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

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 <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"><a:mrow><a:mi>N</a:mi><a:mi>N</a:mi></a:mrow></a:math> in-medium modifications on neutrino-nucleus cross section predictions using the GiBUU transport model. We find that including an in-medium lowering of the <b:math xmlns:b="http://www.w3.org/1998/Math/MathML"><b:mrow><b:mi>N</b:mi><b:mi>N</b:mi></b:mrow></b:math> cross section and density dependence on <c:math xmlns:c="http://www.w3.org/1998/Math/MathML"><c:mi mathvariant="normal">Δ</c:mi></c:math> 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 data sets. The impact of collision broadening of the <e:math xmlns:e="http://www.w3.org/1998/Math/MathML"><e:mi mathvariant="normal">Δ</e:mi></e:math> resonance is also investigated. The absence of <g:math xmlns:g="http://www.w3.org/1998/Math/MathML"><g:mi mathvariant="normal">Δ</g:mi></g:math> broadening is slightly favored, but the larger uncertainties on the pion production data prevent definitive conclusions. Published by the American Physical Society 2024