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New contributions to heavy-quarkonium production

J. P. Lansberg·J. R. Cudell·Yu. L. Kalinovsky
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Abstract

We reconsider quarkonium production in a field-theoretical setting and we show that the lowest-order mechanism for heavy-quarkonium production receives in general contributions from two different cuts. The first one corresponds to the usual colour-singlet mechanism. The second one has not been considered so far. We treat it in a gauge-invariant manner, and introduce new 4-point vertices, suggestive of the colour-octet mechanism. These new objects enable us to go beyond the static approximation. We show that the contribution of the new cut can be as large as the usual colour-singlet mechanism at high transverse momentum for J/psi. In the psi' case, theoretical uncertainties are shown to be large and agreement with data is possible.

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J. P. Lansberg, J. R. Cudell, Yu. L. Kalinovsky. 2005-11-21. New contributions to heavy-quarkonium production. https://doi.org/10.1016/j.physletb.2005.11.073

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