CAREER: Maximizing the Science Output of EXO-200

University Of California-San Diego, La Jolla CA

Investigators

Abstract

Neutrinos are among the most mysterious sub-atomic particles in the Universe. Recent breakthroughs in neutrino oscillation experiments have revealed that they have tiny masses and have raised several intriguing questions. Why are neutrinos so much lighter than the other particles? What is the absolute scale of the neutrino masses? And are the neutrinos their own antiparticles? The keys to addressing these questions may lie in the search for a very rare decay process called neutrinoless double beta decay. During such a decay, two neutrons inside a nucleus simultaneously decay into two protons, emitting two electrons and no neutrino. The goal of the project is to perform one of the most sensitive searches of this rare decay using data from the EXO-200 experiment. A discovery of this elusive decay would signify that neutrinos are their own antiparticles; thus neutrinos obtain their masses differently from other particles. The results may also shed light on the mystery of why there is more matter than anti-matter in the Universe. In addition to his research on neutrinos, the principal investigator will also develop an educational program to strengthen science education at the middle-school level. Specifically, the PI will organize workshops on middle-school physical science teaching in collaboration with the College of Education at the University of Illinois at Urbana-Champaign and build closer connections between middle-school students and science majors at Illinois through a series of innovative outreach activities. The project will integrate research, outreach, and education around the development of novel analysis techniques to enhance the performance of large liquid xenon detectors such as EXO-200. In its Phase-I operation, EXO-200 has demonstrated the unique capability of large liquid xenon detectors in the search for neutrinoless double beta decay in Xe-136. With detector upgrades in 2016 and three years of additional Phase-II running, EXO-200 can improve by threefold its sensitivity to the Xe-136 neutrinoless double beta decay half-life. The work focuses on the development of new analysis techniques to enhance the detector energy resolution and improve its background rejection capabilities, which are essential for maximizing the physics reach of EXO-200. Understanding and demonstrating the ultimate performance of EXO-200 can provide essential inputs to the design of future tonne-scale detectors. The analysis techniques to be developed can also be applied to large noble liquid detectors for particle physics experiments and medical imaging. In parallel, educational and outreach activities are planned to enhance middle school science education. The PI together with colleagues at Illinois will organize workshops for area middle school teachers on physical science teaching in accordance with the New Generation Science Standards and the development of hands-on classroom activities to implement the new standards. The PI will also direct undergraduate volunteers in outreach to middle school students through demonstrations, an online forum, and assisting in school-initiated science programs.