A new probe of relic neutrino clustering using cosmogenic neutrinos

We propose a new probe of cosmic relic neutrinos (C nu B) using their resonant scattering against cosmogenic neutrinos. Depending on the lightest neutrino mass and the energy spectrum of the cosmogenic neutrino flux, a Standard Model vector meson (such as a hadronic rho) resonance can be produced via nu(nu) over bar annihilation. This leads to a distinct absorption feature in the cosmogenic neutrino flux at an energy solely determined by the meson mass and the neutrino mass, apart from redshift. By numerical coincidence, the position of the rho-resonance overlaps with the originally predicted peak of the Greisen-Zatsepin-Kuzmin (GZK) neutrino flux, which offers an enhanced effect at higher redshifts. We show that this absorption feature in the GZK neutrino flux may be observable in future radio-based neutrino observatories, such as IceCube-Gen2 radio, provided there exists a large overdensity in the C nu B distribution. This therefore provides a new probe of C nu B clustering at large redshifts, complementary to the laboratory probes (such as KATRIN) at zero redshift. (C) 2022 The Author(s). Published by Elsevier B.V.

Automated summary

We propose a new method for probing cosmic relic neutrinos by using their resonant scattering against cosmogenic neutrinos. This method relies on the absorption feature produced by the resonant annihilation of relic neutrinos in the cosmogenic neutrino flux, which can provide information about the neutrino mass and meson mass.