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arXiv · 2503.15413

A spacetime model for the perturbative swing

Torbjörn Lundberg·Leif Lönnblad
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Abstract

We present the development of a new colour reconnection model in PYTHIA where the full spacetime separation between partons constrains the reconnection probability throughout the final-state radiative shower. Building upon previous ideas of a perturbative dipole-based model, our objective is to introduce realistic spatially-based colour reconnections within the Angantyr model for heavy-ion collisions. Previous models were limited to the use of a rudimentary separation measure in the transverse plane to control reconnections. We investigate the impact of this novel scheme on final states in $\text{e}^+\text{e}^-$, pp, and pPb collisions as well as in PbPb collision systems and our main goal in this paper is to achieve a reasonable description of basic multiplicities in systems of varying sizes.

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Torbjörn Lundberg, Leif Lönnblad. 2025-03-19. A spacetime model for the perturbative swing. https://arxiv.org/abs/2503.15413

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