${\psi }^{\prime }$ Polarization as a test of colour octet quarkonium production

Abstract

We calculate the ${\alpha }_s$ corrections to the transverse polarization fraction of ${\psi }^{\prime }$'s produced at the Tevatron. If the `${\psi }^{\prime }$-anomaly' is explained by gluon fragmentation into a colour octet Fock component of the ${\psi }^{\prime }$, the ${\psi }^{\prime }$'s should be $100\%$ transversely polarized at leading order in ${\alpha }_s$, up to spin symmetry breaking long-distance corrections. We find that the short-distance correction to the transverse polarization fraction is a few percent, so that a polarization measurement would provide a reliable test of the colour octet mechanism.

Comments: 14 pages, LATEX, 2 figures as uudecoded file