Higgs Decay to Zγ in the Minimal Supersymmetric Standard Model and Its Nonholomorphic Extension

Recent measurements of h → Z γ 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 → Z γ 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 { SARAH}. In the allowed parameter space, MSSM contributions to h → Z γ can significantly surpass SM predictions reaching to the value Γ(h → Z γ)= 9.77 × 10⁻⁶ GeV, thereby bringing Γ (h → Z γ) closer to the experimental value. The SM predicted value deviates from the experimental value by 1.7 σ. However, the MSSM contributions can reduce this deviation to less than 1 σ. In contrast, NHSSM contributions remain negligible and do not produce sizable corrections to the h → Z γ decay width.