Speaker
Denis Epifanov
(BINP)
Description
Michel parameters (MP) define the Lorentz structure of the Charged Weak
Interaction mediated by W boson in the Standard Model (SM).
They are in the list of the basic properties of tau lepton.
The difference of the measured MP from their SM expectation
will exhibit clear signature of the New Physics.
We discuss the key points of the analysis of the huge data
sample of taus collected at Belle to measure MP
in leptonic tau decays. Essential point of the analysis is to
consider the spin-spin correlation of taus, which allows us to
extract MP related to tau polarization. At the e+ e- factories
with unpolarized beams one have to analyze decay products of
both taus to be sensitive to the spin-spin correlation.
Nonzero average polarization of single tau at the Super
Charm-Tau factory with polarized e- beam provides unique
possibility to measure all Michel parameters without tagging
the opposite tau.
Primary author
Denis Epifanov
(BINP)
