MUON IDENTIFICATION AND COMBINED RECONSTRUCTION FOR THE ATLAS DETECTOR AT CERN-LHC

A robust muon reconstruction and identification is crucial to fully exploit the physics potential of the ATLAS experiment at LHC. The ATLAS detector is characterized by two high precision tracking systems, the Inner Detector and the Muon System, and a thick calorimeter that ensures a safe hadron absorption filtering with high purity muons with energy above 3 GeV/c. In order to combine the tracks reconstructed in the Inner Detector and the Muon System, the MuonIdentification (MUID) Object-Oriented software package, currently under development, has been used. While the combination of the momentum measurement improves the resolution in the range from 6 GeV/c up to 100 GeV/c, the matching of the muon track reconstructed independently in the Inner Detector and in the Muon Spectrometer also allows an efficient rejection of muons from secondary interactions. The reconstruction performances with simulated single muons samples of fixed transverse momentum from 3 GeV/c up to 1 TeV/c is presented. In addition, preliminary results on the reconstruction of some physics channel and on the rejection of muons coming from K/pi decays in flight are discussed.