Color-octet quarkonia production
Abstract
Gluon fragmentation represents the dominant source of high energy prompt quarkonia at hadron colliders. Fragmentation approximations break down, however, when a quarkonium's tranvserse momentum becomes comparable to its mass. In this paper we identify a large class of color-octet diagrams that mediate quarkonia production at all energies and reduce to the dominant set of gluon fragmentation graphs in the high p⊥ limit. They contribute to quarkonia differential cross sections at the same order as color-singlet diagrams and bring theoretical predictions for Υ and Ψ production at the Fermilab Tevatron into agreement with experimental measurements. Using recent CDF data we extract numerical values for bottomonia and charmonia color-octet matrix elements which are consistent with NRQCD scaling rules. We also find that quarkonia generated via the color-octet mechanism are strongly polarized at low as well as high energies. Spin alignment measurements can thus test the color-octet quarkonia production picture.
- Publication:
-
Physical Review D
- Pub Date:
- January 1996
- DOI:
- 10.1103/PhysRevD.53.150
- arXiv:
- arXiv:hep-ph/9505329
- Bibcode:
- 1996PhRvD..53..150C
- Keywords:
-
- 14.40.Gx;
- 13.87.Fh;
- Mesons with S=C=B=0 mass>2.5 GeV;
- Fragmentation into hadrons;
- High Energy Physics - Phenomenology
- E-Print:
- 23 pages, harvmac, 11 uuencoded figures