# Is direct observation of strong and weak force ruled out by quantum field theory?

In quantum field theory electromagnetic radiation is described by a theory with an abelian gauge symmetry while the weak and strong force are described by theories with non abelian gauge symmetry. We expect observables to be gauge invariant. The field strength tensor in electromagnetism is gauge invariant while that in a yang-mills theory is not. Does this have anything to do with the fact that we can directly observe the electromagnetic radiation like for example using a photon detector while that can't be done with weak or strong force?

I am not interested in the experimental difficulties in doing the same but rather would like to know whether the theory itself rules out direct observation of gluons,W,Z bosons and whether it has to do with the field strength tensor being non gauge invariant.

• It's a long story, but through "the principle of complementarity", the weak observables are, in fact, gauge invariant quantities involving Higgs fields, which, in some gauges, look like the gauge-noninvariant ones... – Cosmas Zachos Dec 24 '17 at 0:57