Z boson emission by a neutrino in de Sitter expanding universe

TL;DR

This paper investigates the spontaneous emission of Z bosons by neutrinos in an expanding de Sitter universe, providing analytical calculations and showing the process occurs mainly during the early universe's rapid expansion.

Contribution

It offers the first analytical computation of Z boson emission probabilities by neutrinos in de Sitter space, highlighting conditions for this process in the early universe.

Findings

Z boson emission by neutrinos is possible only during rapid early universe expansion.

Analytical expressions for emission probability and transition rate are derived.

Estimated Z boson density relates to neutrino density in the early universe.

Abstract

Production of Z bosons in emission processes by neutrinos in the expanding de Sitter universe is studied by using perturbative methods. The total probability and transition rate for the spontaneous emission of a Z boson by a neutrino is computed analytically, then we perform a graphical analysis in terms of the expansion parameter. Our results prove that this process is possible only for large expansion conditions of the early Universe. Finally the density number of Z bosons is defined and we obtain a quantitative estimation of this quantity in terms of the density number of neutrinos.