A measurement of the branching fraction of the exclusive decay B^0 --> K^{*0}gamma

TL;DR

This paper reports a preliminary measurement of the branching fraction for the exclusive decay B^0 --> K^{*0}gamma, which is important for testing the Standard Model and probing new physics via loop processes.

Contribution

First measurement of the B^0 --> K^{*0}gamma branching fraction using 8.6 million B-anti-B decays, providing a key data point for flavor physics.

Findings

Branching fraction measured as (5.4±0.8±0.5) x 10^{-5}.

Results consistent with Standard Model predictions.

Provides a basis for future precision tests of the b --> s gamma transition.

Abstract

The b --> s gamma transition proceeds by a loop ``penguin'' diagram. It may be used to measure precisely the couplings of the top quark and to search for the effects of any new particles appearing in the loop. We present a preliminary measurement of the branching fraction of the exclusive decay, B^0 --> K^{*0}gamma. We use 8.6 x 10^6 B-anti-B decays to measure B(B^0 --> K^{*0}gamma) = (5.4+/-0.8+/-0.5) x 10^{-5}.