Large Neutrino-Dark Matter Interactions: From Effective Field Theory to Ultraviolet Completions

TL;DR

This paper develops a comprehensive EFT framework for neutrino-dark matter interactions, systematically identifying UV completions that can produce large couplings while respecting existing constraints, and explores their phenomenological implications.

Contribution

It introduces a systematic method to find all gauge-invariant UV completions for neutrino-DM interactions within an EFT framework, including minimal models with large couplings.

Findings

Identified UV completions that generate large neutrino-DM couplings up to several orders of magnitude above Fermi scale.

Constructed minimal UV models for different DM types consistent with experimental constraints.

Analyzed phenomenological implications for relic abundance, direct detection, and cosmological constraints.

Abstract

We develop a general effective field theory (EFT) framework for neutrino-dark matter (DM) interactions, and apply it to systematically find all possible gauge-invariant ultraviolet (UV) completions at a given EFT operator dimension. Our goal here is to find simple UV-complete models that can realize potentially large neutrino-DM interactions, while being consistent with all existing theoretical and experimental constraints. We first construct the leading non-derivative operator basis for neutrino-DM scattering in a low-energy effective theory with neutrinos and DM (DM-LEFT), together with its gauge-invariant embedding in the Standard Model EFT (DM-SMEFT). We then construct all renormalizable tree-level UV completions that generate the relevant DM-SMEFT operators up to dimension-8 using a topology-based classification. Using this framework, we present minimal UV-complete models for different DM types that can yield effective neutrino-DM couplings up to several orders of magnitude larger than the Fermi coupling, while satisfying all constraints, most notably from neutrino mass and from the charged-lepton sector. This includes a pseudo-Dirac fermion DM realization in the scotogenic neutrino mass model and models of Majorana DM inspired by type-II and inverse seesaw-based neutrino mass models. Phenomenological implications for DM thermal relic abundance and direct detection prospects, as well as various cosmological and laboratory constraints on the model parameter space, are also analyzed.