Color-octet mechanism and J/psi polarization at CERN LEP

Abstract

Polarized heavy quarkonium productions in Z(0) decays are considered. We find that polarizations of the produced quarkonia are independent of that of the parent Z(0) provided that one considers the energy distribution or the total production rate. Produced J/psi's via the color-octet and the color-singlet mechanisms are expected to be 19% and 29% longitudinally polarized, respectively. The energy dependence of eta(1,8)(x) = d Gamma(1,8)(L)/dx/d Gamma (1,8)/dx is very sensitive to the production mechanism, and, therefore, the measurement of eta(x)(expt) Will be an independent probe of the color-octet mechanism.