Double gluon fragmentation to Jψ pairs at the tevatron

It has been proposed that the large cross sections for prompt ψ, ψ′, aand χc production at the Fermilab Tevatron pp 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′, ψχc, ψϒ and ψχb production , as well as for Wψ production, using color-octet matrix elements previously determined from charmonium production data. The ψψ signal would already be measurable at the Tevatron, while the ψχc and Wψ signals would be on the edge of present detectability.