Ray, Ipsita2023-07-072023-10-262023-07-072023-10-262023ROLL NO.176121005http://172.17.1.107:4000/handle/123456789/2418Supervisor: Nandi, SoumitraThis thesis focuses on the study of the semileptonic B meson decays via the neutral and charged current exchanges. The charged current transitions occur at tree level in the Standard Model (SM) and the branching fractions of the semileptonic decays of B mesons to lighter leptons (electron and muon) in the final state as considered in this thesis have been determined to be mostly SM-like. In such cases, the charged current transitions provide an important avenue for the clean extraction of the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements which is very crucial for understanding the CKM structure of the Standard Model and for precise theoretical predictions of several observables. In this thesis, we have studied the extraction of the CKM elements |Vub|, |Vcb|, and the ratio |Vub|/|Vcb| which are relatively less precisely known.enFlavor PhysicsB MesonsSemileptonic DecaysCKM ElementsCharged Current TransitionsNeutral Current TransitionsThesis