Detailed report of the MuLan measurement of the positive muon lifetime and determination of the Fermi constant

V. Tishchenko*, S. Battu, R. M. Carey, D. B. Chitwood, J. Crnkovic, P. T. Debevec, S. Dhamija, W. Earle, A. Gafarov, K. Giovanetti, T. P. Gorringe, F. E. Gray, Z. Hartwig, D. W. Hertzog, B. Johnson, P. Kammel, B. Kiburg, S. Kizilgul, J. Kunkle, B. LaussI. Logashenko, R. McNabb, J. P. Miller, F. Mulhauser, C. J. G. Onderwater, Q. Peng, J. Phillips, S. Rath, B.L. Roberts, D. M. Webber, P. Winter, B. Wolfe, μLan Collaboration

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review


We present a detailed report of the method, setup, analysis, and results of a precision measurement of the positive muon lifetime. The experiment was conducted at the Paul Scherrer Institute using a time-structured, nearly 100% polarized surface muon beam and a segmented, fast-timing plastic scintillator array. The measurement employed two target arrangements: a magnetized ferromagnetic target with a similar to 4 kG internal magnetic field and a crystal quartz target in a 130 G external magnetic field. Approximately 1.6 X 10(12) positrons were accumulated and together the data yield a muon lifetime of T-mu(MuLan) = 2196980.3(2.2) ps (1.0 ppm), 30 times more precise than previous generations of lifetime experiments. The lifetime measurement yields the most accurate value of the Fermi constant G(F)(MuLan) = 1.1663787(6) X 10(-5) GeV-2 (0.5 ppm). It also enables new precision studies of weak interactions via lifetime measurements of muonic atoms. DOI: 10.1103/PhysRevD.87.052003
Original languageEnglish
JournalPhysical Review D
Issue number5
Publication statusPublished - 4 Mar 2013
Externally publishedYes




Dive into the research topics of 'Detailed report of the MuLan measurement of the positive muon lifetime and determination of the Fermi constant'. Together they form a unique fingerprint.

Cite this