Results from the ICARUS T600 module: A measurement of the muon decay spectrum

We have studied the muon decay energy spectrum from a sample of stopping muon events acquired during the test run of the ICARUS T600 prototype. This detector allows the spatial reconstruction of the events with fine granularity, hence the precise measurement of the muon range and dE/dx with high sampling rate. This information is used to compute the correction factors needed for the calorimetric reconstruction. The Michel rho parameter is then measured by comparison of the experimental and Monte Carlo simulated muon decay spectra, obtaining rho = 0.72 +/- 0.06 (stat) +/- 0.08 (syst).