Parity doubling structure of nucleon at non-zero density in the holographic mean field theory

TL;DR

This paper develops a holographic mean field theory model including baryons and mesons to study how parity doubling affects the nuclear matter equation of state at non-zero density, revealing a density-dependent decrease in effective nucleon mass.

Contribution

It introduces a bottom-up holographic QCD model with baryons and mesons to analyze the impact of parity doubling on the nuclear matter equation of state at finite density.

Findings

Effective nucleon mass decreases with increasing density.

The rate of mass decrease is faster when more mass originates from chiral symmetry breaking.

The model aligns with Walecka-type models in predicting the equation of state.

Abstract

We develope the holographic mean field theory approach in a bottom-up holographic QCD model including baryons and scalar mesons in addition to vector mesons and pions. We study the effect of parity doubling structure of baryons at non-zero density to the equation of state between the chemical potential and the baryon number density. We first show that we can adjust the amount of nucleon mass coming from the chiral symmetry breaking by changing the boundary value of the five-dimensional baryon fields. Then, introducing the mean field for the baryon fields, we calculate the equation of state between the baryon number density and its corresponding chemical potential. Then, comparing the predicted equation of state with the one obtained in a Walecka type model, we extract the density dependence of the effective nucleon mass. The result shows that the effective mass decreases with increasing density, and that the rate of decreasing is more rapid for the larger percentage of the mass coming from the chiral symmetry breaking.