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.