Question: Do you think there are dark forces linked in with dark matter?

Baptiste Ravina answered on 12 Mar 2020:

If Dark Matter is indeed a particle (or several particles), then it is very likely indeed. The concept of “forces” when talking about quantum theory and particle physics is a bit different from the macroscopical concepts of say, gravity or magnetism, where the force e.g. acts on an object to change its trajectory.

The concept of forces in quantum theory is completely connected with that of the particles they act on (fermions, the particles of matter) or the ones that “carry” them (bosons). If Dark Matter particles can be produced and can decay to other particles, we need a description of their interactions – and that’s exactly what a quantum force is.

We originally thought that the 3 quantum forces we have so far (electromagnetic, weak and strong nuclear forces) would be enough, but that in turns mean that we should see Dark Matter particles interact with ordinary matter about as often as ordinary matter does with itself – and that’s not what we observe. So it’s quite likely that there is a new kind of “dark force” that is much weaker, and would explain both why it’s so hard to produce Dark Matter in the lab and why it’s stable (= rarely decays).