ψ′ polarization as a test of colour octet quarkonium production

• Published in: Physics letters. B Vol. 372; no. 1; pp. 157 - 164
• Main Authors: Beneke, M., Rothstein, I.Z.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 04.04.1996
• ISSN: 0370-2693; 1873-2445
• DOI: 10.1016/0370-2693(96)00030-5

We calculate the α s corrections to the transverse polarization fraction of ψ′'s produced at the Tevatron. If the ‘ψ′-anomaly’ is explained by gluon fragmentation into a colour octet Fock component of the ψ′, the ψ′'s should be 100% transversely polarized at leading order in α s , up to spin symmetry breaking long-distance corrections. We find that the short-distance correction (due to gluon fragmentation) to the transverse polarization fraction is a few percent. A polarization measurement would thus provide a reliable test of the colour octet mechanism, particularly at large p T , where a potential loss of polarization due to non-fragmentation processes is avoided.