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arXiv · 1010.0991

Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant to Part-per-Million Precision

D. M. Webber·V. Tishchenko·Q. ~Peng·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. Lauss·I. Logashenko·K. R. Lynch·R. McNabb·J. P. Miller·F. Mulhauser·C. J. G. Onderwater·J. Phillips·S. Rath·B. L. Roberts·P. Winter·B. Wolfe
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Abstract

We report a measurement of the positive muon lifetime to a precision of 1.0 parts per million (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 x 10^{12} decays. Two different stopping target configurations were employed in independent data-taking periods. The combined results give tau_{mu^+}(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: G_F(MuLan) = 1.1663788 (7) x 10^-5 GeV^-2 (0.6 ppm). It is also used to extract the mu^-p singlet capture rate, which determines the proton's weak induced pseudoscalar coupling g_P.

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D. M. Webber, V. Tishchenko, Q. ~Peng, 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. Lauss, I. Logashenko, K. R. Lynch, R. McNabb, J. P. Miller, F. Mulhauser, C. J. G. Onderwater, J. Phillips, S. Rath, B. L. Roberts, P. Winter, B. Wolfe. 2010-10-05. Measurement of the Positive Muon Lifetime and Determination of the Fermi Constant to Part-per-Million Precision. https://doi.org/10.1103/physrevlett.106.041803 10.1103/physrevlett.106.079901

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