Radiative semileptonic $$ \overline{B} $$ decays

Abstract

We consider the form factors for the radiative semileptonic decays $$ \overline{B} $$ B ¯ (v) → D(*)(v′)ℓ$$ \overline{\nu} $$ ν ¯ ℓγ in the kinematic region where the photon momentum, k, is small enough that heavy quark symmetry (HQS) can be applied without the radiated photon changing the heavy quark velocity (i.e., v(′) ∙ k < m(b,c)). We find that HQS is remarkably powerful, leaving only four new undetermined form factors at leading order in 1/m(b,c). In addition, one of them is fixed in terms of the leading order Isgur-Wise function in the kinematic region, v(′) ∙ k < ΛQCD.

Standard Model predictions for lepton flavour universality ratios of inclusive semileptonic B decays

“…In this work, we do not include structure depend nor ultrasoft QED effects as those are challenging to disentangle from the experimental detector efficiencies (for recent works on QED effects in exclusive semileptonic B decays see e.g. [6][7][8][9]).…”

Structure-dependent QED effects in exclusive B-meson decays

“…In anticipation of the high-precision measurements from LHCb and BELLE II, the investigation of electromagnetic effects in B -meson decays has become an active research field in recent years (besides the articles which have already been mentioned in the main text, more examples can be found in Refs. [55][56][57][58][59][60][61][62][63][64][65]). In this review, we have summarized recent developments in the calculation of structure-dependent QED corrections to exclusive B -meson decays with effective field theory methods.…”

Notes on QED Corrections in Weak Decays

“…Real radiation is only incorporated via the universal soft-photon part (24). And heavy quark symmetry has been found to be constraining in B → D ( * ) ν(γ) decays [59] (in the appropriate kinematic region).…”