In many drawings for jets or hadronization there are outgoing individual quark or gluon lines from which hadrons seem to emerge. But this is wrong: a color-neutral hadron cannot emerge from a single quark or gluon line.
See e.g. page 7 in
The Strong Interaction and LHC phenomenology; Juan Rojo; University of Oxford
There is one process where a color singulet $t\bar{t}$ and eventually the final state on the right emerges from a virtual gluon which is a color octet.
What is the correct description of these processes? Is it possible to do this in principle via Feynman diagrams, even if the calculations are too complex in practice?
