Observation of the Rare Decay B0 --> KsK+/-pi-/+

TL;DR

This paper reports the observation of a rare decay of the neutral B meson into KsK+/-pi-/+ with high statistical significance, measuring its branching fraction using data from the BABAR experiment.

Contribution

First observation of the B0 --> KsK+/-pi-/+ decay mode with a measured branching fraction, expanding knowledge of charmless B meson decays.

Findings

Branching fraction measured as (3.2 +/- 0.5 +/- 0.3) x 10^-6.

Signal significance of 5.2 standard deviations.

Observation confirms theoretical predictions of rare B decay modes.

Abstract

We report an analysis of charmless hadronic decays of neutral B mesons to the final state KsK+/-pi-/+, using a data sample of (465 +/- 5) x 10^6 BB-bar events collected with the BABAR detector at the Y(4S) resonance. We observe an excess of signal events with a significance of 5.2 standard deviations including systematic uncertainties and measure the branching fraction to be BF(B0 --> KsK+/-pi-/+) = (3.2 +/- 0.5 +/- 0.3) x 10^-6, where the uncertainties are statistical and systematic, respectively.