Matching conditions for b → sγ and b → s gluon in extensions of the Standard Model

We evaluate matching conditions for the Wilson coefficients of operators mediating the b --> s gamma and b --> s gluon transitions in a large class of extensions of the Standard Model. The calculation is performed at the leading order in flavour-changing couplings and includes two-loop QCD corrections. These corrections can be numerically important when approximate cancellations occur among the new physics contributions and/or the SM one. (C) 2000 Elsevier Science B.V. All rights reserved.