First observation of χcJ→ωω decays

Physics Letters B, 2005

Decays of χc0,2 → ωω are observed for the first time using a sample of 14.0 × 10 6 ψ(2S) events collected with the BESII detector. The branching ratios are determined to be B(χc0 → ωω) = (2.29 ± 0.58 ± 0.41) × 10 −3 and B(χc2 → ωω) = (1.77 ± 0.47 ± 0.36) × 10 −3 , where the first errors are statistical and the second systematic. The

Fuel and Energy Abstracts, 2004

Using a sample of 58 × 10 6 J/ψ events collected with the BESII detector, radiative decays J/ψ → γγV , where V = ρ or φ, are studied. A resonance around 1420 MeV/c 2 (X(1424)) is observed in the γρ mass spectrum. Its mass and width are measured to be 1424 ± 10 (stat) ± 11 (sys) MeV/c 2 and 101.0 ± 8.8 ± 8.8 MeV/c 2 , respectively, and its branching ratio B(J/ψ → γX(1424) → γγρ) is determined to be (1.07 ± 0.17 ± 0.11) × 10 −4 . A search for X(1424) → γφ yields a 95% C.L. upper limit B(J/ψ → γX(1424) → γγφ) < 0.82 × 10 −4 .

Physical Review D, 2004

Using J/ψ → µ + µ − decays from a sample of approximately 4×10 6 ψ(2S) events collected with the BESI detector, the branching fractions of ψ(2S) → ηJ/ψ, π 0 π 0 J/ψ, and anything J/ψ normalized to that of ψ(2S) → π + π − J/ψ are measured. The results are B(ψ(2S) → ηJ/ψ)/B(ψ(2S) → π + π − J/ψ) = 0.098 ± 0.005 ± 0.010, B(ψ(2S) → π 0 π 0 J/ψ)/B(ψ(2S) → π + π − J/ψ) = 0.570 ± 0.009 ± 0.026, and B(ψ(2S) → anything J/ψ)/B(ψ(2S) → π + π − J/ψ) = 1.867 ± 0.026 ± 0.055.

Physics Letters B, 2005

Based on a sample of 5.8 × 10 7 J/ψ events taken with the BESII detector, the branching fractions of J/ψ → 2(π + π −)η and J/ψ → 3(π + π −)η are measured for the first time to be (2.26 ± 0.08 ± 0.27) × 10 −3 and (7.24 ± 0.96 ± 1.11) × 10 −4 , respectively.

Physical Review D, 2004

Using a sample of 14 million ψ(2S) events accumulated with the BES II detector, evidence for f0(980)f0(980) production in χc0 decays is obtained for the first time; the branching ratio is determined to be B(χc0 → f0(980)f0(980) → π + π − π + π − ) = (7.6 ± 1.9 (stat) ± 1.6 (syst)) × 10 −4 . The significance of the f0(980) signal is about 4.6σ.

2020

√ s = 3.773 GeV and 106.41 × 10 6 ψ(3686) decays taken at √ s = 3.686 GeV with the BESIII detector at the BEPCII collider, we measure the branching fraction and the partial decay width for ψ(3770) → γ χ c0 to be B(ψ(3770) → γ χ c0) = (6.88 ± 0.28 ± 0.67) × 10 −3 and [ψ(3770) → γ χ c0 ] = (187 ± 8 ± 19) keV, respectively. These are the most precise measurements to date.

Physical Review D

Using 1310.6 × 10 6 J/ψ and 447.9 × 10 6 ψ(3686) events collected with the BESIII detector at the BEPCII e + e -collider, the branching fractions and the angular distributions of J/ψ and ψ(3686) decays to Λ Λ and Σ 0 Σ0 final states are measured. The branching fractions are determined, with much improved precision, to be 19.43 ± 0.03 ± 0.33, 11.64 ± 0.04 ± 0.23, 3.97 ± 0.02 ± 0.12 and 2.44 ± 0.03 ± 0.11 for J/ψ → Λ Λ, J/ψ → Σ 0 Σ0 , ψ(3686) → Λ Λ and ψ(3686) → Σ 0 Σ0 , respectively. The polar angular distributions of ψ(3686) decays are measured for the first time, while those of J/ψ decays are measured with much improved precision. In addition, the ratios of branching fractions and B(ψ(3686)→Σ 0 Σ0 ) B(J/ψ→Σ 0 Σ0 ) are determined to test the "12% rule".

Fuel and Energy Abstracts, 1998

Physical Review D, 2005

2021

By analyzing 4.48 × 108 ψ(3686) events collected with the BESIII detector, we observe the decays χcJ → nK0 SΛ̄ + c.c. (J = 0, 1, 2) for the first time, via the radiative transition ψ(3686)→ γχcJ . The branching fractions are determined to be (6.67±0.26stat± 0.41syst) × 10−4, (1.71 ± 0.12stat ± 0.12syst) × 10−4, and (3.66 ± 0.17stat ± 0.23syst) × 10−4 for J = 0, 1, and 2, respectively.