Standardimalli

Standardimalli, or the Standard Model of particle physics, is the prevailing theory describing the electromagnetic, weak, and strong interactions among elementary particles. It is a quantum field theory based on the gauge group SU(3)×SU(2)×U(1) and includes fermions, gauge bosons, and the Higgs field. The model posits three generations of matter: quarks (up, down; charm, strange; top, bottom) and leptons (electrons, muons, taus and their corresponding neutrinos), along with the gauge bosons that mediate the forces—gluons for the strong interaction; photons for electromagnetism; and the W± and Z bosons for the weak interaction—plus the Higgs boson.

Interactions arise from gauge invariance. The strong force is mediated by gluons associated with SU(3) color symmetry; the electroweak sector unifies electromagnetic and weak interactions, yielding the photon and the W and Z bosons after spontaneous symmetry breaking. The Higgs field provides masses through the Higgs mechanism and Yukawa couplings to fermions, giving mass to W and Z bosons and to fermions.

The Standard Model is renormalizable and currently contains about 19 free parameters, including masses, mixing angles, and coupling constants. Neutrino masses require physics beyond the minimal model. Gravity is not included, and the model does not provide a dark matter candidate in its simplest form.

Experiments have validated its predictions with high precision, from deep inelastic scattering and electroweak measurements to the discovery of the Higgs boson in 2012 at the Large Hadron Collider. Ongoing research tests its limits and searches for new physics beyond the Standard Model.