Speaker
Description
The PIENU experiment at TRIUMF has provided, to date, the most precise experimental determination of $R^\pi_{e/\mu}=\frac{\pi^+\rightarrow e^+(\gamma)}{\pi^+\rightarrow \mu^+(\gamma)}$, the ratio of pions decaying to positrons relative to muons. While $R^\pi_{e/\mu}$ is 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 $R^\pi_{e/\mu}$ 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 $R^\pi_{e/\mu}$ and expanding the physics reach by improving on the measurement of the very rare pion beta decay $π^+\rightarrow \pi^0 e^+ \nu$. 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.
| Keyword-1 | pion decay |
|---|---|
| Keyword-2 | lepton flavour universality |
| Keyword-3 | CKM |
