T. Xiao, S. Dobbs, A. Tomaradze, Kamal K. Seth
The BES III Collaboration has reported observation of a resonance, which they call Zc(3900), which decays into J/\psi + a charged pion. This charged state was observed as an intermediate resonance in their analysis of e+e- annihilations into J/psi + pi+pi- at sqrt(s)=4260 MeV, the peak of the vector state Y(4260). We observe this charged state, Zc(3900), at a 6 sigma significance level in the analysis of 586 pb-1 of data taken with the CLEO-c detector at psi(4160). Our results, M(Z)=3885+-5(stat)+-1(syst) MeV, Gamma(Zc)=34+-12(stat)+-4(syst) MeV, and R=sigma(e+e- -> pi-+ Zc+-(3900))/sigma(e+e- -> pi+pi- J/psi)=(35+-11)% are in good agreement with those reported by BES III. We also present evidence for the observation of the neutral Zc0(3900) at a 3 sigma level of significance with parameters in agreement with those of Zc+-(3900). Because our observations are made at the peak of the 2 3D1 state of charmonium, we do not find any reason to attribute any unconventional properties to the initial state formed by the e+e- annihilations.
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http://arxiv.org/abs/1304.3036
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