Particle Reconstruction

Abstract

Secondary particles produced in proton-proton collisions can be identified with the ATLAS detector, by taking a combination of signals at each sub-detector. This chapter describes (1) reconstruction and identification criteria for each particle; and (2) performances and systematic uncertainties on them. Electrons are reconstructed from tracks at the inner detector and energy deposits at the electromagnetic calorimeter. Electron energy scale and resolution are measured in data by the tag-and-probe method using $Z^{0} \rightarrow e^{+}e^{-}$ events. Muons are detected at both the inner detector and the muon spectrometer and identified by combining tracks at both. Muon momentum scale and resolution are also measured in data with the tag-and-probe method using di-muon resonances. Hadrons deposit their energies at the hadronic calorimeter and reconstructed as jets. Jet energy scale is determined by Monte-Carlo simulation and validated with data. Jets originated from bottom quark can be identified using the inner detector information. Missing transverse energy can be reconstructed from negative sum of the 2-component vectors of reconstructed objects. Electron, muon, bottom quark and missing transverse energy are important features of the stop signal in this book.