A theoretical study has investigated how new physics, specifically within the Supersymmetric Standard Model with neutrinos (μνSSM), influences the rare inclusive decay $B \to X_{\mathrm{s}} l^{+} l^{-}$. This decay is of particular interest because its rate and characteristics can be sensitive to particles and forces not accounted for in the Standard Model of particle physics. Researchers have identified the main contributions to the relevant Wilson coefficients, which are parameters describing the strength of interactions in the decay, and the particles associated with them within the μνSSM.

The analysis focused on a systematic scan of the μνSSM parameter space, which allowed for the elucidation of the underlying physical mechanisms governing these dominant contributions. The obtained results are consistent with experimentally allowed regions, suggesting that the μνSSM could offer an explanation for potential future deviations observed in these decays. Experimental constraints from other relevant decays, such as $\bar{B} \to X_{\mathrm{s}}\gamma$, $B_{\mathrm{s}}^{0} \to \mu^{+} \mu^{-}$, and the 125 GeV Higgs boson mass, were also incorporated.

A key part of the study was the systematic interference decomposition of the Wilson coefficient contributions to the forward-backward asymmetry (AFB). It was identified that the $C_7C_{10}$ and $C_9C_{10}$ interference terms are the dominant contributions governing the behavior of the AFB in both low- and high-$q^2$ (momentum transferred to the lepton pair) regions. Understanding these contributions is crucial for interpreting future measurements of the AFB, which is an observable sensitive to new physics and could reveal the existence of supersymmetric particles or other extensions of the Standard Model.