Thermo-magnetic spectral properties of neutral mesons in vector and axial-vector channels using NJL model

Abstract

In this work the neutral meson properties have been investigated in the presence of thermo-magnetic background using a two-flavor Nambu-Jona-Lasinio model. Mass, spectral function, and dispersion relations are obtained in the scalar (σ) and pseudoscalar (π 0) channels as well as in the vector (ρ 0) and axial vector (a 0 1) channels. The general Lorentz structures for the vector and axial-vector meson polarization functions have been considered in detail. The ultraviolet divergences appearing in this work have been regularized using a mixed regularization technique where the gamma functions arising in dimensional regularization are replaced with incomplete gamma functions as is usually done in the proper time regularization procedure. The meson spectral functions obtained in the presence of a magnetic field possess nontrivial oscillatory structure. Similar to the scalar and pseudoscalar channel, the spectral functions for each of the modes of ρ 0 are observed to overlap with the corresponding modes of its chiral partner a 0 1 mesons in the chiral symmetry restored phase. We observe discontinuities in the masses of all the mesonic excitations for a nonzero external magnetic field.

Insignificance of the anomalous magnetic moment of the quarks in presence of chiral imbalance

“…This behaviour of and Φ mentioned above are consistent with the previous results for NJL-type models as can be seen in Refs. [3,65,71,73,75,76,[87][88][89][90]. = 0.15 GeV 2 .…”

The Green function of the NJL--SU(2) model lagrangian with the AMM effect

“…The anomalous magnetic moment (AMM) term is in the first square brackets, related to the sigma matrices and the electromagnetic tensor. It is considered a phenomenological term, like was shown in [10][11][12].…”

“…The key to the anomalous magnetic moment (AMM) effect in the QCD phase diagram has not been understood. From some works [10][11][12][13], we can see that several properties of the QCD phase diagram can be altered. In a path to obtain a form of the density lagrangian to afterward implement some regularization scheme, we can calculate the Green function to this model with the AMM effect.…”

Polarization tensor of magnetized quark-gluon plasma at nonzero baryon density

“…In the regime of nonzero temperature, the polarization tensor was calculated in the lowest Landau level approximation [19] and the weak-field limit [20,21]. Some results beyond the Landau level approximation were obtained as well [22][23][24][25][26]. Among other results, a closed-form analytical expression for the absorptive part of the polarization tensor was derived in Ref.…”