Aug 23 – 28, 2010
Europe/Berlin timezone

Measurement of high-pT jet distributions, properties of jets and inelastic pp events at ATLAS

Aug 24, 2010, 2:17 PM
Kl. Hörsaal Mathematik (Bonn)

Kl. Hörsaal Mathematik


Nussallee 12


Dr Frederik Ruehr (Heidelberg KIP)


Making use of the excellent calorimetry of the ATLAS experiment, measurements of the cross-section for jet production and of jet properties in proton-proton interactions at sqrt(s) = 7 TeV will be presented. The corrected and unfolded inclusive cross-section for high-pT jets will be described, together with the cross-section as a function of the invariant di-jet mass. Special emphasis will be given to the discussion of the initial understanding of the jet energy scale. Furthermore, the corrected distribution of the angular difference between the two leading jets will be shown, both for the azimuthal as well as for the polar angle. Also studies of the shape of the observed jets will be presented. All results will be compared to theoretical predictions. The dijet angular distributions in bins of dijet invariant mass are analyzed with the first $7$~TeV $pp$ collisions recorded with the ATLAS detector. The data are confronted with Standard Model predictions with the goal of searching for new phenomena: contact interactions and gravitationally mediated effects and extra dimension models The measurement of the properties of proton-proton interactions at center-of-mass energies ranging from 900 GeV (injection energy) to 7 TeV in the ATLAS detector are presented for a well defined kinematic region. Using charged particles (unfolded and corrected from observed tracks for detector effects), spectra in transverse momentum, pseudo-rapidity and particle density are studied both in an inclusive manner as well as for identified particles, such as Ks and Lambda. In addition, the momentum flow with respect to a high pT reference track is investigated to study the transition to the underlying event in high pT collisions. Using charged particles allows also to study the kinematic properties of jets built from tracks. The results are compared to Monte Carlo models and have been used to derive Monte Carlo tunes using the first ATLAS measurements from LHC to constrain model parameters.

Primary author

Dr Frederik Ruehr (Heidelberg KIP)

Presentation materials