Add Yahoo as a preferred source to see more of our stories on Google. The particles that are in an atom: protons, neutrons and electrons The particles that are in protons and neutrons: quarks The four ...

In the literal sense, nothing is simpler than an elementary particle: By definition, a particle is considered to be elementary only if there is no evidence that it is made up of smaller constituents.

On one hand there is quantum mechanics and the standard model, which describes the world of the very small. On the other hand there is general relativity, which describes gravity and the world of the ...