The number of J/ψ events collected with the BES detector at the BEPC from June 12 to July 28, 2009 is determined to be (225.3±2.8)×10 6 using J/ψ →inclusive events, where the uncertainty is the systematic error and the statistical one is negligible.

Hadronic transitions of χ cJ → η c π + π − (J = 0, 1, 2) are searched for using a sample of 1.06 × 10 8 ψ(3686) events collected with the BESIII detector at the BEPCII storage ring. The η c is reconstructed with K 0 S K ± π ∓ and K + K − π 0 final states. No signals are observed in any of the three χ cJ states in either η c decay mode. At the 90% confidence level, the upper limits are determined to be B(χ c0 → η c π + π − ) < 0.07%, B(χ c1 → η c π + π − ) < 0.32%, and B(χ c2 → η c π + π − ) < 0.54%. The upper limit of B(χ c1 → η c π + π − ) is lower than the existing theoretical prediction by almost an order of magnitude. The branching fractions of χ cJ → K 0 S K ± π ∓ π + π − , K + K − π + π − π 0 , ωK + K − and φπ + π − π 0 (J = 0, 1, 2) are measured for the first time.

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Using a sample of 1.06 × 10 8 ψ ′ decays collected by the BESIII detector, χ c0 and χ c2 decays into π 0 π 0 and ηη are studied. The branching fraction results are Br(χ c0 → π 0 π 0 ) = (3.23 ± 0.03 ± 0.23 ± 0.14) × 10 −3 , Br(χ c2 → π 0 π 0 ) = (8.8 ± 0.2 ± 0.6 ± 0.4) × 10 −4 , Br(χ c0 → ηη) = (3.44 ± 0.10 ± 0.24 ± 0.2) × 10 −3 , and Br(χ c2 → ηη) = (6.5 ± 0.4 ± 0.5 ± 0.3) × 10 −4 , where the uncertainties are statistical, systematic due to this measurement, and systematic due to the branching fractions of ψ ′ → γχ cJ , respectively. The results provide information on the decay mechanism of χ c states into pseudoscalars.