Contribution of charm to rare radiative leptonic B-decays

Anastasiia Kozachuk

doi:10.1051/epjconf/201819102012

Abstract

We revisit rare radiative leptonic decays Bd,s → γμ+μ- and Bd,s → γe+e- in the Standard Model and obtain predictions for a number of differential distributions in these decays with special emphasis on the contribution of charm-quark loops.

Highlights

Rare FCNC decays of B-mesons are forbidden at tree level in the Standard Model and occur only via loop diagrams, which makes the branching ratios of the decays very small, typical order is 10−8 − 10−10 [1]
New unknown particles can contribute to the loops and such processes are expected to be sensitive to the potential effects of New Physics
We list a few of the results below: 1. The invariant form factors, which parameterize the amplitudes of the processes, were calculated in the wide range of momentum transfer within the relativistic quark model

Summary

Introduction

Rare FCNC decays of B-mesons are forbidden at tree level in the Standard Model and occur only via loop diagrams, which makes the branching ratios of the decays very small, typical order is 10−8 − 10−10 [1]. New unknown particles can contribute to the loops and such processes are expected to be sensitive to the potential effects of New Physics. Several decays of this type have been studied experimentally (see discussion in [2,3,4,5]). A few deviations from the Standard Model of the order of 2 − 3σ have been observed. This talk presents the results of our recent work [8] where rare radiative leptonic decays Bd,s → γμ+μ− and Bd,s → γe+e− have been analyzed. Rare radiative leptonic B-decays represent FCNC decays; their amplitudes contain a number of additional contributions compared to FCNC decays with a meson and l+l− pair in the final state

Effective Hamiltonian

Contributions with t-quarks in the loops

Contributions of the charm-loops

Results

RΜ e Bs

Conclusions