The Dropping of In-Medium Hadron Mass in Holographic QCD

TL;DR

This paper investigates how vector meson and $ ext{eta'}$ masses change with baryon density using holographic QCD, revealing linear decrease at low density and saturation at high density, consistent with QCD relations.

Contribution

It provides a holographic QCD analysis of in-medium hadron mass modifications, including the $ ext{eta'}$ mass and velocity, and compares results with gauge theory models.

Findings

Vector meson mass decreases linearly at low density.

Mass saturates to a finite value at high density.

Model aligns with GMOR relation up to a few times nuclear density.

Abstract

We study the baryon density dependence of the vector meson spectrum using the D4/D6 system together with the compact D4 baryon vertex. We find that the vector meson mass decreases almost linearly in density at low density for small quark mass, but saturates to a finite non-zero value for large density. We also compute the density dependence of the $\eta\prime$ mass and the $\eta\prime$ velocity. We find that in medium, our model is consistent with the GMOR relation up to a few times the normal nuclear density. We compare our hQCD predictions with predictions made based on hidden local gauge theory that is constructed to model QCD.