Colour Octet effects in Quarkonium Physics

Abstract

The importance of including colour octet contributions in describing decay and production of quarkonium states is briefly discussed for two cases : the radiative decays of the ${\rm Y}$ and the production of $J/\psi$ in the inclusive $B$ decays. It is shown how information on the non-perturbative matrix elements can be obtained by comparing the theoretical expressions computed at next-to-leading order in ${\alpha }_s$ with the experimental data.

Comments: 4 pages, Latex (espcrc2.sty), 1 figure. Talk presented at QCD'98, Montpellier, July 2-8, 1998; to appear in Nucl. Phys. B (Proc. Suppl.)