Dijet Azimuthal Correlations in QCD Hard Processes

Abstract

We study the azimuthal correlation distribution for dijet production in QCD hard processes. This observable is sensitive to soft and/or collinear emissions in the backto-back region, giving rise to single and double logarithms. We provide resummed predictions to NLL accuracy for both DIS at HERA and hadronic collisions at Tevatron and perform a NLO matching to NLOJET++ results in the DIS case. Studies of soft gluon radiation and non-perturbative eects in QCD observables are of vital importance. These studies help us better understand the dynamics of QCD and enhance the accuracy of theoretical predictions for measured quantities. In several instances precision in QCD is limited not just by what powers of s are controlled, but also by the lack of better understanding of QCD dynamics such as the all-orders behaviour (embodied in the resummation of large logarithms) and inevitably the process of hadronisation.