Color Octet Contribution to $J/\psi$ Production at a Photon Linear Collider

Abstract

We investigate $J/\psi$ production at a Photon Linear Collider (PLC) in the framework of NRQCD factorization approach. It was shown that color octet contribution is dominating in charmonium production at PLC. The main fraction of $J/\psi$ comes from the single and double resolved photon processes. Expected cross sections of charmonium states production are large enough even at $p_T>5$ GeV to expect several hundreds of $J/\psi$'s through the leptonic decays channel for a projected integral PLC luminosity of $50 fb^{-1}$}