Color-Octet $J/\psi$ Production in the ${\rm Y}$ Decay

Abstract

The direct production rate of $\psi$ in the ${\rm Y}$ decay is shown to be dominated by the process ${\rm Y}\to gg{g}^{\ast }$ followed by $g^{\ast }\to \psi$ via the color-octet mechanism proposed recently to explain the anomalous prompt charmonium production at the Tevatron. We show that this plausibly dominant process has a branching ratio compatible with the experimental data. Further experimental study in this channel is important to test the significance of the color-octet component of $c\bar{c}$ pair inside the $\psi$ system.

Comments: 20 pages, Standard LaTeX, 2 figures; a couple of new processes added, but conclusion unchanged