Hadron spectroscopy using the light-front holographic Schr\"odinger equation and the 't Hooft equation

TL;DR

This paper combines light-front holographic QCD with the 't Hooft equation to improve the understanding of hadron spectra, capturing both transverse confinement and chiral symmetry breaking effects.

Contribution

It introduces a novel approach integrating the holographic Schrödinger equation with the 't Hooft equation to better describe hadron mass degeneracies and spectrum.

Findings

Successfully models hadron spectrum with a universal scale ppa

Captures chiral symmetry breaking effects in hadron masses

Provides a comprehensive description across the full spectrum

Abstract

Light-front holographic QCD provides a successful first approximation to hadron spectroscopy in the chiral limit of $(3+1)$-dim light-front QCD, where a holographic Schr\"odinger-like equation, with an emerging confining scale, $\kappa$, governs confinement in the transverse direction. In its supersymmetric formulation, light-front holography predicts that each baryon has two superpartners: a meson and a tetraquark, with their degenerate masses being generated by the same scale, $\kappa$. In nature, this mass degeneracy is lifted by chiral symmetry breaking and longitudinal confinement. In this paper, we show that the latter can be successfully captured by the 't Hooft equation of $(1+1)$-dim, large $N_c$, QCD. Together, the holographic Schr\"odinger equation and the 't Hooft equation, provide a good global description of the data across the full hadron spectrum with a universal $\kappa$.