First Evidence of Lambda Lambda-bar in \chi_cJ Decays

TL;DR

This paper reports the first observation of J decays to Lambda Lambda-bar, measuring their branching ratios and comparing results with theoretical models, providing new experimental data in charmonium decay studies.

Contribution

First experimental measurement of J (0, 1, 2) decays to Lambda Lambda-bar, including branching ratios, using J produced in (2S) decays.

Findings

Branching ratio for 0 d7 Lambda Lambda-bar: (4.7^{+1.3}_{-1.2} \u00b1 1.0) d7 10^{-4}

Branching ratio for 1 d7 Lambda Lambda-bar: (2.6^{+1.0}_{-0.9} b1 0.6) d7 10^{-4}

Branching ratio for 2 d7 Lambda Lambda-bar: (3.3^{+1.5}_{-1.3} b1 0.7) d7 10^{-4}

Abstract

The first observation of \chi_cJ (J=0,1,2) decays to Lambda Lambda-bar is reported using \psi(2S) data collected with the BESII detector at the BEPC. The branching ratios are determined to be BR(\chi_c0 \to Lambda Lambda-bar) = (4.7^{+1.3}_{-1.2} \pm 1.0)\times 10^{-4}, BR(\chi_c1 \to Lambda Lambda-bar) = (2.6^{+1.0}_{-0.9} \pm 0.6)\times 10^{-4} and BR(\chi_c2 \to Lambda Lambda-bar) = (3.3^{+1.5}_{-1.3} \pm 0.7)\times 10^{-4}. Results are compared with model predictions.