Tevatron-hera colour-octet charmonium anomaly versus higher-order QCD effects

Approximately taking into account the higher-order effects due to multiple-gluon initial-state radiation, we extract from the latest Tevatron data of prompt hadroproduction the leading colour-octet matrix elements within the nonrelativistic-QCD (NRQCD) factorization formalism proposed by Bodwin, Braaten, and Lepage. We find that the matrix elements which describe the formation of mesons from colour-octet pairs in the angular-momentum states and , with , which are responsible for the excess of the predicted cross section of inelastic photoproduction over the existing HERA data at high values of the inelasticity variable , are significantly reduced. We conclude that it is premature to proclaim a discrepancy between the Tevatron and HERA measurements of inclusive production in the NRQCD framework. We also consider mesons originating from the radiative feed down of promptly produced mesons. Received: 10 March 1998 / Revised version: 22 April 1998 / Published online: 30 July 1998