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
Interaction also be called a fundamental force) is a process by which elementary particles interact with each other. An interaction is often described as a physical field, and is mediated by the exchange of gauge bosons between particles. For example, the interaction of charged particles takes place through the mediation of electromagnetic fields, whereas beta decay occurs by means of the weak interaction. An interaction is fundamental when it cannot be described in terms of other interactions. There are four known fundamental interactions in nature: The electromagnetic, strong, weak and gravitational interactions. The weak and electromagnetic interactions are unified in electroweak