Scalar Mesons in weak Semi-leptonic decay of B(s)

Abstract

The decays governed by the flavor-changing-neutral-current-transitions (FCNC), such as b →sl+l−, provide an important tool to test the physics in and beyond the Standard Model (SM). In this dissertation, we study the B → Sl+l− , where S = a0,f0 represent the scalar mesons. Being an exclusive process, the matrix elements of inital and final state meson in volve the form factors (a non-perturbtive quantity). Using the Light-cone-sum-rules (LCSRs) approach, we calculate the corresponding form factors (FFs). In comparison to other models, i.e., Light cone quark model and Shifman-Vainshtein-Zakharov (SVZ) sum rules approach, the calculated value of FFs is approximately twice in the magnitude to that of the corre sponding B meson decaying to pseudoscalar. Using these FFs, we calculate the Branching ratios, lepton’s forward-backward asymmetry and the various lepton polarization asymme tries in the SM. Recently, a Bayesian analysis of the lepton-flavor universalities RK and RK∗ is done in a model independent approach and it puts several constraints on the different Wil son coefficients. Using these constraints, we explore their imprints on the above mentioned observables and see if they show any deviations from the corresponding SM predictions.