In the world of science, a major breakthrough has been achieved in the study of one of the most mysterious particles of the Universe – neutrinos. These extremely light elementary particles have garnered the attention of physicists who are eager to determine their mass more accurately. The main focus is on the world’s largest detector, Karlsruhe Tritium Neutrino Experiment (Katrin), located in Germany, which stands out due to its size and shape. However, the scientific community is constantly evolving, with researchers from various laboratories around the world actively exploring alternative methods for measuring the mass of neutrinos, as seen at the recent Numass 2024 seminar in Genoa, Italy.
Current estimates, based on observations of cosmic structures, suggest that the mass of neutrinos is incredibly small – not exceeding 0.12 electron-volts, which is millions of times less than the mass of an electron. This poses a challenge for Katrin, as the best result achieved by the detector is an upper limit of 0.8 electron-volts, raising doubts about its ability to accurately determine the true mass of neutrinos.
The Numass 2024 seminar unveiled promising approaches, such as the utilization of the Holmium Isotope decay process, involving the capture of an electron as an alternative to tritium beta-decay used in Katrin. Proposed by theoretical physicist Alvaro de Rujula in 1981, this method entails the transformation of a proton into a neutron, releasing neutrinos and photons, ultimately generating heat. While progress on this approach has been varied, a team of researchers managed to place an upper limit on the neutrino mass of 150 electron-volts by 2019, aiming to enhance this result by tenfold.
Another method discussed at the seminar is Project 8, introduced by scientists from the Massachusetts Institute of Technology, which involves the use of low-density fiber gas within a “magnetic bottle” to capture electrons from beta-decay. This approach enables precise measurement of electron energies and may potentially reduce experimental sensitivity to 0.04 electron-volts in the future, surpassing the strict limits set by cosmological experiments.
Despite Katrin’s ongoing efforts and plans to continue its research, the physics community eagerly anticipates new results and advancements that could revolutionize our understanding of neutrino mass, opening up new avenues for exploring the universe.