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A spatially constrained QCD colour reconnection in pp , p A , and AA collisions in the Pythia8/Angantyr model

Lönblad, Leif LU orcid and Shah, Harsh LU (2023) In European Physical Journal C 83(7).
Abstract

We present an updated version of the QCD-based colour reconnection model in Pythia8, where we constrain the range in impact parameter for which reconnections are allowed. In this way, we can introduce more realistic colour reconnections in the Angantyr model for heavy ion collisions, where previously only reconnections within separate nucleon sub-collisions have been allowed. We investigate how the new impact parameter constraint influences final states in pp collisions, and retune parameters of the multi-parton interaction parameters in Pythia to compensate so that minimum bias data are reproduced. We also study multiplicity distributions in p A collisions and find that, in order to counteract the loss in multiplicity due to the... (More)

We present an updated version of the QCD-based colour reconnection model in Pythia8, where we constrain the range in impact parameter for which reconnections are allowed. In this way, we can introduce more realistic colour reconnections in the Angantyr model for heavy ion collisions, where previously only reconnections within separate nucleon sub-collisions have been allowed. We investigate how the new impact parameter constraint influences final states in pp collisions, and retune parameters of the multi-parton interaction parameters in Pythia to compensate so that minimum bias data are reproduced. We also study multiplicity distributions in p A collisions and find that, in order to counteract the loss in multiplicity due to the introduction of global colour reconnections, we need to modify some parameters in the Angantyr model while keeping the parameters tuned to pp fixed. With Angantyr we can then extrapolate to AA collisions without further parameter tuning and retaining a reasonable description of the basic multiplicity distributions.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
European Physical Journal C
volume
83
issue
7
article number
575
publisher
Springer Nature
external identifiers
  • scopus:85164354055
ISSN
1434-6044
DOI
10.1140/epjc/s10052-023-11778-3
language
English
LU publication?
yes
id
1da04a07-4099-4e12-ba20-361b011d4f05
date added to LUP
2023-09-13 09:08:17
date last changed
2025-04-04 14:58:21
@article{1da04a07-4099-4e12-ba20-361b011d4f05,
  abstract     = {{<p>We present an updated version of the QCD-based colour reconnection model in Pythia8, where we constrain the range in impact parameter for which reconnections are allowed. In this way, we can introduce more realistic colour reconnections in the Angantyr model for heavy ion collisions, where previously only reconnections within separate nucleon sub-collisions have been allowed. We investigate how the new impact parameter constraint influences final states in pp collisions, and retune parameters of the multi-parton interaction parameters in Pythia to compensate so that minimum bias data are reproduced. We also study multiplicity distributions in p A collisions and find that, in order to counteract the loss in multiplicity due to the introduction of global colour reconnections, we need to modify some parameters in the Angantyr model while keeping the parameters tuned to pp fixed. With Angantyr we can then extrapolate to AA collisions without further parameter tuning and retaining a reasonable description of the basic multiplicity distributions.</p>}},
  author       = {{Lönblad, Leif and Shah, Harsh}},
  issn         = {{1434-6044}},
  language     = {{eng}},
  number       = {{7}},
  publisher    = {{Springer Nature}},
  series       = {{European Physical Journal C}},
  title        = {{A spatially constrained QCD colour reconnection in pp , p A , and AA collisions in the Pythia8/Angantyr model}},
  url          = {{http://dx.doi.org/10.1140/epjc/s10052-023-11778-3}},
  doi          = {{10.1140/epjc/s10052-023-11778-3}},
  volume       = {{83}},
  year         = {{2023}},
}