N China Elect Power Univ, Dept Appl Phys, Baoding 071003, Peoples R China
; Chengde Teachers Coll Nationalities, Chengde 067000, Peoples R China
; Chinese Acad Sci, Inst High Energy Phys, Beijing 100039, Peoples R China
; Hebei Teachers Univ, Dept Phys, Shijiazhuang 050016, Peoples R China
; CCAST, World Lab, Beijing 100080, Peoples R China
We present a study of associated eta(c) and gamma double diffractive production in p (p) over bar collision based on Ingelman-Schlein model, and the framework of non-relativistic QCD factorization formalism for quarkonia production. The prediction of eta(c) and gamma is more reliable than J/psi production, because the associated eta(c) and gamma production is a pure color-octet process, and the dominant contribution comes from color octet S-1(0)(8) subprocess, which is related to the color octet matrix element of S-1(0)(8) of J/psi by the heavy quark spin symmetry and the large P-T J/psi production data. We find that the ratio of diffractive to inclusive cross sections is independent of the values of color octet matrix elements, but is sensitive to the gluon factor of the Pomeron and renormalized Pomeron flux factors. So experimental measurement of this ratio can give us more information of the nature of Pomeron and test the assumption of hard diffractive factorization in hadron-hadron collisions.