Sterile neutrino searches in MiniBooNE and MicroBooNE

Abstract

Tension among recent short baseline neutrino experiments has pointed toward the possible need for the addition of one or more sterile (non-interacting) neutrino states into the existing neutrino oscillation framework. This thesis first presents the motivation for sterile neutrino models by describing the short-baseline anomalies that can be addressed with them. This is followed by a discussion of the phenomenology of these models. The MiniBooNE experiment and results are then described in detail, particularly the most recent anti-neutrino analysis. This will be followed by a discussion of global fits to world data, including the anomalous data sets. Lastly, future experiments will be addressed, especially focusing on the MicroBooNE experiment and light collection studies. In particular, understanding the degradation source of TPB, designing the TPB-coated plates for MicroBooNE and developing light guide collection systems will be discussed. We find an excess of events in the Mini-anti-neutrinoutrino mode results consistent with the LSND anomaly, but one that has a different energy dependence than the low-energy excess reported in neutrino mode. This disagreement creates tension within global fits which include up to three sterile neutrinos. The low-energy excess will be addressed by the MicroBooNE experiment, which is expected to start taking data in early 2015. Tension among existing experiments calls for additional, more decisive future experiments.