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).