Exploring the Di-Photon Decay of a Light Higgs Boson in the MSSM With Explicit CP Violation

TL;DR

This paper investigates how CP violation and the presence of a light stop influence the di-photon decay of the lightest Higgs boson in the MSSM, revealing significant effects under certain conditions.

Contribution

It provides a detailed analysis of the impact of light stops and CP-violating phases on Higgs decay properties in the MSSM, highlighting conditions for substantial branching ratio changes.

Findings

Light stops can alter the decay BR by over 50% with specific CP phases.

Other sparticles have minimal impact on the decay process.

CP violation effects are significant mainly with light stops and certain parameter choices.

Abstract

The di-photon decay channel of the lightest Higgs boson is considerd as a probe to explore CP violation in the Minimal Supersymmetric Standard Model (MSSM). The scalar/pseudo-scalar mixing is considered along with CP violation entering through the Higgs-sfermion-sfermion couplings, with and without light sparticles. The impact of a light stop on the decay width and Branching Ratio (BR) is established through a detailed study of the amplitude of the process H1 --> gamma.gamma. The other sparticles have little influence even when they are light. With a suitable combination of other MSSM parameters, a light stop can change the BR by more than 50 % with a CP-violating phase phi_mu ~ 90 deg., while the change is almost nil with a heavy stop.