Multi-Jet Merging in Deep Inelastic Scattering with Pythia

TL;DR

This paper enhances deep inelastic scattering simulations by integrating multi-jet merging into Pythia's parton shower, leading to improved jet modeling across various virtualities, validated against HERA data.

Contribution

It introduces multi-jet merging in Pythia's Vincia shower for deep inelastic scattering, improving jet modeling accuracy for low virtuality events.

Findings

Improved jet modeling for low virtuality events.

Better agreement with HERA experimental data.

Effective merging of multiple parton multiplicities.

Abstract

We aim to improve the modelling of deep inelastic scattering by implementing multi-jet merging capabilities in Vincia parton shower in the general-purpose Monte Carlo event generator, Pythia. Merging allows to combine event samples of different parton multiplicities with logarithmically enhanced radiation from parton shower algorithms, without double-counting. Here we consider events up to five outgoing partons and present results for jet analyses compared to experimental data provided by the ZEUS and H1 collaborations of the HERA collider. The analyses span a wide range in photon virtuality, and the results show that the multi-jet merging improves jet modelling especially for low virtuality events.