antimuon

The [[pi].sup.+] ([[pi].sup.-]) mesons (with a mass of [m.sub.[pi]] = 139.6 MeV/[c.sup.2] and a half-life of 2.6 x [10.sup.-8] s) decay due to the weak interaction, the primary decay mode of which (with a probability of 0.999877) is a reaction leading to an antimuon (muon) and a muonic neutrino (muonic antineutrino) as

Lane and colleagues also proposed that a B meson could decay into combinations such as one electron and one antimuon that are banned by the standard model.

The down quark [d.sub.0] and the antidown quark [[bar.d].sub.0] completely annihilate into a muon neutrino [v.sub.[mu]] or an antimuon neutrino [[bar.v].sub.u].