Final-state interactions in neutrino-induced proton knockout from argon in MicroBooNE

TL;DR

This paper compares different intranuclear cascade models for neutrino-induced proton knockout on argon, analyzing their predictions against experimental data and highlighting discrepancies and potential improvements.

Contribution

It provides a systematic comparison of INC models using consistent inputs and evaluates their agreement with MicroBooNE data, revealing limitations and areas for refinement.

Findings

INC models underpredict the data, especially where two-nucleon knockout and resonance production are relevant.

Large variations in spectral functions do not significantly affect the results with current data.

Discrepancies exist between INC results and DWIA calculations, indicating model differences.

Abstract

Neutrino event generators make use of intranuclear cascade models (INCs), to predict the kinematics of hadrons produced in neutrino-nucleus interactions. We perform a consistent comparison of different INCs, by using the same set of events as input to the NEUT, NuWro, Achilles and INCL INCs. The inputs correspond to calculations of the fully differential single-proton knockout cross section, either in the distorted-wave impulse approximation (DWIA) or plane-wave impulse approximation (PWIA), both including realistic nuclear hole spectral functions. We compare the INC results to DWIA calculations with an optical potential, used extensively in the analysis of (e,e'p) experiments. We point out a systematic discrepancy between both approaches. We apply the INC results to recent MicroBooNE data. We assess the influence of the choice of spectral function, finding that large variations in realistic spectral functions are indistinguishable with present data. The data is underpredicted, with strength missing in the region where two-nucleon knockout and resonance production contribute. However, the data is underpredicted also in regions of low transverse missing momentum, where one-nucleon knockout dominates. The inclusion of the interference with two-body currents could lead to additional strength in this region.