Phenomenological Chiral Effective Field Theory for Neutrino Event Generators
Abstract
Single-pion production is a crucial interaction channel for accelerator-based neutrino experiments, which rely on neutrino event generators for its cross sections. However, no model implemented in current generators provides a consistent and systematically improvable description of the resonance region. In this work, we develop a phenomenological chiral effective field theory model of pion production, built from nucleons, pions, and the Δ(1232) with consistent, spin 3/2, gauge-invariant couplings, and we implement it in a fully automated pipeline from the Lagrangian to events using FeynRules, UFO 2.0, and Sherpa. We validate our results with pion photoproduction data and compare against neutrino bubble chamber, MINERvA, T2K, MicroBooNE, MiniBooNE, and electron-carbon scattering data. The framework can be systematically improved by extending the Lagrangian with higher-order operators and additional degrees of freedom, and by refitting couplings and form factors as new data become available. Combined with nuclear model interfaces, our approach opens a path to resonance-region predictions that meet the needs of next-generation experiments.
Related
- Big Bang nucleosynthesis and the neutrino-extended Standard Model Effective Field Theory
- Born-Oppenheimer chiral effective field theory and its application to Xb
- Nucleon Nucleon Potential Using N$3$LO Chiral Effective Field Theory
- Interplay between final-state nucleon distortion, nuclear transparency and intranuclear cascade models in neutrino event generators
- The Triadic Texture: Neutrino Predictions, Viable Vacuum, and Phenomenological Constraints
BibTeX
@misc{grahamjones2026phenomenological,
title = {{Phenomenological Chiral Effective Field Theory for Neutrino Event Generators}},
author = {Zara Graham-Jones and Mareen Hoppe and Joshua Isaacson and Shirley Weishi Li and Miša Toman},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.40866},
eprint = {2610.40866},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.40866},
}
RIS
TY - UNPB
TI - Phenomenological Chiral Effective Field Theory for Neutrino Event Generators
AU - Zara Graham-Jones
AU - Mareen Hoppe
AU - Joshua Isaacson
AU - Shirley Weishi Li
AU - Miša Toman
PY - 2026
DA - 2026/10/29
PB - arXiv
DO - 10.48550/arxiv.2610.40866
UR - https://arxiv.org/abs/2610.40866
AB - Single-pion production is a crucial interaction channel for accelerator-based neutrino experiments, which rely on neutrino event generators for its cross sections. However, no model implemented in current generators provides a consistent and systematically improvable description of the resonance region. In this work, we develop a phenomenological chiral effective field theory model of pion production, built from nucleons, pions, and the Δ(1232) with consistent, spin 3/2, gauge-invariant couplings, and we implement it in a fully automated pipeline from the Lagrangian to events using FeynRules, UFO 2.0, and Sherpa. We validate our results with pion photoproduction data and compare against neutrino bubble chamber, MINERvA, T2K, MicroBooNE, MiniBooNE, and electron-carbon scattering data. The framework can be systematically improved by extending the Lagrangian with higher-order operators and additional degrees of freedom, and by refitting couplings and form factors as new data become available. Combined with nuclear model interfaces, our approach opens a path to resonance-region predictions that meet the needs of next-generation experiments.
ER -