The figure describes the response of the detector and background fluctuations combined. The detector response is formed by filling y-axis as the particle level dijet invariant mass and x-asis as the corresponding detector level dijet invariant mass. Background fluctuations are gathered from the data itself with rotated cones around leading and subleading jets. Combination is done by multiplying the background fluctuation matrix with detector response matrix. The MC which was used is LHC17h6f2 and LHC17h6e2, which is a EPOS+Pythia jet-jet production. Background fluctuations have been subtracted, maximum track cut was set to 100 GeV, jet area cut >0.6*pi*R^2, detector jets with pt>4*pt_hard have been cut.