Events on Thursday, August 21st, 2025
- Qualifying Exam Study Hall
- Time: 1:00 pm - 2:30 pm
- Place: 3320 Chamberlin
- Host: Jim Reardon
- Search for the Highest Energy Neutrinos in IceCube
- Time: 4:00 pm - 6:00 pm
- Place: 5280 Chamberlin
- Speaker: Maxwell Nakos, Physics PhD Graduate Student
- Abstract: Recently, KM3Net has detected a neutrino candidate with a best fit neutrino energy of 220 (-110,+570) PeV, while the highest energy event from IceCube has a best fit neutrino energy of 11.4 (-2.53,+2.46) PeV. Due to the absorption from the Earth, neutrinos with energies greater than 10 PeV are likely to originate from the horizontal and downgoing directions, where there is a large, high energy atmospheric muon background from cosmic rays.
To address this, I develop neural networks to improve background rejection for downgoing tracks from the southern sky, recovering throughgoing neutrinos typically discarded due to high atmospheric muon contamination. These events enable a search for extremely high-energy neutrinos, which are incorporated into a diffuse combined fit - including cosmogenic, astrophysical, and atmospheric components - to probe the apparent tension between KM3NeT and IceCube observations at the highest energies.
In parallel, I am also developing a transient analysis looking for spatial and timing correlations between ultra-high-energy photon candidates detected by the Pierre Auger Observatory and multi-flavor neutrinos detected by the IceCube Neutrino Observatory, the first search for ultra-high-energy transient sources combining neutral particle information from UHE photons and neutrinos. - Host: Lu Lu