Inclusive Four-jet Production at 7 and 13 TeV: Azimuthal Profile in   Multi-Regge Kinematics
  Recently, new observables in LHC inclusive events with three tagged jets were proposed. Here, we extend that proposal to events with four tagged jets. The events are characterised by one jet in the forward direction, one in the backward direction with a large rapidity distance $Y$ from the first one and two more jets tagged in more central regions of the detector. In our setup, non-tagged associated mini-jet multiplicity is present and needs to be accounted for by the inclusion of BFKL gluon Green functions. The projection of the cross section on azimuthal-angle components opens up the opportunity for defining new ratios of correlation functions of the azimuthal angle differences among the tagged jets that can be used as probes of the BFKL dynamics. 
F. Caporale, F. G. Celiberto, G. Chachamis, D. Gordo Gomez, A. Sabio   Vera
hep-ph