Researchers from the United States and Japan have conducted a major joint analysis on neutrinos, offering new insights into these elusive subatomic particles. The study, published in Nature, represents a collaboration between two leading experiments: T2K in Japan and NOvA in the United States. Together, they analyzed 10 years of data from T2K and six years from NOvA.
Mayly Sanchez, the Wyatt-Green Chair of Physics at Florida State University and one of four liaisons coordinating the effort, said, “This was an incredible collaboration with hundreds of scientists with different, but complementary approaches trying to tackle this question of how neutrinos operate. It’s been very rewarding work. I hope this serves as a seed for stronger international collaboration and sparks a new wave of discoveries about these mysterious particles.”
Neutrinos are known for having no electric charge and very little mass. They change types—called flavors—as they travel long distances through a process called neutrino oscillation. By comparing how neutrinos and their antimatter counterparts behave during oscillation, scientists aim to learn more about why matter is more prevalent than antimatter in the universe.
The joint analysis included work by 810 scientists and engineers from 124 institutions across 23 countries. In the T2K experiment, researchers sent a beam of neutrinos over 295 kilometers in Japan. In NOvA, a beam traveled from Fermilab near Chicago to Minnesota’s Ash River detector.
Results showed that there are two possible arrangements for neutrino masses: normal ordering (two light states and one heavy) or inverted ordering (two heavy states and one light). The combined data did not clearly favor either scenario nor did it show significant differences between neutrino and antineutrino behavior.
Sanchez noted that preparations are underway for future experiments to gather more data on these questions. “Neutrinos work in mysterious ways, and the results of our experiments don’t quite align,” Sanchez said. “The result of this paper is there are these two possible universes — inverted or normal — and I’m looking forward to the next generation of experiments to see which one we are living in. Equally exciting is the possibility that neutrinos and antineutrinos may not behave in exactly the same way, which could help us understand why the universe today is made of matter rather than equal parts matter and antimatter.”
The information was adapted from material provided by Fermilab.
