We study J/ production at photon-photon colliders, which can be realized with Compton scattering of laser photons at e ϩ e Ϫ colliders. We find that the production rate through the color-octet channel is comparable to that through the color-singlet channel. Experimentally the two mechanisms can be studied separately because the processes have different signals. ͓S0556-2821͑98͒04301-X͔

The O(v 2 ) relativistic correction for inelastic J/ψ photoproduction, in which heavy quark pairs are in the dominant Fock state of the quarkonium, is studied in the framework of NRQCD factorization. An assessment of its significance, particularly in comparison to the color octet contributions, is made. It is found that the impact on the energy distribution is negative in certain regions of phase space. The predictions are compared with photoproduction data from DESY-HERA.