Deconfinement phase transition due to disappearance of confining colorelectric field correlators is described using nonperturbative equation of state. The resulting transition temperature T c (µ) at any chemical potential µ is expressed in terms of the change of gluonic condensate ∆G 2 and absolute value of Polyakov loop L f und (T c ), known from lattice and analytic data, and is in good agreement with lattice data for ∆G 2 ≈ 0.0035 GeV 4 . E.g. T c (0) = 0.27; 0.19; 0.17 GeV for n f = 0, 2, 3 respectively.

The theory of confinement and deconfinement is discussed as based on the properties of the QCD vacuum. The latter are described by field correlators of colour-electric and colour-magnetic fields in the vacuum, which can be calculated analytically and on the lattice. As a result one obtains a self-consistent theory of the confined region in the (µ, T ) plane with realistic hadron properties. At the boundary of the confining region, the colour-electric confining correlator vanishes, and the remaining correlators describe strong nonperturbative dynamics in the deconfined region with (weakly) bound states. Resulting equation of state for µ = 0, p(T ), ε−3P T are in good agreement with lattice data. Phase transition occurs due to evaporation of a part of the colour-electric gluon condensate, and the resulting critical temperatures Tc(µ) for different n f are in good correspondence with available data. October 22, 2018 5:45 WSPC/INSTRUCTION FILE QGP 2 A.V. Nefediev, Yu.A. Simonov, M.A. Trusov

It is argued that the dominant contribution to the interaction of quark gluon plasma at moderate $T\geq T_c$ is given by the nonperturbative vacuum field correlators. Basing on that nonperturbative equation of state of quark-gluon plasma is computed and in the lowest approximation expressed in terms of absolute values of Polyakov lines for quarks and gluons $L_{fund} (T); L_{adj}(T)=(L_{fund})^{9/4}$known from lattice and analytic calculations. Phase transition at any $\mu$ is described as a transition due to vanishing of one of correlators, $ D^E(x)$, which implies the change of gluonic condensate $\Delta G_2$. Resulting transition temperature $T_c(\mu)$ is calculated in terms of $\Delta$$G_2$ and $L_{fund}(T_c)$. The phase curve $T_c(\mu)$ is in good agreement with lattice data. In particular $T_c(0)=0.27; 0.19; 0.17$ GeV for $n_f=0,2,3$ and fixed $\Delta G_2=0.0035$ GeV$^4$.Comment: 14 pages, 2 figures, 1 table; some abbreviations explained; to appear in Physics Letters

We review the results obtained in an Effective Hamiltonian (EH) approach for the three-quark systems. The EH is derived starting from the Feynman--Schwinger representation for the gauge-invariant Green function of the three quarks propagating in the nonperturbative QCD vacuum and assuming the minimal area law for the asymptotic of the Wilson loop. It furnishes the QCD consistent framework within which to study baryons. The EH has the form of the nonrelativistic three-quark Hamiltonian with the perturbative Coulomb-like and nonperturbative string interactions and the specific mass term. After outlining the approach, methods of calculations of the baryon eigenenergies and some simple applications are explained in details. With only two parameters: the string tension $\sigma=0.15 GeV^2$ and the strong coupling constant $\alpha_s=0.39$ a unified quantitative description of the ground state light and heavy baryons is achieved. The prediction of masses of the doubly heavy baryons not discovered yet are also given. In particular, a mass of $3660 MeV$ for the lightest $\Xi_{cc}$ baryon is found by employing the hyperspherical formalism to the three quark confining potential with the string junction.Comment: 25 pages, 4 figures included, LaTeX 2e; to be published in Phys. Atom. Nuc

We present some piloting calculations of masses and short-range correlation coefficients for the ground states of light and heavy baryons in the framework of the simple approximation within the nonperturbative QCD approach.