Quark contribution for center domain in heavy ion collisions

The center domain structure is revisited with the introduction of a quark contribution to understand the phenomenology in high-energy heavy-ion collisions. We show that the quark contribution may allow metastable states that would lead to a natural and consistent explanation for the temperature dependencies of color opacity and viscosity. We also argue the possibility of indirect observations of the center domain structure in experiments due to a topological critical temperature.

Figure 1

The flavor dependence of the effective potential normalized by $T^4$.

Figure 2

Possible schematic pictures of the temperature dependence of parton scattering by broken center domains. Dashed lines denote $\nu =0$ to/from the 1, 2 boundary with the quark contribution. (a) The mean free path is typically of the domain size in the pure gauge scenario [6]. (b) Domains are partially broken due to metastable minima induced by quarks. (c) $\nu =0$ is significantly favored at higher energies and these domains connect to form large clusters. $\nu =1$, 2 shrinks as their pressures decrease. (d) The metastable states vanish above $T^{\mathrm{cri}}$ before their pressures become negative.