QCD corrections to b -> s gamma gamma induced decays: B -> X_s gamma gamma and B_s -> gamma gamma
arXiv:hep-ph/9706253 · doi:10.1103/PhysRevD.56.5805
Abstract
We present a complete calculation of the Leading Order QCD corrections to the quark level decay amplitude for b -> s gamma gamma and study their relevance for both the inclusive branching ratio BR(B -> X_s gamma gamma) and for the exclusive decay channel B_s -> gamma gamma. In addition to the uncertainties in the short distance calculation, due to the choice of the renormalization scale, an appreciable uncertainty in both B_s -> gamma gamma and B -> X_s gamma gamma is introduced by the matrix element calculation. We also briefly discuss some long distance effects, especially those due to the eta_c resonance for the inclusive rate. Finally, the analysis of the IR singularities of the two photon spectrum in the inclusive case is given.
21 pages, 3 EPS figures, requires Latex2e, epsf.sty, cite.sty and amssymb.sty