Christian Bierlich, Gösta Gustafson, Leif Lönnblad, Harsh Shah
The Angantyr model for Heavy-Ion Collisions in PYTHIA8


We present a new model for building up complete exclusive hadronic final states in high energy collisions involving nuclei. The model is inspired by the old Fritiof model and builds up final states by stacking together parton-level nucleon--nucleon collisions generated by PYTHIA8. Special attention is given to the treatment of diffractive excitation processes and multi-parton interactions in each such sub-collision. Although the sub-collisions are hadronised together, the model currently does not include any final-state collective effects. Nevertheless, the model is able to give a good description of general final-state properties such as multiplicity and transverse momentum distributions both in pA and AA, as well as in pp. The model can therefore serve as a baseline for understanding the non-collective backgrounds to observables sensitive to collective behaviour, as well as a platform for implementing and exploring new and alternative models for such behaviour.

LU TP 18-19