The IceCube Neutrino Observatory is the world’s largest neutrino detector. We recently discovered long sought-after ultrahigh energy astrophysical neutrinos, garnering awards such as Physics World 2013 Breakthrough of the Year. The result was published in the Science journal article Evidence for High-Energy Extraterrestrial Neutrinos at the IceCube Detector. IceCube has now collected over 50 high energy neutrino candidates, as first described in the Physical Review Letters article Observation of High Energy Astrophysical Neutrinos in Three Years of IceCube Data.
IceCube is an extremely versatile instrument. With its DeepCore sub-array it can also perform world-class neutrino oscillation measurements. The Penn State group has contributed to measurements of muon neutrino disappearance and is now actively working on tau neutrino appearance using IceCube DeepCore. DeepCore’s measurement of muon neutrino disappearance places IceCube in the same league as the immensely successful Super-Kamiokande detector and numerous dedicated accelerator-based experiments. For more details, please see our paper in Physical Review D, Determining neutrino oscillation parameters from atmospheric muon neutrino disappearance with three years of IceCube DeepCore data. More recent analysis techniques will give us a factor of several improvement in statistics and promise to improve this result still further.
We are eager to build on IceCube’s success with “IceCube-Gen2” which will extend the detector’s sensitivity to both lower and higher energy neutrinos. Penn State and UW-Madison are the lead US institutions on the Precision IceCube Next Generation Upgrade (PINGU), whose goal is to lower IceCube’s neutrino energy threshold to enable world-leading measurements of neutrino oscillation parameters using atmospheric neutrinos, including the “neutrino mass ordering,” one of the few remaining unknown fundamental parameters of the Standard Model of Particle Physics. With the High Energy Array (HEA), we plan to increase IceCube’s ultrahigh energy neutrino event rate by about a factor of 10 to better measure the spectrum of these mysterious particles, and to increase our chances of identifying their source(s).