Light pseudo-scalar meson masses under strong magnetic fields within the SU(3) Nambu-Jona-Lasinio model

TL;DR

This study investigates how strong magnetic fields affect the masses of pseudoscalar mesons using the SU(3) Nambu-Jona-Lasinio model, comparing results with lattice QCD data to understand meson behavior under extreme conditions.

Contribution

It introduces a magnetic field-dependent coupling in the NJL model and compares neutral and charged meson mass behaviors with lattice QCD results under strong magnetic fields.

Findings

Neutral meson masses decrease with increasing magnetic field.

Charged meson masses increase with magnetic field, contrary to some lattice results.

Magnetic field-dependent coupling improves agreement with lattice data for neutral mesons.

Abstract

We calculate the pole masses of pseudoscalar mesons in a strongly magnetized medium within the framework of the SU(3) Nambu-Jona--Lasinio model, using a magnetic field-independent regularization scheme. We employ both a constant and a magnetic field-dependent coupling $G(B)$, the latter being fitted to reproduce lattice QCD results for the pseudocritical chiral transition temperature. Numerical results for the pole masses are obtained for definite parametrizations of the model. For neutral mesons, the use of $G(B)$ provides closer agreement with lattice QCD results, which reveal a decrease of the mass with the external field. On the contrary, charged mesons masses are enhanced by $B$, showing no sign of the non-monotonous behavior found in recent lattice QCD simulations.