Long Range Interactions in Cosmology: Implications for Neutrinos

TL;DR

This paper investigates how scalar long range interactions affect neutrino behavior in cosmology, revealing that such interactions can relax neutrino mass bounds and enhance the potential for laboratory detection, with implications for future surveys.

Contribution

It introduces a formalism for analyzing long range interactions in cosmology and applies it to neutrinos, showing how these interactions alter mass bounds and observational prospects.

Findings

Current neutrino mass bounds are avoided with long range interactions.

Long range interactions create a complementarity between laboratory experiments and cosmological surveys.

Potential for laboratory neutrino mass detection is increased.

Abstract

Cosmology is well suited to study the effects of long range interactions due to the large densities in the early Universe. In this article, we explore how the energy density and equation of state of a fermion system diverge from the commonly assumed ideal gas form under the presence of scalar long range interactions with a range much smaller than cosmological scales. In this scenario, "small"-scale physics can impact our largest-scale observations. As a benchmark, we apply the formalism to self-interacting neutrinos, performing an analysis to present and future cosmological data. Our results show that the current cosmological neutrino mass bound is fully avoided in the presence of a long range interaction, opening the possibility for a laboratory neutrino mass detection in the near future. We also demonstrate an interesting complementarity between neutrino laboratory experiments and the future EUCLID survey.