Precision Atmospheric Neutrino Oscillation Measurements with IceCube DeepCore

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Embedded deep in the Antarctic polar ice cap, the IceCube Neutrino Observatory is the world's largest and most sensitive high energy neutrino telescope. In the past few years, IceCube has discovered neutrinos of astrophysical origin at energies reaching the PeV scale, and its DeepCore extension has performed measurements of fundamental parameters in particle physics through the measurement of atmospheric neutrinos at energies as low as roughly 5 GeV. Within the course of this project the group will pursue improvements in the simulation and reconstruction of events to sharpen the energy resolution and the identification of the direction from which the neutrinos reach the detector as well as implement general improvements to reduce the interfering background. Opportunities are provided for young physicists at all levels to become involved in particle astrophysics, with a particular emphasis on encouraging participation among women and underrepresented groups. In addition, the PI founded and continues to serve as the faculty mentor to the Physics and Astronomy Women (PAW) student group. PAW provides a forum for open discussion of the challenges facing women as well as their solutions, runs a mentoring program for starting undergraduate and graduate women in physics, increases the local visibility of women in science through outreach activities, and provides networking and professional development opportunities in a friendly environment. DeepCore, situated at the bottom center of the IceCube array, benefits from its unmatched multi-megaton fiducial volume and the availability of surrounding IceCube modules to veto atmospheric muon background events, greatly enhancing the neutrino signal-to-noise ratio. DeepCore has been used to measure muon-neutrino disappearance and tau-neutrino appearance, as well as the flux of atmospheric electron neutrinos, at energies an order of magnitude higher than previous observations, and with uncertainties that are comparable to the world's best current measurements. With this award, the Penn State IceCube group will continue to exploit the DeepCore data to answer fundamental questions of neutrino physics, focusing on better and faster event reconstruction and more effective background rejection to improve its measurement of the tau neutrino normalization, to determine Delta (m_23)^2 and theta_23 with greater precision, and to reduce systematic errors for these and other similar analyses. It will also continue to provide strong support for the use of neutrinos from IceCube and DeepCore to facilitate real-time searches for multi-messenger astrophysical sources via the AMON network headquartered at Penn State.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.