What is a beta particle?
Beta particle
high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus during the process of beta decay
A beta particle, also called beta ray or beta radiation (symbol β), is a high-energy, high-speed electron or positron emitted by the radioactive decay of an atomic nucleus during the process of beta decay. There are two forms of beta decay, β− decay and β+ decay, which produce electrons and positrons respectively.[1]