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.

Comments: 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)