Observation of B- -> J/psi Lambda pbar and searches for B- -> J/psi Sigma0 pbar and B0 -> J/psi p pbar Decays

TL;DR

This study reports the first observation of the decay B- -> J/psi Lambda pbar, measures its branching fraction, and sets upper limits on related decay modes using a large data sample from the Belle detector.

Contribution

It provides the first evidence for the B- -> J/psi Lambda pbar decay and establishes upper limits for two other decay modes, advancing understanding of B meson decay channels.

Findings

Observed B- -> J/psi Lambda pbar decay with 11.1 sigma significance.

Measured branching fraction B(B- -> J/psi Lambda pbar) = (11.6 +/- 2.8 (stat.) +1.8 -2.3 (sys.)) x 10^-6.

Set upper limits for B- -> J/psi Sigma0 pbar and B0 -> J/psi p pbar decays.

Abstract

We report the observation of B- -> J/psi Lambda pbar and searches for B- -> J/psi Sigma0 pbar and B0 -> J/psi p pbar decays, using a sample of 275 million BBbar pairs collected with the Belle detector at the Upsilon(4S) resonance. We observe a signal of 17.2 +/- 4.1 events with a significance of 11.1sigma and obtain a branching fraction of B(B- -> J/psi Lambda pbar) = [11.6 +/- 2.8 (stat.) +1.8 -2.3(sys.)] x 10^-6. No signal is found for either of the two decay modes, B- -> J/psi Sigma0 pbar and B0 -> J/psi p pbar, and upper limits for the branching fractions are determined to be B(B- -> J/psi Sigma0 pbar) < 1.1 x 10^{-5} and B(B0 -> J/psi p pbar) < 8.3 x 10^{-7} at 90% confidence level.