emmision of beta particles by a decaying radioactive atom
In nuclear physics, beta decay is a type of radioactive decay where a beta particle (an electron or a positron) is made and sent away, or emitted. When it is an electron, it is called beta minus, and changes a neutron into a proton. When it is a positron, it is beta plus and changes a proton into a neutron. The weak force makes Beta decay possible.