The. ¦§_c And ¦Ã Associated Production Process Of Nuclear Effects

In this paper, the nuclear effects of the bound nucleon structure are reviewed, two sets of nuclear parton distribution functions are introduced. In 1998, K. J. Eskola et al. used the nuclear structure function ratios from deep-inelastic lepton-nucleus deep inelastic scattering (DIS), and the E772 Drell-Yan experimental data, gave the nuclear partondistribution functions in the range 2.25GeV² < Q² < 10000GeV², 10^-6 ≤ x ≤ 1 , A ≥ 2 by means of the DGLAP evolution equation. In 2001, M. Hirai et al. proposed nuclear parton distribution functions at A≥1,Q²₀ =1GeV² and 10^-9 ≤x≤1 by the x²analyzing of the experimental data on electron-nuclear deep inelastic scattering. Then using the DGLAP evolution equations, they obtained the nuclear parton distributions at1GeV² 2 <10⁵GeV².The conventional quarkonium production has been studied in the color-singlet model (CSM), which assumes the heavy-quark pair is produced in a color-singlet state with the right quantum numbers of the final heavy quarkonium. But the CSM underestimates directJ/ψ production by a factor of 30 to 80 for 5GeV T <18GeV. Recently, the theoryabout the heavy quarkonium production has developed greatly, color-octet mechanism is proposed. It accord with the experimental data very well.In 1999, Hao et al. studied the photo-production of η_c, which is a pure color-octetprocess. We calculated the cross section of the associated η_c and γ in thehardon-nuclear collision, using the EKS98, HKM01 and HKN04 nuclear parton distributions. So comparing our theoretical result with the future experimental data, we can pin down the gluon distribution in bound nucleons.