Measurements of the branching fractions of $\psi (3686)\to {\bar{\Sigma }}^0\Lambda +c.c.$ and ${\chi }_{cJ(J=0,1,2)}\to \Lambda \bar{\Lambda }$

Abstract

Based on $4.481\times 10^8$ $\psi (3686)$ events collected with the BESIII detector at BEPCII, the branching fraction of the isospin violating decay $\psi (3686)\to {\bar{\Sigma }}^0\Lambda +c.c.$ is measured to be $(1.60\pm 0.31\pm 0.13\pm 0.58)\times 10^{-6}$, where the first uncertainty is statistical, the second is systematic, and the third is the uncertainty arising from interference with the continuum. This result is significantly smaller than the measurement based on CLEO-c data sets. The decays ${\chi }_{cJ}\to \Lambda \bar{\Lambda }$ are measured via $\psi (3686)\to \gamma {\chi }_{cJ}$, and the branching fractions are determined to be $\mathcal{B}\left({\chi }_{c0}\to \Lambda \bar{\Lambda }\right)=(3.64\pm 0.10\pm 0.10\pm 0.07)\times 10^{-4}$, $\mathcal{B}\left({\chi }_{c1}\to \Lambda \bar{\Lambda }\right)=(1.31\pm 0.06\pm 0.06\pm 0.03)\times 10^{-4}$, $\mathcal{B}\left({\chi }_{c2}\to \Lambda \bar{\Lambda }\right)=(1.91\pm 0.08\pm 0.17\pm 0.04)\times 10^{-4}$, where the third uncertainties are systematic due to the $\psi (3686)\to \gamma {\chi }_{cJ}$ branching fractions.

11 pages, 8 figures

References in corpus (7)

• ${\Sigma }^{+}$ and ${\bar{\Sigma }}^{-}$ polarization in the $J/\psi$ and $\psi (3686)$ decays
• Hyperon Form Factors & Diquark Correlations
• Further study of the helicity selection rule evading mechanism in ${\eta }_c$, ${\chi }_{c0}$ and $h_c$ decaying to baryon anti-baryon pairs
• Model independent determination of the spin of the ${\Omega }^{-}$ and its polarization alignment in $\psi (3686)\to {\Omega }^{-}{\bar{\Omega }}^{+}$
• Measurements of psi(2S) decays to octet baryon-antibaryon pairs
• Measurements of Baryon Pair Decays of ${\chi }_{cJ}$ Mesons
• Measurement of {\boldmath $J/\psi \to \Xi (1530{)}^{-}{\bar{\Xi }}^{+}$} and evidence for the radiative decay {\boldmath $\Xi (1530{)}^{-}\to \gamma {\Xi }^{-}$}

Cited by in corpus (7)

• Production and decay of polarized hyperon-antihyperon pairs
• Symmetry analysis of charmonium two-body decay
• Isospin strikes back
• Observation of the $\psi (3686)$ decays into ${\Sigma }^{+}{\bar{\Sigma }}^{-}\omega$ and ${\Sigma }^{+}{\bar{\Sigma }}^{-}\varphi$
• Isospin violating decays of vector charmonia
• Observation of ${\chi }_{cJ}\to p\bar{p}{K}_S^0{K}^{-}{\pi }^{+}+c.c.$
• Search for the isospin-violating decays ${\mathbf{\chi }}_{\mathbf{cJ}}\to \mathbf{\Lambda }{\bar{\mathbf{\Sigma }}}^0+\mathbf{c}.\mathbf{c}.$ and ${\mathbf{\eta }}_{\mathbf{c}}\to \mathbf{\Lambda }{\bar{\mathbf{\Sigma }}}^0+\mathbf{c}.\mathbf{c}.$