Scattering Amplitudes of QCD String

TL;DR

This paper reviews the derivation of meson scattering amplitudes in large-N QCD using string theory concepts, highlighting the role of reparametrization and the linear Regge trajectory, and connecting with perturbative QCD.

Contribution

It provides a detailed derivation of QCD meson scattering amplitudes in the Regge regime, emphasizing the importance of the reparametrization path integral and mean-field approximation.

Findings

Linear Reggeon trajectory obtained for QCD string

Mean-field approximation is exact for Nambu-Goto string

Connection established between string model and perturbative QCD

Abstract

I review the derivation of large-N QCD meson scattering amplitudes in the Regge regime, where the effective theory of long strings applies in d=4. A special attention is payed to the reparametrization path integral which plays a crucial role in the consistency of off-shell amplitudes. I show how the linear Reggeon trajectory is obtained for QCD string in the mean-field approximation, which turns out to be exact for the Nambu-Goto string, and discuss the interrelation with perturbative QCD.