Measurements of decays into and

Physical Review D, 2006

Measurement of the branching fractions for J/ψ → γπ 0 , γη and γη ′ The decay modes J/ψ → γπ 0 , γη and γη ′ are analyzed using a data sample of 58 million J/ψ decays collected with the BESII detector at BEPC. The branching fractions are determined to be: Br(J/ψ → γπ 0 ) = (3.13 +0.65 −0.44 ) × 10 −5 , Br(J/ψ → γη) = (11.23 ± 0.89) × 10 −4 , and Br(J/ψ → γη ′ ) = (5.55 ± 0.44) × 10 −3 , where the errors are combined statistical and systematic errors. The ratio of partial widths Γ(J/ψ → γη ′ )/Γ(J/ψ → γη) is measured to be 4.94 ± 0.40, and the singlet-octet pseudoscalar mixing angle of η −η ′ system is determined to be θ P = (−22.08±0.81) • .

Physical Review D, 2005

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

Using the data samples of 1.31 × 10 9 J/ψ events and 4.48 × 10 8 ψ(3686) events collected with the BESIII detector, partial wave analyses on the decays J/ψ and ψ(3686) → π + π -η ′ are performed with a relativistic covariant tensor amplitude approach. The dominant contribution is found to be J/ψ and ψ(3686) decays to ρη ′ . In the J/ψ decay, the branching fraction B(J/ψ → ρη ′ ) is determined to be (7.90 ± 0.19(stat) ± 0.49(sys)) × 10 -5 . Two solutions are found in the ψ(3686) decay, and the corresponding branching fraction B(ψ(3686) → ρη ′ ) is (1.02 ± 0.11(stat) ± 0.24(sys)) × 10 -5 for the case of destructive interference, and (5.69 ± 1.28(stat) ± 2.36(sys)) × 10 -6 for constructive interference. As a consequence, the ratios of branching fractions between ψ(3686) and J/ψ decays to ρη ′ are calculated to be (12.9 ± 1.4(stat) ± 3.1(sys))% and (7.2 ± 1.6(stat) ± 3.0(sys))%, respectively. We also determine the inclusive branching fractions of J/ψ and ψ(3686) decays to π + π -η ′ to be (1.36 ± 0.02(stat) ± 0.08(sys)) × 10 -4 and (1.51 ± 0.14(stat) ± 0.23(sys)) × 10 -5 , respectively.

Physical Review D, 2013

The decay J/ψ → ωpp has been studied, using 225.3 × 10 6 J/ψ events accumulated at BESIII. No significant enhancement near the pp invariant-mass threshold (denoted as X(pp)) is observed. The upper limit of the branching fraction B(J/ψ → ωX(pp) → ωpp) is determined to be 3.9 × 10 −6 at the 95% confidence level. The branching fraction of J/ψ → ωpp is measured to be B(J/ψ → ωpp) = (9.0 ± 0.2 (stat.) ± 0.9 (syst.)) × 10 −4 .

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".

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.

Chinese Physics C, 2017

A measurement of the number of J/ψ events collected with the BESIII detector in 2009 and 2012 is performed using inclusive decays of the J/ψ. The number of J/ψ events taken in 2009 is recalculated to be (223.7 ± 1.4) × 10 6 , which is in good agreement with the previous measurement, but with significantly improved precision due to improvements in the BESIII software. The number of J/ψ events taken in 2012 is determined to be (1086.9 ± 6.0) × 10 6. In total, the number of J/ψ events collected with the BESIII detector is measured to be (1310.6 ± 7.0) × 10 6 , where the uncertainty is dominated by systematic effects and the statistical uncertainty is negligible.

Journal of High Energy Physics, 2021

Using 1310.6 × 106J/ψ and 448.1 × 106ψ(3686) events collected with the BESIII detector, the branching fractions of J/ψ decays to Σ+$$ \overline{\Sigma} $$ Σ ¯ − is measured to be (10.61 ± 0.04 ± 0.36) × 10−4, which is significantly more precise than the current world average. The branching fractions of ψ(3686) decays to Σ+$$ \overline{\Sigma} $$ Σ ¯ − is measured to be (2.52 ± 0.04 ± 0.09) × 10−4, which is consistent with the previous measurements. In addition, the ratio of $$ \mathcal{B} $$ B (ψ(3686) → Σ+$$ \overline{\Sigma} $$ Σ ¯ −)/$$ \mathcal{B} $$ B (J/ψ → Σ+$$ \overline{\Sigma} $$ Σ ¯ −) is determined to be (23.8 ± 1.1)% which violates the “12% rule”.

Physical Review D, 2013