# Glueballs on the Baryonic Branch of Klebanov-Strassler: dimensional deconstruction and a light scalar particle

## TL;DR

This paper investigates the scalar and tensor mass spectra in a gauge/gravity duality setup, revealing a light scalar particle and spectral features consistent with dimensional deconstruction along the baryonic branch of the Klebanov-Strassler system.

## Contribution

It introduces a detailed analysis of fluctuations in a five-dimensional sigma-model on the baryonic branch, highlighting the emergence of a light scalar and spectral interpolation between known backgrounds.

## Key findings

- Tensor spectrum transitions from discrete to continuum
- Scalar spectrum exhibits a dense set of states
- Identification of a parametrically light scalar particle

## Abstract

Within gauge/gravity duality, we compute the scalar and tensor mass spectrum in the boundary theory defined by the five-dimensional sigma-model coupled to gravity obtained by constraining to eight scalars the truncation on T$^{1,1}$ that corresponds to the Papadopoulos-Tseytlin (PT) ansatz. We study fluctuations around the 1-parameter family of backgrounds that lift to the baryonic branch of the Klebanov-Strassler (KS) system, and interpolates between the KS background and the Maldacena-Nunez one (CVMN). We adopt a gauge invariant formalism in the treatment of the fluctuations that we interpret as states of the dual theory. The tensor spectrum interpolates between the discrete spectrum of the KS background and the continuum spectrum of the CVMN background, in particular showing the emergence of a finite energy range containing a dense set of states, as expected from dimensional deconstruction. The scalar spectrum shows analogous features, and in addition it contains one state that becomes parametrically light far from the origin along the baryonic branch.