  The TRIUMF Weak Interaction Symmetry Test (TWIST) experiment was designed to
test the standard model at high precision in the purely leptonic decay of
polarized muons. A general four-fermion interaction model is used to describe
the muon decay. TWIST measures three of the four muon decay parameters of this
model, $\rho$, $\delta$ and $P_{\mu}^{\pi} \xi$, from the shape of the
momentum-angle spectrum. The results of this model independent approach are
compared to the standard model predictions and used to constrain new physics.
Our collaboration has finalized the blind analysis of the final experimental
data taken in 2006 and 2007. This analysis mostly reached our goal of a
precision of an order of magnitude improvement over the pre-TWIST measurements.
