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

V Sharma,K Saraswat,H B Li,Texono Collaboration ,L Singh,V Singh,C.-P Liu,M Deniz,H T Wong,S Kerman,M K Singh,J.-W Chen,M Agartioglu

doi:10.1103/physrevd.103.092002

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.

Highlights

The elastic scattering of a neutrino with a nucleus [1,2]νAel∶ ν þ AðZ; NÞ → ν þ AðZ; NÞ; ð1Þ where AðZ; NÞ denotes the atomic nucleus with its respective atomic, charge, and neutron numbers, is a fundamental electroweak neutral current process in the Standard Model (SM).Studies of neutrino-nucleus elastic scattering can provide sensitive probes to physics beyond the SM (BSM) [3,4] and certain astrophysical processes [1,5]
The deviations from perfect coherency would have to be described and quantified before this interaction can be effectively applied toward other goals like the studies of BSM physics
The functions ΓNP, ΓQM, and ΓDATA can be directly measured from νAel data without input from the underlying physics

Summary

INTRODUCTION

ΝAel∶ ν þ AðZ; NÞ → ν þ AðZ; NÞ; ð1Þ where AðZ; NÞ denotes the atomic nucleus with its respective atomic, charge, and neutron numbers, is a fundamental electroweak neutral current process in the Standard Model (SM). Studies of neutrino-nucleus elastic scattering can provide sensitive probes to physics beyond the SM (BSM) [3,4] and certain astrophysical processes [1,5]. There are several active experimental programs to observe and measure the νAel processes with neutrinos from reactors [12] or from decay-at-rest pions (DAR-π) [4] provided by a spallation neutron source [13]. The νAel interaction provides a laboratory to probe the QM coherency effects [6]. The deviations from perfect coherency would have to be described and quantified before this interaction can be effectively applied toward other goals like the studies of BSM physics.

FORMULATION AND CHARACTERIZATION

PROJECTED EXPERIMENTAL RANGES

MEASUREMENTS FROM CURRENT DATA

Findings

SUMMARY AND PROSPECTS