Impact of late-time neutrino emission on the diffuse supernova neutrino background

TL;DR

This paper investigates how different models of late-time neutrino emission from supernovae affect the predicted diffuse supernova neutrino background, highlighting the importance of cooling-phase uncertainties for future detection efforts.

Contribution

It introduces a hybrid modeling approach combining 3D simulations with new cooling-phase estimates, including a novel correlation based on PNS mass and shock revival time.

Findings

DSNB event rate can vary by a factor of 2-3 based on cooling models.

Uncertainty in neutrino mean energy largely drives the range of predictions.

Better understanding of late-time neutrino emission improves DSNB estimate precision.

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. 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.