Extended Higgs sectors, effective field theory and Higgs phenomenology

TL;DR

This paper explores how charged scalar extensions of the Standard Model Higgs sector, combined with effective field theory couplings, influence Higgs decay processes, offering strategies to identify or constrain new charged Higgs states.

Contribution

It provides a detailed analysis of the effects of charged scalars and EFT couplings on Higgs decay channels, highlighting how combined measurements can reveal or limit new physics.

Findings

Charged scalars modify Higgs loop-induced decays.

Interplay of $H\to \gamma\gamma$ and $H\to Z\gamma$ decays aids in new physics identification.

EFT interactions can weaken constraints from $H\to \gamma\gamma$ measurements.

Abstract

We consider the phenomenological implications of charged scalar extensions of the SM Higgs sector in addition to EFT couplings of this new state to SM matter. We perform a detailed investigation of modifications of loop-induced decays of the 125 GeV Higgs boson, which receives corrections from the propagating charged scalars alongside one-loop EFT operator insertions and demonstrate that the interplay of $H\to \gamma\gamma$ and $H\to Z\gamma$ decays can be used to clarify the additional states phenomenology in case a discovery is made in the future. In parallel, EFT interactions of the charged Higgs can lead to a decreased sensitivity to the virtual presence of charged Higgs states, which can significantly weaken the constraints that are naively expected from the precisely measured $H\to \gamma\gamma$ branching ratio. Again $H\to Z\gamma$ measurements provide complementary sensitivity that can be exploited in the future.