Measurements of J/ψ decays into ϕπ0, ϕη, and ϕη′

Fuel and Energy Abstracts, 1998

2014

Physical Review D, 2013

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

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.

2006

Recently, the BES collaboration has published an extensive partial wave analysis of experimental data on J/ψ → φπ + π − , J/ψ → ωπ + π − , J/ψ → φK + K − and J/ψ → ωK + K −. These new results are analyzed here, with full account of detection efficiencies, in the framework of a chiral unitary description with coupled-channel final state interactions between ππ and KK pairs. The emission of a dimeson pair is described in terms of the strange and nonstrange scalar form factors of the pion and the kaon, which include the final state interaction and are constrained by unitarity and by matching to the next-to-leading-order chiral expressions. This procedure allows for a calculation of the S-wave component of the dimeson spectrum including the f0(980) resonance, and for an estimation of the low-energy constants of Chiral Perturbation Theory, in particular the large Nc suppressed constants L r 4 and L r 6. The decays in question are also sensitive to physics associated with OZI violation in the 0 ++ channel. It is found that the S-wave contributions to φπ + π − , φK + K − and ωπ + π − given by the BES partial-wave analysis may be very well fitted up to a dimeson center-of-mass energy of ∼ 1.2 GeV, for a large and positive value of L r 4 and a value of L r 6 compatible with zero. An accurate determination of the amount of OZI violation in the J/ψ → φπ + π − decay is achieved, and the S-wave contribution to ωK + K − near threshold is predicted.

The European Physical Journal C, 2007

The decay J/ψ → ωpp is studied using a 5.8 × 10 7 J/ψ event sample accumulated with the BES II detector at the Beijing Electron-Positron Collider. The decay branching fraction is measured to be B(J/ψ → ωpp) = (9.8 ± 0.3 ± 1.4) × 10 −4. No significant enhancement near the pp mass threshold is observed, and an upper limit of B(J/ψ → ωX(1860))B(X(1860) → pp) < 1.5 × 10 −5 is determined at the 95% confidence level, where X(1860) designates the near-threshold enhancement seen in the pp mass spectrum in J/ψ → γpp decays.

Physical Review Letters, 2000

Physical Review Letters, 2003

We observe a narrow enhancement near 2mp in the invariant mass spectrum of pp pairs from radiative J/ψ → γpp decays. No similar structure is seen in J/ψ → π 0 pp decays. The results are based on an analysis of a 58 million event sample of J/ψ decays accumulated with the BESII detector at the Beijing electron-positron collider. The enhancement can be fit with either an S-or P -wave Breit Wigner reso-nance function. In the case of the S-wave fit, the peak mass is below 2mp at M = 1859 +3 −10 (stat) +5 −25 (sys) MeV/c 2 and the total width is Γ < 30 MeV/c 2 at the 90 percent confidence level. These mass and width values are not consistent with the properties of any known particle.

Physical Review Letters, 2002