# Correlation between the decays $h^0 \to \gamma \gamma/g g$ in the MSSM with quark flavour violation

## TL;DR

This paper investigates how quark flavour violation in the MSSM can cause significant deviations in Higgs decay rates to photons and gluons, which could be observed at future colliders, indicating new physics beyond the Standard Model.

## Contribution

It provides a detailed analysis of Higgs decay deviations caused by quark flavour violation in the MSSM, highlighting potential observable effects at future colliders.

## Key findings

- Deviations in $h^0 o g g$ decay width can be as large as -15%.
- Deviations in $h^0 o \gamma \, \\gamma$ are correlated with gluon decay deviations.
- Width ratio deviations can reach up to 20%, influenced by squark loops and flavour-violating parameters.

## Abstract

We study the loop-induced decays $h^0 \to \gamma \, \gamma$ and $h^0 \to g \, g$ in the Minimal Supersymmetric Standard Model (MSSM) with quark flavour violation (QFV), identifying $h^0$ with the Higgs boson with a mass of 125 GeV, where $\gamma$ and $g$ are photon and gluon, respectively. We perform a MSSM parameter scan and a detailed analysis around a fixed reference point respecting theoretical constraints from vacuum stability conditions and experimental constraints, such as those from B meson data and electroweak precision data, as well as recent limits on supersymmetric (SUSY) particle masses from LHC experiments. We find that (i) the relative deviation of the decay width $\Gamma(h^0 \to g \, g)$ from the Standard Model value, $DEV(g)$, can be large and negative, $\lesssim - 15\%$, (ii) the analogous deviation of $\Gamma(h^0 \to \gamma \, \gamma)$ is strongly correlated, $DEV(\gamma) \simeq -1/4\,DEV(g)$ for $DEV(g) \lesssim - 4\%$, (iii) the relative deviation of the width ratio $\Gamma(h^0 \to \gamma \, \gamma)/\Gamma(h^0 \to g \, g)$ from the SM value, $DEV(\gamma/g)$, can be large (up to $\sim$ 20\%), (iv) the deviations can be large due to the up-type squark loop contributions, (v) the SUSY QFV parameters can have a significant effect on these deviations. Such large deviations can be observed at a future $e^+e^-$ collider like ILC. Observation of the deviation patterns as shown in this study would favour the MSSM with flavour-violating squark mixings and encourage to perform further studies in this model.