Have gluons been observed? What is really happening during the virtual exchange of a gluon?

Answer 1

In particle physics, gluons are vector gauge bosons that mediate strong color charge interactions of quarks in quantum chromodynamics (QCD). Unlike the neutral photon of quantum electrodynamics (QED), gluons themselves participate in strong interactions. The gluon has the ability to do this as it carries the color charge and so interacts with itself, making QCD significantly harder to analyse than QED.