Beyond Standard Model Searches in the MiniBooNE Experiment

The MiniBooNE experiment has contributed substantially to beyond standard model searches in the neutrino sector. The experiment was originally designed to test the <math id="M1" xmlns="http://www.w3.org/1998/Math/MathML"><mi mathvariant="normal">Δ</mi><msup><mrow><mi>m</mi></mrow><mrow><mn>2</mn></mrow></msup><mo>~</mo><mn>1</mn></math> eV2 region of the sterile neutrino hypothesis by observing <math id="M2" xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mrow><mi>ν</mi></mrow><mrow><mi>e</mi></mrow></msub></mrow></math> ( <math id="M3" xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mrow><mover accent="true"><mrow><mi>ν</mi></mrow><mo>-</mo></mover></mrow><mrow><mi>e</mi></mrow></msub></mrow></math> ) charged current quasielastic signals from a <math id="M4" xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mrow><mi>ν</mi></mrow><mrow><mi>μ</mi></mrow></msub></mrow></math> ( <math id="M5" xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mrow><mover accent="true"><mrow><mi>ν</mi></mrow><mo>-</mo></mover></mrow><mrow><mi>μ</mi></mrow></msub></mrow></math> ) beam. MiniBooNE observed excesses of <math id="M6" xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mrow><mi>ν</mi></mrow><mrow><mi>e</mi></mrow></msub></mrow></math> and <math id="M7" xmlns="http://www.w3.org/1998/Math/MathML"><mrow><msub><mrow><mover accent="true"><mrow><mi>ν</mi></mrow><mo>-</mo></mover></mrow><mrow><mi>e</mi></mrow></msub></mrow></math> candidate events in neutrino and antineutrino mode, respectively. To date, these excesses have not been explained within the neutrino standard model ( <math id="M8" xmlns="http://www.w3.org/1998/Math/MathML"><mrow><mi>ν</mi></mrow></math> SM); the standard model extended for three massive neutrinos. Confirmation is required by future experiments such as MicroBooNE. MiniBooNE also provided an opportunity for precision studies of Lorentz violation. The results set strict limits for the first time on several parameters of the standard-model extension, the generic formalism for considering Lorentz violation. Most recently, an extension to MiniBooNE running, with a beam tuned in beam-dump mode, is being performed to search for dark sector particles. This review describes these studies, demonstrating that short baseline neutrino experiments are rich environments in new physics searches