Fragmentation contribution to quarkonium production in hadron collision

We compute the contributions due to gluon and heavy-quark fragmentation to quarkonium production at large transverse momentum in \bar p p and p p collisions. For inclusive J/\psi production, there is a large contribution from the g \rightarrow \chi_c fragmentation. At large p_T, this is comparable to the conventional charmonium model prediction via gluon fusion at the ISR and dominates over the latter at the Tevatron energy. This may help to explain, at least partly, the large J/\psi production cross-section recently observed by the CDF experiment. However, the fragmentation contribution to \psi^{\prime} production is not large enough to explain the corresponding CDF data. We also present the results for \Upsilon production at ISR and Tevatron energies.