Semileptonic B decays and the inclusive determination of |V(ub)|

TL;DR

This paper introduces a comprehensive theoretical framework for analyzing semileptonic B decays to improve the precision of the inclusive determination of |V(ub)|, accounting for various quantum effects and uncertainties.

Contribution

It develops a new approach that combines perturbative and non-perturbative effects with a Wilsonian cutoff, addressing high q^2 and Weak Annihilation issues for |V(ub)| extraction.

Findings

Provides estimates of |V(ub)| with quantified uncertainties

Highlights problems in high q^2 region and Weak Annihilation effects

Offers a unified framework for B decay analysis

Abstract

We present a new theoretical framework for the study of $B\to X_u \ell \nu$ decays, which includes all known perturbative and non-perturbative contributions and a description of leading and subleading Fermi motion effects. The perturbative and non-perturbative regimes are separated by a ``hard'' Wilsonian cutoff $\mu \sim 1$ GeV. We bring into focus some problems related to the high $q^2$ region and to Weak Annihilation effects. We provide estimates of the CKM parameter $|V_{ub}|$ using the described framework and discuss the related theoretical uncertainty.