Probing the scalar-pseudoscalar mixing in the 125 GeV Higgs particle with current data

TL;DR

This paper explores the possibility that the 125 GeV Higgs boson is a mixture of scalar and pseudoscalar states within a two Higgs doublet model, analyzing current LHC data to constrain the mixing.

Contribution

It provides the first comprehensive analysis of scalar-pseudoscalar mixing in the Higgs sector using current experimental data, within a specific two Higgs doublet model with CP violation.

Findings

Bounds |s_2| < 0.83 at one sigma, indicating a mostly scalar Higgs

Current data constrains the pseudoscalar component of the Higgs

Analysis includes all Higgs production mechanisms and decay channels

Abstract

LHC has found hints for a Higgs particle of 125 GeV. We investigate the possibility that such a particle is a mixture of scalar and pseudoscalar states. For definiteness, we concentrate on a two Higgs doublet model with explicit CP violation and soft Z2 violation. Including all Higgs production mechanisms, we determine the current constraints obtained by comparing h -> gamma gamma with h -> V V*, and comment on the information which can be gained by measurements of h -> b \bar{b}. We find bounds |s_2| < 0.83 at one sigma, where |s_2|=0 (|s_2|=1) corresponds to a pure scalar (pure pseudoscalar) state.