Double Higgcision: 125 GeV Higgs boson and a potential diphoton Resonance

TL;DR

This paper analyzes the potential for a second scalar resonance in the diphoton channel, focusing on the mixing between the 125 GeV Higgs boson and a hypothetical 750 GeV scalar, using existing data to constrain models.

Contribution

It performs a comprehensive Higgs-signal strength analysis incorporating both the 125 GeV Higgs data and the diphoton signal of a potential 750 GeV scalar, exploring the small mixing scenario.

Findings

Best fit indicates very tiny mixing between the two scalars

Models must accommodate minimal mixing to align with data

Analysis constrains properties of potential new scalar resonance

Abstract

Searches for diphoton resonance have been shown to be very useful in discovering new heavy spin-0 or spin-2 particles. Supposing that a new heavy particle shows up in the diphoton channel and it points to a spin-0 boson, it can be allowed to have a small mixing with the observed 125 GeV Higgs-like boson. We borrow the example of the 750 GeV particles hinted with 3.2 fb$^{-1}$ data at the end of 2015 (though it did not appear in the 2016 data) to perform an analysis of "double Higgcision". In this work, we perform a complete Higgs-signal strength analysis in the Higgs-portal type framework, using all the existing 125 GeV Higgs boson data as well as the diphoton signal strength of the 750 GeV scalar boson. The best fit prefers a very tiny mixing between two scalar bosons, which has to be accommodated in models for the 750 GeV scalar boson.