Why do neutral pions decay electromagnetically? Other neutral particles such as the neutron decay weakly, and charged pions decay weakly.
[Physics] Electromagnetic decay of a neutral pion
particle-physicspionsstandard-model
particle-physicspionsstandard-model
Why do neutral pions decay electromagnetically? Other neutral particles such as the neutron decay weakly, and charged pions decay weakly.
Best Answer
Pions and neutrons are hadrons, composite particles built from quarks:
From this information, and knowing that only one type of vertex is allowed in EM (photon, fermion in, fermion out), you can see how the neutral pion decays:
On the other hand, for charged pions you have a quark without the corresponding antiquark, you cannot get rid of them just by EM vertices, as the vertices have the same fermion on both legs.
Also think about the electric charge - photons carry no charge, but the initial charged pion does.