Neutrino Physics with Liquid Argon Detectors: Entering the MicroBooNE Era

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One of the major intellectual achievements of the 20th century was the development of the Standard Model (SM) of particle physics. This model succeeded in classifying all of the elementary particles known at the time into a hierarchy of groups having similar quantum properties. The validity of this model to date was recently confirmed by the discovery of the Higgs boson at the Large Hadron Collider at CERN. However, the Standard Model as it currently exists leaves open many questions about the universe, including such fundamental questions as to why the Higgs mass has the value it has and why there is no antimatter in the universe. One of the primary areas to search for answers to these and other open questions about the universe, how it came to be and why it is the way it is, is to focus on a study of the properties of neutrinos and to use what we know and can learn about neutrinos as probes of science beyond the Standard Model. Neutrinos are those elementary particles that interact with practically nothing else in the universe. They have no electric charge and were once thought to be massless. Like other elementary particles, they were believed to have an antimatter counterpart, the antineutrino. Moreover, the Standard Model predicted that there were actually three different kinds of neutrinos that were distinguishable through the different interactions that they did undergo whenever there was an interaction. But recent measurements have totally changed our picture of neutrinos. We now know that neutrinos do have a mass and because they do, they can actually change from one type to another. Detailed measurements of these changes, along with other current neutrino experiments, form one of the most promising ways to probe for new physics beyond the Standard Model. Such measurements lie at the heart of this project.There is currently a large interest in experimental particle physics in Liquid Argon Time Projection Chambers (LArTPC) spurred in part by the proposed Long Baseline Neutrino Experiment (LBNE) project at Fermi National Accelerator Laboratory (FNAL) and in neutrino physics in general. This award supports work which refines LArTPC technology, using a test beam and at the MicroBooNE experiment at FNAL.LArTPC detector technology is scalable to the very large masses (perhaps 10 kiloTons) needed by next generation neutrino experiments and is capable of recording three-dimensional digital images of particle trajectories. The MicroBooNE will have an active volume of 80 tons of liquid argon and 8256 wires spread over three instrumented wireplanes making up the Time Projection Chamber. MicroBooNE will make a variety of interesting physics measurements, as well as serving as a proving ground for new hardware techniques relevant for future experiments. Among MicroBooNE's primary physics goals is to provide a cross-check of the "low-energy excess" of electron neutrino events previously identified by the MiniBooNE experiment. There have been recent "hints" that there may be a new type of neutrino, the so-called sterile neutrino. The MicroBoone experiment, with the superior LArTPC, should clarify the situation: either rule out or confirm the sterile neutrino evidence. The broader impact of this work will involve graduate students and undergraduates supported by this proposal receiving first-hand experience with High Energy Physics detector development, while also having access to MicroBooNE data that the graduate students will use for their dissertation analyses. The Syracuse group will continue with several outreach efforts as part of this proposal. The group maintains an outreach webpage that includes an "Ask-a-A-Physicist" questionnaire form as well as an active QuarkNet program.