Bs→Dsℓν form factors and the fragmentation fraction ratio

Abstract

We present a lattice quantum chromodynamics determination of the scalar and vector form factors for the B s → D s lν decay over the full physical range of momentum transfer. In conjunction with future experimental data, our results will provide a new method to extract jV cb j, which may elucidate the current tension between exclusive and inclusive determinations of this parameter. Combining the form factor results at nonzero recoil with recent HPQCD results for the B → Dlν form factors, we determine the ratios f

Signature of lepton flavor universality violation in Bs→Dsτν semileptonic decays

“…The value of R D s is quite similar to the value reported in Ref. [62]. We also give the first prediction of the longitudinal polarization fraction of the charged lepton, lepton-side forward-backward asymmetry, and convexity parameter for the B s → D s lν decays.…”

“…The value of the ratio of branching ratio R D s in Table III is quite similar to the value reported in Ref. [62]. The slight difference may come from different choices of input parameters.…”

“…We refer to Ref. [62] for all the omitted details. The differential decay distribution for the B s → D s lν decays can be expressed as …”

“…[71]. The lepton masses (m e , m τ ) and meson masses (B s , D s ) are in GeV units, whereas the Fermi coupling constant G F is in GeV [62]. The uncertainties associated with jV cb j and the form factors parameters are written within parentheses.…”

“…We follow Ref. [62] for various B s → D s transition form factors. For our NP analysis, we impose 1σ constraint coming from the measured ratio of branching ratios R D and R D Ã to obtain the allowed NP parameter space.…”