B. Aubert et al. (BaBar Collaboration) (2005). "Observation of a broad structure in the π+π−J/ψ mass spectrum around 4.26 GeV/c2". arXiv:hep-ex/0506081。
B. Aubert et al. (BaBar Collaboration) (2005). "Observation of a broad structure in the π+π−J/ψ mass spectrum around 4.26 GeV/c2". arXiv:hep-ex/0506081。