About detecting CP-violating processes in J/ψ→K～0K～0 decay

Abstract Questions about detecting the CP-violating decay process of J/ψ→ K^0K^-0→ KsKs are discussed. Possible background and material regeneration effects are analyzed. The discussion can be directly extended to other vector quarkonium decays, like γ, ψ（2S） and Ф → KsKs.

Properties of the coupling constants of J/ψ→VP decays

Based on the branching fractions of J/ψ→VP from different experiments, we investigate the properties of the coupling constants of J/ψ→ VP decays using a model-dependent approach. We find that the octet coupling constant, gs, of strong interaction is about twice larger than that of the singlet coupling constant g1; the electromag- netic breaking parameters g_E^i are larger than the mass breaking parameters g_M^i, moreover, the three parameters of the electromagnetic effect are about equal, but the three parameters of the mass effect are obviously different and their uncertainties are also large; and the phase angle between strong and electromagnetic interactions is in the range of 700-80°. It deepens our understanding of the coupling constant of J/ψ→VP decays.

Pseudoscalar mixing in J/ψ and ψ(2S) decay

Based on the branching fractions of J/ψ（ψ（2S））→ VP from different collaborations, pseudoscalar mixing is extensively discussed with a well established phenomenological model. The mixing angle is determined to be -14° by fitting to the new world average if only quark content is considered. After taking into account the gluonic content in η and η＇ simultaneously, the investigation shows that η favors only consisting of light quarks, while the gluonic content of η＇ is Z2η＇, = 0.30±0.24.

CP asymmetries in Strange Baryon Decays

While indirect and direct C P violation（CPV） has been established in the decays of strange and beauty mesons, no CPV has yet been found for baryons. There are different paths to finding C P asymmetry in the decays of strange baryons; they are all highly non-trivial. The Hyper CP Collaboration has probed CPV in the decays of singleΞ and Λ [1]. We discuss future lessons from e~＋e^-collisions at BESⅢ/BEPCⅡ： probing decays of pairs of strange baryons, namely Λ, Σ and . Realistic goals are to learn about non-perturbative QCD. One can hope to find CPV in the decays of strange baryons; one can also dream of finding the impact of New Dynamics. We point out that an important new era will start with the BESIII/BEPCII data accumulated by the end of 2018. This also supports new ideas to trigger J/ψ→■Λ at the LHCb collaboration.

Recent results on light hadron spectroscopy from BESⅡ

We reported the observation of Y（2175） in Фfo（980） mass spectrum in J/ψ → ηФfo（980） with fo（980） →π＋π^- and the observation of a broad 1^-- resonance of K^＋K^- mass in J/ψ→ K^＋K^-π^0. The results from the partial wave analyses of J/ψ→γπ^＋π^- and γπ^0π^0, as well as J/ψ →pK^-∧. are also presented.