Measurement of Branching Fractions and CP and Isospin Asymmetries in B -> K*(892) gamma Decays

TL;DR

This paper reports precise measurements of branching fractions, CP asymmetry, and isospin asymmetry in B -> K* gamma decays, providing important tests of the Standard Model and constraints on new physics.

Contribution

First measurement of branching fractions and asymmetries in B -> K* gamma decays using a large data sample from BaBar.

Findings

Branching fraction for B0 -> K*0 gamma: 4.47 x 10^-5

Branching fraction for B+ -> K*+ gamma: 4.22 x 10^-5

CP asymmetry constrained between -0.033 and 0.028

Abstract

We present an analysis of the decays B0 -> K*0 gamma and B+ -> K*+ gamma using a sample of 383 million BBbar events collected with the BaBar detector at the PEP2 asymmetric energy B factory. We measure the branching fractions BF[B0 -> K*0 Gamma] = 4.47 +/- 0.10 +/- 0.16 x 10^-5 and BF[B+ -> K*+ Gamma] = 4.22 +/- 0.14 +/- 0.16 x 10^-5. We constrain the direct CP asymmetry to be -0.033 < Acp < 0.028 and the isopin asymmetry to be 0.017 < \Delta0- < 0.116, where the limits are determined at the 90% confidence interval and include both statistical systematic uncertainties.