J/Psi production in hard diffractive gamma-p collision

In the frame of color-octet mechanism and according to NRQCD factorization of q (q) over bar production, using three sets of parton distribution funct ion of Pomeron given by L. ALvero et al.,the cross section of J/psi in gamm a + p-->p + J/psi + X process is calculated and discussed with the root s = 200GeV, 4GeV< p(T) < 10GeV. Our results show that the NRQCD matrix element s had a great influence on cross sections,but a little influence on the rat io of diffractive cross section to inclusive cross section. If the influenc e is eliminated,the ratio is only related to the flux factor and parton dis tribution functions of Pomeron.