Measurement of the Coherent Elastic Neutrino-Nucleus Scattering Cross Section on CsI by COHERENT

TL;DR

This paper reports the most precise measurement of the coherent elastic neutrino-nucleus scattering cross section on CsI, confirming the standard model and constraining new physics using data from the COHERENT experiment at SNS.

Contribution

It provides an improved, high-precision measurement of the extcevns{} cross section with reduced uncertainties and explores neutrino flavor dependence and new physics constraints.

Findings

Cross section measured as (165^{+30}_{-25})×10^{-40} cm^2

Consistent with the standard model predictions

Placed constraints on neutrino non-standard interactions

Abstract

We measured the cross section of coherent elastic neutrino-nucleus scattering (\cevns{}) using a CsI[Na] scintillating crystal in a high flux of neutrinos produced at the Spallation Neutron Source (SNS) at Oak Ridge National Laboratory. New data collected before detector decommissioning has more than doubled the dataset since the first observation of \cevns{}, achieved with this detector. Systematic uncertainties have also been reduced with an updated quenching model, allowing for improved precision. With these analysis improvements, the COHERENT collaboration determined the cross section to be $(165^{+30}_{-25})\times10^{-40}$~cm$^2$, consistent with the standard model, giving the most precise measurement of \cevns{} yet. The timing structure of the neutrino beam has been exploited to compare the \cevns{} cross section from scattering of different neutrino flavors. This result places leading constraints on neutrino non-standard interactions while testing lepton flavor universality and measures the weak mixing angle as $\sin^2\theta_{W}=0.220^{+0.028}_{-0.026}$ at $Q^2\approx(50\text{ MeV})^2$