Nature of the chiral restoration transition in QCD

As the chirally restored phase ends with T coming down to Tc, a phase resembling a mixed phase is realized, during which the hadrons (which are massless at Tc in the chiral limit) get their masses back out of their kinetic energy. The gluon condensation energy is fed into the system to keep the temperature (nearly) constant. Lattice results for the gluon condensation are matched by a Nambu–Jona–Lasinio calculation. The latter shows that below Tc the chiral symmetry is barely broken, so that with an ∼6% drop in the scalar coupling G it is restored at Tc. Nearly half of the glue, which we call epoxy, is not melted at Tc.