Forward Jet Production at small x in Next-to-Leading Order QCD
G. Kramer, B. Pötter
TL;DR
This paper addresses forward jet production in deep inelastic scattering (DIS) at small $x$, where standard LO/NLO predictions underpredict the measured cross sections. The authors implement a full next-to-leading order (NLO) calculation (JetViP) that combines direct and resolved virtual photon contributions, subtracting the $\gamma^* \to q\bar{q}$ splitting term to avoid double counting. They compare to MEPJET (direct only) and to ZEUS/H1 data, showing that the resolved component substantially boosts the forward cross section and yields good agreement within scale uncertainties. The work demonstrates that including the resolved virtual photon in NLO provides a practical, perturbative description of forward jets at small $x$, offering an alternative to the BFKL-based expectations and reducing reliance on purely asymptotic resummations.
Abstract
The production of forward jets of transverse energy E_T\simeq Q and large momentum fraction x_jet >> x is calculated in next-to-leading order including consistently direct and resolved virtual photon contributions. The predictions are compared to recent ZEUS and H1 data. Good agreement with the data is found.