Interfacing Electron and Neutrino Quasielastic Scattering Cross Sections with the Spectral Function in GENIE

TL;DR

This paper develops a Fortran wrapper to integrate advanced microscopic neutrino-nucleus interaction models, specifically the Spectral Function, into the GENIE event generator to improve accuracy and uncertainty quantification.

Contribution

It introduces a novel interface for incorporating sophisticated nuclear models into GENIE, enhancing the realism and uncertainty analysis of neutrino interaction simulations.

Findings

Validated the Spectral Function implementation within GENIE.

Compared model predictions with experimental data.

Demonstrated improved nuclear ground state description.

Abstract

Progress in neutrino-nucleus cross section models is being driven by the need for highly accurate predictions for the neutrino oscillation community. These sophisticated models are being developed within a microscopic description of the nucleus with the goal of encompassing all reaction modes relevant for the accelerator neutrino program. The disconnect between these microscopic models and the event generators that will be used in the next generation of experiments represents a critical obstacle that must be overcome in order to precisely measure the neutrino oscillation parameters. To this end we have developed a Fortran wrapper for lepton-nucleus quasielastic (QE) scattering within the GENIE event generator as a proof of principle, with the broader goal of creating an efficient pipeline for incorporating advanced theoretical models in event generators. As a demonstration of this interface, we have implemented the Spectral Function model into GENIE, offering a more complete description of the nuclear ground state, as well as the ability to provide quantifiable theoretical uncertainties. We validate this implementation and compare its predictions against data and against QE models already available in GENIE.