Semiclassical Regge trajectories of noncritical string and large-N 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 semi classical correction to the classical string (known as the Lüscher term) and obtain in t he 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 GeV2.