Compact neutrino experiment unlocks first-ever reactor mystery

Scientists at the Max Planck Institute for Nuclear Physics (MPIK) have successfully detected antineutrinos from a nuclear reactor using the compact CONUS+ experiment, which employs a small 3 kg germanium semiconductor detector. Positioned 20.7 meters from the core of the Leibstadt nuclear power plant in Switzerland, the detector recorded an excess of 395±106 neutrino signals over 119 days, confirming the observation of Coherent Elastic Neutrino-Nucleus Scattering (CEvNS) at full coherence from a reactor source. This process, where low-energy neutrinos scatter off entire atomic nuclei, had previously only been observed at particle accelerators, making this the first such detection at reactor energies. The CONUS+ experiment’s results align well with theoretical predictions and demonstrate the feasibility of using small, mobile detectors to monitor reactor neutrino emissions. This breakthrough offers new opportunities for fundamental physics research, including tests of the Standard Model with reduced nuclear physics uncertainties and enhanced sensitivity to potential new physics