On the existence of a phase transition for QCD with three light quarks

Abstract

We report full QCD simulations on a 16 3 x4 lattice. For two degenerate flavors no finite-temperature phase transition is found for quark masses of ma =0.01 and 0.025, where a is the lattice spacing, while for three degenerate flavors a first-order transition is easily seen for ma =0.025. Nature, with nearly massless up and down quarks and one heavier strange quark, lies between these two cases. For m u ja =0.025 and m s a =0.1 we find that mK/m p =0.46(1) and that no transition occurs, calling into question the existence of a QCD phase transition.

Finite temperature QCD on the lattice

“…Numerical results obtained so far for the transition with N F = 2 staggered quarks are consistent with a second order chiral transition: No signs of discontinuities are found at m q a 0:0125 for N t = 4 and 6, where N t is the lattice extension in the temporal direction 6,13,14]. Also a nite size scaling for a rst order transition is not compatible with the data obtained at m q a = 0:01 { 0.0125 and N t = 4 14,15].…”

Bulk QCD thermodynamics and sterile neutrino dark matter

“…The position of this critical point in temperature, µ q , and m qs is still under investigation by lattice simulations and may be probed by relativistic heavy ion collision experiments [24]. Lattice calculations indicate m c qs is well below the inferred physical strange quark mass [25,26], but these results are not conclusive [27]. Since production of sterile neutrinos peaks at T ∼ 130 MeV(m s /3 keV) 1/3 , and the QCD transition likely occurs from T crit = 100 − 200 MeV, the effects of the transition on production are unmistakably important.…”

Phase diagram of Nambu–Jona-Lasinio model with dimensional regularization

“…Having obtained the phase diagram for the NJL model in the DR scheme, it may be interesting to discuss the chiral critical boundary, so called Columbia plot [41]. The critical boundary is drawn by searching the order of the phase transition for various m u and m s while the remaining parameters discussed in Sec.…”