Evidence for B+ --> Jpsi p Lambda-bar and Search for B0 --> Jpsi p p-bar

TL;DR

This paper reports a search for specific B meson decays involving J/psi, protons, and lambdas, setting upper limits on their branching fractions based on data from the BaBar experiment.

Contribution

First search for B+ to J/psi p Lambda-bar and B0 to J/psi p p-bar decays, providing experimental upper limits on their branching fractions.

Findings

Observed 4 B+ candidates with low background

Set a 90% CL upper limit of 26 x 10^-6 for B+ decay

Set a 90% CL upper limit of 1.9 x 10^-6 for B0 decay

Abstract

We have performed a search for the decays $B^+\to J/\psi p \bar{\Lambda}$ and $B^0\to J/psi p \bar{p}$ in a data set of $(88.9 \pm 1.0)\times 10^6$ $\Upsilon(4S)$ decays collected by the BaBar experiment at the PEP-II $\e^+e^-$ storage ring at the Stanford Linear Accelerator Center. Four charged $B$ candidates have been observed with an expected background of $0.21\pm 0.14$ events. The corresponding branching fraction is $12^{+9}_{-6}\times 10^{-6}$, where statistical and systematic uncertainties have been combined. The result can be interpreted as a 90% confidence level (CL) upper limit of $26 \times 10^{-6}$. We also find one $B^0$ candidate, with an expected background of $0.64\pm 0.17$ events, implying a 90% CL upper limit of $1.9 \times 10^{-6}$.