# The Isoscalar Mesons and Exotic States in Light Front Holographic QCD

## TL;DR

This paper uses supersymmetric light front holographic QCD to analyze isoscalar mesons and predicts the existence of exotic tetraquark states, successfully matching some experimental data and providing insights into chiral symmetry breaking.

## Contribution

It introduces a systematic approach to describe isoscalar mesons and predicts exotic tetraquark states within light front holographic QCD, including their masses and compositions.

## Key findings

- The $ ext{eta}$ and $h$ mesons are well described with an additional mass parameter.
- The mass difference of $ ext{eta}$ and $ ext{eta'}$ is explained by strange quark content.
- The $f_0(1500)$ is identified as an isoscalar tetraquark with a predicted mass of 1.52 GeV.

## Abstract

In this article a systematic quantitative analysis of the isoscalar bosonic states is performed in the framework of supersymmetric light front holographic QCD. It is shown that the spectroscopy of the $\eta$ and $h$ mesons can be well described if one additional mass parameter -- which corresponds to the hard breaking of chiral $U(1)$ symmetry in standard QCD -- is introduced. The mass difference of the $\eta$ and $\eta'$ isoscalar mesons is then determined by the strange quark mass content of the $\eta'$. The theory also predicts the existence of isoscalar tetraquarks which are bound states of diquarks and anti-diquarks. The candidates for these exotic isoscalar tetraquarks are identified. In particular, the $f_0(1500)$ is identified as isoscalar tetraquark; the predicted mass value 1.52 GeV agrees with the measured experimental value within the model uncertainties.