The Standard Model is the current theory of the fundamental particles and the forces between them. A fundamental particle has no smaller parts.The fundamental particles of matter are:
• six quarks: up, down, strange, charm, top and bottom. Quarks feel the strong force and combine to make hadrons
• six leptons: the electron, muon and tau, and their three neutrinos. Leptons do not feel the strong force
Each quark and lepton has an antiparticle.The forces are carried by exchange particles (bosons):
• the photon carries the electromagnetic force
• the W and Z bosons carry the weak force
• the gluon carries the strong force
The Higgs boson, found at CERN in 2012, is linked to how particles get their mass. Gravity is not included in the Standard Model.Using this quark-lepton model, particles are classified as:
• baryons (e.g. protons and neutrons), made of three quarks
• mesons (e.g. pions), made of a quark and an antiquark
• leptons (e.g. electrons and neutrinos), which are fundamental
• photonsThe quarks and leptons fall into three generations of pairs. This symmetry was a powerful guide: when only five quarks were known, the pattern predicted a sixth, the top quark, which was finally found in 1995.
• six quarks: up, down, strange, charm, top and bottom. Quarks feel the strong force and combine to make hadrons
• six leptons: the electron, muon and tau, and their three neutrinos. Leptons do not feel the strong force
Each quark and lepton has an antiparticle.The forces are carried by exchange particles (bosons):
• the photon carries the electromagnetic force
• the W and Z bosons carry the weak force
• the gluon carries the strong force
The Higgs boson, found at CERN in 2012, is linked to how particles get their mass. Gravity is not included in the Standard Model.Using this quark-lepton model, particles are classified as:
• baryons (e.g. protons and neutrons), made of three quarks
• mesons (e.g. pions), made of a quark and an antiquark
• leptons (e.g. electrons and neutrinos), which are fundamental
• photonsThe quarks and leptons fall into three generations of pairs. This symmetry was a powerful guide: when only five quarks were known, the pattern predicted a sixth, the top quark, which was finally found in 1995.