Sterile Neutrino

This thesis highlights data from MINOS, a long-baseline accelerator neutrino experiment, and details one of the most sensitive searches for the sterile neutrino ever made. Further, it presents a new analysis paradigm to enable this measurement and a comprehensive study of the myriad systematic uncertainties involved in a search for a few-percent effect, while also rigorously investigating the statistical interpretation of the findings in the context of a sterile neutrino model.

This thesis, encompassing both theory to experiment, guides the reader in a pedagogical way through the author’s attempts to resolve the mystery of the so-called MiniBooNE anomaly, where unexpected neutrino oscillations were reported, potentially explainable by the existence of light sterile neutrinos, but in contradiction with several null results. Within this context, this thesis reports one of the first analyses searching for an excess of electrons in the MicroBooNE experiment finding no excess of events and narrowing down the possible explanations for the anomaly. Additionally, this thesis explores non-minimal heavy neutral leptons as potential explanations for the MiniBooNE excess. To search for evidence for this particle, the author performs an analysis using data from the T2K experiment, which searched for pairs of electrons using a gas argon time projection. This thesis provides a comprehensive explanation of the MiniBooNE anomaly and test of its possibile explanation with liquid and gas time projection chambers.

This thesis, encompassing both theory to experiment, guides the reader in a pedagogical way through the author’s attempts to resolve the mystery of the so-called MiniBooNE anomaly, where unexpected neutrino oscillations were reported, potentially explainable by the existence of light sterile neutrinos, but in contradiction with several null results. Within this context, this thesis reports one of the first analyses searching for an excess of electrons in the MicroBooNE experiment finding no excess of events and narrowing down the possible explanations for the anomaly. Additionally, this thesis explores non-minimal heavy neutral leptons as potential explanations for the MiniBooNE excess. To search for evidence for this particle, the author performs an analysis using data from the T2K experiment, which searched for pairs of electrons using a gas argon time projection. This thesis provides a comprehensive explanation of the MiniBooNE anomaly and test of its possibile explanation with liquid and gas time projection chambers.

This current updated and expanded text reflects the large number of scientific advances, both theoretically and experimentally, within the discipline of cosmoparticle physics in the last 10 years.