The Ghent Hybrid Model in NuWro: a new neutrino single-pion production model in the GeV regime

TL;DR

This paper introduces the Ghent Hybrid model for neutrino-induced single-pion production within the NuWro generator, improving agreement with experimental data by combining resonance and non-resonant contributions and accounting for nuclear effects.

Contribution

The paper presents the first implementation of the Ghent Hybrid model in NuWro, integrating resonance, non-resonant, and deep-inelastic contributions for more accurate neutrino interaction simulations.

Findings

Enhanced agreement with recent pion production data

Significance of refined pion-production modeling beyond the Δ region

Effective incorporation of nuclear medium effects

Abstract

Neutrino-induced single-pion production constitutes an essential interaction channel in modern neutrino oscillation experiments, with its products building up a significant fraction of the observable hadronic final states. Frameworks of oscillation analyses strongly rely on Monte Carlo neutrino event generators, which provide theoretical predictions of neutrino interactions on nuclear targets. Thus, it is crucial to integrate state-of-the-art single-pion production models with Monte Carlo simulations to prepare for the upcoming systematics-dominated landscape of neutrino measurements. In this work, we present the implementation of the Ghent Hybrid model for neutrino-induced single-pion production in the NuWro Monte Carlo event generator. The interaction dynamics includes coherently-added contributions from nucleon resonances and a non-resonant background, merged into the pythia branching predictions in the deep-inelastic regime, as instrumented by NuWro. This neutrino-nucleon interaction model is fully incorporated into the nuclear framework of the generator, allowing it to account for the influence of both initial- and final-state nuclear medium effects. We compare the predictions of this integrated implementation with recent pion production data from accelerator-based neutrino experiments. The results of the novel model show improved agreement of the generator predictions with the data and point to the significance of the refined treatment of the description of pion-production processes beyond the $\Delta$ region.