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Direct J/$\psi$ and $\psi$' polarization and cross sections at the Fermilab Tevatron

Transverse polarization of ${}^3 S_1$ charmonium states, produced directly in $p\bar{p}$ collisions at asymptotically large transverse momentum p_t, has emerged as the most prominent test of color octet contributions and spin symmetry in quarkonium production. We present predictions for the polar an...

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Detalles Bibliográficos
Autores principales: Beneke, Martin, Krämer, Michael
Lenguaje:eng
Publicado: 1996
Materias:
Acceso en línea:https://dx.doi.org/10.1103/PhysRevD.55.5269
http://cds.cern.ch/record/314075
Descripción
Sumario:Transverse polarization of ${}^3 S_1$ charmonium states, produced directly in $p\bar{p}$ collisions at asymptotically large transverse momentum p_t, has emerged as the most prominent test of color octet contributions and spin symmetry in quarkonium production. We present predictions for the polar angle distribution at moderate values of p_t \sim 4 - 20 GeV, covered by the Tevatron Run I data. We update the fits of NRQCD matrix elements and discuss their theoretical uncertainties. With our best fit values, no transverse polarization is expected at p_t \sim 5 GeV, but the angular distribution is predicted to change dramatically as p_t increases to 20 GeV.