Complesso Universitario di Monte Sant'Angelo, Edificio 6, via Cintia
Description
In the Standard Model, electrons, muons, and tau leptons have identical
electroweak gauge interactions,
a hypothesis known as lepton universality. PIENU is a precision
measurement of the ratio of the rate of the
pion decay to electron plus neutrino compared to pion decay to muon plus
neutrino.
The SM theoretical prediction of this ratio is one of the most
accurately calculated weak interaction
observables involving quarks with uncertainty of <0.01% and the
experimental value is an order of magnitude less precise.
Testing lepton universality can constrain many non-Standard Model scenarios.
The experimental observation of deviations from universality would be
clear evidence of new physics
with sensitivity to mass scales up to 1000 TeV.
In this talk we present the latest results from the PIENU experiment
which provide the most stringent
test of lepton universality as well as limits on the presence of
massive neutrino states coupled to electrons.
