Search for the decay B0 --> K0_S K0_S K0_L

TL;DR

This paper reports the first search for the decay B0 --> K0_S K0_S K0_L using a large data sample, finding no significant evidence and setting upper limits on the branching fraction.

Contribution

It provides the first experimental search for this decay mode and establishes upper limits on its branching fraction, improving constraints on theoretical models.

Findings

No significant evidence for the decay was observed.

A branching fraction upper limit of 7.4 x 10^{-6} at 90% CL was set.

The analysis constrains theoretical predictions of this decay mode.

Abstract

We present the first search for the decay B0 --> K0_S K0_S K0_L using a data sample of 232 million B Bbar pairs. We find no statistically significant evidence for the non-resonant component of this decay. Our central value for the branching fraction, assuming the true Dalitz distribution is uniform and excluding the phi resonance, is B(B0 --> K0_S K0_S K0_L) = (2.4 +2.7 -2.5 +/- 0.6) x 10^{-6} where the errors are statistical and systematic, respectively. We set a single-sided Bayesian upper limit of B(B0 --> K0_S K0_S K0_L) < 7.4 x 10^{-6} at 90% confidence level using a uniform prior probability for physical values. Assuming the worst-case true Dalitz distribution, where the signal is entirely in the region of lowest efficiency, the 90% confidence level upper limit is B(B0 --> K0_S K0_S K0_L) < 16 x 10^{-6}.