J/ψ production through resolved photon processes at e⁺e^- colliders

Abstract

We consider J/ψ photoproduction in e⁺e^- as well as linear photon colliders. We find that the process is dominated by the resolved photon channel. Both the once-resolved and twice-resolved cross sections are sensitive to (different combinations of) the color octet matrix elements. Hence, this may be a good testing ground for color octet contributions in NRQCD. On the other hand, the once-resolved J/ψ production cross section, particularly in a linear photon collider, is sensitive to the gluon content of the photon. Hence these cross sections can be used to determine the parton distribution functions, especially the gluon distribution, in a photon, if the color octet matrix elements are known.