TESTING QUARKONIUM PRODUCTION WITH PHOTOPRODUCED J PSI+GAMMA/

I compute the leading color-octet contributions to the process gamma+p -->J/psi+gamma(+X) within the nonrelativistic QCD (NRQCD) factorizatio n formalism. In the color-singlet model, J/sigma+gamma can only be pro duced when the photon interacts through its structure function, while the color-octet mechanism allows for production of J/psi+gamma via dir ect photon-gluon fusion. Resolved photon processes can be distinguishe d easily from direct photon processes by examining the fraction of the incident photon energy carried away by the J/psi in the event. Theref ore, this process provides a conclusive test of the color-octet mechan ism. J/psi+gamma production is particularly sensitive to the NRQCD mat rix element which figures prominently in the fragmentation production of J/psi at large p(perpendicular to) in hadron colliders. I also exam ine the predictions of the color evaporation model (CEM) of quarkonium production and find that this process can easily discriminate between the NRQCD factorization formalism and the CEM.