Asymmetric magnetized QCD matter realized by scalar and instanton-induced interactions

Abstract

In a strong magnetic field utilizing a two-flavor NJL model, the isospin symmetry and asymmetry can be realized by altering the fraction parameter [Formula: see text] of the two kinds of interactions, i.e. the scalar coupling and instanton-induced coupling. As [Formula: see text] increases, the [Formula: see text] quark mass decreases while [Formula: see text] quark mass increases monotonously. The two mass lines cross at [Formula: see text] with an isospin symmetry mass [Formula: see text]. Even in the flavor-decoupled state, i.e. the strong isospin asymmetry, the [Formula: see text] and [Formula: see text] mass lines can have a common mass at a critical temperature [Formula: see text]. As the magnetic field becomes stronger, the [Formula: see text] will move towards the chiral restoration phase. The strong isospin asymmetry will lead to a split of the pseudocritical temperatures for [Formula: see text] and [Formula: see text] quarks, which can be reflected by the two peaks of the specific heat and sound velocity.