Abstract:

TBA n decay provides an excellent probe of the Lorentz structure of the weak interaction. The TWIST experiment is searching for new physics in decay by improving the characterization of the energy and angle spectrum of the decay positrons. The ultimate TWIST goal is to measure the parameters to a few parts in 10^4. The initial physics results of TWIST, improved measurements of , constitute the first ever blind analyses of the muon decay parameters. The improved precision places new limits on physics beyond the Standard Model. The physics, experiment, results and implications will be discussed. References: hep-ex/0409063, hep-ex/0410045.