The MUSE experiment: addressing the proton radius puzzle via elastic muon scattering

by Prof. Wolfgang Lorenzon (University of Michigan)

Thursday 22 Aug 2019, 14:00 → 16:00 Asia/Shanghai

B105 (CHEP)

The proton radius puzzle, which surfaced over the past decade from a discrepancy of the proton charge radius measured with muonic hydrogen and electronic probes has challenged our basic understanding of the proton. Ideas to resolve the puzzle involve either beyond standard model physics, novel aspects of conventional physics, or issues in extracting the radius from the experimental data. None of these ideas is generally accepted, however, as the explanation for the puzzle. There are a number of experiments that aim to resolve the puzzle. Among those, the MUon Scattering Experiment (MUSE) at PSI is particularly interesting because it tries to determine the proton radius through μp scattering, which has not been done so far, simultaneously with ep scattering, in addition to performing these reactions with positive and negative leptons. The current status of the proton radius puzzle and the power of the MUSE experiment to resolve the puzzle will be discussed. Personal Introduction: Wolfgang Lorenzon got his PhD in Basel, Switzerland in 1988. He did a postdoc first at Caltech and then at TRIUMF in Canada, before starting his first faculty position at the University of Pennsylvania from 1994-1996. He then moved to the University of Michigan and has been there since. Wolfgang Lorenzon has worked for many years on the HERMES experiment to study the spin structure of the proton. At Fermilab he has been studying the flavor asymmetry in the nucleon sea and has now turned his attention to the puzzle that surrounds the size of the proton. In his talk he will tell us about the status of the proton radius puzzle and how the MUSE experiment will try to resolve it.