Ask Ethan: Are The Smallest Particles Of All Truly Fundamental?
“Is there theoretical or experimental evidence which unambiguously establishes the existence of fundamental particles?”
When we talk about the Standard Model, including the quarks, leptons, their antiparticles, and the bosons that make up the Universe, we implicitly assume that these are fundamental particles. When we say fundamental, we often imply that these are the smallest possible, indivisible structural components of all that exists. Yet there’s a limit as far as how well we actually know this goes. Our experimental reach is limited in terms of energy; better deep inelastic scattering experiments might yet reveal a composite structure to the particles that we presently think are fundamental. There might be a more fundamental structure that makes up these particles, and those structures may not be particles. Dark matter and dark energy may not be particles at all, and space and time might be continuous or discrete, quantum or not, and either fundamental or emergent.