We propose the color-octet mechanism combined with the two gluon exchange model for the diffractive J/ψ production in hadron collisions. In the leading logarithmic approximation (LLA) in QCD, we find that the diffractive J/ψ production rate is related to the off-diagonal gluon density in the proton and to the nonperturbative color-octet matrix element of J/ψ. The rate is found to be very sensitive to the gluon density at very small values of x (down to x = O(10 −6 )). As a result, this process may provide a wide window for testing the two-gluon exchange model, and may be particularly useful in studying the small x physics. And it may also be a golden place to test the color-octet mechanism proposed by solving the ψ ′ (J/ψ) surplus problem at the Tevatron. PACS number(s): 12.40. Nn, 13.85.Ni, 14.40.Gx Typeset using REVT E X 1

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In order to overcome the shortcoming of nonconservation of nuclear momentum existing in the original Q 2 -rescaling model(OQ 2 RM) and avoid introducing nuclear shadowing factor, we proposed a double Q 2 -rescaling model(DQ 2 RM) for the parton distributions of the bound nucleon. Using the experimental data of lepton-nucleus deep inelastic scattering(DIS) and the condition of the nuclear momentum conservation, the Q 2 -rescaling parameters of various partons for Sn, Fe, Ca and C nuclei are determined.The rescaling parameters of valence quark distributions are larger than unity and graduauly increases with atomic number A, on the contrary, the rescaling parameters of sea quark distributions and gluon distribu-