Mass effects in muon and semileptonic b -> c decays

TL;DR

This paper calculates second-order QCD corrections to semileptonic b -> c decays and muon decay, improving theoretical precision for decay rates and energy distributions.

Contribution

It provides the first detailed second-order QCD correction calculations for b -> c decays and muon decay rates, including mass effects.

Findings

QCD corrections decrease muon decay rate by 0.43 ppm

Corrections for decay rate and energy moments are quantified

Enhanced theoretical understanding of semileptonic decays

Abstract

Quantum chromodynamics (QCD) effects in the semileptonic decay b -> c l nu are evaluated to the second order in the coupling constant, O(alpha_s^2), and to several orders in the expansion in quark masses, m_c/m_b. Corrections are calculated for the total decay rate as well as for the first two moments of the lepton energy and the hadron system energy distributions. Applied to the muon decay, they decrease its predicted rate by -0.43 ppm.