Measurement of the $b\bar{b}$ dijet cross section in $pp$ collisions at $\sqrt{s}=7$ TeV with the 2011 dataset collected by 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 4.2 ${\rm{fb}}^{\rm{-1}}$. The cross section is measured for events with two identified $b$-jets with a transverse momentum $p_{T} > 20$ 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 $p_{T} > 270$ 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.