Modification of jet structure in high-multiplicity pp collisions due to multiple-parton interactions and observing a multiplicity-independent characteristic jet size

Research paper by Zoltán Varga, Róbert Vértesi, Gergely Gábor Barnaföldi

Indexed on: 08 May '18Published on: 08 May '18Published in: arXiv - High Energy Physics - Phenomenology


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. Using multiplicity-dependent jet structure observables in various $p_T$ windows might also help understanding the interplay between jet particles and the underlying event (UE). We introduce a definition of a characteristic jet size measure that is independent of multiplicity, regardless of the choice of Monte Carlo and jet reconstruction settings, and use a simplistic model to aid its physical interpretation.