Measurements of Baryon Pair Decays of $\chi_{cJ}$ Mesons

TL;DR

This study measures the decay rates of $ ext{chi}_{cJ}$ mesons into various baryon-antibaryon pairs using BESIII data, providing new precise branching fractions and setting upper limits for certain decay modes.

Contribution

First precise measurements of $ ext{chi}_{cJ}$ baryon pair decay branching fractions using large BESIII data sample, including new upper limits for specific decay channels.

Findings

Branching fractions for $ ext{chi}_{cJ}$ decays into $ ext{Lambda}$, $ extSigma^{0}$, and $ extSigma^{+}$ pairs are measured.

Upper limits are established for $ ext{chi}_{cJ}$ decays into $ extSigma^{0}ar{ extSigma}^{0}$ and $ extSigma^{+}ar{ extSigma}^{-}$.

Results improve understanding of charmonium decay mechanisms into baryons.

Abstract

Using 106 $\times 10^{6}$ $\psi^{\prime}$ decays collected with the BESIII detector at the BEPCII, three decays of $\chi_{cJ}$ ($J=0,1,2$) with baryon pairs ($\llb$, $\ssb$, $\SSB$) in the final state have been studied. The branching fractions are measured to be $\cal{B}$$(\chi_{c0,1,2}\rightarrow\Lambda\bar\Lambda) =(33.3 \pm 2.0 \pm 2.6)\times 10^{-5}$, $(12.2 \pm 1.1 \pm 1.1)\times 10^{-5}$, $(20.8 \pm 1.6 \pm 2.3)\times 10^{-5}$; $\cal{B}$$(\chi_{c0,1,2}\rightarrow\Sigma^{0}\bar\Sigma^{0})$ = $(47.8 \pm 3.4 \pm 3.9)\times 10^{-5}$, $(3.8 \pm 1.0 \pm 0.5)\times 10^{-5}$, $(4.0 \pm 1.1 \pm 0.5) \times 10^{-5}$; and $\cal{B}$$(\chi_{c0,1,2}\rightarrow\Sigma^{+}\bar\Sigma^{-})$ = $(45.4 \pm 4.2 \pm 3.0)\times 10^{-5}$, $(5.4 \pm 1.5 \pm 0.5)\times 10^{-5}$, $(4.9 \pm 1.9 \pm 0.7)\times 10^{-5}$, where the first error is statistical and the second is systematic. Upper limits on the branching fractions for the decays of $\chi_{c1,2}\rightarrow\Sigma^{0}\bar\Sigma^{0}$, $\Sigma^{+}\bar\Sigma^{-}$, are estimated to be $\cal{B}$$(\chi_{c1}\rightarrow\Sigma^{0}\bar\Sigma^{0}) < 6.2\times 10^{-5}$, $\cal{B}$$(\chi_{c2}\rightarrow\Sigma^{0}\bar\Sigma^{0}) < 6.5\times 10^{-5}$, $\cal{B}$$(\chi_{c1}\rightarrow\Sigma^{+}\bar\Sigma^{-}) < 8.7\times 10^{-5}$ and $\cal{B}$$(\chi_{c2}\rightarrow\Sigma^{+}\bar\Sigma^{-}) < 8.8\times 10^{-5}$ at the 90% confidence level.