R × U ( 1 ) Extensions of the Standard Model

The rare radiative decay b → sγ is studied in SU(2)L × SU(2)R × U(1) extensions of the Standard Model. Matching conditions for coefficients of operators appearing in the low energy effective Hamiltonian for this process are derived, and QCD corrections to these coefficients are analyzed. The b → sγ decay rate is then calculated and compared with the corresponding Standard Model result. We find that observable deviations from Standard Model predictions can occur in SU(2)L × SU(2)R × U(1) theories for a reasonable range of parameter values. 10/93 † Work supported in part by by the U.S. Dept. of Energy under DOE Grant no. DE-FG0392-ER40701 and by an SSC Fellowship. ‡ Work supported in part by the German Bundesministerium für Forschung und Technologie under contract 06 TM 732 and by the Polish Committee for Scientific Research.