Di-photon Higgs decay in the MSSM with explicit CP violation

TL;DR

This paper investigates how explicit CP violation in the MSSM affects the di-photon decay of the lightest Higgs, highlighting the significant impact of a light stop on decay rates.

Contribution

It provides a detailed analysis of CP violation effects on Higgs decay in the MSSM, including the influence of light sparticles and scalar/pseudo-scalar mixing.

Findings

Light stops can alter the decay width and branching ratio by over 50%.

CP-violating phases significantly impact Higgs decay properties.

Other light sparticles have minimal effect on the decay process.

Abstract

The Minimal Supersymmetric Standard Model (MSSM) with explicit CP violation is studied with the help of the di-photon decay channel of the lightest neutral Higgs boson. Effects of CP violation, entering via the scalar/pseudo-scalar mixing at higher order as well as through the Higgs-sfermion-sfermion couplings at tree-level, are analyzed in the MSSM with and without light sparticles. A light stop may have a strong impact on the decay width and Branching Ratio (BR) of the decay process H_1 -> gamma gamma, whereas other light sparticles have only little influence. In some regions of the MSSM parameter space with large CP-violating phase phi_mu ~ 90 degrees a light stop can change the BR by more than 50%.