Dependence Of J/ψ- Nucleon Inelastic Cross Section On Feynman Variable

The production of J /ψin high energy collisions has been one of the most active frontiers in nuclear physics and particle physics. J /ψsuppression has been proposed long time ago as a signature of the production of a deconfined state in nucleus-nucleus collisions. However, it was very soon realized that nuclear effects not related to deconfinement or, more generally, to the production of a hot medium may influence the observed J /ψsuppression. Such effects can be investigated through the study of J /ψproduction in p-A collisions. The study on J /ψproduction in proton-nucleus collisions would greatly benefit the clarification of the conventional nuclear suppression mechanism in heavy ion collisions.In this paper, by using HKM and EPS08 nuclear parton distribution functions together with CTEQ6L parton density in the proton , meanwhile taking account of the energy loss of the beam proton in initial state effect and the nuclear absorption of the charmonium states traversing the nuclear matter in the uniform framework of the Glauber model, a leading order phenomenological analysis is given in the color evaporation model to the E866 experimental data on the ratios of J /ψproduction differential cross section ratios ( )RF e /Be x F. It is found that the energy loss effect of proton beam with resulting in the suppression on ( )RF e /Be x F is more important than the nuclear effects on parton distribution functions in high x F region. The J /ψ-nucleon inelastic cross sectionσaJb/sψdepends on the kinematical variable x F, and increases as x F in the region x F> 0.2.