How and why do we even exist? Science may finally have the answer

Scientists combined data from two neutrino experiments, improving measurements that may explain why matter dominates the universe.

Researchers from two major neutrino experiments have combined their data for the first time, producing some of the most precise measurements yet of how neutrinos change as they travel. The joint analysis, published in Nature, brings together results from the T2K experiment in Japan and the NOvA experiment in the United States. Scientists say the findings could help answer one of the biggest questions in physics: why the universe contains more matter than antimatter.

The study was co-led by Michigan State University physics and astronomy professor Kendall Mahn, who also serves as co-spokesperson for the T2K collaboration. The work was supported by the U.S. Department of Energy.

The research builds on a major discovery made over the past few decades that neutrinos have mass and can change from one type, or "flavor," to another as they travel. This process, called neutrino oscillation, is now one of the main ways scientists study these tiny particles and search for answers about how the universe evolved.

One of the biggest unanswered questions is why matter exists at all. Scientists believe the Big Bang should have produced equal amounts of matter and antimatter. If that had happened, the two would have destroyed each other, leaving behind only energy. Instead, matter survived, allowing galaxies, stars, planets and life to form. Physicists think neutrinos may help explain this imbalance if they behave differently from their antimatter counterparts, a phenomenon known as charge-parity (CP) symmetry violation.

“This was a big victory for our field,” said Mahn. “This shows that we can do these tests, we can look into neutrinos in more detail and we can succeed in working together.”

Neutrinos are among the most common particles in the universe, but they are also among the hardest to study because they rarely interact with matter. “Neutrinos are not well understood,” said Michigan State University postdoctoral associate Joseph Walsh, who worked on the project. “Their very small masses mean they don't interact very often. Hundreds of trillions of neutrinos from the sun pass through your body every second, but they almost all pass straight through. We need to produce intense sources or use very large detectors to give them enough opportunity to interact for us to see them and study them.”

The two experiments involved in the study take different approaches to studying neutrinos. T2K, short for Tokai to Kamioka, produces a beam of muon neutrinos at the Japan Proton Accelerator Research Complex (J-PARC) in Tokai and sends it 295 kilometers to the Super-Kamiokande detector in Kamioka. NOvA produces a neutrino beam at the Fermi National Accelerator Laboratory (Fermilab) near Chicago and sends it about 810 kilometers to a detector in northern Minnesota. In both experiments, researchers compare measurements taken close to the neutrino source with those recorded at the distant detector to track how the particles change during their journey.

Although T2K and NOvA are designed to answer similar scientific questions, they use different beam energies and distances. These differences give scientists two complementary sets of data. By combining them, the researchers were able to measure neutrino properties more precisely than either experiment could on its own.

“By making a joint analysis, you can get a more precise measurement than each experiment can produce alone,” said NOvA collaborator Liudmila Kolupaeva. “As a rule, experiments in high-energy physics have different designs, even if they share the same science goal. Joint analyses allow us to use complementary features of these designs.”

The combined analysis also improves measurements related to neutrino masses. Scientists know neutrinos exist in three mass states, but they still do not know how those masses are arranged. The two possible patterns are called the normal ordering and the inverted ordering.

The researchers found no clear evidence favoring either mass ordering. If future experiments confirm the normal ordering, more data will still be needed to determine whether neutrinos violate CP symmetry. However, if the inverted ordering turns out to be correct, the combined results provide evidence consistent with CP symmetry violation. The study also delivers the most precise measurement so far of one of the key differences between neutrino mass states, helping scientists better understand how neutrinos oscillate.

The researchers said these findings do not solve the remaining mysteries surrounding neutrinos. Instead, they provide more precise measurements and a stronger foundation for future experiments that will continue testing current theories and searching for new physics.

The collaboration itself was also a major international effort. NOvA includes more than 250 scientists and engineers from 49 institutions across eight countries, while T2K has more than 560 members from 75 institutions in 15 countries. Work on the joint analysis began in 2019, combining eight years of NOvA data with a decade of T2K observations. Both experiments are still collecting data, and researchers are already preparing updated analyses.

“These results are an outcome of cooperation and mutual understanding between two unique collaborations — both involving many experts in neutrino physics, detection technologies and analysis techniques, working in very different environments and using different methods and tools,” said T2K collaborator Tomáš Nosek.

TL;DR:

• Scientists from the T2K (Japan) and NOvA (U.S.) experiments combined their data for the first time.

• The joint study produced more precise measurements of how neutrinos change, or oscillate, as they travel

• Researchers hope these measurements will help explain why the universe contains more matter than antimatter after the universe began, allowing stars, planets and life to exist.

• The results do not favor either possible neutrino mass ordering, but they narrow down key properties for future studies.

• The work also demonstrates that combining data from different experiments can produce more accurate results than either experiment alone.

• Both collaborations are continuing to collect data, with updated joint analyses already underway.

   

Source: Michigan State University, Nature

This article was generated with some help from AI and reviewed by an editor. Under Section 107 of the Copyright Act 1976, this material is used for the purpose of news reporting. Fair use is a use permitted by copyright statute that might otherwise be infringing.

Source

Hope you enjoyed this news post. Feedback welcome.

Posted Sunday 26 July 2026 at 7:53 am AEST (my time).

News posts: 2023 5,800+ | 2024 5,700+ | 2025 5,700+ | 2026 (to end of June) 2,475

RIP Matrix