Search for nucleon-nucleon correlations in neutrino-argon scattering

A sample of two-proton and no-pion events selected in the ArgoNeuT neutrino scattering experiment on a liquid argon target [Phys. Rev. D 90, 012008 (2014)] is analyzed with the nuwro Monte Carlo event generator. An attempt is made to estimate how likely it is to obtain observed numbers of laboratory frame and reconstructed back-to-back nucleon pairs. For laboratory frame back-to-back events, a clear data/Monte Carlo discrepancy is seen. For the reconstructed nucleon pairs, a good agreement is reported. We provide a simple kinematical argument that explains why this accordance is expected.

Figure 1

Impact of FSI effects on the sample of two-proton events. Fractions of two-proton events with and without FSI effects are shown. Normalization is the same as in Table 1. (a) LFG model and (b) SF approach.

Figure 2

Distribution of the cosine of the angle between two protons in the final state. (a) LFG model and (b) SF approach.

Figure 3

Distribution of the cosine of the angle between two protons in the final state. Subsample with both protons' momenta above the argon Fermi momentum. (a) LFG model and (b) SF approach.

Figure 4

Distribution of the cosine of the reconstructed angle between two protons in the final state. (a) LFG model and (b) SF approach.

Figure 5

Missing transverse momentum distribution for two-proton events. (a) LFG model and (b) SF approach.

Figure 6

Missing transverse momentum distribution for two-proton hammer events. (a) LFG model and (b) SF approach.