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Physics Colloquium

Thursday, November 9, 2023
4:00pm to 5:00pm
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Online and In-Person Event
The Cosmic Neutrino Background (CνB): Its distribution on the surface of the Earth and its manipulation on laboratory scales
Mina Arvanitaki, Perimeter Institute,

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. 

Join via Zoom:
Meeting ID: 818 6692 9019

The colloquium is held in Feynman Lecture Hall, 201 E. Bridge.

For more information, please contact Denise Lu by email at [email protected].