B -> X_u l nu decay distributions to order alpha_s

TL;DR

This paper provides an analytic calculation of the O(alpha_s) corrections to the B -> X_u l nu decay rate, including various differential distributions and the hadronic invariant mass spectrum, accounting for Fermi motion effects.

Contribution

It presents the first analytic results for O(alpha_s) corrections to multiple decay distributions in B meson decays, extending previous known results and including Fermi motion effects.

Findings

Analytic O(alpha_s) corrections to decay distributions derived.

Results applicable for arbitrary kinematic cuts and spectra.

Inclusion of Fermi motion effects near infrared sensitive regions.

Abstract

An analytic result for the O(alpha_s corrections to the triple differential B -> X_u l nu decay rate is presented, to leading order in the heavy-quark expansion. This is relevant for computing partially integrated decay distributions with arbitrary cuts on kinematic variables. Several double and single differential distributions are derived, most of which generalize known results. In particular, an analytic result for the O(alpha_s) corrections to the hadronic invariant mass spectrum is presented. The effects of Fermi motion, which are important for the description of decay spectra close to infrared sensitive regions, are included. The behaviour of perturbation theory in the region of time-like momenta is also investigated