A five-dimensional toy-model for light hadron excitations

TL;DR

This paper introduces a novel five-dimensional holographic model for light hadron excitations, where the meson spectrum arises from scalar field coupling related to gluon condensate, showing Regge-like behavior.

Contribution

It proposes an alternative 5D holographic approach where meson spectra are generated by scalar field condensation linked to gluon condensate, differing from traditional background-based models.

Findings

Spectrum includes finite discrete states and continuum.

Model exhibits Regge-like behavior at strong coupling.

Spectrum reflects scale anomaly effects in QCD.

Abstract

In the usual holographic approach to QCD, the meson spectrum is generated due to a non-trivial 5-dimensional background. We propose an alternative 5-dimensional scenario in which the spectrum emerges due to coupling to a scalar field whose condensation is supposed to be dual to the formation of gluon condensate and mimics the scale anomaly in QCD. The spectrum of model has finite number of discrete states plus continuum and reveals a Regge-like behavior in the strong coupling regime.