Charmonium Production at High $p_t$ at RHIC

Understand

We calculate transverse-momentum ($p_t$) spectra and elliptic flow of $J/\psi$'s in $Au$-$Au$ and $Cu$-$Cu$ collisions at RHIC.

• We employ an earlier constructed 2-component approach for direct and regenerated charmonia which is fairly consistent with the centrality dependence of inclusive $J/\psi$ yields at SPS and RHIC.
• Discrepancies with high-$p_t$ data in $Cu$-$Cu$ collisions are addressed by implementing effects of a finite formation time and an estimate of $B$ meson feeddown, which largely resolve the problem.
• The sensitivity of the spectra to the Cronin effect and different in-medium dissociation rates is studied.