Quark-hadron crossover equations of state for neutron stars: constraining the chiral invariant mass in a parity doublet model

Remarks on nuclear matter: how an $ω_0$ condensate can spike the speed of sound, and a model of $Z(3)$ baryons

“…This leaves open the question of how to match the EoS for quarks onto that of baryons about k F Q , where neither is close to ideal. The Quantum HadroDynamics (QHD) of Serot and Walecka [3][4][5] can be used for baryons, although to be capable of modeling a confined but chirally symmetric phase, all chiral partners of the nucleons and mesons must be included in a parity-doubled QHD (PdQHD) [60][61][62][63][64][65][66][67][69][70][71][72][73]. The quark EoS can be modeled by coupling quarks and gluons to a linear sigma model for mesons.…”

“…( 4), since φ transforms nontrivially under SU (2) L × SU (2) R . The ω µ meson does interact with pions through anomalous interactions generated by the the Wess-Zumino-Witten Lagrangian, such as ω µ → 3π [59,[66][67][68][69][70][71][72][73][74][75][76]. These interactions survive in the chirally symmetric phase, and typically become ω → σπππ, Eq.…”

“…For the usual analyses of QHD [3][4][5], Refs. [35][36][37][38][39][40][41][42][43][44], and PdQHD [60][61][62][63][64][65][66][67][68][69][70][71][72][73], the σ and ω 0 masses both decrease, as the balance between σ attraction and ω 0 repulsion gives a soft EoS.…”