B -> X_d gamma and constraints on new physics

Understand

We combine recent progress in measuring the branching ratio of the decay B->X_d gamma$ with the discovery that hadronic uncertainties in the CP-averaged branching ratio drop out to a large extent.

• Implications of these improvements on the size of possible new physics effects are investigated.
• We find the updated SM prediction for the CP-averaged branching ratio to be Br[B->X_d gamma]^SM_E_gamma>1.6 GeV = 1.54^+0.26-0.31*10^-5, which should be compared with the experimental value of Br[B->X_d gamma]^exp_E_gamma>1.6GeV = (1.41+-0.57) 10^-5.
• After performing a model independent analysis, we consider different new physics models: the MSSM with generic sources of flavor violation, the two Higgs doublet model of type III and a model with right-handed charged currents.