Direct observation of coherent elastic antineutrino-nucleus scattering
N Ackermann1, H Bonet1, A Bonhomme1,2
1Max-Planck-Institut für Kernphysik, Heidelberg, Germany.
Nature
|July 30, 2025
Summary
The CONUS+ experiment detected a neutrino signal from coherent elastic neutrino-nucleus scattering, a process enabling smaller detectors. This observation opens new avenues for exploring physics beyond the Standard Model.
Area of Science:
- Particle Physics
- Nuclear Physics
- Cosmology
Background:
- Neutrinos are fundamental particles with extremely weak interactions, necessitating large detectors for most experiments.
- Coherent elastic neutrino-nucleus scattering offers significantly enhanced interaction rates, allowing for smaller, more manageable detector designs.
- Studying this interaction provides crucial insights into physics beyond the Standard Model.
Purpose of the Study:
- To achieve the first detection of elastic neutrino-nucleus scattering in the fully coherent regime.
- To utilize low-energy neutrinos originating from nuclear reactors for this detection.
- To develop and employ highly sensitive semiconductor detectors for observing these interactions.
Main Methods:
- Utilized the CONUS+ experiment, featuring high-purity germanium semiconductor detectors with ultra-low energy thresholds.
- Operated the experiment at the Leibstadt nuclear power plant, leveraging reactor-produced neutrinos.
- Collected data over 119 days of reactor operation.
Main Results:
- Reported the first observation of a neutrino signal from coherent elastic neutrino-nucleus scattering with a statistical significance of 3.7σ.
- Measured (395 ± 106) neutrino events, which is consistent with the Standard Model prediction of (347 ± 59) events.
- Demonstrated the feasibility of using smaller detectors for neutrino physics.
Conclusions:
- The CONUS+ experiment successfully observed neutrino-nucleus scattering in the coherent regime.
- This achievement marks a significant step towards a new era in neutrino physics research.
- Future high-precision measurements hold the potential for fundamental discoveries beyond the Standard Model.
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