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

Understand

Radiative corrections to $B \to D \ell \nu_{\ell}$ decays may have an impact on predictions and measurements of the lepton flavour universality observables $\mathcal{R}(D^+)$ and $\mathcal{R}(D^0)$.

• In this paper, a comparison between recent calculations of the effect of soft-photon corrections on $\mathcal{R}(D^+)$ and $\mathcal{R}(D^0)$, and corrections generated by the widely used package PHOTOS is given.
• The impact of long-distance Coulomb interactions, which are not simulated in PHOTOS, is discussed.
• Furthermore, the effect of high-energy photon emission is studied through pseudo-experiments in an LHCb-like environment.