This section discusses the particles our theory will have to explain.
We start with the force-carrying particles, or bosons, for the four known forces.
The strong force is mediated by gluons (g) which come in 8 distinct types.
Electromagnetism is mediated by photons (γ) which have a polarisation.
The weak force is mediated by Z0, W+ and W– particles. The latter two interact with electromagnetism which are indicated in the figure with a little blue square.
No particles mediating gravity are known.
The other particles are known as fermions.
Up (u) and down (d) are quarks which feel the strong force as well as the electromagnetic force; this is to say they have a colour charge and an electromagnetic charge. We indicate this in the diagram above with two coloured boxes.
The electron (e) feels only electromagnetism and has no colour charge.
The electron neutrino (νe) interacts neither with electromagnetism nor the strong force.
All these four particle types are triplicated using the weak force, shown by light green arrows. (The up quark (u) as charmed (c) and top (t), the down quark (d) as strange (s) and bottom (b) etc.) Furthermore each also exists as an antiparticle; this duplication is not shown in the diagram.
Recently a new boson has been discovered at CERN. [i]
Each particle also has an intrinsic energy, its mass, which is not noted on the diagrams above.