Precise Capture Rates of Cosmic Neutrinos and Their Implications on Cosmology

TL;DR

This paper analyzes how precise measurements of cosmic neutrino capture rates on tritium can reveal cosmological effects, neutrino properties, and potential new physics, with implications for experiments like PTOLEMY.

Contribution

It provides detailed calculations of neutrino capture rates considering cosmological effects and compares Dirac and Majorana neutrinos, informing experimental detection strategies.

Findings

Precise capture rate estimates including cosmological effects.

Differences between Dirac and Majorana neutrino capture rates.

Requirements for energy resolution in neutrino detection.

Abstract

We explore the potential of measurements of cosmological effects, such as neutrino spectral distortions from the neutrino decoupling and neutrino clustering in our Galaxy, via cosmic neutrino capture on tritium. We compute the precise capture rates of each neutrino species including such cosmological effects to probe them. These precise estimates of capture rates are also important in that the would-be deviation of the estimated capture rate could suggest new neutrino physics and/or a non-standard evolution of the universe. In addition, we discuss the precise differences between the capture rates of Dirac and Majorana neutrinos for each species, the required energy resolutions to detect each neutrino species and the method of reconstruction of the spectrum of cosmic neutrinos via the spectrum of emitted electrons, with emphasis on the PTOLEMY experiment.