We report a measurement of the positive muon lifetime to a precision of 1.0 ppm; it is the most precise particle lifetime ever measured. The experiment used a time-structured, low-energy muon beam and a segmented plastic scintillator array to record more than 2×1012 decays. Two different stopping target configurations were employed in independent data-taking periods. The combined results give τμ+(MuLan)=2196980.3(2.2)ps, more than 15 times as precise as any previous experiment. The muon lifetime gives the most precise value for the Fermi constant: GF(MuLan)=1.1663788(7) ×10-5GeV-2 (0.6 ppm). It is also used to extract the μ-p singlet capture rate, which determines the proton's weak induced pseudoscalar coupling gP.
|Journal||Physical Review Letters|
|State||Published - Jan 25 2011|
ASJC Scopus subject areas
- Physics and Astronomy (all)