Forward-central jet correlations in pp collisions at CMS

The azimuthal correlation between central and forward jets has been measured in proton-proton collisions at the LHC recorded with the CMS detector at a centre-of-mass energy of 7 TeV. Both jets were required to have a minimum transverse momentum of 35 GeV. The forward jet was reconstructed in the hadronic forward calorimeter within the pseudo-rapidity range 3.2< vertical stroke η vertical stroke < 4.7, while the central jet was limited to vertical stroke η vertical stroke < 2.8. The measurement is performed inclusively and also differentially for different separations in pseudo-rapidity, the largest separation allowed by the CMS detector being Δη=7.5 units. The analysis is carried out for inclusive dijet events which is then divided into two sub-samples. In one of these sub-samples, an additional jet with pT>20 GeV in the pseudo rapidity interval between the forward and the central jet is required, while in the second sub-sample events containing such jets are explicitly vetoed. Furthermore, observables describing additional jets outside of the pseudo-rapidity interval spanned by the dijet system are measured. Most of the results are found to be well described by DGLAP-based Monte Carlo event generators.