Nuclear Structure Physics in Coherent Elastic Neutrino-Nucleus Scattering

Abstract

The prospects of extracting new physics signals in a coherent elastic neutrino-nucleus scattering (CEνNS) process are limited by the precision with which the underlying nuclear structure physics, embedded in the weak nuclear form factor, is known. We present microscopic nuclear structure physics calculations of charge and weak nuclear form factors and CEνNS cross sections on 12 C, 16 O, 40 Ar, 56 Fe and 208 Pb nuclei. We obtain the proton and neutron densities, and charge and weak form factors by solving Hartree-Fock equations with a Skyrme (SkE2) nuclear potential. We validate our approach by comparing 208 Pb and 40 Ar charge form factor predictions with elastic electron scattering data. In view of the worldwide interest in liquid-argon based neutrino and dark matter experiments, we pay special attention to the 40 Ar nucleus and make predictions for the 40 Ar weak form factor and the CEνNS cross sections. Furthermore, we attempt to gauge the level of theoretical uncertainty pertaining to the description of the 40 Ar form factor and CEνNS cross sections by comparing relative differences between recent microscopic nuclear theory and widely-used phenomenological form factor predictions. Future precision measurements of CEνNS will potentially help in constraining these nuclear structure details that will in turn improve prospects of extracting new physics.

Modeling quasielastic interactions of monoenergetic kaon decay-at-rest neutrinos

“…We therefore compute the argon single particle wavefunctions and mean-field potential with the same self-consistent Hartree-Fock procedure as for carbon and calcium, but with fractional occupation numbers for these outerlying shells. This procedure yields good results for the charge-distribution and compares well with RMF [39] and no-core shell-model [40] calculations for the neutron distributions [41]. In Ref.…”

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“…CEνNS data for studying nuclear structure [101,102], searching for physics beyond the Standard Model [103], and, perhaps, for monitoring reactors [104], this process is the subject of increasing theoretical and experimental attention worldwide. While proprietary codes are currently used by some experiments to simulate CEνNS, the GENIE v3 implementation represents the first realistic treatment of this process in a widely-distributed neutrino event generator.…”

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“…To reduce the nuclear uncertainties subsumed into F w (q 2 ), either measurements need to be performed at very small momentum transfer, or improved nuclearstructure calculations are required, whose most uncertain part, again related to the neutron distribution in the nucleus, could be constrained in future global analyses of CEνNS and PVES off multiple nuclear targets. At present, ab-initio calculations are becoming available for medium-size nuclei [134], while currently most calculations are based on (relativistic) mean field methods [135][136][137][138][139] and the large-scale nuclear shell model [133,[140][141][142].…”