From the Higgs to the top: Couplings and Rare Decays

TL;DR

This paper explores how multi-Higgs models with Froggart-Nielsen mechanisms can alter Higgs couplings and induce rare top and Higgs decays, contrasting with Standard Model predictions.

Contribution

It analyzes a specific 3+1 Higgs doublet model with a singlet FN field, highlighting new coupling patterns and rare decay possibilities.

Findings

Diagonal couplings can lie on different lines from the Standard Model.

Flavor-violating Higgs couplings can appear in the model.

Constraints from LHC Higgs searches limit the model parameters.

Abstract

Within the Standard Model the Higgs couplings to fermions and gauge bosons, as function of the particle mass, are predicted to lay on a single line. However, new patterns appear in multi-Higgs models that employ the Froggart-Nielsen mechanism, where the diagonal couplings could lay on different lines and flavor-violating Higgs couplings could appear too. These aspects are studied for a specific model with 3+1 Higgs doublets and a singlet FN field. Constraints on the model are derived from the Higgs search at LHC, and some remarks are presented on their implications for the rare top and Higgs decay, t -> ch and h -> \tau \mu.