Effective String Theory and QCD Scattering Amplitudes

TL;DR

This paper uses effective string theory to analyze QCD scattering amplitudes, demonstrating Regge behavior and a linear trajectory in the semiclassical regime, with implications for meson scattering.

Contribution

It applies the Polchinski--Strominger effective string theory to QCD scattering, deriving Regge behavior and intercepts semiclassically, advancing understanding of nonperturbative QCD dynamics.

Findings

Regge behavior with linear trajectories derived

Small expansion parameter in Regge regime confirmed

Semiclassical Luscher term computed for intercepts

Abstract

QCD string is formed at the distances larger than the confinement scale and can be described by the Polchinski--Strominger effective string theory with a nonpolynomial action, which has nevertheless a well-defined semiclassical expansion around a long-string ground state. We utilize modern ideas about the Wilson-loop/scattering-amplitude duality to calculate scattering amplitudes and show that the expansion parameter in the effective string theory is small in the Regge kinematical regime. For the amplitudes we obtain the Regge behavior with a linear trajectory of the intercept (d-2)/24 in d dimensions, which is computed semiclassically as a momentum-space Luscher term, and discuss an application to meson scattering amplitudes in QCD.