Perturbative corrections to semileptonic b decay distributions

Abstract

We compute O(α s ) and O(α n s β n−1 0 ) (BLM) corrections to the five structure functions relevant for b → qℓν decays and apply the results to the moments of a few distributions of phenomenological importance. We present compact analytic one-loop formulae for the structure functions, with proper subtraction of the soft divergence.

Kinetic operator effects in at

“…The complete O(α s ) and O(α 2 s β 0 ) corrections have been computed some time ago (see [10] and refs. therein), while the remain-ing two-loop corrections to the width and to the first few moments have been calculated in Refs.…”

Neural network parametrization of the lepton energy spectrum in semileptonic B meson decays

“…16 and 17 but this time with an estimation of the theoretical uncertainties associated to the predictions of Ref. [16]. These theoretical uncertainties are obtained by varying the b quark mass m b 100 MeV above and below the central value, and similarly for the strong coupling α s (m 2 b ).…”

“…For example, the complete set of O(α s ) corrections for all the differential distributions that can be constructed from Eq. 2.2 with arbitrary kinematical cuts have recently become available [15,16].…”

“…[16] (AGRU). Their formalism allows the computation of moments of different differential distributions from semileptonic B meson decays, with arbitrary kinematical cuts, like the lepton energy spectrum in charmed decays that is analyzed in the present work.…”

“…In Figs. 16 and 17 5 , the results of [16] both at leading order (LO) and at next-toleading order (NLO) are compared with the moments obtained from our parametrization as a function of the lower cut in the lepton energy E 0 . Comparing results at different perturbative orders is interesting to asses the behaviour of the perturbative expansion.…”