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hubie writes:

While this result rejects the sterile neutrino hypothesis quite strongly, it serves as a further support of the Standard Model and its neutrino content:

After several years of operation, the STEREO collaboration published the final results of their antineutrino studies. With their data, the researchers excluded hints for the existence of sterile neutrinos, an additional neutrino state expected in many theories. The result, which appears in the January 11 issue of Nature, has important implications for many areas of fundamental physics.

[...] Today three different types of neutrinos are known. These neutrinos can change their identity between these different states due to their very small, but non-zero mass. These so-called neutrino oscillations were established about two decades ago.

In 2011, increased precision led to an anomaly between the observed and predicted antineutrino flux emitted by nuclear reactors. This triggered the hypothesis of the existence of a supplementary neutrino state that would be sterile i.e. not interacting via the weak interaction. This particle could also possibly explain physical phenomena that are still not fully understood, such as dark matter.

[...] "We were able to observe a total of more than 100,000 neutrinos in the years 2017 to 2020, but could not determine any trace of potential sterile neutrinos within these measurements," explains Christian Buck, one of the lead researchers of the experiment from the MPIK. "Most likely the observed anomalies result from underestimated uncertainties in the nuclear data from the radioactive decays used for the flux prediction rather than the neutrino experiments itself."

Journal Reference:
The STEREO Collaboration, STEREO neutrino spectrum of 235U fission rejects sterile neutrino hypothesis, Nature (2023). DOI: 10.1038/s41586-022-05568-2

Original Submission