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The Angantyr model for heavy-ion collisions in Pythia8

Bierlich, Christian LU ; Gustafson, Gösta LU ; Lönnblad, Leif LU orcid and Shah, Harsh LU (2018) In Journal of High Energy Physics 2018(10).
Abstract

We present a new model for building up complete exclusive hadronic final states in high energy nucleus collisions. It is a direct extrapolation of high energy pp collisions (as described by Pythia), and thus bridges a large part of the existing gap between heavy ion and high energy physics phenomenology. The model is inspired by the old Fritiof model and the notion of wounded nucleons. Two essential features are the treatment of multi-parton interactions and diffractive excitation in each NN sub-collision. Diffractive excitation is related to fluctuations in the nucleon partonic sub-structure, and fluctuations in both projectile and target are here included for the first time. The model is able to give a good description of general... (More)

We present a new model for building up complete exclusive hadronic final states in high energy nucleus collisions. It is a direct extrapolation of high energy pp collisions (as described by Pythia), and thus bridges a large part of the existing gap between heavy ion and high energy physics phenomenology. The model is inspired by the old Fritiof model and the notion of wounded nucleons. Two essential features are the treatment of multi-parton interactions and diffractive excitation in each NN sub-collision. Diffractive excitation is related to fluctuations in the nucleon partonic sub-structure, and fluctuations in both projectile and target are here included for the first time. 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 collisions. The model can therefore serve as a baseline for understanding the non-collective background to observables sensitive to collective behaviour. As Pythia does not include a mechanism to reproduce the collective effects seen in pp collisions, such effects are also not reproduced by the present version of Angantyr. Effects of high string density, shown to be able to reproduce e.g. higher strangeness ratios and the ridge in pp, will be added in future studies.

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author
; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Heavy Ion Phenomenology, Phenomenological Models
in
Journal of High Energy Physics
volume
2018
issue
10
article number
134
publisher
Springer
external identifiers
  • scopus:85055339746
ISSN
1029-8479
DOI
10.1007/JHEP10(2018)134
project
QCD Phenomenology and Event Generator Development
Innovative Network for Monte Carlo Event Generators for LHC Physics
Heavy-ion physics in Pythia
language
English
LU publication?
yes
id
cb5cf4e8-9b75-43a9-8077-b4becbdff57e
date added to LUP
2018-11-16 08:34:15
date last changed
2021-10-10 04:46:56
@article{cb5cf4e8-9b75-43a9-8077-b4becbdff57e,
  abstract     = {<p>We present a new model for building up complete exclusive hadronic final states in high energy nucleus collisions. It is a direct extrapolation of high energy pp collisions (as described by Pythia), and thus bridges a large part of the existing gap between heavy ion and high energy physics phenomenology. The model is inspired by the old Fritiof model and the notion of wounded nucleons. Two essential features are the treatment of multi-parton interactions and diffractive excitation in each NN sub-collision. Diffractive excitation is related to fluctuations in the nucleon partonic sub-structure, and fluctuations in both projectile and target are here included for the first time. 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 collisions. The model can therefore serve as a baseline for understanding the non-collective background to observables sensitive to collective behaviour. As Pythia does not include a mechanism to reproduce the collective effects seen in pp collisions, such effects are also not reproduced by the present version of Angantyr. Effects of high string density, shown to be able to reproduce e.g. higher strangeness ratios and the ridge in pp, will be added in future studies.</p>},
  author       = {Bierlich, Christian and Gustafson, Gösta and Lönnblad, Leif and Shah, Harsh},
  issn         = {1029-8479},
  language     = {eng},
  number       = {10},
  publisher    = {Springer},
  series       = {Journal of High Energy Physics},
  title        = {The Angantyr model for heavy-ion collisions in Pythia8},
  url          = {http://dx.doi.org/10.1007/JHEP10(2018)134},
  doi          = {10.1007/JHEP10(2018)134},
  volume       = {2018},
  year         = {2018},
}