Measurement of Branching Fractions, and CP and Isospin Asymmetries, for $B \to K^* \gamma$

Abstract

The branching fractions of the decays B->K*0,gamma and B->K*+,gamma are measured using a sample of 88 x 10^6 B\bar{B} events collected with the BaBar detector at the PEP-II asymmetric-energy e^+e^- collider. We find B(B->K*0,gamma) = 3.92 +/- 0.20 (stat) +/- 0.24 (syst) x 10^{-5} and B(B->K*_,gamma) = 3.87 +/- 0.28 (stat) +/- 0.26 (syst) x 10^{-5}. Our measurements also constrain the direct $\CP$ asymmetry to be -0.74 < A_{CP}(B->K*,gamma) < 0.049, and the isospin asymmetry to be -0.46 < \Delata_{0-} < 0.146, both at the 90% confidence level.