Semiclassical Regge trajectories of noncritical string and large-N QCD

TL;DR

This paper derives semiclassical Regge trajectories in noncritical string theory and large-N QCD, showing how boundary effects influence scattering amplitudes and trajectory intercepts, relevant for understanding quark-antiquark interactions.

Contribution

It introduces a boundary ansatz in noncritical string theory that reproduces semiclassical corrections and connects string trajectories to large-N QCD phenomenology.

Findings

Derived off-shell scattering amplitudes in d=26 dimensions.

Obtained a linear Regge trajectory with intercept (d-2)/24.

Explained dominance of nonperturbative trajectories over perturbative QCD.

Abstract

By properly treating the path integral over the boundary value of the Liouville field (associated with reparametrizations of the boundary contour) in open string theory, we derive consistent off-shell scattering amplitudes in d=26 dimensions. In d<26 we consider a recently proposed boundary ansatz which reproduces a semiclassical correction to the classical string (known as the Luscher term) and obtain in the semiclassical approximation a linear Regge trajectory with the intercept (d-2)/24. We associate it with the quark-antiquark Regge trajectory in large-N QCD and explain why it dominates over perturbative QCD when t > -few GeV^2.