Tau lepton distributions in semileptonic B decays

Abstract

Analytic formulae are given for order α s perturbative QCD corrections to the double differential distribution of the τ lepton energy and the invariant mass of the τ + antineutrino system in semileptonic decays of the bottom quark. The corresponding distribution for B meson decays are obtained by combining these results and the nonperturbative QCD corrections calculated by Falk et al. The moments of the energy distribution of the τ lepton are calculated. * [

Inclusive semitauonic B decays to orderO(ΛQCD3/mbMannel1, Rusov2, Shahriaran3 2017Nuclear Physics B405320View full textAdd to dashboardCite

“…The derived expressions for C (0) 0 , C µ 2 π and C µ 2 G are in agreement with the corresponding results of [9,10], while analytic formula for C ρ 3 D represents a new result of this paper which in the particular case m → 0 (or equivalently η → 0) reproduces the corresponding expression in [8] originally derived in [11]. Moreover, we include perturbative radiative corrections to the partonic level of the decay width using results of [12]. This correction is presented as C (1) 0 in eq.…”

Precise predictions forB→Xcτν¯decay distributions

“…The phase space limits for theq 2 and y distributions are given in Eqs. (17) and (16). Restoring the dimensions of the variables,…”

“…[31], while the corrections to the lepton energy spectrum can be obtained by integrating d 2 Γ/dy dq 2 calculated in Ref. [16]. In particular, the fractional corrections at order α s to both dΓ/dq 2 and dΓ/dy are remarkably independent ofq 2 and y, and so have very little effect on the shape of the spectra except very close to their end points.…”

The determination of Vub from inclusive semileptonic B decays

“…Although we also use results for the semileptonic b → c decay rate, the latter is considered in the partonic framework solely. In fact, we only need the total rate with a single lower cut on the electron energy for b → c; we thus refer the reader to [8] for further discussion of the kinematics of this process. The initial state b quark has a momentum p b = m b v, where v is the velocity of the B meson.…”

“…The perturbative corrections are taken into account to one loop [8], while the non-perturbative ones are included to leading twist. The b → c decay rate in the denominator is evaluated including O(α s ) corrections.…”