Measurement of B Decays to phi K gamma

TL;DR

This paper reports measurements of B meson decays to phi K gamma, including branching fractions and CP asymmetry, using data from BaBar, providing insights into rare decay processes and CP violation.

Contribution

First measurement of B -> phi K gamma branching fractions and CP asymmetry using a large BaBar dataset.

Findings

Branching fraction B(B- -> phi K- gamma) = (3.5 +/- 0.6 +/- 0.4) x 10^-6

Upper limit B(B0bar -> phi K0bar gamma) < 2.7 x 10^-6 at 90% CL

Direct CP asymmetry A_CP = (-26 +/- 14 +/- 5)%

Abstract

We search for the decays B- -> phi K- gamma and B0bar -> phi K0bar gamma in a data sample of 228 million BBbar pairs collected at the Upsilon(4S) resonance with the BaBar detector. We measure the branching fraction B(B- -> phi K- gamma) = (3.5 +/- 0.6 +/- 0.4) x 10^-6 and set an upper limit B(B0bar -> phi K0bar gamma) < 2.7 x 10^-6 at the 90% confidence level. We also measure the direct CP asymmetry in B- -> phi K- gamma, A_CP = (-26 +/- 14 +/- 5)%. The uncertainties are statistical and systematic, respectively.