|Vub| from exclusive semileptonic B to pi decays revisited

TL;DR

This paper refines the determination of the CKM matrix element |Vub| from exclusive B to pi decays by integrating updated theoretical form factors with experimental data, confirming previous exclusive measurements and highlighting discrepancies with inclusive methods.

Contribution

It provides a revised extraction of |Vub| using new form factor calculations and Omnes parametrizations, improving the precision and consistency of the exclusive decay analysis.

Findings

The extracted |Vub| value is 3.47×10^-3 with uncertainties.

The result aligns with other CKM fit inputs.

There is a discrepancy with inclusive decay measurements.

Abstract

We update the extraction of |Vub| from exclusive semileptonic B to pi decays, combining experimental partial branching fraction information with theoretical form factor calculations, using the recently revised HPQCD results for the form factors f_+ and f_0. We use Omnes representations to provide the required parametrisations of the form factors. The extracted value is 10^3 |Vub| = 3.47+/-0.29+/-0.03, in striking agreement with |Vub| extracted using all other inputs in CKM fits and showing some disagreement with |Vub| extracted from inclusive semileptonic B to pi decays.