Constraining the Two-Higgs-Doublet-Model parameter space

TL;DR

This paper systematically constrains the Two-Higgs-Doublet Model parameter space by applying experimental data and theoretical conditions, revealing highly restricted viable regions especially at high aneta and low M_{H^0}^0.

Contribution

It provides a comprehensive analysis of the parameter space of the Two-Higgs-Doublet Model considering multiple experimental and theoretical constraints, outlining the remaining allowed regions.

Findings

Model is highly constrained by experimental data.

Allowed regions depend on neutral Higgs masses and aneta.

High aneta values are excluded by perturbative unitarity.

Abstract

We confront the Two-Higgs-Doublet Model with a variety of experimental constraints as well as theoretical consistency conditions. The most constraining data are the \bar B\to X_s\gamma decay rate (at low values of M_{H^\pm}), and \Delta\rho (at both low and high M_{H^\pm}). We also take into account the B\bar B oscillation rate and R_b, or the width \Gamma(Z\to b\bar b) (both of which restrict the model at low values of \tan\beta), and the B^-\to\tau\nu_\tau decay rate, which restricts the model at high \tan\beta and low M_{H^\pm}. Furthermore, the LEP2 non-discovery of a light, neutral Higgs boson is considered, as well as the muon anomalous magnetic moment. Since perturbative unitarity excludes high values of \tan\beta, the model turns out to be very constrained. We outline the remaining allowed regions in the \tan\beta-M_{H^\pm} plane for different values of the masses of the two lightest neutral Higgs bosons, and describe some of their properties.