  Recently, Liou, Mueller and Munier have argued that proton-nucleus collisions
at the LHC may give access to the full statistics of the event-by-event
fluctuations of the gluon density in the proton. Indeed, the number of
particles produced in an event in rapidity slices in the fragmentation region
of the proton may, under some well-defined assumptions, be directly related to
the number of gluons which have a transverse momentum larger than the nuclear
saturation scale present in the proton at the time of the interaction with the
nucleus. A first calculation of the probability distribution of the number of
gluons in a hadron was performed, using the color dipole model. In this talk,
we review this proposal, and present preliminary numerical calculations which
support the analytical results obtained so far.
