Speaker
Description
The PIENU experiment at TRIUMF has provided, to date, the most precise experimental determination of R$^{e/\mu}_\pi$ , the ratio of pions decaying to positrons relative to muons. While more than an order
of magnitude less precise that the Standard Model (SM) calculation, the PIENU result is a precise test of the universality of charged leptons interaction, a key principle of the Standard Model (SM), constrains a large range of new physics scenario, and allows dedicated searches for exotics such as sterile neutrinos. I’ll go over a short overview of R$^{e/\mu}_\pi$ measurements and introduce the next generation precision pion decay experiment in the making: PIONEER. This newly proposed experiment aims at pushing the boundaries of precision on R$^{e/\mu}_\pi$ and expanding the physics reach by improving on the measurement of the very rare pion beta decay $\pi^+ \rightarrow \pi^0 e^+ \nu$.
This will provide a new and competitive input to the determination of |V$_{ud}$|, an element of the Cabibbo- Kobayashi-Maskawa (CKM) quark-mixing matrix.
