The Underlying Event in Herwig++

TL;DR

This paper reviews Herwig++'s modeling of multiple interactions and introduces improved color reconnection models inspired by statistical physics, with implications for LHC data analysis.

Contribution

It presents novel improvements to the color reconnection model in Herwig++, enhancing the simulation of underlying events.

Findings

Enhanced color reconnection model improves data description

Tuning results better match LHC minimum-bias data

Model advances lead to more accurate underlying event simulations

Abstract

We review the modelling of multiple interactions in the event generator Herwig++ and study implications of recent tuning efforts to LHC data. A crucial ingredient to a successful description of minimum-bias and underlying-event observables is a model for colour reconnection. Improvements to this model, inspired by statistical physics, are presented.