Collaborative experiments focus on uncovering the unusual properties of the ghost particle.
In a recent study, physicists have created the clearest and most detailed view so far of how neutrinos shift their “flavor” as they move through space.
Neutrinos are among the universe’s basic building blocks, yet they remain some of the hardest particles to study. They pass effortlessly through matter, making them nearly impossible to detect. Although much about them is still unknown, scientists have identified three distinct kinds of neutrinos: electron, muon, and tau.
Understanding these different identities can help scientists learn more about neutrino masses and answer key questions about the evolution of the universe, including why matter came to dominate over antimatter in the early universe, said Zoya Vallari, an assistant professor of physics at The Ohio State University.
“The reason neutrinos are really, really fun is because they change their flavors,” she said. “Imagine getting chocolate ice cream, walking down the street, and suddenly it turns into mint, and every time it moves, it changes again.”
The Science Behind Neutrino Oscillations
This process, known as neutrino oscillation, occurs both in neutrinos that form naturally and in those created by scientists in laboratory settings. To investigate this remarkable shape-shifting behavior, researchers from two major international projects, the NOvA (the NuMI Off-axis νe Appearance) experiment in the United States and the T2K experiment in Japan, joined efforts. Together, they directed beams of neutrino particles across hundreds of miles, tracking how their “flavor” changed along the way.
Zoya Vallari, a leading member of the NOvA collaboration, is now assembling a research group at The Ohio State University to help design a next-generation neutrino detector, which is expected to begin operations near the end of the decade.
The findings from this joint study were recently published in Nature.
Although NOvA and T2K share similar scientific goals, each uses a distinct approach. The NOvA experiment sends a beam of muon neutrinos from the U.S. Department of Energy’s Fermi National Accelerator Laboratory near Chicago, Illinois, to a far detector in Ash River, Minnesota. Meanwhile, T2K launches its muon neutrino beam from Japan’s east coast and measures it at a detector located in the mountains of western Japan.
“While our goals were the same, differences in our experiment design adds more information when we pool our data together, in that the sum is more than its parts,” said Vallari.
Searching for Clues Beyond the Standard Model
While this study builds on previous work that found tiny, but still very consequential, differences in neutrino mass for each type, researchers sought deeper hints that neutrinos operate outside the standard laws of physics. One such question is whether neutrinos and their antimatter counterparts behave differently, a phenomenon called Charge-Parity violation. If future data confirms that they do, researchers would be closer to discovering how the universe became mostly matter, rather than being wiped out by antimatter after the Big Bang.
While these findings don’t definitively answer what role neutrinos play in the fabric of the universe, they do increase scientists’ knowledge about them.
“Our results show that we need more data to be able to significantly answer these fundamental questions,” said Vallari. “That’s why building the next generation of experiments is important.”
According to the study, combining the results of both experiments allowed researchers to get a handle on these pressing physics questions from different angles, as two experiments with different baselines and energies have a better chance of answering them than a single experiment alone.
“This work is extraordinarily complex, and each collaboration involves hundreds of people,” said John Beacom, a professor of physics and astronomy at Ohio State. “Collaborations like these are usually competing, so that they are co-operating here shows how high the stakes are.”
Researchers plan to continue using the NOvA and T2K collaborations to study evolving neutrino behavior and will update their analysis with new data accordingly. The lessons learned from this paper could lay a foundation for forthcoming neutrino experiments that will succeed in shaking up the field.
“Particle physics has given us many technologies, but for me, the primary motivation remains the human curiosity to understand our origin and place in the universe,” said Vallari.
Reference: “Joint neutrino oscillation analysis from the T2K and NOvA experiments” by The NOvA Collaboration, and The T2K Collaboration, 22 October 2025, Nature.
DOI: 10.1038/s41586-025-09599-3
Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.
6 Comments
thanks for this
Ohio state press department releases a very vague description.
Compare with this (lengthy) excerpt from the Italian Institute for Nuclear Physics press release:
“One of the great mysteries in neutrino physics is to determine the ordering of the masses of these three states. There are two possible orderings, conventionally referred to as “normal” and “inverted”. In the normal ordering, two mass states are light and one is heavy; in the inverted ordering, two are heavy and one light. In the normal case, muon neutrinos are more likely to oscillate into electron neutrinos, but muon antineutrinos are less likely to oscillate into electron antineutrinos. In the inverted case, the opposite occurs. However, it is possible that the difference in behaviour between neutrinos and antineutrinos depends not only on the mass ordering, but also on intrinsic differences between the two, a phenomenon known as CP (charge–parity) symmetry violation. This violation implies that neutrinos do not behave like their antiparticles and, if confirmed, could help explain why, after the Big Bang, matter prevailed over antimatter, giving rise to the universe as we know it.
The combined results from NOvA and T2K do not favour one ordering over the other. If the ordering turns out to be normal, the current results would not fully clarify the question of CP symmetry, requiring additional data. If the ordering were inverted, the results would provide evidence for CP symmetry violation.
“Neutrino physics is a strange field. It’s very difficult to isolate the effects”, explained Kendall Mahn, co-spokesperson of the T2K scientific collaboration. “Combining the analyses allows us to isolate one of these effects, and that’s progress”.”
The combined analysis has produced one of the most precise measurements of the difference in mass between the neutrino mass states, a quantity known as Δm²₃₂. With an uncertainty below 2%, this new value will make it possible to compare results from other experiments with great precision and to verify whether the theory of neutrino oscillations is complete.”
Ohio state press department releases a very vague description.
Compare with the Italian Institute for Nuclear Physics press release, which explains in detail the physics of neutrino mass ordering (“normal” or “inverted”) and CP symmetry violation needed to explain matter-antimatter symmetry violation. (As in, we see matter dominates.) They note that the result can’t yet say anything on either, but at least they have narrowed a parameter in mass ordering to less than 2 %.
“With an uncertainty below 2%, this new value will make it possible to compare results from other experiments with great precision and to verify whether the theory of neutrino oscillations is complete.”
Ačiū
You mean lightweight statements like this one: “The reason neutrinos are really, really fun is because they change their flavors,” she said. “Imagine getting chocolate ice cream, walking down the street, and suddenly it turns into mint, and every time it moves, it changes again.”
I would study the firm of the electron for the pattern of fusion needed. orange properties such as citric acid can break down the pattern to be less complicated and sugar granuals if broken down with I would guess slectricity could be the start of a way to study said theory