The Quantum Chromodynamic Black Body Radiation and the Universe

Abstract

The pressure of the black body radiation which consists of quarks, antiquarks and gluons is calculated by a perturbation method up to the third order of the gauge coupling constant g. It is found that the pressure obtained in this way becomes negative in the temperature below a few hundred MeV due to the plasma shielding effect. Using this result, a possible archaeology of the hadron era of the big bang universe is constructed, and the number ratio of the baryons to the photons is explained.