On the failure of the Drell-Yan parton model to account for production of the J/Psi in nucleon-nucleon interactions.
We calculate the cross sections for the production of the J/Psi in nucleon-nucleon interactions on the basis of a naive Drell-Yan-type parton model where the Psi production is considered as production through the resonant or fusion interaction of quarks and antiquarks resident in the colliding nucleons. The interacting quarks are assumed to act as free point Dirac particles obeying the Bethe-Heitler description of annihilation to lepton pairs. Unitarity limits on Psi production established by calculations conducted on this basis are shown to be much smaller than the measured cross section, indicating that such models are unsatisfactory. Similar considerations suggest that the Psi production cannot be described by the interactions of nearly free gluons.
Department of Physics, Yale University, New Haven, Connecticut 06520.
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