Azimuthal Correlations in Dijet Events from Deep Inelastic Positron-Proton Scattering at HERA

Sammanfattning: Correlations in the azimuthal angle between dijets produced in deep inelastic $e^{+}p$ scattering events, collected by the H1 experiment during 1999-2000, have been investigated. Cross sections are presented as a function of the azimuthal separation between the two jets in the hadronic center of mass frame, $Deltaphi^{'}$, in different regions of the photon virtuality $Q^{2}$ and in different regions of the Bjorken scaling variable $x_{Bj}$. The results are compared to the predictions of QCD models implementing LO matrix elements, matched parton showers and hadronisation as well as to NLO di-jet ($alpha _s ^{2}$) and NLO three-jet ($alpha _s ^{3}$) parton level calculations corrected for hadronisation effects. Also, a fit of the unintegrated gluon density is presented, in which a first attempt to constrain the intrinsic transverse momentum distribution is performed.