Non-relativistic effective theory for Quarkonium Production in Hadron Collisions

Abstract

I review recent progress in understanding inclusive quarkonium production in hadron collisions. The first part focuses on non-relativistic QCD as an effective theory. I discuss its differences from and similarities with effective theories describing bound states of a single heavy quark, as far as matching calculations beyond tree-level and power counting are concerned. The second part summarizes predictions for charmonium and bottomonium production at collider and fixed target experiments and their comparison with data. The emphasis here is on novel signatures due to color octet production, polarization of quarkonia and the $χ_1/χ_2$ ratio in fixed target collisions.