<|im_start|>user
What is a lepton?<|im_end|>
<|im_start|>assistant
A lepton is an elementary particle that interacts via the weak force and has a half-integer spin. Examples of leptons include the electron, muon and tau particles and their corresponding neutrinos - the electron neutrino, the muon neutron and the tau neutrino.<|im_end|>
