Cosmic Neutrino Background as a Ferromagnet

Abstract

If cosmic background neutrinos interact very weakly with each other, through spin-spin interactions, then they may have experienced a phase transition, leading to a ferromagnetic ordering. The small magnetic field resulting from ferromagnetic ordering -- if present before galaxy formation -- could act as a primordial seed of the magnetic fields observed in several galaxies. Our findings suggest that the magnetization could occur in the right epoch, if the exchange boson of neutrino-neutrino interaction is a massless boson beyond the Standard Model, with a coupling constant of $2.2\times 10^{-13}{\left(\frac{m_{\nu }}{10^{-4}\mathrm{eV}}\right)}^2<g<2.3\times 10^{-7}$. The estimation of the magnetic seed is $2.3\times 10^{-27}\mathrm{G}\lesssim {\mathrm{B}}_{\mathrm{CNB}}\lesssim 6.8\times 10^{-10}\mathrm{G}$.

4 pages. Accepted for publication in Physics Letters B

References in corpus (4)

• Generation of Primordial Magnetic Fields on Linear Over-density Scales
• The Search for a Primordial Magnetic Field
• Are cosmological neutrinos free-streaming?
• Anisotropies in the Cosmic Neutrino Background after WMAP 5-year Data

Cited by in corpus (1)

• Analogies between nuclear physics and Dark Matter