$b\to s\gamma$ AND $b\to sg$: A THEORETICAL REAPPRAISAL

Abstract

We present upgraded theoretical predictions for inclusive and exclusive radiative decays of {\it B} mesons. Our results include those next-to-leading order corrections that have already been computed. Our best estimates in the Standard Model are $BR(B\to K^{\ast }\gamma )=(4.3\pm 0.9_{-1.0}^{+1.4})\times 10^{-5}$, $BR(B\to X_s\gamma )=(1.9\pm 0.2\pm 0.5)\times 10^{-4}$, $\Gamma (B\to K^{\ast }\gamma )/\Gamma (B\to X_s\gamma )=0.23\pm 0.09$ and $BR(B\to X_{s}g)=(1.57\pm 0.15_{-0.59}^{+0.86}\pm 0.23)\times 10^{-3}$. We also consider limits found with two-Higgs-doublet models.

Comments: 17 pages (4 postscript file included), LaTeX, CERN-TH.7283/94, ROME prep. 94/1020, ULB-TH 09/94