Study of J/ψ and ψ(3686) decay to Λ

M. Ablikim¹,

М. Н. Ачасов²,

S. Ahmed³

et al.

Abstract

Using 1310.6 × 10 6 J=ψ and 447.9 × 10 6 ψð3686Þ events collected with the BESIII detector at the BEPCII e þ e − collider, the branching fractions and the angular distributions of J=ψ and ψð3686Þ decays to ΛΛ and Σ 0Σ0 final states are measured. The branching fractions are determined, with much improved precision, to be 19.43 AE 0.03 AE 0.33, 11.64 AE 0.04 AE 0.23, 3.97 AE 0.02 AE 0.12 and 2.44 AE 0.03 AE 0.11 for J=ψ → ΛΛ, J=ψ → Σ 0Σ0 , ψð3686Þ → ΛΛ and ψð3686Þ → Σ 0Σ0 , respectively. The polar angular distributions of ψð3686Þ 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 Bðψð3686Þ→ΛΛÞBðJ=ψ→ΛΛÞ and Bðψð3686Þ→Σ 0Σ0 Þ BðJ=ψ→Σ 0Σ0 Þ are determined to test the "12% rule."

Cross section measurements of e+e−→ωχc0 from s=

“…A measurement of their strengths can be helpful to extract information about the underlying dynamics of the decay process. We therefore performed an angular analysis [38] [9]). The helicity angle, θ ω , defined by the scattering angle of the ω with respect to the electron beam in the e þ e − center-of-mass frame was reconstructed for each event.…”

Polarization observables in e+e− annihilation to a baryon-antibaryon pair

“…ΛΛ 440675 ± 670 19.43 ± 0.03 ± 0.33 ψ(2S) → ΛΛ 31119 ± 187 3.97 ± 0.02 ± 0.12 J/ψ → Σ 0Σ0 111026 ± 335 11.64 ± 0.04 ± 0.23 ψ(2S) → Σ 0Σ0 6612 ± 82 2.44 ± 0.03 ± 0.11 J/ψ → Σ(1385) 0Σ (1385) 0 102762 ± 852 10.71 ± 0.09 J/ψ → Ξ 0Ξ0 134846 ± 437 11.65 ± 0.04 ψ(2S) → Σ(1385) 0Σ (1385) 0 2214 ± 148 0.69 ± 0.05 ψ(2S) → Ξ 0Ξ0 10839 ± 123 2.73 ± 0.03 J/ψ → Ξ −Ξ+ 42811 ± 231 10.40 ± 0.06 J/ψ → Σ(1385) −Σ (1385) + 42595 ± 467 10.96 ± 0.12 J/ψ → Σ(1385) +Σ (1385) − 52523 ± 596 12.58 ± 0.14 ψ(2S) → Ξ −Ξ+ 5337 ± 83 2.78 ± 0.05 ψ(2S) → Σ(1385) −Σ (1385) + 1375 ± 98 0.85 ± 0.06 ψ(2S) → Σ(1385) +Σ (1385) − 1470 ± 95 0.84 ± 0.05 TABLE I. Available B1B2 data samples and the branching fractions from recent BESIII publications[11][12][13].…”

CP symmetry tests in the cascade-anticascade decay of charmonium

“…We show that the same information can TABLE I. Branching fractions for some J/ψ, ψ → BB decays and the estimated sizes of the data samples from the full data set of 10 10 J/ψ and 3.2×10 9 ψ in the BESIII proposal [11]. The approximate detection efficiencies for the final states reconstructed using Λ → pπ − and Ξ → Λπ decay modes are based on the published BESIII analyses using partial data sets [12][13][14].…”