Beta Decay

In beta-minus decay, a neutron changes into a proton, β-minus particle(electron) and an antineutrino.The W^- boson decays into a β^- particle and an antineutrino.
In beta-plus decay, a proton changes into a neutron, β-plus particle(positron) and a neutrino.The W⁺ boson decays into a β⁺ particle and a neutrino.If a W boson meets a neutrino or antineutrino it changes them into a beta minus or beta plus particle.If no neutrino or anti-neutrino is present, the W^- boson decays into a β- particle and an antineutrino and the W⁺ boson decays into a β+ particle and a neutrino.