Forward-Central Jet Correlations in $pp$ Collisions at CMS

The azimuthal correlation b etween central and forward jets has b een measured in protonproton 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 pseudorapidity range 3.2 < j j < 4.7, while the central jet was limited to j j < 2.8. The measurement is p erformed inclusively and also dierentially for dierent separations in pseudorapidity, the largest separation allowed by the CMS detector b eing = 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 p T > 20 GeV in the pseudorapidity interval b etween the forward and the central jet is required, while in the second sub-sample events containing such jets are explicitly veto ed. 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 b e well describ ed by DGLAP based Monte Carlo event generators.