Color-Octet Contribution to $J/\psi$ Hadroproduction with Nonzero $p_T$ at Fixed Target Energies

Abstract

We calculated the color-octet contribution to the $\text{ps}$ hadroproduction at fixed target energies $\sqrt{(}s)\simeq 40$ GeV. We consider the $\text{ps}$ production with transverse momenta which can not be explained by primordial motion of partons, $p_T>1.5$ GeV. It is shown that color octet contribution is dominant at these energies and reduces large dicrepancies between experimental data and color singlet model predictions. Having taken into account both contribution one needs a K-factor about 2-3 to explain the experimental data.

Comments: Contribution to the III German -- Russian Workshop on Heavy Quark Physics, Dubna, Russia, May 20-22, 1996. 8 pages, LaTeX, 2 Postscript figures