Events Daily

Wednesday, November 29, 2023

The Cosmic Neutrino Background (CνB): Its distribution on the surface of the Earth and its manipulation on laboratory scales
Asimina Arvanitaki, Perimeter Institute
Event Type: HEP Seminar
Time: 2:00 PM - 3:15 PM
Location: 726 Broadway, 940, CCPP Seminar
Abstract: The CνB is a cosmological relic analogous to the CMB, and contains information about the universe when it was just one-second-old. I will argue that reflection of relic neutrinos from the surface of the Earth creates a significant local neutrino-antineutrino asymmetry in a shell seven meters thick around the Earth's surface. This asymmetry far exceeds the expected primordial lepton asymmetry. The resulting gradient of the net neutrino density provides a way-out of a forty-year-old “no-go” theorem on the vanishing of O(G_Fermi) neutrino forces on matter. These forces can be further enhanced by using 1-100 meter structures with shape reminiscent of a sea-urchin: they consist of rods of width w and length L>>w periodically arranged on the surface of the sphere of radius R~L. Such a structure functions as a diffraction grating for relic neutrinos and the induced neutrino-antineutrino asymmetry at its center may point to a new class of experiments to detect the CνB in a laboratory setting. At the same time, such structures can be used to similarly manipulate dark matter.

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