Beam Stability in PSI MUSE*

The proton radius puzzle is a 4% discrepancy in the proton radius when measured with muonic hydrogen spectroscopy compared to normal hydrogen spectroscopy or electron proton scattering. For further investigation of the puzzle, the Muon-proton Scattering Experiment (MUSE) is being performed at the Paul Scherrer Institute (PSI). MUSE runs in the PiM1 beamline at PSI, using a beam of electrons (e), muons (μ) and pions (π). The interactions of μ and e with protons allow the proton radius to be determined, along with any differences between the interactions of muons and electrons, which might indicate new physics. I will discuss analysis and observations of the RF time, the time relative to the accelerator RF signal, of the three particles at the experiment’s Beam Hodoscope and Beam Monitor detectors. The e RF time should be constant, since for e’s beta ~ 1, so this measurement serves to check the combined stability of the accelerator and electronics systems. The difference in μ and π RF times reflects the flight paths and momenta of the particles, and its variation with time checks the stability of the PiM1 channel, the detectors, and the electronics. I present studies of the RF times of the particles and their stability, along with the stability of the channel and particle momenta.