Hyperons and $\Theta_s^+$ in Holographic QCD

TL;DR

This paper uses holographic QCD to model strange baryons and pentaquarks, finding that the spectrum aligns with experiments and that the pentaquark $ heta_s^+$ is unbound.

Contribution

It introduces a holographic approach to strange baryons with heavy quark mass, extending the Sakai-Sugimoto model and analyzing the spectrum and stability of pentaquarks.

Findings

Holographic hyperon spectrum matches empirical data.

The $ heta_s^+$ pentaquark is shown to be unbound.

The spectrum is derived from a Landau problem analogy.

Abstract

We revisit the holographic description of strange baryons in the context of the Sakai-Sugimoto construction, by considering the strange quark mass as heavy. Hyperons are described by a massive $(K,K^*)$ multiplet, bound to a light-flavor instanton in bulk, much in the spirit of the Callan-Klebanov construction. The modular Hamiltonian maps onto the Landau problem, a charged particle in a 2-dimensional external magnetic field, induced by the bulk Chern-Simons interaction, plus spin-orbit coupling. The ensuing holographic hyperon spectrum compares fairly with the empirical one. The holographic strange pentaquark baryon $\Theta^+_s$ is shown to be unbound.