Muon decay analysis with TWIST: recent progress

After a decade of design, construction, improvement, data-taking, simulation, and analysis, the TRIUMF Weak Interaction Symmetry Test (TWIST) muon decay parameter measurements are nearly complete. While the final results are yet to be unblinded, a preliminary estimate of the final precision is available. The goal of an order-of-magnitude improvement on pre-TWIST precisions for the ρ, δ, and Pμξ decay parameters has essentially been achieved, making possible some tighter constraints on parameters of the left-right symmetric extension to the standard model as well as the fundamental coupling constants of the muon.