Neutrino Cross Sections
MiniBooNE's neutrino flux (with a mean energy of ~700 MeV) dictates the type of neutrino interactions the experiment
sees. At these energies, quasi-elastic (QE) and single pion
production processes dominate. For MiniBooNE, the
contributions from multi-pion production and deep inelastic
scattering (DIS) are small.
image: neutrino cross sections vs energy
There are several cross sections which contribute at these
energies. Here is a plot of the
charged current (CC) cross section predictions divided
by energy as a function of neutrino energy (in GeV) for
the various contributing processes at low energy. Also
shown are some of the existing data from a variety of
experiments.
image: neutrino event types in oil for the MiniBooNE flux
This pie chart shows the resultant event fractions
at MiniBooNE before any selection cuts. The dominant
event contributions are QE, neutral current
elastic scattering (NC EL), CC charged pion
production (CC π+), and NC neutral pion production
(NC π0).
The MiniBooNE experiment uses the
NUANCE event generator to model the cross sections and kinematics for the
possible different neutrino interactions in mineral oil, of which the above
interactions dominate. The NUANCE predictions are additionally modified based
on measurements from our own high statistics samples:
- QE scattering: QE events comprise the largest single event
sample at MiniBooNE. MiniBooNE has analyzed a sample of over 190,000
muon neutrino QE interactions in our detector. This high statistics,
high purity sample allows us to tune QE cross section model parameters
for carbon and achieve improved kinematic agreement for these events.
The results are then applied to the modeling of electron neutrino
QE events, allowing us to accurately predict the kinematics of
potential signal events in the MiniBooNE oscillation search sample.
- NC π0 production: While only ~10% of the total neutrino events
in MiniBooNE, NC π0 events can pass electron neutrino selection
criteria and comprise the dominant neutrino-induced background in
the MiniBooNE electron neutrino appearance search. The high
statistics sample of well identified NC π0 events at MiniBooNE
affords a precise constraint of NC π0 events which are
misidentified.
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