Studies of quantum-mechanical coherency effects in neutrino-nucleus elastic scattering

Neutrino-nucleus elastic scattering (A₄₋) 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 (q^2). The relations between and the underlying nuclear physics in terms of nuclear form factors are derived. The dependence of cross section on (q^2) for the various neutrino sources is presented. The (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. 110^3 MeV^2 and p=0. 016 at q^2=2. 310^3 MeV^2, respectively, verifying that both QM superpositions and nuclear many-body effects contribute to A₄₋ interactions.