PINGU and the Neutrino Mass Hierarchy

Abstract

The nature of the neutrino mass hierarchy is one of the most interesting open questions in particle physics today, and thus has drawn a great deal of attention from the neutrino physics community. The measurement of a large mixing angle between the first and third neutrino mass eigenstates has made possible several methods of measuring this hierarchy. One of these methods is a proposed expansion of the IceCube/DeepCore detector called PINGU (Precision IceCube Next Generation Upgrade) which would use atmospheric neutrinos to make the determination. This extension is made up of additional strings of optical sensors (similar to those already deployed in the IceCube detector) which will be located in the ice at the centre of IceCube. The spacing between these sensors would be smaller than even the existing DeepCore detector (both vertically and horizontally) and this increased density would permit the lowering of the neutrino detection threshold to substantially below 10 GeV. The physical nature of the detector as well as the methods used to make this measurement are presented.