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

Neutrino-nucleus elastic scattering (νAel) 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 α(q²). The relations between α and the underlying nuclear physics in terms of nuclear form factors are derived. The dependence of cross section on α(q²) for the various neutrino sources is presented. The α(q²) 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 q²=3.1×10³ MeV² and p=0.016 at q²=2.3×10³ MeV², respectively, verifying that both QM superpositions and nuclear many-body effects contribute to νAel interactions. [ABSTRACT FROM AUTHOR]