Diffuse Neutrino Signals from Dark Stars Seeding Supermassive Black Holes

Dark stars (DSs)—first stars powered by dark matter (DM) heating rather than fusion—could form in the early Universe. They can grow to ≳10 5 M ⊙ masses and collapse into seeds of supermassive black holes (SMBHs). We demonstrate that diffuse neutrino flux generated by DSs can be observable in existing experiments and have energies reaching hundreds of MeV, providing a novel window for probing SMBH progenitors. We establish first constraints on DSs as SMBH progenitors based on DM annihilations using data from Super-Kamiokande and IceCube neutrino experiments, and consistent with James Webb Space Telescope observations. Upcoming experiments such as Hyper-Kamiokande, DUNE, and JUNO will be able to explore DS properties with enhanced sensitivity.