This white paper addresses the hypothesis of light sterile neutrinos based on recent anomalies observed in neutrino experiments and the latest astrophysical data.
The MiniBooNE experiment at Fermilab has amassed the largest sample to date of $pi^0$s produced in neutral current (NC) neutrino-nucleus interactions at low energy. This paper reports a measurement of the momentum distribution of $pi^0$s produced in
mineral oil (CH$_2$) and the first observation of coherent $pi^0$ production below 2 GeV. In the forward direction, the yield of events observed above the expectation for resonant production is attributed primarily to coherent production off carbon, but may also include a small contribution from diffractive production on hydrogen. Integrated over the MiniBooNE neutrino flux, the sum of the NC coherent and diffractive modes is found to be (19.5 $pm$1.1 (stat) $pm$2.5 (sys))% of all exclusive NC $pi^0$ production at MiniBooNE. These measurements are of immediate utility because they quantify an important background to MiniBooNEs search for $ u_{mu} to u_e$ oscillations.
An analysis of inclusive pion production in proton-beryllium collisions at 6.4, 12.3, and 17.5 GeV/c proton beam momentum has been performed. The data were taken by Experiment 910 at the Alternating Gradient Synchrotron at the Brookhaven National Lab
oratory. The differential $pi^+$ and $pi^-$ production cross sections ($d^2sigma/dpdOmega$) are measured up to 400 mRad in $theta_{pi}$ and up to 6 GeV/c in $p_{pi}$. The measured cross section is fit with a Sanford-Wang parameterization.
Sterile neutrino ($ u_s$) conversion in meter scale baselines can be sensitively probed using mono-energetic, sub-MeV, flavor pure $ u_e$s from an artificial MCi source and the unique technology of the LENS low energy solar $ u_e$ detector. Active-st
erile {em oscillations} can be directly observed in the granular LENS detector itself to critically test and extend results of short baseline accelerator and reactor experiments.
