Apr 4 – 10, 2022
Auditorium Maximum UJ
Europe/Warsaw timezone
Proceedings submission deadline extended to August 15, 2022

The spatially constrained QCD colour re-connection for heavy-ion collisions in Pythia8/Angantyr model

Apr 6, 2022, 7:14 PM
Poster Hadron production and collective dynamics Poster Session 2 T14_2


Harsh Shah (Lund University)


We have extended the so-called QCD colour re-connection model with spatial constraints on the allowed re-connection between the colour strings in the Pythia8/Angantyr model. The Angantyr model uses the Pythia8 event generator machinery with sophisticated stacking of pp-like collisions to simulate heavy-ion events, without any assumption of a thermalized medium of QGP. So far, all sub-collisions are colour reconnected and hadronized independently in the heavy-ion collisions in the Angantyr model. In this work, we introduce a parameter that constrains the allowed colour re-connection between two colour strings based on the transverse spatial separation between the strings. This new parameter now allows us to combine all sub-collisions in a heavy-ion collision event at the parton level in Angantyr and perform re-connections between partons from different sub-collisions. We use the so-called QCD colour re-connection model of Pythia8, because its feature of junction formation enhances the baryon production with increasing multiplicity in collision events. We constrain the re-tuning of our model parameters to the pp collision level, and only parameters introduced in the Angantyr model are re-tuned at the pA collision level. We will show the effects of the spatial constraint in the colour re-connection model on the final state charged multiplicity, and production of identified hadron (and their ratios) in pp and pA collisions.

Primary authors

Harsh Shah (Lund University) Leif Lönnblad (Lund University (SE))

Presentation materials