New contributions to heavy-quarkonium production
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.
Keywords
Cite
@article{arxiv.hep-ph/0507060,
title = {New contributions to heavy-quarkonium production},
author = {J. P. Lansberg and J. R. Cudell and Yu. L. Kalinovsky},
journal= {arXiv preprint arXiv:hep-ph/0507060},
year = {2009}
}
Comments
16 pages, 12 figures, LaTeX. References updated, typo fixed, discussion of the scale dependence, minor corrections to the text