Hadroproduction of heavy quarkonia at high energies within the kT-factorization approach

On the basis of the kT-factorization approach, heavy-quarkonium Σ(c-bar c,b-bar b) hadroproduction at high energies is considered within nonrelativistic QCD in the leading order in αs and v. The pT spectra of various S-and P-wave quarkonium states at the Tevatron collider energies (run I and run II) are fitted, and sets of octet nonperturbative matrix elements are obtained for three different versions of the noncollinear gluon distribution in the proton