  Renormalization group evolution of QCD composite light-cone operators, built
from two and more quark and gluon fields, is responsible for the logarithmic
scaling violations in diverse physical observables. We analyze spectra of
anomalous dimensions of these operators at large conformal spins at weak and
strong coupling with the emphasis on the emergence of a dual string picture.
The multi-particle spectrum at weak coupling has a hidden symmetry due to
integrability of the underlying dilatation operator which drives the evolution.
In perturbative regime, we demonstrate the equivalence of the one-loop cusp
anomaly to the disk partition function in two-dimensional Yang-Mills theory
which admits a string representation. The strong coupling regime for anomalous
dimensions is discussed within the two pictures addressed recently, -- minimal
surfaces of open strings and rotating long closed strings in AdS background. In
the latter case we find that the integrability implies the presence of extra
degrees of freedom -- the string junctions. We demonstrate how the analysis of
their equations of motion naturally agrees with the spectrum found at weak
coupling.
