Production and polarization of prompt J/ψ to O(α_s^3) in the improved color evaporation model

One of the best ways to understand hadronization in QCD is to study the production of quarkonium. The color evaporation model (CEM) and Nonrelativistic QCD (NRQCD) can describe production yields rather well but spin-related measurements like the polarization are stronger tests. In this talk, we will present recent results of quarkonium polarization in the improved color evaporation model (ICEM), and how feed down from higher states affect the polarization in this approach.