Probing small length scales in heavy-ion collisions with event-by-event correlation analysis

I consider recent proposals of fluctuation suppression for certain global event variables in heavy-ion collisions as a signature of QGP formation. I relate these proposals to possible formation of a pion lattice at chemical freeze out due to rapid traversal of the QCD phase boundary reflecting the greater symmetry of a locally equilibrated prehadronic state. I then present a method to detect this structure in the transverse phase space of heavy-ion collisions which depends on a newly-identified effect of local transverse Hubble flow on two-particle distributions and suggest that such structure may have been observed already in the transverse phase space of Pb-Pb collisions at the SPS