New Constraints on Neutrino-Dark Matter Interactions: A Comprehensive Analysis

TL;DR

This paper provides a detailed analysis of neutrino-dark matter interactions, deriving exact formulas, applying comprehensive constraints, and showing most previous benchmarks are ruled out, impacting future detection prospects.

Contribution

It offers the first complete analytic formulas for neutrino-dark matter scattering cross sections and a thorough constraint analysis, challenging previous assumptions about observable effects.

Findings

Most benchmark models are excluded by combined constraints.

Laboratory bounds are more robust than astrophysical ones.

Detecting neutrino-DM interactions in supernova neutrinos is highly challenging.

Abstract

We present a comprehensive analysis of the interactions of neutrinos with the dark sector within the simplified model framework. We first derive the exact analytic formulas for the differential scattering cross sections of neutrinos with scalar, fermion, and vector dark matter (DM) for light dark sector models with mediators of different types. We then implement the full catalog of constraints on the parameter space of the neutrino-DM and neutrino-mediator couplings and masses, including cosmological and astrophysical bounds coming from Big Bang Nucleosynthesis, Cosmic Microwave Background, DM and neutrino self-interactions, DM collisional damping, and astrophysical neutrino sources, as well as laboratory constraints from 3-body meson decays and invisible $Z$ decays. We find that most of the benchmarks in the DM mass-coupling plane adopted in previous studies to get an observable neutrino-DM interaction effect are actually ruled out by a combination of the above-mentioned constraints, especially the laboratory ones which are robust against astrophysical uncertainties and independent of the cosmological history. To illustrate the consequences of our new results, we take the galactic supernova neutrinos in the MeV energy range as a concrete example and highlight the difficulties in finding any observable effect of neutrino-DM interactions. Finally, we identify new benchmark points potentially promising for future observational prospects of the attenuation of the galactic supernova neutrino flux and comment on their implications for the detection prospects in future large-volume neutrino experiments such as JUNO, Hyper-K, and DUNE. We also comment on the ultraviolet-embedding of the effective neutrino-DM couplings.