hep-ph/9603266 Color-Octet J/ψ Production at Low p⊥

We study contributions from color-octet quarkonium formation mechanisms to J/ψ hadroproduction at low p⊥. We include transitions of color-octet cc̄ states into “direct ” J/ψ and into χ1,2 which decay radiatively into a J/ψ. Together with earlier work, this calculation constitutes a complete analysis of p⊥-integrated J/ψ production at leading twist. We find that the leading-twist contribution is not sufficient to reproduce the observed production rates and polarization of the J/ψ and χ1,2. Hence there must exist other important quarkonium production mechanisms at low p⊥