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Gluon fragmentation into polarized charmonium

Journal Article · · Physical Review, D (Particles Fields); (United States)
;  [1];  [2]
  1. Lauritsen Laboratory, California Institute of Technology, Pasadena, California 91125 (United States)
  2. Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, Illinois 60510 (United States)

Gluon fragmentation to [chi][sub [ital cJ]](1[ital P]) followed by single photon emission represents the dominant source of prompt [ital J]/[psi]'s at the Fermilab Tevatron for [ital p][sub [perpendicular]][approx gt]6 GeV. Since fragmenting gluons are approximately transverse, their products are significantly polarized. We find that gluon fragmentation populates the helicity levels of [chi][sub [ital c]1], [chi][sub [ital c]2], and [ital J]/[psi] according to [ital D][sub [chi]][sub [ital c]1][sup ([ital h]=0)]:[ital D][sub [chi]][sub [ital c]1][sup ([vert bar][ital h][vert bar]=1)] [congruent]1:1, [ital D][sub [chi]][sub [ital c]2][sup ([ital h]=0)]: [ital D][sub [chi]][sub [ital c]2][sup ([vert bar][ital h][vert bar]=1)]:[ital D][sub [chi]][sub [ital c]2][sup ([vert bar][ital h][vert bar]=2)] [congruent]1:2.8:6.0, and [ital D][sub [ital J]/[psi]][sup ([ital h]=0)]:[ital D][sub [ital J]/[psi]][sup ([vert bar][ital h][vert bar]=1)][congruent]1:3.4. We also speculate that gluon fragmentation to the radially excited [chi][sub [ital c]2](2[ital P]) state followed by radiative decay could represent a large source of [psi][prime](2[ital S])'s. A measurement of these states' polarizations would test this idea.

DOE Contract Number:
FG03-92ER40701; AC02-76CH03000
OSTI ID:
6579878
Journal Information:
Physical Review, D (Particles Fields); (United States), Journal Name: Physical Review, D (Particles Fields); (United States) Vol. 51:5; ISSN PRVDAQ; ISSN 0556-2821
Country of Publication:
United States
Language:
English