Dijet asymmetries in Pb+Pb and pp collisions with the ATLAS detector

Laura Havener

doi:10.1088/1742-6596/832/1/012007

Abstract

Measurements of dijet pT correlations in both Pb+Pb and pp collisions at a nucleon–nucleon centre-of-mass energy of = 2.76 TeV are presented. The measurements were performed with the ATLAS detector at the Large Hadron Collider (LHC) using Pb+Pb and pp data samples with integrated luminosities of 0.14 nb−1 and 4.0 pb−1, respectively. Jets were reconstructed using the anti-kt algorithm with R = 0.4. A background subtraction procedure was applied to correct the jets for the large underlying event present in Pb+Pb collisions. The leading and subleading jet transverse momenta are denoted pT1 and pT2. An unfolding procedure is applied to the two-dimensional pT1-pT2 distributions to account for experimental effects in the measurement of both jets. Distributions of , where , are presented as a function of pT1 and collision centrality. The distributions are found to be similar in peripheral Pb+Pb collisions and pp collisions, but highly modified in central Pb+Pb collisions. The results are qualitatively consistent with expectations from partonic energy loss.

Highlights

N dN dxJPT2 pT1 for experimental , are presented as a function of pT1 and collision centrality
Jets have been an important tool for probing the hot, dense medium produced in heavy-ion collisions known as the quark-gluon plasma (QGP)
These proceedin√gs present a new measurement of the dijet asymmetry in Pb+Pb and pp collisions [4] at sNN =2.76 TeV using the observable xJ = pT 1/pT 2 that has been fully corrected for detector effects

Summary

N dN dxJ

PT2 pT1 for experimental , are presented as a function of pT1 and collision centrality. The distributions are found to be similar in peripheral. Pb+Pb collisions and pp collisions, but highly modified in central Pb+Pb collisions. The results are qualitatively consistent with expectations from partonic energy loss

Introduction

Results

Conclusion