QCD equation of state: Physical quark masses and asymptotic temperatures

Abstract

Within a phenomenological quasiparticle model, the quark mass and temperature dependence of the QCD equation of state is discussed and compared with lattice QCD results. Different approximations for the quasiparticle dispersion relations are employed, scaling properties of the equation of state with quark mass and deconfinement temperature are investigated and a continuation to asymptotically large temperatures is presented.

High-temperature limit of Breit–Wheeler pair production in a black-body field

“…This is complicated, though, by the fact that we have just shown that the Breit-Wheeler is peculiarly coupled to the low-energy regime. To get a qualitative idea of the impact of the effects neglected, consider that one of the most important non-perturbative effects of a thermal background is to introduce a ''thermal mass'' to the constituent particles, 𝑚 th ∶= 𝜇𝑘 𝐵 𝑇 𝛾 ∕𝑐 2 , where 𝜇 ∼ √ 𝛼 [9,11,12]. (Taking this to be the only thermal adjustment of the dispersion relations becomes a good approximation in the hard momentum regime.)…”