Status of the two-Higgs-doublet model of type II

TL;DR

This paper analyzes the parameter space of the CP-conserving two-Higgs-doublet model of type II, considering theoretical and experimental constraints, and finds significant restrictions on Higgs boson properties and masses.

Contribution

It provides a comprehensive update on the allowed parameter space of the 2HDM type II with current theoretical and experimental constraints.

Findings

Deviations from SM Higgs couplings are disfavoured at one sigma.

Light non-standard Higgs bosons below 300 GeV are excluded at two sigma.

Constraints on heavy Higgs masses impact decay mode possibilities.

Abstract

We determine the allowed parameter space of the CP-conserving two-Higgs-doublet model (2HDM) of type II with a softly broken Z_2 symmetry. Our analysis includes theoretical constraints from vacuum stability and perturbativity as well as experimental constraints from signal strengths of the 126 GeV Higgs boson, the non-observation of additional Higgs resonances and electroweak precision and flavour observables. If the 126 GeV resonance is interpreted as the light CP-even Higgs boson of the 2HDM our analysis shows that scenarios where the couplings of this boson deviate substantially from those of the SM Higgs boson are disfavoured at one standard deviation and completely excluded for small values of tan(beta). We also discuss bounds on the masses of the heavy 2HDM Higgs bosons and their implications for the possible decay modes of these particles. We find that the region in which both non-standard neutral Higgs bosons are simultaneously lighter than 300 GeV is excluded at two standard deviations.