Higgs Signals in a Type I 2HDM or with a Sister Higgs

TL;DR

This paper explores how extended Higgs models, like Type I 2HDM and sister Higgs frameworks, alter Higgs signals, especially enhancing gamma gamma channels, and discusses associated constraints and potential experimental signatures.

Contribution

It analyzes Higgs phenomenology in extended models with additional Higgs doublets or sister Higgs fields, highlighting unique signal modifications and constraints.

Findings

Enhanced gamma gamma signals via vector boson fusion in these models

Light charged Higgs states impact flavor physics and Higgs decay channels

Additional colored states may serve as experimental evidence for these models

Abstract

In models where an additional SU(2)-doublet that does not have couplings to fermions participates in electroweak symmetry breaking, the properties of the Higgs boson are changed. At tree level, in the neighborhood of the SM-like range of parameter space, it is natural to have the coupling to vectors, cV, approximately constant, while the coupling to fermions, cf, is suppressed. This leads to enhanced VBF signals of gamma gamma while keeping other signals of Higgses approximately constant (such as WW* and ZZ*), and suppressing higgs to tau tau. Sizable tree-level effects are often accompanied by light charged Higgs states, which lead to important constraints from b to s gamma and top to b H+, but also often to similarly sizable contributions to the inclusive h to gamma gamma signal from radiative effects. In the simplest model, this is described by a Type I 2HDM, and in supersymmetry is naturally realized with "sister Higgs" fields. In such a scenario, additional light charged states can contribute further with fewer constraints from heavy flavor decays. With supersymmetry, Grand Unification motivates the inclusion of colored partner fields. These G-quarks may provide additional evidence for such a model.