Speaker
Description
Sterile neutrinos are compelling dark matter candidates, but production solely from active-sterile oscillations is excluded by astrophysical observations. Non-standard self-interactions in either active or sterile sector can modify production to some extent. Here we propose a novel solution where scalar-mediated non-standard interactions between active and sterile neutrinos generate new production channels for $\nu_s$, independent of the active-sterile mixing and without the need for any fine-tuned resonance or primordial lepton asymmetry. Focusing on the heavy-mediator regime ($m_\phi \gtrsim 5\,\mathrm{GeV}$), these interactions efficiently populate the sterile sector even for vanishingly small mixing, while remaining consistent with cosmology and structure-formation bounds. The mechanism broadens the viable parameter space relative to scenarios that rely on mixing and implies potentially observable neutrino-dark matter interactions in astrophysical environments.
