Neutrino decay and the supernova relic neutrino background

Future experiments will be able to observe the neutrinos coming from all the past supernovae in the universe, the so-called Supernova Relic Neutrino Background (SRNB). These neutrinos have travelled from cosmological distances before reaching the Earth. The measure of this background would be possible in the next generation of neutrino detectors. We show that the measure of the SRNB flux could give information on very long-life neutrino decays, in particular for “invisible decays”, such as ν decay into Majoron.