extension of the SM with an additional doublet Higgs $H^{'}$ and a singlet $s$. We consider the neutral component $H^{\prime }_0$ of $H'$ as the 750 GeV resonance, and assume that $s$ is lighter than 2.6 GeV. In particular, $H^{\prime }_0$ can be produced at tree level via $q{\bar q}$ production, and decay into a pair of $s$ at tree level. And then $s$ can decay into a pair of collimated photons, which cannot be distinguished at the LHC. We show that the diphoton production cross section can be from 3 to 13 ${\rm fb}$, the decay width of $H^{\prime }_0$ can be from 30 to 60 GeV, and all the current experimental constraints including dijet constraint can be satisfied.