Scattered Particle Tracking and Vertex Reconstruction in the MUSE Experiment

The “Proton Radius Puzzle” was sparked when the proton radius was measured with muons to be ~ 0.842 ± 0.001fm, a deviation of about 5σ from the CODATA average value when measured with electrons at the time. Possible explanations include violation of lepton universality, two photo exchange effects or underestimated systematic uncertainties in extracting the form factor from our scattering data. The MUon Scattering Experiment (MUSE) aims to perform new measurements of the proton radius using simultaneous e-p and μ-p scattering, with both positive and negative polarity leptons at the πM1 beamline located in the Paul Scherrer Institute. This unique setup allows us to perform several high-precision tests of the various explanations of the radius puzzle. The experiment will use a liquid hydrogen target with precision tracking via straw tube detectors (STT) for a precise position measurement coupled with a scintillator array (SPS) for precise timing. In this talk, we will show how efficiently and precise one can determine tracks from the STT/SPS combination using a χ² minimization. We will also show vertices reconstructed using the STT and GEM detectors which precisely determine the lepton scattering angle.