Jet Reconstruction and Jet Quenching in Heavy Ion Collisions at ATLAS

We present a measurement of dijet asymmetry and dijet azimuthal correlations in Pb+Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV using the ATLAS detector. This measurement provides the first evidence of a strong jet quenching in relativistic heavy ion collisions at TeV energies. The jet reconstruction procedure is discussed as well as studies which have been performed to check that the observed asymmetry is not produced by detector effects and underlying event backgrounds.