Baryonic States in QCD From Gauge/String Duality at Large N_c

TL;DR

This paper uses gauge/string duality to compute the baryon spectrum in a supersymmetric Yang-Mills theory, revealing a spectrum that closely resembles real QCD baryons and exhibits suppressed spin-orbit interactions.

Contribution

It introduces a novel approach to modeling baryons in AdS/CFT by matching string wavefunctions to operator dimensions, extending the duality to include baryonic states.

Findings

Baryon spectrum resembles QCD baryons

Suppression of spin-orbit interactions observed

Method links string wavefunctions to baryon quantum numbers

Abstract

We have computed the baryon spectrum in the context of $\mathcal{N} = 4$ super-conformal Yang-Mills theory using AdS/CFT duality. Baryons are included in the theory by adding an open string sector, corresponding to quarks in the fundamental and higher representations. The hadron mass scale is introduced by imposing boundary conditions at the wall at the end of AdS space. The quantum numbers of each baryon, are identified by matching the fall-off of the string wavefunction $\Psi(x,r)$ at the asymptotic 3+1 boundary to the operator dimension of the lowest three-quark Fock state, subject to appropriate boundary conditions. Higher Fock states are matched quanta to quanta with quantum fluctuations of the bulk geometry about the fixed AdS background, maintaining conformal invariance. The resulting four-dimensional spectrum displays a remarkable resemblance to the physical baryon spectrum of QCD, including the suppression of spin-orbit interactions.