Improved measurement of the positive-muon lifetime and determination of the Fermi constant

Chitwood D. B., BANKS T. I., BARNES M. J., BATTU S., CAREY R. M., CHEEKATMALLA S., ...More

PHYSICAL REVIEW LETTERS, vol.99, no.3, 2007 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 99 Issue: 3
  • Publication Date: 2007
  • Doi Number: 10.1103/physrevlett.99.032001
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Istanbul Technical University Affiliated: No


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, tau(mu)=2.197013(24) mu s, is in excellent agreement with the previous world average. The new world average tau(mu)=2.197019(21) mu s determines the Fermi constant G(F)=1.166371(6)x10(-5) GeV-2 (5 ppm). Additionally, the precision measurement of the positive-muon lifetime is needed to determine the nucleon pseudoscalar coupling g(P).