Study of $e^{+}{e}^{-}\to \hat{I}{\pounds }^0\overline{\hat{I}}\pounds {}^0$ and $\hat{I}{\pounds }^{+}\overline{\hat{I}}\pounds {}^{-}$ by Initial State Radiation Method at Belle

Abstract

The processes $e^{+}{e}^{-}\to \hat{I}{\pounds }^0\overline{\hat{I}}\pounds {}^0$ and $e^{+}{e}^{-}\to \hat{I}{\pounds }^{+}\overline{\hat{I}}\pounds {}^{-}$ are studied using initial-state-radiation events in a sample of 980 $\,\mbox{fb}^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The cross sections from the mass threshold to $3\mathrm{Ge}\mathrm{V}/c^2$ and the effective form factors of $\hat{I}{\pounds }^0$ and $\hat{I}{\pounds }^{+}$ are measured. In the charmonium region, we observe the decays $J/\ddot{I}ˆ\to \hat{I}{\pounds }^0\overline{\hat{I}}\pounds {}^0$ and $J/\ddot{I}ˆ\to \hat{I}{\pounds }^{+}\overline{\hat{I}}\pounds {}^{-}$ and determine the respective branching fractions.

accepted by Phys. Rev. D