QED effects in inclusive semi-leptonic $B$ decays

TL;DR

This paper provides a detailed analysis of QED corrections in inclusive semi-leptonic B decays, improving theoretical predictions and comparing with existing Monte Carlo tools, paving the way for more accurate simulations.

Contribution

It introduces comprehensive QED corrections to B decay calculations, including effects not present in current MC tools, and advances towards a fully differential higher-order QED Monte Carlo generator.

Findings

Good agreement with PHOTOS for many effects

QED effects not included in PHOTOS are identified

First steps towards a differential higher-order QED MC generator

Abstract

We analyse in detail the QED corrections to the total decay width and the moments of the electron energy spectrum of the inclusive semi-leptonic $B \to X_c e \nu$ decay. Our calculation includes short-distance electroweak corrections, the complete ${\cal O}(\alpha)$ partonic terms and leading-logarithmic QED effects up to ${\cal O}(\Lambda^3_{\rm QCD}/m_b^3)$. A comprehensive numerical comparison of our results against those obtained with the Monte Carlo (MC) tool PHOTOS is presented. While the comparison indicates good overall agreement, our computation contains QED effects not included in PHOTOS and should therefore better describe photon radiation to $B \to X_c e \nu$ as measured by the $B$-factories. Our calculations represent the first steps in the construction of a fully differential higher-order QED MC generator for inclusive semi-leptonic $B$ decays.