CHARMONIUM PRODUCTION VIA FRAGMENTATION AT HIGHER ORDERS IN ALPHA(S)

Quarkonium production at a given large p(T) is dominated by parton fra gmentation: a parton which is produced with transverse momentum p(T)/z fragments into a quarkonium state which carries a fraction z of the p arton momentum. Since parton production cross sections fall steeply wi th p(T), high z fragmentation is favored. However, quantum number cons traints may require the emission of gluons in the fragmentation proces s, and this softens the z dependence of the fragmentation function. We discuss the possibility that higher-order processes may enhance the l arge z part of fragmentation functions and thus contribute significant ly to the quarkonium cross section. An explicit calculation of light q uark fragmentation into eta(c) shows that the higher-order process q - -> q eta(c) in fact dominates the lowest-order process q --> qg eta(c) .