Flavor SU(3) Symmetries in Particle Physics

The development of the so‐called standard model of the strong and electroweak interactions of particle physics is one of the most remarkable accomplishments of 20th century science. The standard model is based on the idea of gauge symmetry, in which the mathematical idea of symmetry determines the dynamics. According to the model, the strong, weak and electromagnetic forces are mediated by an exchange of particles: The strong force is mediated by the gluons, the weak force by the $W+,$ $W−$ and Z bosons, and the electromagnetic force by the photon. In turn the gluons, the bosons and the photon are associated with the SU(3), SU(2) and U(1) symmetries of the standard model. In this article I shall discuss a different kind of symmetry, the so‐called flavor symmetry, which turns out to be only approximate. Flavor symmetry is not associated with the forces of the standard model; instead it pertains to the particles, especially the quarks, between which the forces act.