  We derive the rapidity evolution equation for the gluon four-point function
in the dilute regime and at small x from the JIMWLK functional equation. We
show that beyond leading order in Nc the mean field (Gaussian) approximation
where the four point function is factorized into a product of two point
functions is violated. We calculate these factorization breaking terms and show
that they contribute at leading order in Nc to correlations of two produced
gluons as a function of their relative rapidity and azimuthal angle, for
generic (rather than back-to-back) angles. Such two-particle correlations have
been studied experimentally at the BNL-RHIC collider and could be scrutinized
also for pp (and, in the future, also AA) collisions at the CERN-LHC
accelerator.
