On Relation Between the Quark Gluon Bag Surface Tension and the Colour Tube String Tension

Here we revisit the bag phenomenology of the deconfining phase transition to replenish it by introducing systematically the bag surface tension. Comparing the free energy of such bags and that one of the strings confining the static quark-antiquark pair, we express the string tension in terms of the bag surface tension and thermal pressure in order to estimate the bag characteristics using the lattice QCD data. Our analysis of the bag entropy density demonstrates that the surface tension coefficient is amazingly negative at the cross-over (continuous transition). This approach allows us to naturally account for an appearance of a very pronounced maximum (observed in the lattice QCD simulations) of the entropy of the bound static quark-antiquark pair. The vicinity of the (tri)critical endpoint is also analyzed to clarify the meaning of vanishing surface tension coefficient.