Blinding for the MUSE Experiment

The MUon Scattering Experiment (MUSE) at the Paul Scherrer Institute (PSI), motivated by the proton radius puzzle, performs simultaneous high-precision measurements of elastic electron-proton and muon-proton scattering. The cross sections, form factors and proton radius obtained with electrons and muons can be directly compared. The use of beams of both positively and negatively charged particles allows a direct determination of two-photon exchange, which makes the positive and negative polarity cross sections differ and impacts the determination of form factors and the radius. In an effort to produce a high-precision measurement of the proton radius with minimal experimenter bias, MUSE has decided to perform a blinded analysis. This blinding is particle species, momentum, and charge polarity dependent, as well as different for simulation and data. The blinding is applied to scattered tracks in such a way that it introduces structure in the angular dependence of the extracted cross section, preventing a reliable determination of cross section ratios or of the radius. The details of the MUSE blinding scheme will be presented in this talk.