Enhanced $h\to \gamma \gamma$ rate in MSSM singlet extensions

Abstract

We study the di-photon rate in Higgs decays within singlet extensions of the supersymmetric standard model. In particular we point out that light charginos as well as a light charged Higgs can significantly contribute to the corresponding partial decay width, allowing for an explanation of the experimental indication whithin a natural supersymmetric model. This is in contrast to the `light stau scenario' proposed within the framework of the MSSM which requires a large amount of electroweak fine tuning.

Comments: 19 pages, 8 figures; v2: added discussion on constraints from $b\to s\gamma$ and $\delta crho$. Matches version accepted by JHEP