Signals of initial state quantum entanglement in relativistic particle collisions

I will show thermodynamic entropy calculations based on charged particle multiplicity data from proton-proton collisions at the LHC in comparison to entanglement entropy calculations based on initial state gluon distributions. The commonalities between the initial and final state distributions suggest that entanglement could be a possible source for the seemingly thermal and collective behavior in small systems. I will pose the question on when such a picture could and will break down due to decoherence of the initial state. I will also try to show that a rather simple final state measurement should be sensitive to gluon saturation, in particular when properly binned in rapidity space.