The Chiral Model of Sakai-Sugimoto at Finite Baryon Density

TL;DR

This paper investigates the Sakai-Sugimoto holographic QCD model at finite baryon density, revealing that baryonic matter remains in a chiral symmetry broken phase and exploring how density affects meson properties.

Contribution

It provides a detailed analysis of baryon density effects in the Sakai-Sugimoto model, including the behavior of meson masses and couplings at finite density.

Findings

Baryonic matter remains in the chiral symmetry broken phase at all densities.

Baryons exhibit repulsive interactions mediated by omega mesons.

Baryon density influences pion and vector meson masses and couplings.

Abstract

In the context of holographic QCD we analyze Sakai-Sugimoto's chiral model at finite baryon density and zero temperature. The baryon number density is introduced through compact D4 wrapping S^4 at the tip of D8-\bar{D8}. Each baryon acts as a chiral point-like source distributed uniformly over R^3, and leads a non-vanishing U(1)_V potential on the brane. For fixed baryon charge density n_B we analyze the bulk energy density and pressure using the canonical formalism. The baryonic matter with point like sources is always in the spontaneously broken phase of chiral symmetry, whatever the density. The point-like nature of the sources and large N_c cause the matter to be repulsive as all baryon interactions are omega mediated. Through the induced DBI action on D8-\bar{D8}, we study the effects of the fixed baryon charge density n_B on the pion and vector meson masses and couplings. Issues related to vector dominance in matter in the context of holographic QCD are also discussed.