Colour-Octet Contributions to J/psi Production via Fragmentation at HERA

Abstract

We study J/psi photoproduction via fragmentation at next-to-leading order in the QCD-improved parton model, using the nonrelativistic factorization formalism proposed by Bodwin, Braaten, and Lepage. We predict that measurements of J/psi photoproduction at DESY HERA should show a distinctive excess over the expectation based on the colour-singlet model at small values of the inelasticity variable z.

Comments: 3 pages (Latex), 2 figures (Postscript), to appear in the Proceedings of the International Europhysics Conference on High Energy Physics, Jerusalem, Israel, 19 - 26 August 1997