Taming the higher power corrections in semileptonic B decays

TL;DR

This paper investigates the impact of higher-dimension operators on inclusive semileptonic B decays and finds that these corrections minimally affect the extraction of the CKM matrix element |Vcb|.

Contribution

It introduces the first comprehensive fit including O(1/mb^{4,5}) contributions to the heavy quark expansion using moments and LLSA.

Findings

Higher power corrections have a negligible effect on |Vcb| extraction.

Inclusion of dimension 7 and 8 operators refines the theoretical understanding.

The global fit confirms the robustness of |Vcb| determination.

Abstract

We study the effect of dimension 7 and 8 operators on inclusive semileptonic B decays and the extraction of |Vcb|. Using moments of semileptonic B decay spectra and information based on the Lowest-Lying State saturation Approximation (LLSA) we perform a global fit of the nonperturbative parameters of the heavy quark expansion including for the first time the O(1/mb^{4,5}) contributions. Higher power corrections appear to have a very small effect on the extraction of |Vcb|, independently of the weight we attribute to the LLSA.