How would you best describe beta particles?

Beta particles are best described as charged particles, specifically either an electron or a positron. Beta decay is a type of radioactive decay in which a neutron is transformed into a proton or a proton into a neutron, leading to the emission of either an electron (beta minus decay) or a positron (beta plus decay).

In beta minus decay, a neutron converts into a proton while emitting an electron and an antineutrino. Conversely, in beta plus decay, a proton converts to a neutron, emitting a positron and a neutrino. Both forms of beta particles are characterized by their charge—electrons carry a negative charge, while positrons carry a positive charge—making them distinct from other particles like alpha particles, which are helium nuclei, or gamma rays, which are uncharged electromagnetic radiation.

Thus, the defining feature of beta particles is their charge, either positive or negative, depending on the type of beta decay, which makes the description of them as charged particles, either an electron or a positron, the most accurate.