$SU(2)_L$ triplet scalar as the origin of the 95 GeV excess?

TL;DR

This paper proposes that an $SU(2)_L$ triplet scalar with hypercharge 0 could explain the 95 GeV diphoton excess, predicting distinctive collider signatures and a potential shift in the W boson mass.

Contribution

It introduces a triplet scalar model with small Higgs mixing to account for the excess, providing specific collider signatures and electroweak fit implications.

Findings

The $ ext{diphoton}$ signal has a unique $p_T$ spectrum.

Associated production leads to photons with tau leptons and jets.

A charged Higgs around 95 GeV could be discovered in Run 3.

Abstract

We explore the possibility that an $SU(2)_L$ triplet scalar with hypercharge $Y=0$ is the origin of the $95\,$GeV diphoton excess. For a small mixing angle with the Standard Model Higgs, its neutral component has naturally a sizable branching ratio to $\gamma\gamma$ such that its Drell-Yan production via $pp\to W^*\to H H^\pm$ is sufficient to obtain the desired signal strength, where $H^\pm$ is the charged Higgs component of the triplet. The predictions of this setup are: 1) The $\gamma\gamma$ signal has a $p_T$ spectrum different from gluon fusion but similar to associated production. 2) Photons are produced in association with tau leptons and jets, but generally do not fall into the vector-boson fusion category. 3) The existence of a charged Higgs with $m_{H^\pm}\approx\!(95\pm5)\,$GeV leading to $\sigma(pp\to \tau\tau\nu\nu)\approx0.4\,$pb, which is of the same level as the current limit and can be discovered with Run 3 data. 4) A positive definite shift in the $W$ mass as suggested by the current global electroweak fit.