2021/08/20 by Robert M. Carey, Carey, Robert, Tim Gorringe +3
Engineering · Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #Instrumentation and Detectors (physics.ins-det) #Muon and positron interactions and applications #Neutrino Physics Research #Nuclear Experiment (nucl-ex) #Particle physics theoretical and experimental studies
paper · pdf · doi:10.48550/arxiv.2108.09182
openalex publication_date 2021/08/20 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
The part-per-million measurement of the positive muon lifetime and\ndetermination of the Fermi constant by the MuLan experiment at the Paul\nScherrer Institute is reviewed. The experiment used an innovative,\ntime-structured, surface muon beam and a near-4pi, finely-segmented, plastic\nscintillator positron detector. Two in-vacuum muon stopping targets were used:\na ferromagnetic foil with a large internal magnetic field, and a quartz crystal\nin a moderate external magnetic field. The experiment obtained a muon lifetime\n2 196 980.3(2.2) ps (1.0 ppm) and a Fermi constant 1.166 378 7(6) 10-5 GeV-2\n(0.5 ppm). The thirty-fold improvement in the muon lifetime has proven valuable\nfor precision measurements in nuclear muon capture and the commensurate\nimprovement in the Fermi constant has proven valuable for precision tests of\nthe standard model.\n