We report the result of a measurement of the positive muon lifetime τ μ to one part-per-million (ppm) by the MuLan collaboration using a low-energy pulsed muon beam and a segmented array of plastic scintillators to record over 2×10 12 decay positrons. Two different in-vacuum muon-stopping targets were used in separate data-taking periods. The combined result gives τμ+(MuLan)=2196980.3(2.2)ps(1ppm). This measurement of the muon lifetime provides the most precise determination of the Fermi constant, G F(MuLan)=1.1663788(7)×10 -5 GeV -2(0.6 ppm), and will be used to extract the capture rates of the negative muon on the proton and the deuteron in the ongoing MuCap and MuSun experiments.
|Number of pages||4|
|Journal||Nuclear Physics B - Proceedings Supplements|
|State||Published - Apr 2012|
Bibliographical noteFunding Information:
The financial support during this project was provided by the National Science Foundation (NSF). The data analysis for this work was supported by the National Center for Supercomputing (NCSA). We thank PSI for support and provision of muon beamtime, and TRIUMF for the kicker design.
- Fermi constant
- Muon lifetime
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Nuclear and High Energy Physics