Imprints of New Physics in the Angular Distribution of Rare Semileptonic B → a1(→ ρπ)l+l− Decay

Abstract

Rare semileptonic B meson decays induced by b → dl+l− flavor changing neutral current transitions hold immense significance in exploring the quark-flavor sector of the Standard Model and also provide search area to test New Physics. In Standard Model they are not allowed at tree level, but induced by loops and are governed by GIM mechanism. In this work I have studied B → a1(1260)(→ ρπ)l+l− decay which proceed via b → d transition at quark level. I have focused mainly on physical observables such as branching ratio, forward-backward asymmetry and angular coefficient functions in this decay channel in Standard Model as well as in family non-universal Z′ model. Remarkable deviation can be seen from Standard Model values of these physical observables for this decay. It is a clear indication for New Physics appearing due to Z′ gauge boson.