Theoretical Uncertainties in Gamma_sl(b->u)

TL;DR

This paper reviews the small theoretical uncertainties involved in extracting |V_ub| from b->u semileptonic decays, emphasizing the minimal impact of nonperturbative effects on the precision of |V_ub|.

Contribution

It provides a comprehensive analysis of the theoretical uncertainties in relating decay widths to |V_ub|, highlighting the near-negligible nonperturbative effects.

Findings

Theoretical error in |V_ub| is only a few percent.

Nonperturbative effects have negligible impact.

Uncertainties are well-controlled in current models.

Abstract

I review the existing theoretical uncertainties in relating the semileptonic decay width in b->u transitions to the underlying Kobayashi-Maskawa mixing element |V_ub|. The theoretical error bars are only a few percent in |V_ub|, with uncertainties from the impact of the nonperturbative effects nearly negligible.