Eur. Phys. J. C (2006) 48: 451-456
https://doi.org/10.1140/epjc/s10052-006-0044-2

Theoretical Physics

Prompt J/ψ plus photon associated electroproduction at DESY HERA

¹ II. Institut für Theoretische Physik, Universität Hamburg, Luruper Chaussee 149, 22761, Hamburg, Germany
² National Institute of Physics, University of the Philippines, Diliman, Quezon City, 1101, Philippines

^* e-mail: kniehl@desy.de

Received: 3 July 2006
Published online: 24 October 2006

Abstract

We study the production of a prompt J/ψ meson in association with a prompt photon in ep deep-inelastic scattering within the factorisation formalism of non-relativistic quantum chromodynamics (NRQCD) and demonstrate that this process provides a clean probe of the colour-octet mechanism at DESY HERA. Our analysis is based on an updated set of non-perturbative NRQCD matrix elements obtained through a joint fit to data on charmonium inclusive hadroproduction from runs I and II at the Fermilab Tevatron.