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 π. 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.Comment: Text improved in response to PRC referee comment
