We study jet physics in the high energy regime of QCD. Based on the NLO BFKL equation, we construct a vertex for the production of a jet at central rapidity in k_T-factorization. A jet algorithm is introduced, and we take special care of the separation of multi-Regge and quasi-multi-Regge kinematics. The connection with the energy scale of the evolution is investigated in detail. The result is discussed for two situations: scattering of highly virtual photons, which requires a symmetric energy scale to separate the impact factors from the gluon Greens function, and hadron-hadron collisions, where a non-symmetric scale choice is needed. For the second case we are able to define a NLO unintegrated gluon density, valid in the small-x regime, and give the evolution equation for this density as well. In the second part, we examine the angular decorrelation of Mueller-Navelet jets. Using an operator formalism in the space of anomalous dimension and conformal spin, we implement the NLO BFKL Greens function to study the rapidity dependence of angular decorrelations. We incorporate the necessary summation of collinearly enhanced corrections beyond NLO accuracy. We compare our results with data from the Tevatron ppbar-collider and provide predictions for the LHC as well. We also extend our study to the angular decorrelation between a forward jets and the electron in deep inelastic ep scattering. The angular decorrelation has not been measured in DIS so far, but we give theoretical results for this observable which already implement the experimental cuts.
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