Chiral Symmetry Breaking in Brane Models

TL;DR

This paper explores chiral symmetry breaking in intersecting D-brane models, revealing spontaneous symmetry breaking and associated Nambu-Goldstone bosons through holographic analysis, including finite temperature effects.

Contribution

It provides a holographic description of chiral symmetry breaking in intersecting D-brane models, identifying conditions for spontaneous breaking and Nambu-Goldstone bosons.

Findings

Chiral symmetry is spontaneously broken in the models.

Pseudo-Nambu-Goldstone bosons appear due to symmetry breaking.

Finite temperature effects influence the symmetry breaking pattern.

Abstract

We discuss the chiral symmetry breaking in general intersecting Dq/Dp brane models consisting of N_c Dq-branes and a single Dp-brane with an s-dimensional intersection. There exists a QCD-like theory localized at the intersection and the Dq/Dp model gives a holographic description of it. The rotational symmetry of directions transverse to both of the Dq and Dp-branes can be identified with a chiral symmetry, which is non-Abelian for certain cases. The asymptotic distance between the Dq-branes and the Dp-brane corresponds to a quark mass. By studying the probe Dp-brane dynamics in a Dq-brane background in the near horizon and large N_c limit we find that the chiral symmetry is spontaneously broken and there appear (pseudo-)Nambu-Goldstone bosons. We also discuss the models at finite temperature.