Study of the reaction e^{+}e^{-}->psi(2S)pi^{-}pi^{-} via initial state radiation at BaBar

We study the process $e^{+}{e}^{-}\to \psi (2S){\pi }^{+}{\pi }^{-}$ with initial-state-radiation events produced at the PEP-II asymmetric-energy collider. The data were recorded with the \BaBar detector at center-of-mass energies at and near the $\mathrm{{\rm Y}}(\mathrm{n}\mathrm{S})$ (n = 2, 3, 4) resonances and correspond to an integrated luminosity of 520$f{b}^{-}$. We investigate the $\psi (2S){\pi }^{+}{\pi }^{-}$ mass distribution from 3.95 to 5.95 $GeV\mathrm{/}{c}^2$, and measure the center-of-mass energy dependence of the associated $e^+e^-\to \psi(2S)\pi^{+}\pi^{-}$ cross section. The mass distribution exhibits evidence of two resonant structures. A fit to the $\psi (2S){\pi }^{+}{\pi }^{-}$ mass distribution corresponding to the decay mode $\psi(2S)\to J/\psi \pi^{+}\pi^{-}$yieldsamassvalueof$4340 \pm16$(stat)$\pm 9$(syst)${\mathrm {MeV/c^{2}}}and a width of $94\pm 32$ (stat) $\pm 13$ (syst) MeV for the first resonance, and for the second a mass value of $4669\pm 21$ (stat) $\pm 3$ (syst) $\mathrm{M}\mathrm{e}\mathrm{V}\mathrm{/}{\mathrm{c}}^2$ and a width of $104\pm 48$ (stat) $\pm 10$(syst)MeV\mathrm{.}Inaddition,weshowthe$pi^{+}\pi^{-}$ mass distributions for these resonant regions.