May 13 – 19, 2018
Venice, Italy
Europe/Zurich timezone
The organisers warmly thank all participants for such a lively QM2018! See you in China in 2019!

Microscopic collectivity: The ridge and strangeness enhancement from string-string interactions in Pythia8

May 15, 2018, 4:00 PM
Sala Mosaici-1, 3rd Floor (Palazzo del Casinò)

Sala Mosaici-1, 3rd Floor

Palazzo del Casinò

Parallel Talk Collectivity in small systems Collectivity in small systems


Christian Bierlich (Lund University (SE))


The observation of collective effects in small systems, such as strangeness enhancement and the appearance of a ridge, have posed a challenge to conventional models for multiparton interactions and hadronization underlying general purpose MC event generators.
In this talk I will present the microscopic model for collective effects recently implemented in the Pythia8 and DIPSY event generators. In this model collectivity is generated from interactions between Lund strings, referred to as “string shoving” and “rope hadronization”. Rope hadronization is shown to give a good description of strangeness enhancement across pp, pA and AA collisions systems, while string shoving qualitatively describes the ridge observed in pp collisions.
A defining feature of the microscopic model is that all effects are generated without assuming a deconfined plasma or thermalization. Ongoing efforts aim towards further extending the models to pA and AA.

Content type Theory
Centralised submission by Collaboration Presenter name already specified

Primary author

Christian Bierlich (Lund University (SE))


Gosta Gustafson (Lund University) Leif Lönnblad (Lund University (SE))

Presentation materials