Can we detect the cosmic neutrino background?
James Alvey, GRAPPA Amsterdam
Weekly Theory Seminar.
The Cosmic Neutrino Background (CNB) is a definitive prediction of the standard cosmological model and its direct discovery would represent a significant milestone in cosmology and neutrino physics. The PTOLEMY project – who are looking to use the capture of relic neutrinos on a beta-decaying atomic target as a possible way to make such a detection – is arguably the most detailed proposal to date. Crucial parameters that control the reach of their approach are (i) the absolute neutrino mass, and (ii) the local neutrino number density. Within the minimal ΛCDM model, however, cosmology provides a stringent upper limit on the sum of neutrino masses of 0.12 eV, with further improvements expected soon from galaxy surveys by DESI and EUCLID. This makes the prospects for a direct CNB detection, and indeed a laboratory neutrino mass measurement, extremely challenging. In this talk, I will ask the following question: to what extent are these prospects cosmological-model independent, and do there exist scenarios that are compatible with all cosmological data where a direct detection is more feasible*?
*spoiler, we think the answer to the second question could be yes!
(The slides will be available here)