Pion
However, there is some probability (from <0.1% to 1.2%) involved with the decay of some pions, as they can also decay into different forms. For π+, the second most likely decay product is one positron (an anti-electron) and one electron neutrino. π– will sometimes decay into one electron and one electron antineutrino. π0 will sometimes decay into one highly energized photon, one electron, and one positron. (Keep in mind that positrons and electrons can annihilate each other, and this annihilation produces highly energized photons).