Complete next-to-leading-order corrections to J/psi photoproduction in nonrelativistic quantum chromodynamics.

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 {1}S{0}{[8]}, {3}S{1}{[8]}, and {3}P{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.