Towards a global fit to extract the B->Xs gamma decay rate and Vub

TL;DR

This paper introduces a model-independent framework for accurately determining the B->Xs gamma decay rate and Vub by fitting shape functions to experimental data, aiding in the search for new physics.

Contribution

It develops a novel basis-function expansion method for the shape function, enabling a global fit to experimental data with reliable uncertainties.

Findings

Successful implementation of a basis-function expansion for the shape function

Global fit to BaBar and Belle data achieved

Improved precision in extracting B->Xs gamma decay rate

Abstract

The total B->Xs gamma decay rate and the CKM-matrix element Vub play an important role in finding indirect evidence for new physics affecting the flavor sector of the Standard Model, complementary to direct searches at the LHC and Tevatron. Their determination from inclusive B-meson decays requires the precise knowledge of the parton distribution function of the b quark in the B meson, called the shape function. We implement a new model-independent framework for the shape function with reliable uncertainties based on an expansion in a suitable set of basis functions. We present the current status of a global fit to BaBar and Belle data to extract the shape function and the B->Xs gamma decay rate.