A Vision for Neutrino and Particle Physics at the South Pole
Athayde Marcondes de Andra (right) presented PINGU and the south pole detectors for neutrino and particle physics. He started by discussing the issue of measuring neutrino oscillations with atmospheric neutrinos. If one does not assume unitarity of the PMNS matrix one has nine parameters to measure. For the third row in the matrix, one must look for tau neutrino appearance. Opera and SK measured it, and in both cases they saw too many tau neutrino events. Although not statistically significant, this warrants precision measurements.
In IceCUBE, one gigaton of ice is instrumented, optimized for TeV-PeV neutrinos. At its center there is DeepCore, 10 Mtons with denser instrumentation. This allows to study neutrinos at a lower energy threshold, and oscillations; the surrounding detectors provide good shielding and veto.
The first result of DeepCore was shown in Lake Louise this year. Based on a 3-year sample of data, they get a very competitive result for delta_m^2_23 and theta_23. One can improve the detector with more strings tightly packed, and study the tau neutrino appearance. A proposal to the NSF has been put forth.
The signal for tau neutrino appearance in IceCube-Gen2 Phase 1 is a dip in the L/E distribution at 2 to 4 in log(km/GeV) as a ratio to standard oscillation signal. The speaker showed a breakdown of systematic uncertainties one would be looking at. The results for tau appearance would give better than 10% on the flux.
Going forward beyond Phase-1, there is PINGU. Adding more strings one could see much more clearly the events of low energy. There are a number of analysis goals. For the hierarchy, the signal is a resonance effect due to matter effects. The speaker showed maps in cosine of zenith angle versus energy. They cannot differentiate the neutrinos and antineutrinos, and only rely on the flux. The precision they would get is a three-sigma measurement, but they can go beyond with some values of theta_23.