  In [arXiv:0804.2630], we have analyzed the leading logarithms of energy that
appear in the inclusive spectrum of gluons produced in heavy ion collisions,
calculated in the Color Glass Condensate framework. The main result of this
paper was that these logarithms are intrinsic properties of the colliding
projectiles, and that they can be resummed by letting the distributions of
color sources in the nuclei evolve according to the JIMWLK equation.
  An essential step in the proof of this factorization result is the
calculation of the gluon spectrum at Next-to-Leading order, and in particular a
functional relationship that expresses the NLO correction as the action of a
certain operator on the LO spectrum.
  In this paper, we show that this type of relation between spectra at LO and
NLO is not specific to the production of gluons, but that it is in fact generic
for inclusive spectra in heavy ion collisions. To illustrate this, we compute
up to NLO the inclusive spectrum of some hypothetical scalar fields, either
color neutral or colored, that couple to gluons.
