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arXiv · hep-ph/9410237

Hadroproduction and Polarization of Charmonium

M. Vänttinen·P. Hoyer·S. J. Brodsky·W. -K. Tang
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Abstract

In the limit of heavy quark mass, the production cross section and polarization of quarkonia can be calculated in perturbative QCD. We study the $p_\perp$-averaged production of charmonium states in $πN$ collisions at fixed target energies. The data on the relative production rates of $\jp$ and $χ_J$ is found to disagree with leading twist QCD. The polarization of the $\jp$ indicates that the discrepancy is not due to poorly known parton distributions nor to the size of higher order effects ($K$-factors). Rather, the disagreement suggests important higher twist corrections, as has been surmised earlier from the nuclear target $A$-dependence of the production cross section.

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M. Vänttinen, P. Hoyer, S. J. Brodsky, W. -K. Tang. 1994-10-06. Hadroproduction and Polarization of Charmonium. https://doi.org/10.1103/physrevd.51.3332

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