A model independent determination of the B -> Xs gamma decay rate

TL;DR

This paper presents a comprehensive, model-independent analysis of the B -> Xs gamma decay rate, utilizing a global fit to experimental data to determine key parameters like the shape function and CKM matrix elements, while assessing theoretical uncertainties.

Contribution

It introduces a novel global fit approach to extract the B -> Xs gamma rate and related parameters without relying on specific models, improving precision and robustness.

Findings

Determined the total B -> Xs gamma decay rate from experimental data.

Quantified the impact of scale variations on theoretical uncertainties.

Provided updated values for the shape function and |C7^incl Vtb Vts*|.

Abstract

The goal of the SIMBA collaboration is to provide a global fit to the available measurements of inclusive B -> X_s gamma and B -> X_u l nu decays. By performing a global fit one is able to simultaneously determine the relevant normalizations, i.e. the total B -> X_s gamma rate and the CKM-matrix element |Vub|, together with the required hadronic parameters, most importantly the b-quark mass and the b-quark distribution function in the B-meson, called the shape function. In this talk, the current status on the model-independent determination of the shape function and |C7^\incl Vtb Vts*|, which parametrizes the total B -> Xs gamma rate, from a global fit to the available B -> X_s gamma measurements from Babar and Belle is presented. In particular, the theoretical uncertainties originating from variations of the different factorization scales are evaluated.