First Measurement of Coherent Elastic Neutrino-Nucleus Scattering on Argon

Area of Science:

• Nuclear Physics
• Particle Physics
• Neutrino Physics

Background:

• Coherent elastic neutrino-nucleus scattering (CEvNS) is a fundamental process predicted by the Standard Model.
• Experimental confirmation of CEvNS is crucial for validating neutrino physics theories and probing beyond-Standard Model physics.
• Previous measurements have provided some evidence, but further confirmation with different target nuclei is needed.

Purpose of the Study:

• To report the first measurement of CEvNS on argon.
• To confirm the existence of the CEvNS process independently.
• To provide precise cross-section data and constrain nonstandard neutrino interactions.

Main Methods:

• Utilized a liquid argon detector at the Oak Ridge National Laboratory Spallation Neutron Source.
• Performed two independent analyses to distinguish CEvNS signal from background.
• Measured the CEvNS cross section on argon.

Main Results:

• Achieved a greater than 3σ significance for CEvNS over the background-only hypothesis in both analyses.
• Measured the CEvNS cross section on argon to be (2.2±0.7)×10^{-39} cm².
• The result is consistent with the Standard Model prediction and, combined with previous CsI data, confirms CEvNS and constrains nonstandard neutrino interactions.

Conclusions:

• The first measurement of CEvNS on argon provides strong evidence for this fundamental neutrino interaction.
• The results validate Standard Model predictions and enhance constraints on potential nonstandard neutrino interactions.
• This work paves the way for future precision measurements of CEvNS with various target nuclei.