Color-Octet Contributions in the Associate J/psi+gamma Hadroproduction

Abstract

Color-octet contributions to the associate J/psi+gamma hadroproduction are studied in detail, and found to be negligible, compared to the ordinary color-singlet contribution. Within the color-singlet model the J/psi+gamma production in the leading order is possible only through gluon-gluon fusion process. Therefore, the associate J/psi+gamma hadroproduction remains to be useful as a clean channel to probe the gluon distribution inside proton, to study heavy quarkonia production mechanism, and to find proton's spin structure.

25 pages, LaTeX using revtex and epsfig, corrections made for trivial misprints in labeling of figs. 6-8(should be read as nb not pb)