Soft-Collinear Factorization and the Calculation of the B->Xs+gamma Rate
Abstract
Using results on soft-collinear factorization for inclusive B-meson decay distributions, a systematic study of the partial B->Xs+gamma decay rate with a cut E_gamma<E_0 on photon energy is performed. For values E_0<1.9 GeV the rate can be calculated without reference to shape functions. The result depends on three large scales: m_b, \sqrt{m_b Delta}, and Delta=m_b-2E_0. The sensitivity to the scale Delta=1.1 GeV (for E_0=1.8 GeV) introduces significant uncertainties, which have been ignored in the past. Our new prediction for the B->Xs+gamma branching ratio with E_gamma<1.8 GeV is Br(B->Xs+gamma)=(3.44+-0.53+-0.35)*10^{-4}, where the errors refer to perturbative and parameter uncertainties, respectively. The implications of larger theory uncertainties for New Physics searches are explored with the example of the type-II two-Higgs-doublet model.
Keywords
Cite
@article{arxiv.hep-ph/0408208,
title = {Soft-Collinear Factorization and the Calculation of the B->Xs+gamma Rate},
author = {Matthias Neubert},
journal= {arXiv preprint arXiv:hep-ph/0408208},
year = {2009}
}
Comments
Invited talk presented at the 39th Rencontres de Moriond: Electroweak Interactions and Unified Theories (La Thuile, Italy, 21-28 March 2004), and at Continuous Advances in QCD 2004 (Minneapolis, Minnesota, 13--16 May 2004). 11 pages, 1 figure