Two-body current and axial form factor effects in charged-current quasielastic neutrino-nucleus scattering within the NEUT event generator

Fuente: arXiv
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Main Authors: Franco-Munoz, T., McKean, J., García-Marcos, J., Hooft, M., González-Jiménez, R., Jachowicz, N., Udías, J. M.
Format: Preprint
Published: 2026
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author Franco-Munoz, T.
McKean, J.
García-Marcos, J.
Hooft, M.
González-Jiménez, R.
Jachowicz, N.
Udías, J. M.
author_facet Franco-Munoz, T.
McKean, J.
García-Marcos, J.
Hooft, M.
González-Jiménez, R.
Jachowicz, N.
Udías, J. M.
contents We present a charged-current quasielastic neutrino-nucleus scattering model based on an unfactorized representation of the spectral function, employing relativistic momentum distributions for bound nucleons and the relativistic distorted-wave impulse approximation with an energy-dependent relativistic potential to describe the scattered nucleon. The model incorporates two-body meson-exchange currents contributing to one-particle-one-hole final states and tests several axial form factor parametrizations, including recent LQCD and MINERvA fits. It is implemented in the NEUT event generator and benchmarked against T2K and MINERvA $ν_μ$-$^{12}$C CC0$π$ measurements. We find that two-body meson-exchange currents lead to a sizeable increase of the total cross section, arising from an enhancement of the transverse response, which is the dominant component in charged-current neutrino scattering. On the other hand, recent fits of the axial form factor predict larger values than the standard dipole form, yielding a systematic enhancement of the cross section. The LQCD+MINERvA parametrization tends to overestimate the data, while the MINERvA-only fit provides a more moderate increase. Overall, no single configuration consistently provides the best agreement with the different datasets.
format Preprint
id arxiv_https___arxiv_org_abs_2605_00756
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Two-body current and axial form factor effects in charged-current quasielastic neutrino-nucleus scattering within the NEUT event generator
Franco-Munoz, T.
McKean, J.
García-Marcos, J.
Hooft, M.
González-Jiménez, R.
Jachowicz, N.
Udías, J. M.
Nuclear Theory
We present a charged-current quasielastic neutrino-nucleus scattering model based on an unfactorized representation of the spectral function, employing relativistic momentum distributions for bound nucleons and the relativistic distorted-wave impulse approximation with an energy-dependent relativistic potential to describe the scattered nucleon. The model incorporates two-body meson-exchange currents contributing to one-particle-one-hole final states and tests several axial form factor parametrizations, including recent LQCD and MINERvA fits. It is implemented in the NEUT event generator and benchmarked against T2K and MINERvA $ν_μ$-$^{12}$C CC0$π$ measurements. We find that two-body meson-exchange currents lead to a sizeable increase of the total cross section, arising from an enhancement of the transverse response, which is the dominant component in charged-current neutrino scattering. On the other hand, recent fits of the axial form factor predict larger values than the standard dipole form, yielding a systematic enhancement of the cross section. The LQCD+MINERvA parametrization tends to overestimate the data, while the MINERvA-only fit provides a more moderate increase. Overall, no single configuration consistently provides the best agreement with the different datasets.
title Two-body current and axial form factor effects in charged-current quasielastic neutrino-nucleus scattering within the NEUT event generator
topic Nuclear Theory
url https://arxiv.org/abs/2605.00756