Impact of late-time neutrino emission on the Diffuse Supernova Neutrino Background

Abstract

In the absence of high-statistics supernova neutrino measurements, estimates of the diffuse supernova neutrino background (DSNB) hinge on the precision of simulations of core-collapse supernovae (CCSNe). Understanding the cooling phase of protoneutron star (PNS) evolution ($\gtrsim1\,{\rm s}$ after core bounce) is crucial, since approximately 50% of the energy liberated by neutrinos is emitted during the cooling phase. We model the cooling phase with a hybrid method, by combining the neutrino emission predicted by 3D hydrodynamic simulations with several cooling phase estimates, including a novel two-parameter correlation depending on the final baryonic PNS mass and the time of shock revival. We find that the predicted DSNB event rate at Super-Kamiokande can vary by a factor of $\sim2-3$ depending on the cooling phase treatment. We also find that except for one cooling estimate, the range in predicted DSNB events is largely driven by the uncertainty in the neutrino mean energy. With a good understanding of the late time neutrino emission, more precise DSNB estimates can be made for the next generation of DSNB searches.Comment: 13 pages, 6+4 figures, 5 tables. Comments welcom