The Inclusive Radiative B X S Gamma Decay In The Standard Model PDF Download

Radiative decays of the B meson, B 2!X{sub s}[gamma], proceed via virtual flavor changing neutral current processes that are sensitive to contributions from high mass scales, either within the Standard Model of electroweak interactions or beyond. In the Standard Model, these transitions are sensitive to the weak interactions of the top quark, and relatively robust predictions of the inclusive decay rate exist. Significant deviation from these predictions could be interpreted as indications for processes not included in the minimal Standard Model, like interactions of charged Higgs or SUSY particles. The analysis of the inclusive photon spectrum from B 2!X{sub s}[gamma] decays is rather challenging due to high backgrounds from photons emitted in the decay of mesons in B decays as well as ee− annihilation to low mass quark and lepton pairs. Based on 88.5 million B{bar B} events collected by the BABAR detector, the photon spectrum above 1.9 GeV is presented. By comparison of the first and second moments of the photon spectrum with QCD predictions (calculated in the kinetic scheme), QCD parameters describing the bound state of the b quark in the B meson are extracted: m{sub b} = (4.45 ± 0.16) GeV/c2; [mu]{sub {pi}}2 = (0.65 ± 0.29) GeV2. These parameters are useful input to non-perturbative QCD corrections to the semileptonic B decay rate and the determination of the CKM parameter.