Some properties of the newly observed X(1835) state at BES
Journal
European Physical Journal C
Journal Volume
49
Journal Issue
3
Pages
731-736
Date Issued
2007
Author(s)
Abstract
Recently the BES collaboration has announced the observation of a resonant state in the π+π-η′ spectrum in J/ψ → γπ+π-η′ decay. Fitting the data with a 0-+ state, the mass is determined to be 1833.7 MeV with 7.7σ statistic significance. This state is consistent with the one extracted from previously reported pp̄ threshold enhancement data in J/ψ → γpp̄. 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|GG̃|Gp〉, leading to branching ratios of (2.61-7.37) × 10-3 and (2.21-10.61) × 10-2 for J/ψ → γGp and for Gp → π+π-η′, respectively. Combining the calculated branching ratio of J/ψ → γGp and data on threshold enhancement in J/ψ → γpp̄, we determine the coupling for the Gp-p-p̄ interaction. We finally study the branching ratios of the other J/ψ → γ+ three mesons decay modes. We find that J/ψ → γGp → γ(π +π-η,KKπ0) can provide useful tests for the mechanism proposed. © 2006 Springer-Verlag.
Type
journal article