ISSN - 00319007, EISSN - 10797114, Physical Review Letters, 2007, vol. 99, p. -
Observation of two resonant structures in e+e-→π+π-ψ(2S) via initial-state radiation at Belle
The cross section for e+e-→π+π-ψ(2S) between threshold and s=5.5GeV is measured using 673fb-1 of data on and off the Υ(4S) resonance collected with the Belle detector at KEKB. Two resonant structures are observed in the π+π-ψ(2S) invariant-mass distribution, one at 4361±9±9MeV/c2 with a width of 74±15±10MeV/c2, and another at 4664±11±5MeV/c2 with a width of 48±15± 3MeV/c2, if the mass spectrum is parametrized with the coherent sum of two Breit-Wigner functions. These values do not match those of any of the known charmonium states. © 2007 The American Physical Society.