First observation of the $η_{c}\toΞ^{0} \barΞ^{0}$ decay
hep-ex
/ Authors
BESIII Collaboration, M. Ablikim, M. N. Achasov, P. Adlarson, X. C. Ai, C. S. Akondi, R. Aliberti, A. Amoroso, Q. An, Y. H. An
and 756 more authors
Y. Bai, O. Bakina, H. R. Bao, X. L. Bao, V. Batozskaya, K. Begzsuren, N. Berger, M. Berlowski, M. B. Bertani, D. Bettoni, F. Bianchi, E. Bianco, A. Bortone, I. Boyko, R. A. Briere, A. Brueggemann, D. Cabiati, H. Cai, M. H. Cai, X. Cai, A. Calcaterra, G. F. Cao, N. Cao, S. A. Cetin
/ Abstract
Using $(10087\pm 44)\times 10^6$ $J/ψ$ events collected with the BESIII detector at the BEPCII collider, we report the first observation of the decay $η_{c} \to Ξ^{0} \barΞ^{0}$. The interference between $J/ψ\toγη_c\toγΞ^0\barΞ^0$ and $J/ψ\toγΞ^0\barΞ^0|_{\rm non-resonance}$ is considered in the $Ξ^0 \barΞ^0$ mass spectrum fits. The branching fractions are measured to be $B(η_c \to Ξ^0 \barΞ^0)=(1.33 \pm 0.03 \pm 0.18) \times 10^{-3}$ for the constructive interference and $B(η_c \to Ξ^0 \barΞ^0)=(1.63 \pm 0.04 \pm 0.21) \times 10^{-3}$ for the destructive interference, where the first uncertainties are statistical and the second are systematic.