Measurement of Dijet Azimuthal Decorrelations inppCollisions ats=7  TeV

Abstract

Azimuthal decorrelations between the two central jets with the largest transverse momenta are sensitive to the dynamics of events with multiple jets. We present a measurement of the normalized differential cross section based on the full data set (∫Ldt=36 pb(-1)) acquired by the ATLAS detector during the 2010 sqrt(s)=7 TeV proton-proton run of the LHC. The measured distributions include jets with transverse momenta up to 1.3 TeV, probing perturbative QCD in a high-energy regime.

ATLAS measurements of the properties of jets for boosted particle searches

“…Performance studies [50] have shown that there is excellent agreement between the measured positions of clusters and tracks in data, indicating no systematic misalignment between the calorimeter and inner detector. The Monte Carlo modeling of the position of clusters with respect to tracks is also good, indicating that the detector simulation models the calorimeter position resolution adequately; however, there remains a small discrepancy between data and Monte Carlo in the mean and RMS of the track-cluster separation.…”

Performance of jet substructure techniques for large-R jets in proton-proton collisions at $ \sqrt{s}=7 $ TeV using the ATLAS detector

“…Track-jets have a different set of systematic uncertainties and allow a reliable determination of the relative systematic uncertainties associated with the calorimeter-based measurement. Performance studies [90] have shown that there is excellent agreement between the measured positions of clusters and tracks in data, indicating no systematic misalignment between the calorimeter and the inner detector. The use of track-jets reduces or eliminates the impact of additional pp collisions by requiring the jet inputs (tracks) to come from the hard-scattering vertex.…”

Determination of the strong coupling constant $$\alpha _\mathrm {s}$$ α s from transverse energy–energy correlations in multijet events at $$\sqrt{s} = 8~\hbox {TeV}$$

“…1 are dominated by gluon radiation, which is decorrelated from the main event axis as predicted by QCD and measured in Refs. [65,66].…”

“…This is motivated by the track-to-cluster matching studies done in Ref. [65]. This impacts the TEEC measurement at the level of 0.5%.…”