Physics beyond the Standard Model through b → s μ + μ − transition

Abstract

A comprehensive study of the impact of new-physics operators with different Lorentz structures on decays involving the b → sμ + μ− transition is performed. The effects of new vector–axial vector (VA), scalar–pseudoscalar (SP) and tensor (T) interactions on the differential branching ratios, forward–backward asymmetries (AFB’s), and direct CP asymmetries of \({\bar B}_{\rm s}^0 \to \mu^+ \mu^-\), \({\bar B}_{\rm d}^0 \to\)\( X_{\rm s} \mu^+ \mu^-\), \({\bar B}_{\rm s}^0 \to \mu^+ \mu^- \gamma\), \({\bar B}_{\rm d}^0 \to {\bar K} \mu^+ \mu^-\), and \({\bar B}_{\rm d}^0\to {\bar{K}^*} \mu^+ \mu^-\) are examined. In \({\bar B}_{\rm d}^0\to {\bar{K}^*} \mu^+ \mu^-\), we also explore the longitudinal polarization fraction fL and the angular asymmetries \(A_{\rm T}^{(2)}\) and ALT, the direct CP asymmetries in them, as well as the triple-product CP asymmetries \(A_{\rm T}^{\rm (im)}\) and \(A^{\rm (im)}_{\rm LT}\). While the new VA operators can significantly enhance most of the observables beyond the Standard Model predictions, the SP and T operators can do this only for AFB in \({\bar B}_{\rm d}^0 \to {\bar K} \mu^+ \mu^-\).