Herwig 7 with the Lund string model: tuning and comparative hadronization studies

Abstract The modelling of the formation of colour-singlet hadrons from coloured partons, known as Hadronization, is crucial for generating realistic events in Monte Carlo Event Generators. Due to limited understanding of the non-perturbative regime, physically motivated phenomenological hadronization models with tunable parameters are used and later tuned to the experimental data. Modern Monte Carlo generators primarily employ one of two hadronization models: the Lund string model, which is the default in , and the cluster model, which is the default in and . In this work, we combine the Lund string hadronization model, as implemented in , with using interface. We tune the string model with ’s Angular Ordered Parton Shower (AOPS) to lepton and hadron collision data, resulting in the Les Houches Tune ( LH Tune ), which shows good performance across a wide range of observables. The LH Tune will be included in the release. (It can also be used with , provided that the relevant patch is applied to the installation script which can be provided by the authors.) This development enables a direct comparative study of the two hadronization models within , both interfaced with the Angular Ordered Parton Shower, which serves as the main motivation behind this work.