Double gluon fragmentation to $J/ψ$ pairs at the Tevatron

Abstract

It has been proposed that the large cross sections for prompt $ψ$, $ψ'$, and $χ_c$ production at the Fermilab Tevatron $p\bar p$ collider can be explained by a dominant color-octet term in the fragmentation function for a gluon to split into quarkonium. We show that this mechanism makes testable predictions for double-quarkonium $ψψ$, $ψψ'$, $ψχ_c$, $ψΥ$ and $ψχ_b$ production, as well as for $W ψ$ production, using color-octet matrix elements previously determined from charmonium production data. The $ψψ$ signal would already be measurable at the Tevatron, while the $ψχ_c$ and $Wψ$ signals would be on the edge of present detectability.