Speaker
Description
The MUon proton Scattering Experiment (MUSE) was built to address the proton radius puzzle by simultaneously measuring the proton radius from both $e^\pm p$ and $\mu^\pm p$ elastic scattering in a momentum transfer range sensitive to the radius extraction. The experiment is carried out at the Paul Scherrer Institute (PSI) and uses a mixed e, $\mu$, and $\pi$ beam, alternating between positive and negative polarities, in the PiM1 secondary beam line. This, in combination with a large-acceptance, non-magnetic detector system allows the MUSE apparatus to measure the elastic $e^\pm p$ and $\mu^\pm p$ scattering cross sections and cross section ratios in 0.002 $< $Q$^2 <$ 0.08 (GeV/c)$^2$ and 0.26 $< \epsilon <$ 0.94 regime over a wide momentum range (115 to 210 MeV/c). Each of the four sets of data will allow the extraction of the proton charge radius. In combination, the data test possible differences between the electron and muon interactions and two-photon exchange effects. MUSE has commissioned its apparatus to the level needed for the measurements and began data collection in 2021. In this talk, the current status of the experiment will be discussed.
