Measurements of ψ(2S) decays to octet baryon–antibaryon pairs

Study ofe+e−→ΛΛ¯,ΛAubert1, Bóna2, Boutigny3 et al. 2007Phys. Rev. DSelf Cite1243560View full textAdd to dashboardCite

“…Both results are higher than the current world-average values [13]: (1.54 ± 0.19) × 10 −3 and (2.5 ± 0.7) × 10 −4 , but in reasonable agreement with the more precise recent measurements: (2.03 ± 0.15) × 10 −3 by BES [16] and (3.33 ± 0.25) × 10 −4 by CLEO [22] and BES [23].…”

Study ofψdecays to theΞ−Ξ¯+andAblikim1, Ачасов2, Ai3 et al. 2016Phys. Rev. DSelf Cite422200View full textAdd to dashboardCite

“…The theoretical models are expected to be improved in order to understand the origin of these discrepancies. To test the "12% rule", the branching fraction ra- 10.40 ± 0.06 ± 0.74 10.96 ± 0.12 ± 0.71 12.58 ± 0.14 ± 0.78 2.78 ± 0.05 ± 0.14 0.85 ± 0.06 ± 0.06 0.84 ± 0.05 ± 0.05 MarkI [5] 14.00 ± 5.00 --< 2.0 --MarkII [6] 11.40 ± 0.80 ± 2.00 8.60 ± 1.80 ± 2.20 10.3 ± 2.4 ± 2.5 ---DM2 [7] 7.00 ± 0.60 ± 1.20 10.00 ± 0.40 ± 2.10 11.9 ± 0.4 ± 2.5 ---BESII [8,12] 9.00 ± 0.30 ± 1.80 12.30 ± 0.70 ± 3.00 15.0 ± 0.8 ± 3. …”

“…Experimental efforts are useful to measure α in order to test the hadron helicity conservation rule and study the validity of the various theoretical approaches. In the previous experiments, the angular distributions are measured with a few decays, such as ψ(3686) → pp [12] and J/ψ → BB (pp, ΛΛ, Σ 0Σ0 , Ξ −Ξ+ , Σ(1385)Σ(1385)) [8,[13][14][15]. Among them, the angular distributions for the J/ψ → Ξ −Ξ+ , Σ(1385) ∓Σ (1385) ± decays are determined with a low precision, while for the decays ψ(3686) → Ξ −Ξ+ , Σ(1385) ∓Σ (1385) ± have not yet been measured.…”

Heavy quarkonium: progress, puzzles, and opportunities

“…by Mark II [556], and became known as the ρπ puzzle. Since then, many two-body decay modes of the ψ(2S) (and some multibody ones) have been measured by BES [557][558][559][560][561][562][563] and CLEO [564]; some decays obey the rule while others violate it to varying degrees.…”

“…There are enough measurements of ψ(2S) and J/ψ decays for an extensive study of the "12% rule" [18,[557][558][559][560][561][562][563][564][568][569][570], among which the Vector-Pseudoscalar (VP) modes, like the ρπ, have been measured with the highest priority. The ratios of the branching fractions are generally suppressed relative to the 12% rule for the non-isospin-violating VP and Vector-Tensor (VT) modes (i.e., excluding modes like ωπ 0 and ρ 0 η), while Pseudoscalar-Pseudoscalar (PP) modes are enhanced.…”