  Two-hadron correlations are a sensitive probe of the dynamics of gluon
saturation and the Color Glass Condensate formalism where the degrees of
freedom are Wilson lines of the gluon field. It is shown that unlike structure
functions in DIS and single hadron production in proton-nucleus collisions,
higher point functions of Wilson lines appear in two-hadron production cross
section. We derive equations for the energy ($x$) evolution of these higher
point functions using the JIMWLK Hamiltonian and show that dipole
approximation, employed in the literature to fit the di-hadron data measured by
the STAR collaboration in the forward rapidity region, breaks down. This
necessitates an investigation of the full hierarchy of the JIMWLK evolution
equations for these higher point functions and their solutions. This can then
be used to make a quantitative analysis of the di-hadron correlations in the
forward rapidity region in deuteron-gold collisions at RHIC and in the long
range rapidity correlations observed in proton-proton collisions at the LHC.
