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 J/ψ hadroproduction the leading colour-octet matrix elements within the nonrelativisticQCD (NRQCD) factorization formalism proposed by Bodwin, Braaten, and Lepage. We find that the matrix elements which describe the formation of J/ψ mesons from colour-octet cc̄ pairs in the angular-momentum states LJ = S0 and PJ , with J = 0, 1, 2, which are responsible for the excess of the predicted cross section of inelastic J/ψ photoproduction over the existing HERA data at high values of the inelasticity variable z, are significantly reduced. We conclude that it is premature to proclaim a discrepancy between the Tevatron and HERA measurements of inclusive J/ψ production in the NRQCD framework. We also consider J/ψ mesons originating from the radiative feed down of promptly produced χcJ mesons. PACS numbers: 13.60.-r, 13.85.-t, 13.85.Ni, 14.40.Lb ∗Supported by Bundesministerium für Forschung und Technologie, Bonn, Germany, under Contract 05 7 HH 92P (5), and by EU Program Human Capital and Mobility through Network Physics at High Energy Colliders under Contract CHRX–CT93–0357 (DG12 COMA).