$J/\psi$ Pair Production at the Tevatron with   $\sqrt{s}=1.96~\mathrm{TeV}
  We revisit the $J/\psi$ pair production issue at the Fermilab Tevatron Run II with the center-of-mass energy $\sqrt{s}=1.96 \mathrm{TeV}$. Both color-singlet and -octet production mechanisms are considered. Our result shows that the transverse momentum($p_T$) scaling behaviors of double $J/\psi$ differential cross sections in color-singlet and -octet deviate distinctively from each other while $p_T$ is larger than $8 \mathrm{GeV}$, and with the luminosity of ${5 \mathrm{fb^{-1}}}$ the $J/\psi$ pair events from color-singlet scheme are substantially measurable in Tevatron experiments, even with certain lower transverse momentum cut. Hence the Tevatron is still possibly a platform to check the heavy quarkonium production mechanism. 
Cong-Feng Qiao, Li-Ping Sun
hep-ph