Impacts of radiative corrections on measurements of lepton flavour universality in B D`n` decays
Radiative corrections to B D`n` decays may have an impact on predictions and measurements of the lepton flavour universality observables R(D) and R(D) In this paper, a comparison between recent calculations of the effect of soft photon corrections on R(D) and R(D) 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. It is found that overor underestimating these emissions can cause a bias on R(D) as high as 7% However, this bias depends on individual analyses, and future high precision measurements require an accurate evaluation of these QED corrections.