Research Papers in Physics and Astronomy


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Published by American Physical Society. Phys. Rev. Lett. 85, 2886 (2000). Copyright © 2000 American Physical Society. Permission to use.


We have measured the polarization of J/ψ and ψ(2S) mesons produced in pp̅ collisions at √s= 1.8 TeV, using data collected at the Collider Detector at Fermilab during 1992–1995. The polarization of promptly produced J/ψ[ψ(2S)] mesons is isolated from those produced in B-hadron decay, and measured over the kinematic range 4 [5.5] < PT < 20 GeV/c and |y| < 0.6. For PT≥ 12 GeV/c we do not observe significant polarization in the prompt component.

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