# XIIIth Quark Confinement and the Hadron Spectrum

31 July 2018 to 6 August 2018
Maynooth University
Europe/Dublin timezone

## Rare FCNC radiative leptonic B→ γl+l- decays in the standard model

1 Aug 2018, 14:40
20m
Hall H (Arts Bldg.)

### Hall H

#### Arts Bldg.

Talk C: Heavy quarks

### Speaker

Anastasiia Kozachuk (M.V. Lomonosov Moscow State University (RU))

### Description

We revisit rare radiative leptonic decays B_(s,d) → γee and B_(s,d) → γμμ in the standardmodel and provide the updated estimates for various differential distributions (the branching ratios, the forward-backward asymmetry, and Rμ=e, the ratio of the differential distribution for muons over electrons in the final state). The new ingredients of this work compared to the existing theoretical analyses are the following: (i) we calculate all B → γ form factors induced by the vector, axial-vector, tensor and pseudotensor quark currents within the relativistic dispersion approach based on the constituent quark picture; (ii) we perform a detailed analysis of the charm-loop contributions to radiative leptonic decays: we obtain constraints imposed by electromagnetic gauge invariance and discuss the existing ambiguities in the charmonia contributions.

### Primary authors

Anastasiia Kozachuk (M.V. Lomonosov Moscow State University (RU)) Dmitri Melikhov (HEPHY) Nikolai Nikitin (M.V. Lomonosov Moscow State University (RU))