Cosmological Dependence of Non-resonantly Produced Sterile Neutrinos

Understand

We discuss how a laboratory detection of a sterile neutrino not only would constitute a fundamental discovery of a new particle, but could also provide an indication of the evolution of the Universe before Big-Bang Nucleosynthesis (BBN), a fundamental discovery in cosmology.

• These "visible" sterile neutrinos could be detected in experiments such as KATRIN/TRISTAN and HUNTER in the keV mass range and PTOLEMY, KATRIN and reactor neutrino experiments in the eV mass range.
• Standard assumptions are usually made to compute the relic abundance and momentum distribution of particles produced before the temperature of the Universe was 5 MeV, an epoch from which there are no observed remnants thus far.
• However, non-standard pre-BBN cosmologies based on other assumptions that are equally in agreement with all existing data can arise in some theoretical models.