  We study the multiplicity dependence of jet structures in pp collisions using
Monte Carlo event generators. We give predictions for multiplicity-differential
jet structures and present evidence for a non-trivial jet shape dependence on
charged hadron event multiplicity, that can be used as a sensitive tool to
experimentally differentiate between equally well-preforming simulation tunes.
We also propose a way to validate the presence and extent of effects such as
multiple parton interactions (MPI) or color reconnection (CR), based on the
detection of non-trivial jet shape modification in high-multiplicity events at
high pT. Using multiplicity-dependent jet structure observables in various pT
windows might also help understanding the interplay between jet particles and
the underlying event (UE). We introduce a multiplicity-independent
characteristic jet size measure, and use a simplistic model to aid its physical
interpretation.
