Theoretical uncertainties and phenomenological aspects of B → XSγ decay

• Published in: Nuclear physics. B Vol. 424; no. 2; pp. 374 - 398
• Main Authors: Buras, A.J., Misiak, M., Münz, M., Pokorski, S.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 08.08.1994
• ISSN: 0550-3213; 1873-1562
• DOI: 10.1016/0550-3213(94)90299-2

We analyze uncertainties in the theoretical prediction for the inclusive branching ratio BR[ B → X s γ]. We find that the dominant uncertainty in the leading order expression comes from its μ-dependence. We discuss a next-to-leading order calculation of B → X s γ in general terms and check to what extent the μ-dependence can be reduced in such a calculation. We present constraints on the Standard and Two-Higgs-Doublet Model parameters coming from the measurement of b → sγ decay. The current theoretical uncertainties do not allow one to definitively restrict the Standard Model parameters much beyond the limits coming from other experiments. The bounds on the Two-Higgs-Doublet Model remain very strong, though significantly weaker than the ones present in the recent literature. In the Two-Higgs-Doublet Model case, the b → sγ, Z → b b and b → cτ ν τ processes are enough to give the most restrictive bounds in the M H ±−tan β plane.