- Composite Particles
In a previous section, we looked at the Standard Model of particle physics which addresses the fundamental elementary particles, and particle theorists believe that they do not have component particles; although, string theorists will tell you that they all comprise a string with different vibration patterns. Some elementary particles, the Quarks, are building blocks used to construct other particles; predominantly mesons and baryons. In this section we shall explore these composite particles including some familiar particles, neutrons & protons, and some less familiar, for example, the pion, lambda and omegas. Unless stated otherwise, all the particles discussed have been identified experimentally. The lists are by no means exhaustive, but give a representation of the wealth of sub-atomic particles that have been found; for example, there are at least 16 different types of X (Xi or Cascade) particle all of which contain an up or down plus two heavier quarks. The masses are not all necessarily defined exactly to the values shown, but the figures are representative approximations. Details of quark properties are shown on the Standard Model page, with a summary in each relevant page of this section.