Strange quark matter in the presence of explicit symmetry breaking interactions

TL;DR

This paper demonstrates a first order phase transition in strange quark matter within a generalized three-flavor NJL model, highlighting the role of explicit symmetry breaking interactions in facilitating strange quark matter production.

Contribution

It introduces a comprehensive NJL model including LO and NLO explicit chiral symmetry breaking interactions, showing their impact on phase transitions and strange quark matter formation.

Findings

First order transition at moderate chemical potential (~400 MeV)

Explicit symmetry breaking interactions act as a catalyst for strange quark matter

Inclusion of OZI-violating interactions reproduces scalar meson mass ordering

Abstract

It is shown that a first order transition associated with a jump in the strange quark mass appears in a generalized 3 flavour Nambu--Jona-Lasinio (NJL) treatment of quark matter. The generalization of the Lagrangian displays the complete set of spin 0 interactions at leading and subleading orders (LO and NLO) in $\frac{1}{N_c}$counting, including the recently derived NLO explicit chiral symmetry breaking interactions which are of the same order as the 't Hooft flavour determinant. The parameters of the model are tightly constrained by the low energy characteristics in both the pseudoscalar and scalar meson sectors. The transition occurs in a moderate chemical potential region ($\mu \simeq 400~\mathrm{MeV}$ for zero temperature) in addition to the usual chiral transition associated with the light quark sector. This feature has at its root the inclusion of the explicit chiral symmetry breaking interactions, which therefore can be seen to act as a catalyst in the production of strange quark matter when compared to the conventional version of the model that takes only into account the 't Hooft interaction in the NLO. It can be traced back to the effect of the interactions which do not violate the Okubo-Zweig-Iizuka rule (OZI), without which the empirical ordering of the scalars ($m_{K^\star}< m_{a_0}\approx m_{f_0}$) is not reproduced.