He, XG , Nankai Univ, Dept Phys, Tianjin 300071, Peoples R China
部门归属:
Nankai Univ, Dept Phys, Tianjin 300071, Peoples R China; Natl Taiwan Univ, Dept Phys, NCTS TPE, Taipei 10764, Taiwan; Acad Sinica, Inst Theoret Phys, Beijing 100080, Peoples R China
英文摘要:
Recently the BES collaboration has announced the observation of a resonant state in the pi(+)pi(-)eta' spectrum in J/psi -> gamma pi(+)pi(-)eta' decay. Fitting the data with a 0(-+) state, the mass is determined to be 1833.7 MeV with 7.7 sigma statistic significance. This state is consistent with the one extracted from previously reported p (p) over bar threshold enhancement data in J/psi gamma p (p) over bar. We study the properties of this state using QCD anomaly and QCD sum rules, assuming X( 1835) to be a pseudoscalar, and we show that it is consistent with the data. We find that this state has a sizeable matrix element < 0 vertical bar G (G) over tilde vertical bar G(p)> , leading to branching ratios of (2.61-7.37) x 10(-3) and (2.21-10.61) x 10(-2) for J/psi -> gamma G(p) and for Gp -> pi(+)pi(-)eta', respectively. Combining the calculated branching ratio of J/psi -> gamma G(p) and data on threshold enhancement in J/psi -> gamma p (p) over bar, we determine the coupling for the Gp-p-(p) over bar interaction. We finally study the branching ratios of the other J/psi -> gamma + three mesons decay modes. We find that J/psi -> gamma G(p) -> gamma(pi(+)pi(-)eta', KK pi(0)) can provide useful tests for the mechanism proposed.
He, Xiao-Gang,Li, Xue-Qian,Liu, Xiang,et al. Some properties of the newly observed X(1835) state at BES[J]. EUROPEAN PHYSICAL JOURNAL C,2007,49(3):731-736.
