Sensitivity of multi-PMT Optical Modules in Antarctic Ice to Supernova Neutrinos of MeV energy

Abstract

New optical sensors with a segmented photosensitive area are being developed for the next generation of neutrino telescopes at the South Pole. In addition to increasing sensitivity to high-energy astrophysical neutrinos, we show that this will also lead to a significant improvement in sensitivity to MeV neutrinos, such as those produced in core-collapse supernovae (CCSN). These low-energy neutrinos can provide a detailed picture of the events after stellar core collapse, testing our understanding of these violent explosions. We present studies on the event-based detection of MeV neutrinos with a segmented sensor and, for the first time, the potential of a corresponding detector in the deep ice at the South Pole for the detection of extra-galactic CCSN. We find that exploiting temporal coincidences between signals in different photocathode segments, a $27\ \mathrm{M}_{\odot}$ progenitor mass CCSN can be detected up to a distance of 269 kpc with a false detection rate of $0.01$ year$^{-1}$ with a detector consisting of 10000 sensors. Increasing the number of sensors to 20000 and reducing the optical background by a factor of 140 expands the range such that a CCSN detection rate of $0.08$ per year is achieved, while keeping the false detection rate at $0.01$ year$^{-1}$.