Physics is also called "high-energy physics" because many elementary particles do not occur naturally but are created only during high-energy collisions of other particles. Currently, the interactions of elementary particles and fields are described by the Standard Model. The model accounts for the 12 known particles of matter (quarks and leptons) that interact via the strong, weak, and electromagnetic fundamental forces. Dynamics are described in terms of matter particles exchanging gauge bosons (gluons, W and Z bosons, and photons, respectively). The Standard Model also predicts a particle known as the Higgs boson. In July 2012 CERN, the European laboratory for particle
Resonance (particle physics) Resonance (particle physics) In particle physics, a resonance is the peak located around a certain energy found in differential cross sections of scattering experiments. These peaks are associated with subatomic particles, which include a variety of bosons, quarks and hadrons (such as nucleons, delta baryons or upsilon mesons) and their excitations. In common usage, "resonance" only describes particles with very short lifetimes, mostly high-energy hadrons existing for or less. The width of the resonance ("Γ") is related to the mean lifetime ("τ") of the particle (or its excited state) by the relation where "h" is the Planck constant and formula_2.