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.

• Received 15 September 2009

DOI:https://doi.org/10.1103/PhysRevLett.104.072001