Quarkonium Production through Hard Comover Scattering. II
  We extend to large transverse momentum pt an approach to quarkonium hadroproduction previously suggested for low pt. The dynamics involves a perturbative rescattering of the heavy quark pair off a comoving color field which originates from gluon radiation prior to the heavy quark production vertex. Assuming simple properties of the comoving field we find the rescattering scenario to be in reasonable agreement with data. At large pt, psi' is predicted to be unpolarized, and chi1 production is favoured compared to chi2. We predict the chi1 polarization to be transverse at low pt, and to get a longitudinal component at large pt. 
Nils Marchal, Stephane Peigne and Paul Hoyer