  We prove that the inclusive single-gluon production cross section for a
hadron colliding with a high-density target factorizes into the gluon
distribution function of the projectile, defined as usual within the DGLAP
collinear approximation, times the cross section for scattering of a single
gluon on the strong classical color field of the target. We then derive the
gluon-proton (nucleus) inelastic cross section and show that it is (up to
logarithms) infrared safe and that it grows slowly with center of mass energy.
Furthermore, we discuss jet transverse momentum broadening for the case of
nuclear targets. We show that in the saturation regime, in contrast to the
perturbative regime, the width of the transverse momentum distribution is
infrared finite and grows rapidly with energy and rapidity. In both regimes,
however, transverse momentum broadening exibits the same dependence on atomic
number A.
