Search for New Physics in the Dijet Mass Distribution using 1 fb^-1 of pp Collision Data at sqrt(s) = 7 TeV collected by the ATLAS Detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Phys.Lett.B 708 (2012) 37-54, 2012.
Inspire Record 925933 DOI 10.17182/hepdata.57981

Invariant mass distributions of jet pairs (dijets) produced in LHC proton-proton collisions at a centre-of-mass energy sqrt(s)=7 TeV have been studied using a data set corresponding to an integrated luminosity of 1.0 fb^-1 recorded in 2011 by ATLAS. Dijet masses up to ~4 TeV are observed in the data, and no evidence of resonance production over background is found. Limits are set at 95% CL for several new physics hypotheses: excited quarks are excluded for masses below 2.99 TeV, axigluons are excluded for masses below 3.32 TeV, and colour octet scalar resonances are excluded for masses below 1.92 TeV.

1 data table

The observed di-jet mass distribution together with the background QCD prediction.


Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abdallah, Jalal ; et al.
Eur.Phys.J.C 71 (2011) 1846, 2011.
Inspire Record 930220 DOI 10.17182/hepdata.58001

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.

10 data tables

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.

More…