Measurement of Charged-Particle Event Shape Variables in Inclusive √(s̅) = 7 TeV Proton-Proton Interactions with the ATLAS Detector


The measurement of charged-particle event shape variables is presented in inclusive inelastic pp collisions at a center-of-mass energy of 7 TeV using the ATLAS detector at the LHC. The observables studied are the transverse thrust, thrust minor, and transverse sphericity, each defined using the final-state charged particles' momentum components perpendicular to the beam direction. Events with at least six charged particles are selected by a minimum-bias trigger. In addition to the differential distributions, the evolution of each event shape variable as a function of the leading charged-particle transverse momentum, charged-particle multiplicity, and summed transverse momentum is presented. Predictions from several Monte Carlo models show significant deviations from data.



Deep inelastic collisions, Colliders (Nuclear physics), Quantum chromodynamics


CC BY 3.0 (Attribution), ©2013 CERN, for the ATLAS Collaboration