The Shape of Mesons in Holographic QCD

TL;DR

This paper explores how the orbital angular momentum of quark-antiquark pairs in light mesons can inform the holographic dual string models of large N QCD, suggesting the need for world-sheet fermions.

Contribution

It proposes a connection between constituent quark model features and holographic dual string models, emphasizing the role of world-sheet fermions in capturing meson spin properties.

Findings

Orbital angular momentum insights guide holographic QCD modeling.

World-sheet fermions are necessary in dual strings to incorporate quark spins.

Discussion on meson size within holographic frameworks.

Abstract

Based on the expectation that constituent quark model may capture right physics in the large N limit, we point out that orbital angular momentum of the quark-antiquark pair inside light mesons of low spins in the constituent quark model may provide a clue for the holographic dual string model of large N QCD. Our discussion, relying on a few suggestive assumptions, leads to a necessity of world-sheet fermions in the bulk of dual strings that can incorporate intrinsic spins of fundamental QCD degrees of freedom. We also comment on an interesting issue of the size of mesons in the context of holographic QCD.