Observation of the decay & chi;cJ & RARR; & omega;-& omega; over bar

Using an e thorn e- collision data sample of o27.08 ⠂ 0.14 thorn x 108 & psi;o3686 thorn events collected by the BESIII detector, we report the first observation of & chi;cJ & RARR; & omega;- over bar & omega; thorn (J 1/4 0, 1, 2) decays with significances of 5.6 & sigma;, 6.4 & sigma;, and 18 & sigma;, respectively, where the & chi;cJ mesons are produced in the radiative & psi;o3686 thorn decays. The branching fractions are determined to be Bo & chi;c0 & RARR; & omega;- over bar & omega; thorn thorn 1/4 o3.51 ⠂ 0.54 ⠂ 0.29 thorn x 10-5, Bo & chi;c1 & RARR; & omega;- over bar & omega; thorn thorn 1/4 o1.49 ⠂ 0.23 ⠂ 0.10 thorn x 10-5, and Bo & chi;c2 & RARR; & omega;- over bar & omega; thorn thorn 1/4 o4.52 ⠂ 0.24 ⠂ 0.18 thorn x 10-5, where the first and second uncertainties are statistical and systematic, respectively.

Automated summary

Using the BESIII detector, we have observed the χcJ→ω-ω decays for the first time, where J=0, 1, 2, with significances of 5.6σ, 6.4σ, and 18σ, respectively, in an e+e- collision data sample of (2.708±0.014)×10^8 ψ(3686) events. The branching fractions are determined to be B[χc0→ω-ω]=(3.51±0.54±0.29)×10^-5, B[χc1→ω-ω]=(1.49±0.23±0.10)×10^-5, and B[χc2→ω-ω]=(4.52±0.24±0.18)×10^-5, where the first and second uncertainties are statistical and systematic, respectively.