QUARKONIUM PRODUCTION - VELOCITY-SCALING RULES AND LONG-DISTANCE MATRIX-ELEMENTS

The hierarchy of long-distance matrix elements (MEs) for quarkonium pr oduction depends on their scaling with the velocity v of the heavy qua rk in the bound state. Ranges for the velocities in various bound stat es and uncertainties of colour-singlet MEs are estimated in a quark-po tential model. Different possibilities for the scaling with v of the M Es are discussed; they depend on the actual values of v and the QCD sc ale. As an application, J/psi polarization in e(+) e(-) annihilation i s discussed. The first non-perturbative estimates of colour-octet MEs are presented and compared with phenomenological determinations. Final ly, various predictions of prompt quarkonium production at LEP are com pared.