A New Measurement of the Muon Lifetime and the Determination of the Fermi Coupling Constant

A new measurement of the muon lifetime, \textit{$\tau $}$_{\mu }$, at the 11 ppm level will be reported. This is the first result from the MuLan experiment, which is pursuing the ambitious goal of a 1~ppm determination of the muon lifetime---a 20-fold improvement. The experiment is motivated by recent theoretical improvements in extracting the Fermi coupling constant $G_{F}$, from the measured lifetime; the theoretical uncertainty is now less than 1~ppm. The coupling constant $G_{F}$ is an essential parameter of the standard model and represents the strength of the weak interaction. Progress, highlights and future plans for this experiment will also be discussed.