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

Neutrino event generators make use of intranuclear cascade models (INCs) to predict the kinematics of hadron production 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 or plane-wave impulse approximation, 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 are underpredicted, with strength missing in the region where two-nucleon knockout and resonance production contribute. However, the data are 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.