WoU-MMA: Demonstrating Ultrahigh-Energy-Neutrino Observations with Compact Air-Shower-Imaging Telescopes

The discovery of a new window with which to observe the Universe, whether X-ray, gamma-ray, or gravitational waves, has provided transformative impact on the fields of astrophysics and particle astrophysics. The most recent new messengers observed are high-energy astrophysical neutrinos, now detected to approximately 10 peta-electron-Volts in energy.

While the sources of these neutrinos are yet unknown, they are fully expected to be linked to the most extreme cosmic ray accelerators, implying that ultra-high-energy (UHE) neutrinos that far exceed the current observed energies must exist. The detection of UHE neutrinos remains an outstanding challenge for the field but hold the potential to answer some longstanding questions, including the sources of the most energetic particle in the Universe, how these cosmic accelerators behave, and large-scale evolution of the Universe.

The Trinity project aims to open the window to UHE neutrinos by utilizing advancements of air Chereknov telescope techniques, and this award facilitates the development and deployment of the first demonstrator instrument. The project provides several opportunities to train the next generation of scientists and engineers; in particular undergraduate students will significantly contribute to the design and construction of the proposed instrument, gaining hands-on and real-world experience.

The awarded program also furthers the development of novel light sensors based on silicon photomultiplier (SiPM) technology that have a broad range of applications from medical imaging to LIDARs for automotive driving.

UHE neutrinos must exist but detecting them is an extraordinary challenge. Neutrinos in general are elusive particles that require monitoring large volumes of water, ice, or atmosphere. The primary task in their detection is to achieve a scalable instrument with the highest possible sensitivity for the lowest possible cost.

The Trinity design is a system of air-shower imaging Cherenkov telescope that aims to realize these goals. As a first step in demonstrating this approach, a one-square meter (5 degree x 5 degree) air-shower imaging telescope with a SiPM camera will be developed, installed and operated at Frisco Peak in Utah. The telescope will image upward-going particle showers and search for those that result when a UHE tau neutrino enters the Earth under a shallow angle, interacts, and produces a tau lepton that emerges from the ground and decays in the atmosphere, a technique known as Earth-skimming.

The project's objectives are to realize the crucial steps to advance this technique towards the first detection of UHE neutrinos and introduce a new messenger to the extreme Universe. They include: demonstrate the long-term stability and reliability of the detection technique, the light-sensor and camera technology and remote operation of the telescope; and the study of background events and the advancement of analysis techniques. This project advances the goals of the NSF Windows on the Universe Big Idea.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.