Evidence from Very Large Transverse Momenta of a Change with Temperature of Velocity of Sound in Hadronic Matter

The most recent CERN intersecting storage-rings data on very large transverse momenta show that the velocity of sound in hadronic matter increases from $\ensuremath{\simeq}1\sqrt{7} \mathrm{to} \ensuremath{\simeq}1\sqrt{3.5}$, implying a phase transition from a strongly interacting (hadron) phase to a weakly interacting (parton?) phase.