The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector array. The result, τμ=2.197013(24)μs, is in excellent agreement with the previous world average. The new world average τμ=2.197019(21)μs determines the Fermi constant GF=1.166371(6)×10-5GeV-2 (5 ppm). Additionally, the precision measurement of the positive-muon lifetime is needed to determine the nucleon pseudoscalar coupling gP.
ASJC Scopus subject areas
- Physics and Astronomy(all)