Pimesons
The positive pimeson, +, is the lightest particle in the group of medium heavy particles, the mesons. It consists of a quark (u) and the antiquark (anti-d). + is instable and decays into µ+, which in turn decays into a positron e+; neutrinos are also created. In these decays it is the quarks that are transformed. The charges of the quarks in + is +2/3 (u) and +1/3 (anti-d), which gives the total charge +1.
The neutral pimeson, 0, consists of the quark pairs (u, anti-u) or (d, anti-d). Both combinations give the total charge 0. 0 decays when its quarks annihilates each other; photons are created in such a decay.
Finally, the negative pimeson, -, consists of the quark pair (anti-u, d). It is easy to see how the charges of the quarks combine into -1. - decays through quark transformation into µ-, which decays into an e-; neutrinos are also created in this process.
The pimesons are created "naturally" in the cosmic radiation.