Partial wave analysis of ψ' →γχ_(c0) →γpK-Λ used for searching for baryon resonance

Abundant ψ＇ events have been collected at the Beijing Electron Positron Collider-Ⅱ （BEPCⅡ） that could undoubtedly provide us with a great opportunity to study the more attractive charmonium decays. As has been noticed before, in the process of J/ψ＇ decaying to the baryonic final states, pK-Λ, the evident Λ＊ and N＊ bands have been observed. Similarly, by using the product of χcJ from ψ＇ radiative decay, we may confirm this or find some extra new resonances. χc0＇s data samples will be more than χc1,2, taking into account the larger branching ratio of ψ＇ →γχc0. Here, we provide explicit partial wave analysis formulae for the very interesting channel ψ＇ →γχc0 →γpK-Λ.

Lepton mass correction in partial wave analyses of charmed meson semi-leptonic decays

We derive a parameterization formula for the partial wave analyses of charmed meson semi-leptonic decays while considering the effects of lepton mass.Because the proposed super-tau-charm factory will reach a significantly enhanced luminosity and BESIII is collecting newψ(3770)→DD data,our results will help improve the measurement precision of future partial wave analyses of charmed meson semi-muonic decays.

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.

Search for exotic state 1^(-+) π_1(1400) at BESⅢ

The J/ψ hadronic decays provide good laboratory to search for the hybrid states with exotic quantum numbers. A full Partial Wave Analysis （PWA） is performed to the generated Monte Carlo J/ψ→ ρηπ data, based on the design of BESⅢ detector, to study the sensitivity of searching for a possible exotic state at BESⅢ.

Centrifugal–Barrier Efects and Determination of Interaction Radius

The interaction radius of a resonance is an important physical quantity to describe the structure of a resonance. But, for a long time, physicists do not find a reliable way to measure the magnitude of the interaction radius of a resonance. In this paper, a method is proposed to measure the interaction radius in physics analysis. It is found that the centrifugal barrier effects have great influence to physical results obtained in the PWA fit, and the interaction radius of some resonances can be well measured in the fit.

Nucleon resonances in πN→η'N and J/ψ→pη'

We are aiming to study the J/ψ →pqη′ decay in an isobar model and the effective Lagrangian approach on the basis of the coupling constants extracted from the πN→η′ reaction. After a careful exploration of the contributions of the S11（1535）, P11（1710）, P13（1900）, S11（2090） and Pl,（2100） resonances, we conclude that either a subthreshold resonance or a broad P-wave state in the near threshold range seems to be indispensable to describe the present data of the πN→η′.Furthermore, at least one broad resonance above rl＇N threshold is preferred. With this detailed analysis, we give the invariant mass spectrum and Dalitz plot of the J/ψ →pqη′decay for the purpose of assisting the future detailed partial wave analysis. It is found that the J/ψ →pqη′ data are useful for disentangling the above or below threshold resonant contribution, though it still further needs the differential cross section data of πN→η′ to realize some of the resonant and non-resonant contribution.

Disentangling the nature of resonances in coupled-channel models

We present severM possible hadronic states found in coupled-channel models within the on-shell approx- imation. The interaction potential is constructed as a sum of the tree-level Feynman diagrams calculated with the effective Lagrangians. Based on the recent empirical data, we illustrate the possible existence of severM baryonic and mesonic states with definite quantum numbers in the model. We give their properties for the purpose of further study and discuss the potential of finding them in future experiments.