Beta decay is type of radioactive decay where atomic nucleus emitts positron (fast electron) and neutrino.
Beta decay of carbon: 11C(isotope of carbon) → 11B(isotope of boron) + e+(positron) + νe(electron neutrino) + 0.96 MeV (energy released).
Decay is energetically possible because energy is released, but occurs only 0,25% of time.
