Charm production at HERA

Selected recent measurements of charm quark production in lepton-proton collisions performed at HERA by the experiments H1 and ZEUS are reviewed. The experimental results are compared in detail with theoretical predictions, based on QCD calculations in both leading order and next-to-leading order perturbative approaches. No large deviations from the expectations were observed within the theoretical uncertainties. Results on inelastic leptoproduction of ((J)/(ψ)) mesons are directly compared with predictions based on NRQCD/factorisation approaches. A search for colour octet processes predicted within this approach is conducted in many regions of phase space, but no unambiguous evidence has been found