A spacetime model for the perturbative swing

Abstract We present the development of a new colour reconnection model in P ythia 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 $$\text {e}^+\text {e}^-$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mtext>e</mml:mtext> <mml:mo>+</mml:mo> </mml:msup> <mml:msup> <mml:mtext>e</mml:mtext> <mml:mo>-</mml:mo> </mml:msup> </mml:mrow> </mml:math> , $$\text {pp}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mtext>pp</mml:mtext> </mml:math> , 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.