Three-loop QCD corrections andb-quark decays

Abstract

We present three-loop (NNNLO) corrections to the heavy-to-heavy quark transitions in the limit of equal initial and final quark masses. In analogy with the previously found NNLO corrections, the bulk of the result is due to the β 2 0 α 3 s corrections. The remaining genuine three-loop effects for the semileptonic b → c decays are estimated to increase the decay amplitude by 0.2(2)%. The perturbative series for the heavy-heavy axial current converges very well.

Semileptonic decays in the limit of a heavy daughter quark

“…[19] with two-loop accuracy, and in Ref. [20] at three loops. (Full q 2 dependence at two loops can be found in Refs.…”

Massive three-loop form factor in the planar limit

“…[11] after adapting the large-N c limit. F 1 (x = 1) = 0 is a welcome check of our calculation, see also [31].…”

Three-loop massive form factors: complete light-fermion and large-Nc corrections for vector, axial-vector, scalar and pseudo-scalar currents

“…[25] can be extended to three loops. Three-loop corrections to F v 2 (0) and F a 1 (0) have been computed in [26] (see [27] for the QED limit) and [28], respectively.…”