Probing secret interactions of eV-scale sterile neutrinos with the diffuse supernova neutrino background

Understand

Sterile neutrinos with mass in the eV-scale and large mixings of order $\theta_0\simeq 0.1$ could explain some anomalies found in short-baseline neutrino oscillation data.

• Here, we revisit a neutrino portal scenario in which eV-scale sterile neutrinos have self-interactions via a new gauge vector boson $\phi$.
• Their production in the early Universe via mixing with active neutrinos can be suppressed by the induced effective potential in the sterile sector.
• We study how different cosmological observations can constrain this model, in terms of the mass of the new gauge boson, $M_\phi$, and its coupling to sterile neutrinos, $g_s$.