Meson spectroscopy from holomorphic probes on the warped deformed conifold

TL;DR

The paper investigates supersymmetric D7 brane probes in the Klebanov-Strassler background to model fundamental flavors in a confining ${\mathcal N}=1$ gauge theory. Using $\kappa$-symmetry, it shows that holomorphic embeddings of the form $z_4=f(z_1^2+z_2^2)$, including $z_4=\mu$, preserve supersymmetry and allow a tractable fluctuation analysis. Solving the quadratic action for vector and scalar modes yields a discrete meson spectrum with a mass gap set by the glueball scale $m_{gb}$, with vector states heavier than scalars and masses growing roughly linearly with excitation number $n$. The work provides a controlled holographic description of flavored mesons in KS and highlights several avenues for extending the analysis to other embeddings, finite quark masses, and backreacted backgrounds.

Abstract

We study D7 brane probes holomorphically embedded in the Klebanov-Strassler model. Analyzing the $κ$-symmetry condition for D7 branes wrapping a 4-cycle of a deformed conifold we find configurations that do not break N=1 supersymmetry of the background. We compute the fluctuations of the probe around one of these configurations and obtain the spectrum of vector and scalar flavored mesons in the dual gauge theory. The spectrum is discrete and exhibits a mass gap.