What group of particles do leptons belong to?

Leptons belong to one of the two groups of matter particles, which include fermions. Fermions are characterized by having half-integer spin and include not only leptons but also quarks, which make up hadrons. The distinction of leptons as a separate group is important because they do not experience strong interactions, which distinguishes them from other matter particles in the universe.

Leptons include familiar particles such as the electron, muon, and tau, along with their corresponding neutrinos. The classification into two groups—leptons and quarks—helps physicists understand the structure of matter at a fundamental level, as it outlines how these particles interact and are involved in various physical processes.

Understanding that leptons are not composite particles (which would include hadrons made of quarks) is crucial. Rather, they are fundamental particles that participate in weak and electromagnetic interactions, distinguishing them from other categories of matter particles. Therefore, recognizing that leptons constitute a primary category of matter particles further solidifies their significance in the field of particle physics.