118076876
Study of a0(980)-f0(980) mixing at BESIII and study of charged kappa at BESII
Recent BES results on light scalars are reported in this talk, including the observation of a charged kappa decaying to K pi0 with 5.8 * 10^7 J/psi data at BES II and the direct measurements of a0(980)-f0(980) mixing in the processes J/psi --> phi f0(980) --> phi a0(980) --> phi eta pi0 and chi_c1 --> pi0 a0(980) --> pi0 f0(980) --> pi0 pi+ pi- with 2.26 * 10^8 J/psi data and 1.06 * 10^8 psi' data at BES III.
123670989
Recent BES results on hadron spectroscopy
Light hadron spectroscopy is a powerful tool in hadronic physics. Several recent BES results on hadron spectroscopy are reported in this proceeding, including the confirmation of the enhancement in p invariant mass in radiative J/Ψ decays, the observation of a charged κ± decaying to K±π0 and the measurement of exclusive decays of the χc0 and χc2 to π0π0 and ηη.
122681826
ChPT Calculation for Two Pion Production in NN Collision Reaction at Threshold
We investigate the two pion production in NN collision reaction at threshold with Chiral Perturbation Theory (ChPT). The leading-order diagrams are presented and as an example we give the results of complete calculation of the reaction pn → d ππ at threshold. It is found that the leading order diagrams are of equal importance as expected by power counting. The role of initial, intermediate and final state interactions in nucleon-nucleon system is also investigated and found to be very important. The calculations also show that the non-resonant contributions near threshold in the two-pion production in NN collision reaction is sizable and important.
118860372
Evidence for a narrow $D_{03}$ state in $K^- p \rightarrow \eta \Lambda$ near threshold
Recently, we reported a theoretical study on the $K^- p \to \eta \Lambda$ reaction near threshold by using an effective Lagrangian approach. It was found that the description of angular distribution data measured by the Crystal Ball Collaboration needs a $D_{03}$ resonance with mass $M=1668.5\pm 0.5$ MeV and total decay width $\Gamma=1.5\pm 0.5$ MeV, which is not the conventional $\Lambda$(1690) or other $\Lambda$ state listed in the Particle Data Group book. In the present work, we study the $\Lambda$ polarization in the $K^- p \to \eta \Lambda$ reaction within the same framework. The results show that the existence of this narrow $D_{03}$ state is also compatible with current $\Lambda$ polarization data and that the more accurate $\Lambda$ polarization data at $P_{K^-}=735$MeV can offer further evidence for the existence of this resonance. Furthermore, the role of the $\Lambda(1690)$ resonance in this reaction is also discussed.