Exciting prospects for detecting late-time neutrinos from core-collapse supernovae

The importance of detecting neutrinos from a Milky Way core-collapse supernova is well known. An understudied phase is proto-neutron star cooling. For SN 1987A, this seemingly began at about 2 s and is thus probed by only 6 of the 19 events (and only the (nu) over bar (e) flavor) in the Kamiokande-II and IMB detectors. With the higher statistics expected for present and near-future detectors, it should be possible to measure detailed neutrino signals out to very late times. We present the first comprehensive study of neutrino detection during the proto-neutron star cooling phase, considering a variety of outcomes, using all flavors, and employing detailed detector physics. For our nominal model, the event yields (at 10 kpc) after 10 s-the approximate duration of the SN 1987A signal-far exceed the entire SN 1987A yield, with similar or equal to 250 (nu) over bar (e) events (to 50 s) in Super-Kamiokande, similar or equal to 110 nu(e) events (40 s) in the Deep Underground Neutrino Experiment (DUNE), and similar or equal to 10 nu(mu), nu(tau), (nu) over bar (mu), (nu) over bar (tau) (to 20 s) in the Jiangmen Underground Neutrino Observatory. These data would allow unprecedented probes of the proto-neutron star, including the onset of neutrino transparency and hence its transition to a neutron star. If a black hole forms, even at very late times, this can be clearly identified. But will the detectors fulfill their potential for this perhaps once-ever opportunity for an all-flavor, high-statistics detection of a core collapse? Maybe. Further work is urgently needed, especially for DUNE to thoroughly investigate and improve its MeV capabilities.

Automated summary

The detection of neutrinos from a Milky Way core-collapse supernova is crucial, especially during the understudied proto-neutron star cooling phase. With higher statistics expected from present and near-future detectors, detailed neutrino signals during this phase can be measured, providing insights into the properties and formation process of neutron stars.