Impacts of radiative corrections on measurements of lepton flavour universality in $B \to D \ell \nu_{\ell}$ decays

Abstract

Radiative corrections to $B \to D \ell \nu_{\ell}$ decays can have an impact on predictions and measurements of the lepton universality ratios $\mathcal{R}(D^+)$ and $\mathcal{R}(D^0)$. These proceedings summarise a study on the comparison between recent calculations of soft-photon corrections on these ratios and the corrections simulated by the PHOTOS package. Also the impact of Coulomb interactions, not simulated in PHOTOS, is discussed. Using pseudo-experiments, the effect of high-energy photon emission is studied in an LHCb-like environment, showing a bias of up to 7\% on measurements of $\mathcal{R}(D)$.