NOvA and T2K Experiments Zero In on Uncommon Properties of Neutrinos

In each NOvA (NuMI Off-axis νe Appearance experiment) and T2K experiments, neutrinos are fired from particle accelerators and detected after touring lengthy distances underground. The problem is immense: out of trillions upon trillions of particles, solely a handful depart detectable traces. Sophisticated detectors and software program then reconstruct these uncommon occasions, offering clues about how neutrinos change ‘flavor’ as they journey transfer.

The world’s first neutrino remark in a hydrogen bubble chamber. It was discovered November 13, 1970, on this {photograph} from the Zero Gradient Synchrotron’s 12-foot bubble chamber. The invisible neutrino strikes a proton the place three particle tracks originate (decrease proper). The neutrino turns right into a mu-meson, the lengthy heart observe (extending up and left). The quick observe is the proton. The third observe (extending down and left) is a pi-meson created by the collision. Image credit score: Argonne National Laboratory.

Neutrinos are among the many most ample particles within the Universe.

They haven’t any electrical cost and almost no mass, making them terribly tough to detect. But that very same elusiveness makes them scientifically priceless.

Understanding neutrinos might assist clarify one of many best puzzles in cosmology: why the Universe is manufactured from matter.

Theoretically, the Big Bang ought to have produced equal components matter and antimatter, which might have annihilated one another utterly; when a particle meets its mirror reverse, each disappear in a burst of vitality.

But when the Big Bang occurred one thing tipped the steadiness, making a higher abundance of matter, which led to the formation of stars, galaxies, and life as we speak.

Physicists suspect that neutrinos could maintain the reply.

Neutrinos are available three sorts, or ‘flavors,’ electron, muon, and tau, primarily three variations of the identical tiny particle.

They possess the weird potential to oscillate and rework from one taste to a different as they journey by means of house, and the way in which these oscillations happen, and whether or not they differ between neutrinos and their antimatter counterparts, might reveal why matter gained out over antimatter within the early Universe.

“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,” stated Dr. Zoya Vallari, a physicist on the Ohio State University.

“The reason neutrinos are really, really fun is because they change their flavors.”

“Imagine getting chocolate ice cream, walking down the street, and suddenly it turns into mint, and every time it moves, it changes again.”

In an effort to raised perceive this shape-shifting conduct, NOvA and T2K experiments mixed forces to shoot beams of neutrino particles over lots of of km.

NOvA sends a beam of neutrinos by means of the Earth 810 km from its supply on the Fermi National Accelerator Laboratory close to Chicago to a 14,000-ton detector in Ash River, Minnesota.

Japan’s T2K shoots a beam of neutrinos 295 km from the J-PARC accelerator in Tokai to the enormous Super-Kamiokande detector below Mount Ikenoyama.

“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,” Dr. Vallari stated.

While this examine builds on earlier work that discovered tiny, however nonetheless very consequential, variations in neutrino mass for every sort, the researchers sought deeper hints that neutrinos function outdoors the usual legal guidelines of physics.

One such query is whether or not neutrinos and their antimatter counterparts behave in another way, a phenomenon referred to as Charge-Parity violation.

“Our results show that we need more data to be able to significantly answer these fundamental questions,” Dr. Vallari stated.

“That’s why building the next generation of experiments is important.”

According to the examine, combining the outcomes of each experiments allowed the scientists to get a deal with on these urgent physics questions from totally different angles, as two experiments with totally different baselines and energies have a greater likelihood of answering them than a single experiment alone.

“This work is extraordinarily complex, and each collaboration involves hundreds of people,” stated Ohio State University’s Professor John Beacom.

“Collaborations like these are usually competing, so that they are co-operating here shows how high the stakes are.”

The new findings have been printed within the journal Nature.

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NOvA Collaboration & T2K Collaboration. 2025. Joint neutrino oscillation evaluation from the T2K and NOvA experiments. Nature 646, 818-824; doi: 10.1038/s41586-025-09599-3