# Tuning the GENIE Pion Production Model with MINERvA Data

## TL;DR

This paper improves the GENIE neutrino interaction model by tuning it with MINERvA data and other experiments, addressing discrepancies in pion production predictions at few-GeV energies.

## Contribution

It introduces specific parameter tunings and corrections to enhance GENIE's agreement with experimental data, including a new correction for low-Q^2 effects.

## Key findings

- Tuned GENIE model better matches MINERvA data
- Identified discrepancies between nuclear and nucleon target data
- Developed a framework for future model extensions

## Abstract

Faced with unresolved tensions between neutrino interaction measurements at few-GeV neutrino energies, current experiments are forced to accept large systematic uncertainties to cover discrepancies between their data and model predictions. In this paper, the widely used pion production model in GENIE is compared to four MINERvA charged current pion production measurements using NUISANCE. Tunings, ie, adjustments of model parameters, to help match GENIE to MINERvA and older bubble chamber data are presented here. We find that scattering off nuclear targets as measured in MINERvA is not in good agreement with scattering off nucleon (hydrogen or deuterium) targets in the bubble chamber data. An additional ad hoc correction for the low-$Q^2$ region, where collective effects are expected to be large, is also presented. While these tunings and corrections improve the agreement of GENIE with the data, the modeling is imperfect. The development of these tunings within the NUISANCE frameworkallows for straightforward extensions to other neutrino event generators and models, and allows omitting and including new data sets as they become available.