# Extragalactic neutrinos as tracers of Dark Matter?

## TL;DR

This paper investigates how extragalactic neutrinos interacting with dark matter can reveal properties of dark matter through flavor-oscillation patterns and pointer-states, considering various density profiles and interaction effects.

## Contribution

It introduces a model for neutrino flavor evolution influenced by dark matter interactions, exploring different density profiles and identifying potential dark matter tracers.

## Key findings

- Neutrino flavor states are affected by dark matter interactions, showing oscillation enhancement or suppression.
- Decoherence and MSW effects coexist, influencing neutrino flavor evolution.
- Neutrinos can serve as tracers for dark matter characteristics based on their flavor oscillation patterns.

## Abstract

Neutrinos produced in extragalactic sources may experience flavor-oscillations and decoherence on their way to Earth due to their interaction with dark matter (DM). As a result, they may be detected in pointer-states other than the flavor states at the source. The oscillation pattern and the structure of the pointer-states can give us information on the characteristics of the DM and the kind of interaction that has taken place. From this perspective, neutrinos can be viewed as DM-tracers. We study the local evolution of neutrino flavor-eigenstates due to local effects produced by the presence of DM. To explore the sensitivity of the model, we consider different DM density profiles, masses and interactions. Starting from the eigenstates of the neutrino-mass Hamiltonian, we construct the flavor-states with the neutrino mixing-matrix in vacuum. We then include local interactions with DM, acting along the neutrino path towards the Earth, and analyse the resulting probabilities. In doing so, we adopt different DM density profiles, e.g. a constant, a local isotropic and a Navarro-Frenk-White density distribution. Finally, by following the time evolution of the flavor-states, we identify pointer-states and interpret the results in terms of the adopted DM model. Due to the interaction with DM, neutrinos experience the MSW effect, the extent of which depends on the DM density profile. The interaction with DM produces the enhancement or suppression of oscillations. Decoherence effects may take place. We model the time evolution of extragalactic neutrino flavor-states by letting them interact with DM. The features of the calculated response seem to support the notion that these neutrinos can be taken as DM tracers. From a theoretical point of view, the coexistence and/or competition of decoherence and MSW effects is sustained by the results.