Abstract:
Measurements are presented of the cross section for the production of at least four jets, of which at least two originate from b quarks, in proton-proton collisions. Data collected with the CMS detector at the LHC at a center-of-mass energy of 7 TeV are used, corresponding to an integrated luminosity of 3 pb − 1 . The cross section is measured as a function of the jet transverse momentum for p T > 20 GeV , and of the jet pseudorapidity for | η | < 2.4 ( b jets), 4.7 (untagged jets). The correlations in azimuthal angle and p T between the jets are also studied. The inclusive cross section is measured to be σ ( p p → 2 b + 2 j + X ) = 69 ± 3 ( stat ) ± 24 ( syst ) nb . The η and p T distributions of the four jets and the correlations between them are well reproduced by event generators that combine perturbative QCD calculations at next-to-leading-order accuracy with contributions from parton showers and multiparton interactions.