The *Standard Model of Particle Physics* is our best description of how Nature works on the smallest scales. It describes, for example, how [[Quark|quarks]] build [[Proton|protons]] and [[Neutron|neutrons]], the particles that build the cores of [[Atom|atoms]]. The *Standard Model* consists of four groups of particles: [[Quark|quarks]], [[Lepton|leptons]], vector bosons and a scalar boson. We already met the quarks (in yellow): they are the elementary constituents of matter, i.e. everything that we see and touch around us is made of quarks. They make up [[Fermion|fermionic matter]]. [[Lepton|Leptons]] (in blue) are particles that occur as matter, but they are not made up of [[Quark|quarks]]. They cannot interact via the [[Strong Force|strong force]], more about that later. The most famous [[Lepton|lepton]] is the electron. It is part of every [[Atom|atom]] and balances the positive charge in the nucleus to make sure that atoms are electrically neutral. Particles like [[Muon|muons]] and [[Tau|taus]] are usually part of [[Cosmic Ray|cosmic rays]]. Until now, we have described particles that make up matter, but they cannot interact yet. This is the job of the [[Boson|bosons]] of the theory. Three out of four [[Fundamental Forces|fundamental forces]] (strong, weak and electromagnetic force) are described by the so-called gauge bosons (in red). Only gravity has so far resisted our best attempts to include it into the *Standard Model*. [[Gluon|Gluons]] are moderating the [[Strong Force|strong force]], while [[Z Boson|Z bosons]] and [[W Boson| W bosons]] cause the [[Weak Force]]. Finally, the electromagnetic interaction is carried by the [[Photon|photon]]. Finally, one special particle was added to the model, the [[Higgs Boson|Higgs boson]] to fix a problem of the standard model: it could not explain how mass was generated. ![[standard_model.excalidraw.light.svg]] >[!read]- Further Reading >- [[Fermion]] >- [[Boson]] >- [[Quantum Field Theory]] >- [[Fundamental Forces]] >[!ref]- References >- S. F. Novaes, _Standard Model: An Introduction_, arXiv:hep-ph/0001283. >- _The Standard Model_, [https://home.cern/science/physics/standard-model](https://home.cern/science/physics/standard-model). >- W. N. Cottingham and D. A. Greenwood, _An Introduction to the Standard Model of Particle Physics_, 2nd ed. (Cambridge University Press, Cambridge, 2007).