Calorimeter in MUSE Experiment

The MUon proton Scattering Experiment (MUSE) at the PiM1 beam line of the Paul Scherrer Institute is simultaneously measuring the elastic scattering of electrons and muons from a liquid hydrogen target to extract the charge radius of the proton. Both beam polarities will be measured over the course of the experiment. By comparing the four scattering cross sections, the experiment will provide unique muon proton scattering data with a precision sufficient to address the proton radius puzzle, and will directly measure two-photon exchange effects for both muons and electrons. Measuring precise cross sections requires understanding both the incident beam energy and the radiative corrections. MUSE will use a lead-glass calorimeter located downstream in the beam to investigate and control radiative corrections by suppressing high energy initial state photons. In this presentation, we will discuss the calibration of the detector by measuring its response to particles with various energies. Latest data and comparison to simulation will be shown to demonstrate the performance of the detector.