Stanford University
APPLIED PHYSICS/PHYSICS COLLOQUIUM
Tuesday, January 23, 2023
Asimina Arvanitaki, Perimeter Institute for Theoretical Physics
“The Distribution of Cosmic Neutrino Background on the Surface of the Earth”
The Cosmic Neutrino Background (CNB) is a relic of the pre-CMB era which encodes a trove of information about the early Universe and the neutrino sector dating back to when the Universe was less than a second old. In this talk, I will argue that the Earth can significantly alter the local distribution of relic neutrinos and antineutrinos. While neutrinos are repelled from the Earth due to the weak interaction with matter, antineutrinos are attracted. This difference in behavior results in a relative over density of neutrinos close to the Earth’s surface that enhances the primordial neutrino-antineutrino asymmetry by 5 orders of magnitude. This enhancement persists in a 7-meter band around the Earth’s surface, a scale set by the evanescent wave scale for neutrinos. This effect opens up new opportunities for the detection of these elusive relic neutrinos in a laboratory setting.