After attending a seminar, a confusion arose. I attempted to ask the speaker the question, but it seems that my question may not be well posed, so I'll try here. As I understand it, gluon saturation are places we expect there to be gluons based on some transverse momentum after our interactions. From these saturations, we then expect there to be some gluon-gluon interactions coming out? I'm not sure, I don't understand QCD all too well. Since (I believe) conventional QFT uses Minkowski spacetime, my particle states are therefore representations of the poincare group AKA, give me symmetry. So, I have a momentum, but an indeterminate position, which isn't a problem on this flat spacetime. Thus, I will get a distribution of where I expect my gluons to be at, but nothing exact. If that is the case, then here is where my confusion arises! This doesn't seem to be a consequence of QCD, but rather a consequence of QFT on a flat spacetime. So I don't understand what is so special about this, and why it would show experimental validation of QCD. So where in QCD does this pop up? Am I correct in thinking this is just a consequence of QFT on a flat spacetime? Sorry if my assumptions are wrong, or I understood gluon saturation wrong, but hopefully you see where my confusion arises. Thanks for your time and, hopefully, your help!