Hammer events, neutrino energies, and nucleon-nucleon correlations

Abstract

Neutrino oscillation measurements depend on a difference between the rate of neutrino-nucleus interactions at different neutrino energies or different distances from the source. Knowledge of the neutrino energy spectrum and neutrino-detector interactions are crucial for these experiments. Short range nucleon-nucleon correlations in nuclei (SRC) affect properties of nuclei. The ArgoNeut liquid Argon Time Projection Chamber (lArTPC) observed neutrino-argon scattering events with two protons back-to-back in the final state ("hammer" events) which they associated with SRC pairs. The MicroBoone lArTPC will measure far more of these events. We simulate hammer events using two simple models. We use the well-known electron-nucleon cross section to calculate e-argon interactions where the e- scatters from a proton, ejecting a pi+, and the pi+ is then absorbed on a moving deuteron-like $np$ pair. We also use a model where the electron excites a nucleon to a Delta, which then deexcites by interacting with a second nucleon. The pion production model results in two protons very similar to those of the hammer events. These distributions are insensitive to the momentum of the $np$ pair that absorbed the $\pi$. The incident neutrino energy can be reconstructed from just the outgoing lepton. The Delta process results in two protons that are less similar to the observed events. ArgoNeut hammer events can be described by a simple pion production and reabsorption model. These hammer events in MicroBooNE can be used to determine the incident neutrino energy but not to learn about SRC. We suggest that this reaction channel could be used for neutrino oscillation experiments to complement other channels with higher statistics but different systematic uncertainties.

Text improved in response to PRC referee comments

References in corpus (5)

• Probing Cold Dense Nuclear Matter
• Momentum sharing in imbalanced Fermi systems
• Evidence for the Strong Dominance of Proton-Neutron Correlations in Nuclei
• Neutrino Interactions with Nucleons and Nuclei: Importance for Long-Baseline Experiments
• The detection of back-to-back proton pairs in Charged-Current neutrino interactions with the ArgoNeuT detector in the NuMI low energy beam line

Cited by in corpus (9)

• Nucleon-Nucleon Correlations, Short-lived Excitations, and the Quarks Within
• NuSTEC White Paper: Status and Challenges of Neutrino-Nucleus Scattering
• The nuclear contacts and short range correlations in nuclei
• The center of mass motion of short-range correlated nucleon pairs studied via the A(e,e'pp) reaction
• Seagull and pion-in-flight currents in neutrino-induced $1N$ and $2N$ knockout
• Pion-proton correlation in neutrino interactions on nuclei
• Two-nucleon emission in neutrino and electron scattering from nuclei: the modified convolution approximation
• Emission of neutron-proton and proton-proton pairs in electron scattering induced by meson-exchange currents
• Coarse grained short-range correlations