Tracking and Vertex Reconstruction in MUSE*

The “Proton Radius Puzzle” began when in 2010, via μ spectroscopy, the radius of the proton was measured to be ~ 0.842  +/- 0.001fm, which represents a deviation of ~ 5σ from the CODATA value at the time. Possible explanations include questions of lepton universality, radiative corrections not being handled properly or underestimated systematic uncertainties in the proton form factors. The MUon Scattering Experiment (MUSE) aims to shed light on the proton radius puzzle via concurrent ep and μp scattering at both charge polarities. MUSE is housed at the πM1 beam line at the Paul Scherrer Institute, which is a mixed beam of e, π and μ. As well, MUSE has the unique capability to directly test lepton universality and the two-photon exchange effect. Imperative to the extraction of rp is the tracking of the incoming and scattered particles in MUSE, handled by our Gas Electron Multiplier (GEM) and Straw Tube Tracker (STT) detectors, respectively. In this talk, we will discuss how the tracking of both incoming and scattered particles is approached for this experiment, the efficiencies of said tracking and, as well, how well these tracks combine to precisely reconstruct the interaction vertex and scattering angle.