Session D10 - Charm Quark States.
ORAL session, Saturday afternoon, May 01
Governor's Square 11, Adam's Mark Hotel
We report on a study of double c\barc production in e^+e^- annihilations around \sqrts=10.56 GeV with the BaBar detector, based on a total of 92 fb^-1. Signals for \eta_c, \chi_c0, and \eta_c(2S) are observed in the spectra of recoil mass against fully reconstructed J/\psi and \psi(2S) decays. These double charmonium events are interpreted as exclusive e^+e^-\rightarrow c\barc\,c\barc interactions. Masses and widths of these charmonia are obtained from fits to the signal peaks in the recoil mass spectra. Exclusive e^+e^-\rightarrow J/\psi\eta_c signal is observed in the data for the first time, where J/\psi is detected via J/\psi\rightarrow\ell^+ \ell^-, and the \eta_c is recontructed with charged tracks and photons recoiling against the J/\psi. Searches for e^+e^-\rightarrow J/\psi\,D\,X have been carried out. A full Monte Carlo study has been done.