A part-per-million measurement of the positive muon lifetime and a determination of the Fermi constant
The mean life of the positive muon has been measured to part-per-million precision using a time-structured beam, a ferromagnetic target, and a fast, multi-segmented and symmetric scintillator detection array. The result, based on data acquired in 2006, is $\tau_{\mu^+} = \unit[2196980.1 \pm 2.6 \pm 1.9]{ps},$ where the first uncertainty is statistical and the second is systematic. When combined with the measurement based on our 2007 dataset, the average is $\tau_{\mu^+}^{\rm avg} = \unit[2196980.3 \pm 2.8]{ps}$ and the derived value for the Fermi constant is $G_F = \unit[1.1663818 (8) \times 10^{-5}]{GeV^{-2}}$. This thesis describes the motivation for the measurement, the experimental technique, the data analysis, and the systematic uncertainties for the 2006 dataset.
Fermi constant, MuLan collaboration, positive muon, muon lifetime, precision measurement
University of Illinois - Urbana-Champaign
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University of Illinois at Urbana-Champaign