Leptons are a type of elementary particle that are fundamental to the structure of matter. They are part of the Standard Model of particle physics and include particles such as electrons, muons, and tau particles. Leptons do not experience the strong nuclear force, which distinguishes them from other particles like quarks. Each lepton has an associated neutrino, which is a nearly massless particle that interacts very weakly with matter. Leptons come in three "flavors" based on their charge: the negatively charged electron, the positively charged positron, and the neutral neutrinos.