China's new JUNO neutrino observatory has [1]delivered world-leading measurements after just 59 days , offering the most precise readings yet of two key neutrino oscillation parameters. "The physics result is already world-leading in the areas that it touches," says particle physicist Juan Pedro Ochoa-Ricoux of the University of California, Irvine, who co-leads a team on JUNO. "In particular, we measured two neutrino oscillation parameters, and that measurement is already for both parameters the best in the world." The results were [2]published in two [3]separate preprints on arXiv.org. Scientific American reports:

> JUNO's spherical detector, which is akin to a 13-story-tall fishbowl, primarily measures so-called electron antineutrinos spewing from the nearby Yangjian and Taishan nuclear plants. When the particles strike a proton inside the detector, a reaction triggers two light flashes that ping photomultiplier tubes and get converted into electrical signals. The new measurements from these neutrino-proton collisions are now considered the most precise for two oscillation parameters, which act as proxies for differences in their mass, according to Ochoa-Ricoux.

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> "It is the first time we've turned on a scientific instrument like JUNO that we've been working on for over a decade. It's just tremendously exciting," Ochoa-Ricoux says. "And then to see that we're able to already do world-leading measurements with it, even with such a small amount of data, that's also really exciting." Still, the physicists will need years' worth of neutrino detections to answer the mass-ordering conundrum.



[1] https://www.scientificamerican.com/article/juno-neutrino-observatory-releases-first-results/

[2] https://arxiv.org/abs/2511.14593

[3] https://arxiv.org/pdf/2511.14590