Latest results on multi-jets production, and beyond-DGLAP (BFKL, saturation) studies with jets

The recent ATLAS results of the measurement of additional jet activity in dijet events is presented. The measurement uses pp collisions at ATLAS at the LHC with a centre-of-mass energy of 7 TeV. In each event, the two jets with the highest transverse momentum are taken as the dijet system and a rapidity interval is defined as the region in rapidity between the centroids of these two jets. The fraction of dijet events without an additional jet in this rapidity interval, the mean jet multiplicity in the interval, correlation between the azimuthal angles of the dijets, and double differential cross-sections are shown, as a function of the mean transverse momentum of the dijets and of the rapidity interval size. The predictions from HEJ, BFKL-like calculation, and POWHEG, DGLAP-like calculation are compared to the measured data.