Improved Measurement of the Positive-Muon Lifetime and Determination of the Fermi Constant
Abstract
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.
- Publication:
-
Physical Review Letters
- Pub Date:
- July 2007
- DOI:
- 10.1103/PhysRevLett.99.032001
- arXiv:
- arXiv:0704.1981
- Bibcode:
- 2007PhRvL..99c2001C
- Keywords:
-
- 14.60.Ef;
- 13.35.Bv;
- Muons;
- Decays of muons;
- High Energy Physics - Experiment;
- Nuclear Experiment
- E-Print:
- As published version (PRL, July 2007)