Forward Jet Production in ep-collisions at HERA

The production of forward jets has been measured in deep inelastic $ep$ collisions at HERA. The results are presented in terms of single differential cross sections as a function of the Bjorken scaling variable ($x_{Bj}$) and as triple differential cross sections $d^3 sigma / dx_{Bj}dQ^2dp_{t,jet}^2$, where $Q^2$ is the four momentum transfer squared and $p_{t,jet}^2$ is the squared transverse momentum of the forward jet. Also cross sections for events with a di-jet system in addition to the forward jet are shown as a function of the rapidity separation between the forward jet and the two additional jets. The measurements are compared with the predictions of next-to-leading order QCD calculations and various QCD-based models.