Hard Processes with Spin-Dependent Parton Distributions

Abstract

To test a possible color-octet contribution of heavy quarkonium productions, we propose $\ddot{I}ˆ$'-productions for small-$p_T$ regions, where the color-singlet $\ddot{I}ˆ$' state cannot be produced by the gluon-gluon fusion owing to charge conjugation. We also point out that these processes are very useful to deduce informations of spin-dependent gluon distributions $\hat{I}”g$.

4 pages + 3 Postscript figures(2 PS files), LaTeX, Talk presented at International Workshop HELION97, Kobe, Japan, 20-24 Jan. 1997