The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.
Inclusive double differential b-jet cross section as a function of PT for the |rapidity| range 0.0-0.3 from the lifetime-based analysis.
Inclusive double differential b-jet cross section as a function of PT for the |rapidity| range 0.3-0.8 from the lifetime-based analysis.
Inclusive double differential b-jet cross section as a function of PT for the |rapidity| range 0.8-1.2 from the lifetime-based analysis.
The STAR collaboration at RHIC presents measurements of \Jpsi$\to{e^+e^-}$ at mid-rapidity and high transverse momentum ($p_T>5$ GeV/$c$) in \pp and central \cucu collisions at \sNN = 200 GeV. The inclusive \Jpsi production cross section for \cucu collisions is found to be consistent at high $p_T$ with the binary collision-scaled cross section for \pp collisions, in contrast to previous measurements at lower $p_T$, where a suppression of \Jpsi production is observed relative to the expectation from binary scaling. Azimuthal correlations of $J/\psi$ with charged hadrons in \pp collisions provide an estimate of the contribution of $B$-meson decays to \Jpsi production of $13% \pm 5%$.
J/psi differential production cross section in sqrt(s).
J/psi transverse momentum distribution in sqrt(s).
J/psi transverse momentum distribution in sqrt(s).
We report on measurements of the inclusive jet production cross section as a function of the jet transverse momentum in pp-bar collisions at sqrt{s} = 1.96 TeV}, using the k_T algorithm and a data sample corresponding to 1.0 fb^-1 collected with the Collider Detector at Fermilab in Run II. The measurements are carried out in five different jet rapidity regions with |yjet| < 2.1 and transverse momentum in the range 54 < \ptjet < 700 GeV/c. Next-to-leading order perturbative QCD predictions are in good agreement with the measured cross sections.
Measured inclusive jet differential cross section as a function of PT for the rapidity range -0.1 to 0.1 with the jet resolution parameter D = 0.7.
Measured inclusive jet differential cross section as a function of PT for the absoloute rapidity range 0.1 to 0.7 with the jet resolution parameter D = 0.7.
Measured inclusive jet differential cross section as a function of PT for the absolute rapidity range 0.7 to 1.1 with the jet resolution parameter D = 0.7.
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