Pions can undergo a rare beta-like decay into leptons:
Pion beta decay (with probability of about $10^{−8}$) into a neutral pion plus an electron and electron antineutrino (or for positive pions, a neutral pion, positron, and electron neutrino).
- Why is the quark composition of the neutral pion is so different to the charged pion after pion decay?
$$\pi^{+}(\overline u,d) \to \pi^{0} \left(\frac {\overline u,u-\overline d, d}{\sqrt 2} \right)+e^{+}+ \nu_e$$
$$\pi^{-}(\overline d,u) \to \pi^{0} \left(\frac {\overline u,u-\overline d, d}{\sqrt 2} \right)+e^{-}+\overline \nu_e$$
- Why is the quark composition of the neutral pion is so different with neutral hadron (like neutron)?