Light baryons below and above the deconfinement transition: medium effects and parity doubling

Abstract

Abstract We study what happens to the N , Δ and Ω baryons in the hadronic gas and the quark-gluon plasma, with particular interest in parity doubling and its emergence as the plasma is heated. This is done using simulations of lattice QCD, employing the FASTSUM anisotropic N f = 2 + 1 ensembles, with four temperatures below and four above the deconfinement transition temperature. Below T c we find that the positive-parity groundstate masses are largely temperature independent, whereas the negative-parity ones are reduced considerably as the temperature increases. This may be of interest for heavy-ion phenomenology. Close to the transition, the masses are nearly degenerate, in line with the expectation from chiral symmetry restoration. Above T c we find a clear signal of parity doubling in all three channels, with the effect of the heavier s quark visible.

Keywords

• Lattice Quantum Field Theory
• Phase Diagram of QCD
• Quark-Gluon Plasma
• Thermal Field Theory