The Fermilab muon g-2 experiment is a scientific experiment that aims to measure the magnetic properties of a particle called a muon. Muon is an elemental particle similar to electrons but much heavier. Its property, "spin," makes it act like a tiny magnet. If placed in a magnetic field, it will cycle and decay into an electron. The experiment involves sending muons into a magnetic field and measuring their movement. Specifically, we are interested in the "g-factor," which measures how much the muon's spin interacts with the magnetic field. This experiment helps us understand some of the fundamental properties of the universe. There are currently discrepancies between the theoretical prediction and experimental measurements. By measuring the muon g-factor precisely, the experiment helps us learn more about the fundamental interaction in the universe. The experiment is an international collaboration. It consists of 189 collaborators from 34 institutions from 7 countries.
MUonE is a muon-electron scattering experiment at CERN. It proposes a novel approach to determine the hadronic contribution to the muon anomalous magnetic moment, by measuring the running of the QED coupling through the analysis of muon-electron elastic scattering events. The experiment will be carried out at CERN North Area, by scattering the high intensity 160 GeV muon beam available on a low-Z target. A test run was performed in September 2023 with a reduced detector to validate the basic concepts of the proposal.
J-PARC Muon g-2/EDM experiment takes a different approach to Fermilab Muon g-2 experiment. It is now under construction and expected to have the first data taking from 2029 and beyond.