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

TL;DR

This paper investigates quantum-mechanical coherency effects in neutrino-nucleus elastic scattering, analyzing how deviations from perfect coherence relate to nuclear form factors and experimental data, revealing contributions from superpositions and many-body effects.

Contribution

It introduces a coherency parameter to quantify deviations in neutrino-nucleus scattering and derives its relation to nuclear physics, supported by experimental data analysis.

Findings

Complete coherency is excluded by COHERENT data

Decoherency effects are significant in neutrino-nucleus interactions

Both quantum superpositions and nuclear many-body effects influence the scattering

Abstract

Neutrino-nucleus elastic scattering ($\nu {\rm A}_{el}$) 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 $\alpha ( q^2 )$. The relations between $\alpha$ and the underlying nuclear physics in terms of nuclear form factors are derived. The dependence of cross-section on $\alpha ( q^2 )$ for the various neutrino sources is presented. The $\alpha ( q^2 )$-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 $q^2 {=} 3.1 {\times} 10^{3} ~ {\rm MeV^2}$ and with $p {=} 0.016$ at $q^2 {=} 2.3 {\times} 10^{3} ~ {\rm MeV^2}$, respectively, verifying that both QM superpositions and nuclear many-body effects contribute to $\nu {\rm A}_{el}$ interactions.