standard model of particle physics
matter field fermions (spinors, Dirac fields)
1st | 2nd | 3d |
---|---|---|
up? | charm | top |
down? | strange? | bottom |
hadron (bound states of the above quarks)
minimally extended supersymmetric standard model
bosinos:
dark matter candidates
Exotica
The standard model of particle physics has the curious property that its content of fermions appears in three sets of particles that share all properties except that their rest mass increases drastically from one set to the next. These are called the three “generations” of fermionic particles.
The first generation contains the
type of fundamental particle | First generation | Second generation | Third generation |
---|---|---|---|
up-type quark | up quark? | charm quark | top quark |
down-type quark | down quark? | strange quark? | bottom quark |
charged lepton | electron | muon | tau? |
neutrino | electron neutrino? | muon neutrino? | tau neutrino? |
Any reason for this striking pattern presently remains mysterious.
While the particle content of any one single generation would naturally be explained by GUT models, in terms of a single irreducible representation of a simple gauge group containing that of the standard model of particle physics, this does not explain why there are three almost identical copies of this.
One suggestion to explain this phenomenon appears in intersecting D-brane models. See there at Generations of fermions.
See also
On model building with realistic Yukawa couplings and fermion masses in an MSSM Pati-Salam GUT model with 3 generations of fermions realized on intersecting D6-branes KK-compactified on a toroidal orbifold $T^6\sslash (\mathbb{Z}_2 \times \mathbb{Z}_2)$ are claimed in
Ching-Ming Chen, Tianjun Li, Van Eric Mayes, Dimitri Nanopoulos, A Realistic World from Intersecting D6-Branes, Phys.Lett.B665:267-270, 2008 (arXiv:hep-th/0703280, doi:10.1016/j.physletb.2008.06.024)
Ching-Ming Chen, Tianjun Li, Van Eric Mayes, Dimitri Nanopoulos, Realistic Yukawa Textures and SUSY Spectra from Intersecting Branes, Phys.Rev.D77:125023, 2008 (arXiv:0711.0396)
Van Eric Mayes, All Fermion Masses and Mixings in an Intersecting D-brane World (arXiv:1902.00983)
Jordan Gemmill, Evan Howington, Van E. Mayes, One String to Rule Them All: Neutrino Masses and Mixing Angles (arXiv:1907.07106)
Last revised on July 17, 2019 at 05:55:38. See the history of this page for a list of all contributions to it.