  We derive a high energy factorization theorem for inclusive gluon production
in A+A collisions. Our factorized formula resums i) all order leading
logarithms (g^2 \ln(1/x_{1,2}))^n of the incoming partons momentum fractions,
and ii) all contributions (g \rho_{1,2})^n that are enhanced when the color
charge densities in the two nuclei are of order of the inverse coupling--
\rho_{1,2}\sim g^{-1}. The resummed inclusive gluon spectrum can be expressed
as a convolution of gauge invariant distributions W[\rho_{1,2}] from each of
the nuclei with the leading order gluon number operator. These distributions
are shown to satisfy the JIMWLK equation describing the evolution of nuclear
wavefunctions with rapidity. As a by-product, we demonstrate that the JIMWLK
Hamiltonian can be derived entirely in terms of retarded light cone Green's
functions without any ambiguities in their pole prescriptions. We comment on
the implications of our results for understanding the Glasma produced at early
times in A+A collisions at collider energies.
