Complete next-to-leading-order corrections to J/psi photoproduction in nonrelativistic quantum chromodynamics
Mathias Butenschoen, Bernd A. Kniehl
备注：
5 pages, 4 figures; minor changes to the text, references added and updated, preliminary H1 data replaced by final ones; accepted for publication by Physical Review Letters
We calculate the cross section of inclusive direct J/psi photoproduction at next-to-leading order within the factorization formalism of nonrelativistic quantum chromodynamics, for the first time including the full relativistic corrections due to the intermediate ^1S_0^[8], ^3S_1^[8], and ^3P_J^[8] color-octet states. A comparison of our results to recent H1 data suggests that the color octet mechanism is indeed realized in J/psi photoproduction, although the predictivity of our results still suffers from uncertainties in the color-octet long-distance matrix elements.
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