ATLAS Muon Barrel Sagitta Resolution versus Momentum at 2004 H8 Test Beam and comparison with Geant4 Simulation

This note presents the studies performed on muon sagitta reconstruction with the ATLAS Muon Barrel Chambers at the H8 Combined Test Beam. The H8 setup gives a unique possibility to measure this quantity in a realistic setup before the installation of the ATLAS experiment. The sagitta resolution of the barrel muon spectrometer has been measured for various muon momenta, thus disentangling the intrinsic resolution term from the multiple scattering contribution. The results obtained from the analysis of the data collected during the 2004 test beam have been compared to the prediction of the Geant4 simulation of the test beam setup. This comparison constitutes an important validation step for the Geant4 simulation of the Muon Spectrometer.