New Cosmic Low Energy States of Neutrino

TL;DR

This paper introduces a new class of neutrino states called Cosmo-Low Energy Physics (CLEP) states, where neutrino properties dynamically evolve with the universe's expansion, potentially impacting dark energy and dark matter models.

Contribution

It proposes a theoretical framework for CLEP states of neutrinos, linking their properties to dark energy and expanding the understanding of fermion behavior in cosmology.

Findings

Neutrinos in CLEP states have masses increasing as the universe expands.

Dark matter composed of CLEP neutrinos exhibits negative pressure similar to dark energy.

The universe's total energy density can be lower with CLEP neutrinos than without fermionic matter.

Abstract

A field theory is studied where the consistency condition of equations of motion dictates strong correlation between states of "primordial" fermion fields and local value of the dark energy. In regime of the fermion densities typical for normal particle physics, the primordial fermions split into three families identified with regular fermions. When fermion energy density is comparable with dark energy density, the theory allows transition to new type of states. The possibility of such Cosmo-Low Energy Physics (CLEP) states is demonstrated in a model of FRW universe filled with homogeneous scalar field and uniformly distributed nonrelativistic neutrinos. Neutrinos in CLEP state are drawn into cosmological expansion by means of dynamically changing their own parameters. One of the features of the fermions in CLEP state is that in the late time universe their masses increase as $a^{3/2}$ ($a=a(t)$ is the scale factor). The energy density of the cold dark matter consisting of neutrinos in CLEP state scales as a sort of dark energy; this cold dark matter possesses negative pressure and for the late time universe its equation of state approaches that of the cosmological constant. The total energy density of such universe is less than it would be in the universe free of fermionic matter at all.