Search for Quark Contact Interactions in Dijet Angular Distributions in pp Collisions at sqrt(s) = 7 TeV Measured with the ATLAS Detector

TL;DR

This paper reports on measurements of dijet angular distributions at the LHC using the ATLAS detector, setting new limits on quark contact interactions and the compositeness scale, with results consistent with the Standard Model.

Contribution

First measurement of dijet angular distributions at 7 TeV with ATLAS, setting new limits on quark contact interactions and compositeness scale.

Findings

Excluded quark contact interactions with Λ < 3.4 TeV at 95% CL

Measured dijet distributions up to 2.8 TeV mass

Results agree with Standard Model predictions

Abstract

Dijet angular distributions from the first LHC pp collisions at center-of-mass energy sqrt(s) = 7 TeV have been measured with the ATLAS detector. The dataset used for this analysis represents an integrated luminosity of 3.1 pb-1. Dijet $\chi$ distributions and centrality ratios have been measured up to dijet masses of 2.8 TeV, and found to be in good agreement with Standard Model predictions. Analysis of the $\chi$ distributions excludes quark contact interactions with a compositeness scale $\Lambda$ below 3.4 TeV, at 95% confidence level, significantly exceeding previous limits.