Higgs precision study of the 750 GeV diphoton resonance and the 125 GeV standard model Higgs boson with Higgs-singlet mixing

TL;DR

This paper explores the potential 750 GeV diphoton resonance at the LHC, analyzing how Higgs-singlet mixing and additional particles can explain its properties while remaining consistent with existing Higgs data.

Contribution

It introduces a model with Higgs-singlet mixing and vector-like fermions to explain the 750 GeV resonance's large production rate and width without conflicting with prior Higgs measurements.

Findings

The model can account for the observed diphoton excess and width.

Higgs-singlet mixing affects the Higgs boson properties.

Additional non-SM particles contribute to the resonance decay.

Abstract

We interpret the potential observation of the 750 GeV di-photon resonance at the LHC in models, in which an $SU(2)$ isospin-singlet scalar boson mixes with the Standard Model (SM) Higgs boson through an angle $\alpha$. Allowing the singlet scalar boson to have renormalizable couplings to vector-like leptons and quarks and introducing sizable decay width of the 750 GeV di-photon resonance into non-SM particles such as dark matters, we can explain the large production cross section $\sigma(H_2) \times B(H_2 \to \gamma\gamma)$ as well as the apparent large total width of the boson without conflicts from the results obtained by previous global fits to the SM Higgs boson data.