M. Ciuchini et al., SCHEME INDEPENDENCE OF THE EFFECTIVE HAMILTONIAN FOR B-]S-GAMMA AND B-]SG DECAYS, Physics letters. Section B, 316(1), 1993, pp. 127-136
We present a calculation of the effective weak Hamiltonian which gover
ns b --> sgamma and b --> sg transitions in two different renormalizat
ion schemes (NDR and HV). In the leading logarithmic approximation, we
show that the coefficients of the effective Hamiltonian are scheme in
dependent only when one takes correctly into account the scheme depend
ence of one- and two- loop diagrams. We demonstrate that in NDR there
are contributions which were missed in previous calculations. These co
ntributions are necessary to obtain scheme independent coefficients in
the final results.