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Leif Lönnblad

Professor

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

Author

  • Leif Lönblad
  • Harsh Shah

Summary, in English

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.

Department/s

  • Particle and nuclear physics

Publishing year

2023-07

Language

English

Publication/Series

European Physical Journal C

Volume

83

Issue

7

Document type

Journal article

Publisher

Springer

Topic

  • Subatomic Physics

Status

Published

ISBN/ISSN/Other

  • ISSN: 1434-6044