The MUSE experiment

Abstract

Abstract. The proton radius puzzle is the difference between the proton radius as measured with electron scattering and in the excitation spectrum of atomic hydrogen, and that measured with muonic hydrogen spectroscopy. The MUSE experiment seeks to resolve this puzzle by simultaneously measuring elastic electron and muon scattering on the proton, in both charge states, thereby providing new information to the puzzle. MUSE addresses issues of two-photon effects, lepton universality and, possibly, new physics, while providing simultaneous form factor, and therefore radius, measurements with both muons and electrons.

Dispersion-theoretical analysis of the electromagnetic form factors of the nucleon: Past, present and future

“…-For the neutron data basis, a thorough analysis of the existing electron-deuteron and electron- 3 Finally, let us point out that the dispersion-theoretical approach to the nucleons electromagnetic form factors has matured and become a precision tool to analyze electron scattering and form factor ratio data. In the future, it will also be extended to analyze the upcoming muon-proton scattering data from the MUSE [180] and AMBER [181] experiments. to one nucleon, is depicted in graph a).…”

Dispersion-theoretical analysis of the electromagnetic form factors of the nucleon: Past, present and future

“…Finally, let us point out the the dispersion-theoretical approach to the nucleons electromagnetic form factors has matured and become a precision tool to analyze electron scattering and form factor ratio data. In the future, it will also be extended to analyze the upcoming muon-proton scattering data from the MUSE [179] and AMBER [180].…”

The proton radius and its relatives - much ado about nothing?

“…Any deviation from the value measured in ep scattering would challenge the concept of lepton-flavor universality, which is a cornerstone of the so successful Standard Model of particle physics, that was put into question in recent experiments on certain decay modes of B mesons. There are experiments that are pursuing such proton radius measurements, namely MUSE at PSI [59] and AMBER at CERN [60]. Both experiments were triggered by the abovementioned proton radius discrepancy.…”