Measurement of $e^+e^- to pi^+pi^-psi(2S)$ via Initial State Radiation at Belle

We report measurement of the cross section of $e^+e^-to pi^+pi^-psi(2S)$ between 4.0 and $5.5 {rm GeV}$, based on an analysis of initial state radiation events in a $980 rm fb^{-1}$ data sample recorded with the Belle detector. The properties of the $Y(4360)$ and $Y(4660)$ states are determined. Fitting the mass spectrum of $pi^+pi^-psi(2S)$ with two coherent Breit-Wigner functions, we find two solutions with identical mass and width but different couplings to electron-positron pairs: $M_{Y(4360)} = (4347pm 6pm 3) {rm MeV}/c^2$, $Gamma_{Y(4360)} = (103pm 9pm 5) {rm MeV}$, $M_{Y(4660)} = (4652pm10pm 8) {rm MeV}/c^2$, $Gamma_{Y(4660)} = (68pm 11pm 1) rm MeV$; and ${cal{B}}[Y(4360)to pi^+pi^-psi(2S)]cdot Gamma_{Y(4360)}^{e^+e^-} = (10.9pm 0.6pm 0.7) rm eV$ and ${cal{B}}[Y(4660)to pi^+pi^-psi(2S)]cdot Gamma_{Y(4660)}^{e^+e^-} = (8.1pm 1.1pm 0.5) rm eV$ for one solution; or ${cal{B}}[Y(4360)to pi^+pi^-psi(2S)]cdot Gamma_{Y(4360)}^{e^+e^-} = (9.2pm 0.6pm 0.6) rm eV$ and ${cal{B}}[Y(4660)to pi^+pi^-psi(2S)]cdot Gamma_{Y(4660)}^{e^+e^-} = (2.0pm 0.3pm 0.2) rm eV$ for the other. Here, the first errors are statistical and the second systematic. Evidence for a charged charmoniumlike structure at $4.05 {rm GeV}/c^2$ is observed in the $pi^{pm}psi(2S)$ intermediate state in the $Y(4360)$ decays.

Observation of psi(4040) and psi(4160) decay into eta J/psi

The cross section for e^+e^- to eta J/psi between sqrt{s}=3.8 GeV/c^2 and 5.3 GeV/c^2 is measured via initial state radiation using 980 fb^{-1} of data on and around the Upsilon(nS)(n=1,2,3,4,5) resonances collected with the Belle detector at KEKB. Two resonant structures at the psi(4040) and psi(4160) are observed in the eta J/psi invariant mass distribution. Fitting the mass spectrum with the coherent sum of two Breit-Wigner functions, one obtains BR(psi(4040)toeta J/psi)cdotGamma_{ee}^{psi(4040)} = (4.8pm0.9pm1.4) eV and BR(psi(4160)toeta J/psi)cdotGamma_{ee}^{psi(4160)} = (4.0pm0.8pm1.4) eV for one solution and BR(psi(4040)toeta J/psi)cdotGamma_{ee}^{psi(4040)} = (11.2pm1.3pm1.9) eV and BR(psi(4160)toeta J/psi)cdotGamma_{ee}^{psi(4160)} = (13.8pm1.3pm2.0) eV for the other solution, where the first errors are statistical and the second are systematic. This is the first measurement of this hadronic transition mode of these two states, and the partial widths to eta J/psi are found to be about 1 MeV. There is no evidence for the Y(4260), Y(4360), psi(4415), or Y(4660) in the eta J/psi final state, and upper limits of their production rates in e^+e^- annihilation are determined.