Does $H \to \gamma \gamma$ Taste like vanilla New Physics?

TL;DR

This paper investigates how new uncolored charged fermions in Standard Model extensions affect Higgs to diphoton decay rates and electroweak precision constraints, including collider production cross sections and current experimental bounds.

Contribution

It provides a detailed analysis of the impact of uncolored charged fermions on Higgs decay and electroweak measurements, with new calculations of fermion pair production cross sections.

Findings

Uncolored charged fermions can significantly alter the Higgs to diphoton rate.

Electroweak precision constraints limit the parameter space of these fermions.

Current collider bounds restrict the mass range of the lightest fermion.

Abstract

We analyse the interplay between the Higgs to diphoton rate and electroweak precision measurements contraints in extensions of the Standard Model with new uncolored charged fermions that do not mix with the ordinary ones. We also compute the pair production cross sections for the lightest fermion and compare them with current bounds.