Thursday, September 27, 2007, 16:00
WHGA Auditorium
W. Fetscher,
ETHZ
Abstract:
Two decades ago it was shown that a selected set of precision
experiments in normal and inverse muon decay completely determine the
decay interaction, with all leptons being lefthanded. There is still
room, however, for extensions of the standard model, all of which have
at least partially righthanded couplings. I will report about our
measurement of the transverse polarization of the decay positrons which
yields improved limits on the decay parameter eta needed for a
model-independent determination of the Fermi constant G_F as well as on
a possible violation of time reversal invariance in a purely leptonic
reaction.