Stringent constraint on the scalar-neutrino coupling constant from quintessential cosmology

TL;DR

This paper derives a very strict limit on the scalar-neutrino coupling constant within quintessential cosmology, using cosmological and solar neutrino data, significantly improving previous constraints.

Contribution

It introduces a new, more stringent constraint on the scalar-neutrino coupling constant based on cosmological and solar neutrino observations in the context of quintessence models.

Findings

Scalar-neutrino coupling constant is constrained to be many orders of magnitude smaller than previous limits.

Current solar neutrino data can test violations of the equivalence principle at the 10^{-10} level.

The study links quintessence cosmology with neutrino physics to set new bounds.

Abstract

An extremely light ($m_{\phi} \ll 10^{-33} {\rm eV}$), slowly-varying scalar field $\phi $ (quintessence) with a potential energy density as large as 60% of the critical density has been proposed as the origin of the accelerated expansion of the Universe at present. The interaction of this smoothly distributed component with another predominately smooth component, the cosmic neutrino background, is studied. The slow-roll approximation for generic $\phi $ potentials may then be used to obtain a limit on the scalar-neutrino coupling constant, found to be many orders of magnitude more stringent than the limits set by observations of neutrinos from SN 1987A. In addition, if quintessential theory allows for a violation of the equivalence principle in the sector of neutrinos, the current solar neutrino data can probe such a violation at the 10^{-10} level.