Published: 2009
Total Pages: 43
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There is accumulating evidence for a difference between neutrino and antineutrino oscillations at the H" eV2 scale. The MiniBooNE experiment observes an unexplained excess of electron-like events at low energies in neutrino mode, which may be due, for example, to either a neutral current radiative interaction, sterile neutrino decay, or to neutrino oscillations involving sterile neutrinos and which may be related to the LSND signal. No excess of electron-like events ( -0.5 ± 7.8 ± 8.7), however, is observed so far at low energies in antineutrino mode. Furthermore, global 3+1 and 3+2 sterile neutrino fits to the world neutrino and antineutrino data suggest a difference between neutrinos and antineutrinos with significant (sin2 2[theta]{sub [mu]{mu}} H"35%) {bar [nu]}{sub {mu}} disappearance. In order to test whether the low-energy excess is due to neutrino oscillations and whether there is a difference between [nu]{sub {mu}} and {bar [nu]}{sub {mu}} disappearance, we propose building a second MiniBooNE detector at (or moving the existing MiniBooNE detector to) a distance of H"00 m from the Booster Neutrino Beam (BNB) production target. With identical detectors at different distances, most of the systematic errors will cancel when taking a ratio of events in the two detectors, as the neutrino flux varies as 1/r2 to a calculable approximation. This will allow sensitive tests of oscillations for both {nu}{sub e} and {bar {nu}} appearance and {nu}{sub {mu}} and {bar {nu}}{sub {mu}} disappearance. Furthermore, a comparison between oscillations in neutrino mode and antineutrino mode will allow a sensitive search for CP and CPT violation in the lepton sector at short baseline ([Delta]m2> 0.1 eV2). Finally, by comparing the rates for a neutral current (NC) reaction, such as NC [pi]° scattering or NC elastic scattering, a direct search for sterile neutrinos will be made. The initial amount of running time requested for the near detector will be a total of H"E20 POT divided between neutrino mode and antineutrino mode, which will provide statistics comparable to what has already been collected in the far detector. A thorough understanding of this short-baseline physics will be of great importance to future long-baseline oscillation experiments.