A short history of the smallest

Abstract

Abstract This paper tells the story of the Standard Model of particle physics. That starts in the 1930s with the idea of the pion and then traces its roots from an embryonic quark theory to its contemporary form. Early scepticism towards the quark model dissolved as it elegantly elucidated baryon and meson structures, and helped to uncover the intricacies of the weak and strong interactions. The Δ++ particle’s existence demanded the introduction of ‘colour’ charge, giving birth to Quantum Chromodynamics. Successive discoveries of heavy quarks, heavy leptons and their corresponding neutrinos fortified the Standard Model. The verification of the existence of gluons, the discovery of the W and Z bosons, and - finally - the Higgs boson are considered triumphs of the theory. However, despite its success, the model has inadequacies, notably with regard to dark matter and energy, but also in explaining the very origin of its many free parameters. New ideas and discoveries are needed to help solve these mysteries.