arXiv subjects

Joni O. Laulainen

Publications and source records attributed to Joni O. Laulainen.

3 recordsLinked to original sources

arXiv2026

Multiplicative matching of neutral current deep-inelastic scattering processes at next-to-leading order in PYTHIA 8

We introduce a method for matching the neutral-current deep inelastic scattering process with parton showers in Pythia 8, at first order in the strong coupling. The implementation, based on the well-established multiplicative matching approach, is achieved by reweighting leading-order Born-level events and requires that the first parton-shower emission is distributed according to the real matrix-element. The method is implemented as an internal matching strategy in the Pythia 8 event generator applicable to both currently available parton-shower algorithms, the default one and Vincia. The validity of higher-order corrections is verified with comparisons against existing next-to-leading order simulations. The strategy is used to describe reduced cross-sections measured at the HERA collider, and we find better overall agreement and reduced uncertainties with the matching.

hep-ph↗

arXiv2026

Multiplicative NLO matching in DIS with Pythia 8

We present a new multiplicative next-to-leading order (NLO) matching scheme in Pythia 8 for deep-inelastic scattering (DIS) processes in electron-proton collisions. The implementation is based on numerical event-by-event integration over the virtual corrections and real-emission phase-space and matrix-element corrections (MECs) for the first parton-shower emission. The latter has been included for two parton-shower options currently available in Pythia 8 to handle DIS processes, the default shower with dipole-recoil option and Vincia. The implementation has been validated against other available NLO-capable event generators and compared to experimental data from the HERA collider. In all cases we find very good agreement confirming the validity of the new Pythia implementation. We also study the impact of the MECs in each shower and consider the implications for the upcoming Electron-Ion collider.

hep-ph↗

arXiv2025

Multi-Jet Production in Deep Inelastic Scattering with Pythia

We introduce multi-jet merging for deep inelastic scattering in the Vincia parton shower in the Monte Carlo event generator Pythia 8. Merging combines event samples of different parton multiplicities with logarithmically enhanced parton-shower radiation. We consider up to five outgoing partons using two different merging algorithms. We vary the relevant scale choices and compare to experimental data by H1 collaboration at the HERA collider. Results show that multi-jet merging improves description to data, especially for low virtuality events, and that jet cross-sections converge when the partonic multiplicity exceeds the number of reconstructed jets.

hep-ph↗