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Electrons reveal the need for improved neutrino models
Experiments on electrons interacting with atomic nuclei have shown that the models used to measure neutrino oscillations — and thereby possibly to understand the formation of the Universe — are less accurate than we thought.
Neutrinos are among the most elusive particles in the Universe — they can pass through sophisticated particle detectors without leaving a trace. And yet precise measurement of neutrinos is one of the highest priorities in particle physics, because it will provide crucial information about the Universe and how it was formed. It might also explain why the Universe seems to be mostly made of matter, even though the Big Bang should have created just as much antimatter. To obtain such measurements, experiments rely on theoretical models that predict how neutrinos interact with the nuclei of atoms. Writing in Nature, Khachatryan et al.1 (members of the CLAS and e4ν collaborations) report evidence that these models are not as accurate as expected — suggesting that analysis of current and future experiments designed to characterize the properties of neutrinos might need to be rethought.