Evidence of a Broad Structure at an Invariant Mass of4.32 GeV/c2in the Reactione+e−→π+π−ψ(2S)Measured atBABAR

We present a measurement of the cross section of the process ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\ensuremath{\psi}(2S)$ from threshold up to 8 GeV center-of-mass energy using events containing initial-state radiation, produced at the SLAC PEP-II ${e}^{+}{e}^{\ensuremath{-}}$ storage rings. The study is based on $298\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data recorded with the BABAR detector. A structure is observed in the cross section not far above threshold, near 4.32 GeV. We also investigate the compatibility of this structure with the $Y(4260)$ previously reported by this experiment.

Evidence of a Broad Structure at an Invariant Mass of4.32 GeV/c2in the Reactione+e−→π+π−ψ(2S)Measured atBABAR | Litlas