Production of Prompt Charmonia in $e^{+}{e}^{-}$ Annihilation at $\sqrt{s}\approx 10.6$ GeV

Abstract

The production of prompt $J/\ddot{I}ˆ$, $\ddot{I}ˆ(2S)$, $\ddot{I}{‡}_{c1}$ and $\ddot{I}{‡}_{c2}$ is studied using a $32.4f{b}^{-1}$ data sample collected with the Belle detector at the $\hat{I}\yen (4S)$ and 60 MeV below the resonance. The yield of prompt $J/\ddot{I}ˆ$ mesons in the $\hat{I}\yen (4S)$ sample is compatible with that of continuum production; we set an upper limit $\mathcal{B}(\hat{I}\yen (4S)\to J/\ddot{I}ˆX)<1.9\times 10^{-4}$ at the 95% confidence level, and find $\ddot{I}ƒ(e^{+}{e}^{-}\to J/\ddot{I}ˆX)=1.47\pm 0.10\pm 0.13$ pb. The cross-sections for prompt $\ddot{I}ˆ(2S)$ and direct $J/\ddot{I}ˆ$ are measured. The $J/\ddot{I}ˆ$ momentum spectrum, production angle distribution and polarization are studied.

submitted to Phys. Rev. Lett