  We review the state-of-the-art of Glauber-inspired models for estimating the
distribution of the number of participating nucleons in pA and AA collisions.
We argue that there is room for improvement in these models when it comes to
the treatment of diffractive excitation processes, and present a new simple
Glauber-like model where these processes are better taken into account. We also
suggest a new way of using the number of participating, or wounded, nucleons to
extrapolate event characteristics from pp collisions, and hence get an estimate
of basic hadronic final-state properties in pA collisions, which may be used to
extract possible nuclear effects. The new method is inspired by the Fritiof
model, but based on the full, semi-hard multiparton interaction model of Pythia
8.
