The Density of Relic Neutrinos Near the Surface of Earth

TL;DR

This paper reevaluates the matter effects on relic neutrino densities near Earth's surface, concluding the effect is significantly smaller and more localized than previously claimed.

Contribution

It provides a revised estimate of the matter effect on relic neutrino asymmetry, reducing the expected magnitude and spatial extent compared to earlier claims.

Findings

The matter effect is of order 10^{-8} instead of 10^{-4}.

The vertical extent of the effect is about 1mm, not 10m.

The asymmetry in relic neutrino density is negligible at Earth's surface.

Abstract

It has been claimed that matter effects cause an asymmetry in the density of relic neutrinos versus antineutrinos near the surface of Earth, of order $O(G_F^{1/2})\sim 10^{-4}$, with the vertical extent $\sim 10$m. We argue that the effect is of order $O(G_F)\sim 10^{-8}$, with the vertical extent $\sim 1$mm.