IceCube, located at the South Pole, is the world’s largest neutrino detector and plays a central role in exploring the high-energy neutrinos from the universe as well as fundamental neutrino properties. It enables the detection of neutrinos from astrophysical sources as well as those produced in Earth’s atmosphere.

Our group is engaged in both the analysis of neutrino data and the development of experimental hardware, with the goal of advancing the scientific reach of the IceCube Neutrino Observatory and its planned upgrades. 

On the analysis side, we focus on atmospheric neutrino oscillations. These measurements are sensitive to the neutrino mass ordering—one of the remaining unknowns in the Standard Model—and also offer a unique window into potential non-standard neutrino interactions, which could signal new physics.

In parallel, we contribute to the design and development of next-generation detector technologies, particularly in the area of low-noise, high-efficiency photosensors. Our group contributes to the design and implementation of Wavelength-shifting Optical Modules (WOMs)—a novel class of photosensors that combine wavelength-shifting materials and light-guiding geometries. WOMs offer significantly improved light collection efficiency and drastically reduced noise rates, making them ideal for low-energy neutrino detection.

Within the group, we are also developing the Neutron Echo technique to improve event classification of high-energy events, which will provide a deeper understanding of the production mechanisms in astrophysical sources. This novel approach has the potential to enhance flavor discrimination between electron and tau neutrino showers beyond what is achievable using shower topology alone.

There have been significant gains in characterizing neutrino properties in recent years, however the absolute neutrino mass scale continues to be elusive. The Project 8 collaboration seeks to probe this quantity directly via kinematic analysis of tritium beta decay, using the cyclotron radiation emission spectroscopy (CRES) technique. In order to make neutrino mass measurements with a design sensitivity of 40meV, the Project 8 experiment must use atomic tritium. Our working group together with AG Fertl are performing critical R&D for atomic tritium production. In the lab, a Mainz Atomic Test Stand dissociates hydrogen (a safe substitute for tritium) at temperatures in excess of 2000K, while diagnostic tools (calorimetry and spectrometry) are being developed to characterize the atomic beam. Future versions of the test stand will include a beam-cooling element, prototyping of which is underway.

The NuDoubt⁺⁺ experiment is focused on detecting the rare nuclear process of double beta plus decay, which involves the emission of two positrons. Measuring this decay is challenging due to its low probability, difficult-to-detect signatures, and the scarcity of suitable candidate nuclei. To address these challenges, we have developed an innovative detector concept that combines hybrid and opaque scintillation detector technologies with new light read-out techniques using novel wavelength shifting fibers. This combination is particularly effective for identifying positrons, for which we are developing novel background rejection techniques.

We anticipate that with just one tonne-week of exposure, our detector will be capable of discovering two-neutrino double beta plus decay modes. Furthermore, it has the potential to significantly improve the detection limits for neutrinoless double beta plus decays compared to current experiments.