Measurement of the $$b\overline{b}$$ b b ¯ dijet cross section in pp collisions at $$\sqrt{s} = 7$$ s = 7 TeV with the ATLAS detector

The dijet production cross section for jets containing a b-hadron (b-jets) has been measured in proton–proton collisions with a centre-of-mass energy of $$\sqrt{s} = 7$$  TeV, using the ATLAS detector at the LHC. The data used correspond to an integrated luminosity of $$\mathrm 4.2\,\text {fb}^{-1}$$ . The cross section is measured for events with two identified b-jets with a transverse momentum $$p_{\text {T}} > 20$$  GeV and a minimum separation in the $$\eta $$ – $$\phi $$ plane of $$\Delta R = 0.4$$ . At least one of the jets in the event is required to have $$p_{\text {T}} > 270$$  GeV. The cross section is measured differentially as a function of dijet invariant mass, dijet transverse momentum, boost of the dijet system, and the rapidity difference, azimuthal angle and angular distance between the b-jets. The results are compared to different predictions of leading order and next-to-leading order perturbative quantum chromodynamics matrix elements supplemented with models for parton-showers and hadronization.