Study of J/Psi -> gamma (piplus-piminus-piplus-piminus)

Understand

BES II data for the channel J/Psi -> gamma (piplus-piminus-piplus-piminus) are analysed from a sample of 58M J/Psi hadronic interactions.

• They reveal further detail in the J^{PC} = 0^{-+} sector for the 4pi channel.
• A broad 0^{-+} -> rho-rho component extending from 1500 to 2400 MeV is fitted.
• A narrower structure reveals a new J^P = 0^- contribution requiring a resonance of mass 1970 +- 25(stat) +- 60(syst) MeV and width Gamma = 210 +- 25(stat) +- 60(syst) MeV.