In-medium changes of nucleon cross sections tested in neutrino-induced reactions

TL;DR

This paper investigates how in-medium modifications of nucleon-nucleon cross sections affect neutrino-nucleus interaction predictions, finding that certain modifications improve agreement with experimental data, though some uncertainties remain.

Contribution

It introduces a detailed analysis of in-medium nucleon-nucleon cross section effects on neutrino scattering using the GiBUU model, highlighting the importance of density dependence and resonance broadening.

Findings

In-medium lowering of NN cross sections improves data agreement.

Density dependence on $\Delta$ excitation enhances model accuracy.

Absence of $\Delta$ broadening is slightly favored by data.

Abstract

Historically studied in the context of heavy-ion collisions, the extent to which free nucleon-nucleon cross sections are modified in-medium remains undetermined by these data sets. Therefore, we investigate the impact of NN in-medium modifications on neutrino-nucleus cross section predictions using the GiBUU transport model. We find that including an in-medium lowering of the NN cross section and density dependence on $\Delta$ excitation improves agreement with MicroBooNE neutrino-argon scattering data. This is observed for both proton and neutral pion spectra in charged-current muon neutrino and neutral-current single pion production datasets. The impact of collision broadening of the $\Delta$ resonance is also investigated. The absence of $\Delta$ broadening is slightly favored, but the larger uncertainties on the pion production data prevent definitive conclusions.