On possible tachyonic state of neutrino dark matter

TL;DR

This paper explores a novel dark matter model based on tachyonic neutrinos, proposing a new group-theoretical framework that maintains causality and unitarity, and fits observational data of galactic halos.

Contribution

It introduces a group-theoretical algorithm for describing tachyonic neutrinos and develops a dark matter model that aligns with galactic rotation curves without central singularities.

Findings

Density distributions match observational data

Rotation curves are consistent with galaxy observations

Model avoids causality violations with new Lorentz group

Abstract

We revive the historically first dark matter model based on neutrinos, but with an additional assumption that neutrinos might exist in tachyonic almost sterile states. To this end, we propose a group-theoretical algorithm for the description of tachyons. The key point is that we employ a distinct tachyon Lorentz group with new (superluminal) parametrization which does not lead to violation of causality and unitarity. Our dark matter model represents effectively scalar tachyonic neutrino-antineutrino conglomerate. Distributed all over the universe, such fluid behaves as stable isothermal/stiff medium which produces somewhat denser regions (`halos') around galaxies and clusters. To avoid the central singularity inherent to the isothermal profile, we apply a special smoothing algorithm which yields density distributions and rotation curves consistent with observational data.