Higgs Decay to $Z\gamma$ in the Minimal Supersymmetric Standard Model and Its Nonholomorphic Extension

TL;DR

This paper explores how the minimal supersymmetric standard model (MSSM) and its nonholomorphic extension (NHSSM) affect the Higgs decay to Z gamma, aiming to explain recent experimental excesses over the Standard Model predictions.

Contribution

It provides detailed calculations of MSSM and NHSSM contributions to Higgs to Z gamma decay, showing MSSM can significantly align theory with experimental data, unlike NHSSM.

Findings

MSSM can enhance the decay width to approach experimental values.

NHSSM contributions are negligible for this decay process.

MSSM reduces the deviation from experimental measurements to below 1 sigma.

Abstract

Recent measurements of $ h \rightarrow Z \gamma $ from CMS and ATLAS indicate an excess over Standard Model (SM) predictions, suggesting the presence of new physics. In this work, we investigate the $ h \rightarrow Z \gamma $ decay within the minimal supersymmetric standard model (MSSM) and its nonholomorphic extension, the NHSSM. Calculations are performed using the FeynArts/FormCalc setup, utilizing the pre-existing model file for MSSM and generating the NHSSM model file with the support of {\tt SARAH}. In the allowed parameter space, MSSM contributions to $h \rightarrow Z \gamma$ can significantly surpass SM predictions reaching to the value $\Gamma(h \rightarrow Z \gamma)= 9.77 \times 10^{-6} \text{GeV}$, thereby bringing $ \Gamma (h \rightarrow Z \gamma) $ closer to the experimental value. The SM predicted value deviates from the experimental value by $1.7 \sigma$. However, the MSSM contributions can reduce this deviation to less than $1 \sigma$. In contrast, NHSSM contributions remain negligible and do not produce sizable corrections to the $ h \rightarrow Z \gamma $ decay width.