On emergent particles and stable neutral plasma balls in SU(2) Yang-Mills thermodynamics

For a pure SU(2) Yang-Mills theory in 4D we revisit the spatial (3D), ball-like region of radius $r_0$, in its bulk subject to the pressureless, deconfining phase at $T_0=1.32\,T_c$ where $T_c$ denotes the critical temperature for the onset of the deconfining-preconfining phase transition. Such a region possesses of a finite energy density and represents the self-intersection of a figure-eight shaped center-vortex loop if a BPS monopole of core radius $\sim \frac{r_0}{52.4}$, isolated from its antimonopole by repulsion externally invoked through a transient shift of (anti)caloron holonomy (pair creation), is trapped therein. The entire soliton (vortex line plus region of self-intersection of mass $m_0$ containing the monopole) can be considered an excitation of the pressureless and energyless ground state of the confining phase. Correcting an earlier estimate of $r_0$, we show that the vortex-loop self-intersection region associates with the {\sl central part} of a(n) (anti)caloron and that this region carries one unit of electric U(1) charge via the (electric-magnetic dually interpreted) charge of the monopole. The monopole core quantum vibrates at a thermodynamically determined frequency $\omega_0$ and is unresolved. For a deconfining-phase plasma oscillation about the zero-pressure background at $T=T_0$ we compute the lowest frequency $\Omega_0$ within a {\sl neutral} and homogeneous spatial ball (no trapped monopole) in dependence of its radius $R_0$. For $R_0=r_0$ a comparison of $\Omega_0$ with $\omega_0$ reveals that the neutral plasma oscillates much slower than the same plasma driven by the oscillation of a monopole core.