First Measurement of Coherent Elastic Neutrino-Nucleus Scattering on Argon

We report the first measurement of coherent elastic neutrino-nucleus scattering (CEvNS) on argon using a liquid argon detector at the Oak Ridge National Laboratory Spallation Neutron Source. Two independent analyses prefer CEvNS over the background-only null hypothesis with greater than 3 sigma significance. The measured cross section, averaged over the incident neutrino flux, is (2.2 +/- 0.7) x 10(-39) cm(2)-consistent with the standard model prediction. The neutron-number dependence of this result, together with that from our previous measurement on CsI, confirms the existence of the CEvNS process and provides improved constraints on nonstandard neutrino interactions.

Automated summary

We present the first measurement of coherent elastic neutrino-nucleus scattering (CEvNS) on argon using a liquid argon detector at the Oak Ridge National Laboratory Spallation Neutron Source. Two independent analyses support CEvNS over the background-only null hypothesis with more than 3 sigma significance. The measured cross section, averaged over the incident neutrino flux, is (2.2 +/- 0.7) x 10(-39) cm(2)-consistent with the standard model prediction, confirming the existence of the CEvNS process and providing improved constraints on nonstandard neutrino interactions.