Comments on |V ub /V cb | and |V ub | from non-leptonic B decays within the perturbative QCD approach

The Color String Percolation Model (CSPM) is used to determine the equation of state (EOS) of the Quark–Gluon Plasma (QGP) produced in central Au–Au collisions at $\sqrt{s_{\mathit{NN}}} = 200$  A GeV using STAR data at RHIC. When the initial density of interacting colored strings exceeds the 2D percolation threshold a cluster is formed, which defines the onset of color deconfinement. These interactions also produce fluctuations in the string tension which transforms the Schwinger particle (gluon) production mechanism into a maximum entropy thermal distribution analogous to QCD Hawking–Unruh radiation. The single string tension is determined by identifying the known value of the universal hadron limiting temperature T _c =167.7±2.6 MeV with the CSPM temperature at the critical percolation threshold parameter ξ _c =1.2. At midrapidity the initial Bjorken energy density and the initial temperature determine the number of degrees of freedom consistent with the formation of a ～2+1 flavor QGP. An analytic expression for the equation of state, the sound velocity $C_{s}^{2}(\xi)$ is obtained in CSPM. The CSPM $C_{s}^{2}(\xi)$ and the bulk thermodynamic values energy density ε/T ⁴ and entropy density s/T ³ are in excellent agreement in the phase transition region with recent lattice QCD simulations (LQCD) by the HotQCD Collaboration.