Studies of Quantum-Mechanical Coherency Effects in Neutrino-Nucleus Elastic Scattering

Abstract

Neutrino-nucleus elastic scattering ($\hat{I}½{\mathrm{A}}_{el}$) provides a unique laboratory to study the quantum-mechanical (QM) coherency effects in electroweak interactions. The deviations of the cross-sections from those of completely coherent systems can be quantitatively characterized through a coherency parameter $\hat{I}\pm (q^2)$. The relations between $\hat{I}\pm$ and the underlying nuclear physics in terms of nuclear form factors are derived. The dependence of cross-section on $\hat{I}\pm (q^2)$ for the various neutrino sources is presented. The $\hat{I}\pm (q^2)$-values are evaluated from the measured data of the COHERENT CsI and Ar experiments. Complete coherency and decoherency conditions are excluded by the CsI data with $p=0.004$ at $q^2=3.1\times 10^3\mathrm{Me}{\mathrm{V}}^2$ and with $p=0.016$ at $q^2=2.3\times 10^3\mathrm{Me}{\mathrm{V}}^2$, respectively, verifying that both QM superpositions and nuclear many-body effects contribute to $\hat{I}½{\mathrm{A}}_{el}$ interactions.

V2 Published Version, 10 pages, 10 figures