Cosmic Neutrinos

TL;DR

This paper reviews the role of neutrinos in particle physics and cosmology, discussing their properties, contributions to dark matter, interactions at high energies, and prospects for detection.

Contribution

It provides a comprehensive overview of neutrino characteristics, their cosmological significance, and the potential for observing relic neutrinos and ultrahigh-energy neutrino interactions.

Findings

Neutrinos have a significant role in electroweak theory and cosmology.

Ultrahigh-energy neutrino interactions are influenced by neutrino oscillations.

Detecting relic neutrinos via Z-resonance annihilation remains a remote possibility.

Abstract

I recall the place of neutrinos in the electroweak theory and summarize what we know about neutrino mass and flavor change. I next review the essential characteristics expected for relic neutrinos and survey what we can say about the neutrino contribution to the dark matter of the Universe. Then I discuss the standard-model interactions of ultrahigh-energy neutrinos, paying attention to the consequences of neutrino oscillations, and illustrate a few topics of interest to neutrino observatories. I conclude with short comments on the remote possibility of detecting relic neutrinos through annihilations of ultrahigh-energy neutrinos at the $Z$ resonance.