Using high-energy astrophysical neutrinos, with TeV-PeV energies, we have placed limits on secret neutrino-neutrino interactions for mediator masses in the 1-100 MeV range.

While propagating to Earth, high-energy astrophysical neutrinos may interact resonantly with the cosmic neutrino background.  This would introduce a gap in the energy spectrum of the high-energy neutrinos.  We looked for this gap in 6 years of publicly available IceCube High Energy Starting Events (HESE).

Bounds on secret neutrino interactions from high-energy astrophysical neutrinos
Mauricio Bustamante, Charlotte Amalie Rosenstroem, Shashank Shalgar, Irene Tamborra

This complements our earlier work (1912.09115), which used supernova neutrinos to place limits on secret interactions, both from neutrino interactions inside the supernova core and from the propagation of neutrinos to Earth (these are the regions labeled “Shashank et al.” in the plot above).