====== Quark and lepton 'generations' ======

It's been known since the 1970s that there are three 'generations' of [[content/physics/quantum_physics/quarks|quarks]] (the building components of neutrons and protons)  and also leptons (electrons and similar particles).

All the particles have been rigorously confirmed in multiple experiments, and the three 'generations' (possibly better understood as 'families') are now firmly part of the Standard Model of nuclear physics.

^ Fermion categories |^ Elementary particle generation ||^
^ //Type// ^ //Subtype// ^ //First// ^ //Second// ^ //Third// ^
^ Quarks\\ (coloured) ^ down-type | down | strange | bottom |
| ::: ^ up-type | up | charm | top |
^ Leptons\\  (colour-free) ^ charged | electron | muon | tauon |
| ::: ^ neutral | electron neutrino | muon neutrino | tau neutrino |

<sup>[ table from [[https://en.wikipedia.org/wiki/Generation_(particle_physics)|Wikipedia]] ]</sup>

There is currently no explanation as to why there should be// three //distinct generations of each.

Several experiments have attempted to find fourth generations of various particles, but none has yet been found ([[https://cerncourier.com/a/boosting-searches-for-fourth-generation-quarks/|example research from CERN]]).