Detailed report of the MuLan measurement of the positive muon lifetime and determination of the Fermi constant
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 ∼4 kG internal magnetic field and a crystal quartz target in a 130 G external magnetic field. Approximately 1.6×1012 positrons were accumulated and together the data yield a muon lifetime of τμ(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 GF(MuLan)=1. 1663787(6)×10-5 GeV-2 (0.5 ppm). It also enables new precision studies of weak interactions via lifetime measurements of muonic atoms. © 2013 American Physical Society.
Tishchenko, V.; Battu, S.; Carey, R. M.; Chitwood, D. B.; Crnkovic, J.; Debevec, P. T.; Dhamija, S.; Earle, W.; Gafarov, A.; Giovanetti, K.; Gorringe, T. P.; Gray, F. E.; Hartwig, Z.; Hertzog, D. W.; Johnson, B.; Kammel, P.; Kiburg, B.; Kizilgul, S.; Kunkle, J.; Lauss, B.; Logashenko, I.; Lynch, K. R.; McNabb, R.; Miller, J. P.; Mulhauser, F.; Onderwater, C. J.G.; Peng, Q.; Phillips, J.; Rath, S.; Roberts, B. L.; Webber, D. M.; Winter, P.; and Wolfe, B., "Detailed report of the MuLan measurement of the positive muon lifetime and determination of the Fermi constant" (2013). Regis University Faculty Publications. 704.