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, MuLan Collaboration

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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



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