Measuring the flavor composition of ultra-high energy neutrinos

• Applicant: Dr. Christoph Welling
• Subject Area: Nuclear and Elementary Particle Physics, Quantum Mechanics, Relativity, Fields ; Astrophysics and Astronomy
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 512689354

The goal of this project is to measure the flavor composition astrophysical neutrinos with energies at the EeV scale. As these neutrinos are expected to be associated with sources of ultrahigh-energy cosmic rays, this measurement can provide valuable insights into their origin. Two detectors that are sensitive to EeV-neutrinos are the Radio Neutrino Observatory Greenland (RNO-G), which is currently under construction on the Greenland ice sheet, and the Payload for Ultrahigh Energy Observations (PUEO), which is scheduled to launch on a high-altitude balloon in 2024. Both experiments are based on the detection of radio signals that are emitted by neutrino-induced particle showers. While both experiments will be sensitive to all three neutrino flavors, the charged lepton that is created in charged-current neutrino interactions can cause distinct signatures in the radio signals. This will allow RNO-G to measure the electron-neutrino and the combined muon and tau neutrino composition of the neutrino flux. As PUEO can measure the fraction of tau neutrinos, both experiments combined allow for sensitivity to all three neutrino flavors. The goal of this project is to first develop methods to identify each of the distinct flavor signatures associated with a specific flavor that can be detected by RNO-G and PUEO and to assess their sensitivity. Based on this, the potential of RNO-G and PUEO to determine the UHE neutrino flavor composition will be determined.

• DFG Programme: WBP Fellowship
• International Connection: USA
• Host: Professorin Dr. Abigail Vieregg