GEM data analysis for the MUSE experiment at PSI

The Muon Scattering Experiment at the PiM1 beam line of the Paul-Scherrer Institute (PSI) will~contribute to the resolution of the proton radius puzzle by measuring the~proton charge radius with simultaneous electron and muon scattering. Both positive and negative beam polarities will be used. Precise measurements of the elastic~differential cross sections require accurate determinations of the~scattering angle. The secondary PiM1 beam has a large divergence, which necessitates measuring both the incoming and outgoing trajectories of scattered particles. High resolution Gas Electron Multiplier (GEM) detectors~are used to determine the incoming beam~particle trajectory. I will discuss recent improvements in pedestal and noise subtraction, hot/dead channel~masking, suppression of cross talk of electronics and subsequently~improved cluster finding and tracking~efficiency of the GEM detector telescope.