What is the name of a lepton discovered during beta decay?

The lepton discovered during beta decay is known as a neutrino. In the process of beta decay, a neutron in an atomic nucleus transforms into a proton while emitting an electron and a neutrino. The neutrino is a fundamental particle that carries away some energy and momentum, ensuring the conservation laws are upheld in the decay process. It is notable for its very small mass and neutral charge, making it extremely elusive and difficult to detect, which contributed to its delayed discovery. The existence of the neutrino was proposed by Wolfgang Pauli in 1930 to address discrepancies in energy conservation observed in beta decay processes, and it was later confirmed through experimental evidence.

While muons and tau particles are also types of leptons, they are not directly involved in the beta decay process. Gluons, on the other hand, are responsible for mediating the strong force between quarks and are not considered leptons.