Charm production in high multiplicity pp events

Studying proton-proton scattering at 7 TeV, the ALICE collaboration found the
unexpected result that the D meson multiplicity increases more than linear as a function of the
charged particle multiplicity. We try to understand this behavior using the EPOS3 approach.
Two issues play an important role in this context: multiple scattering, in particular its impact
on multiplicity fluctuations, and the collective hydrodynamic expansion. These data contain
therefore valuable information about very basic features of the reaction mechanism in protonproton collisions.