subatomiques

Subatomiques, or subatomic particles, are the constituents of matter and radiation smaller than atoms. They are categorized as elementary particles, which have no internal structure, and composite particles, which are bound states of more fundamental entities. The study of subatomic particles underpins particle physics, describing interactions via the electromagnetic, weak, and strong forces, with gravity negligible at the microscopic scale.

Historically, subatomic research began with the discovery of the electron in 1897, followed by the identification of the atomic nucleus in 1911, and the discovery of protons and neutrons in the 1910s–1930s. The quark model, proposed in 1964, provided a framework in which protons, neutrons, and many other hadrons are composed of quarks. The Standard Model of particle physics integrates these ideas into a coherent theory of fundamental particles and their interactions.

The elementary fermions divide into leptons (electron, muon, tau and their neutrinos) and quarks (up, down, charm, strange, top, bottom). Elementary bosons include the gauge bosons—photon, W and Z bosons, gluons—as well as the Higgs boson, which endows particles with mass. Composite particles, or hadrons, include baryons (such as protons and neutrons) and mesons (such as pions). For every particle, an antiparticle with opposite quantum numbers exists. Hadrons are bound by the strong force, while leptons do not participate in strong interactions.

Properties of subatomic particles—mass, electric charge, spin, and lifetimes—are measured in high-energy experiments using accelerators and detectors. The Standard Model successfully explains a wide range of phenomena but leaves questions unresolved, including the nature of dark matter, neutrino masses, and gravity. Ongoing experiments seek new particles and forces that could extend or supersede the current framework.