Detecting the Diffuse Supernova Neutrino Background with LENA

TL;DR

This paper evaluates LENA, a large liquid scintillator detector, for detecting the diffuse supernova neutrino background, analyzing background challenges, detection prospects, and potential to test supernova models over a decade.

Contribution

It provides a detailed assessment of LENA's capability to detect the DSNB, including background suppression techniques and significance estimates for long-term data collection.

Findings

Approximately 5 to 10 DSNB events per year expected.

Background from atmospheric neutrinos can be suppressed with pulse shape discrimination.

Detection of DSNB possible with 2 sigma significance after 10 years.

Abstract

LENA (Low Energy Neutrino Astronomy) has been proposed as a next generation 50 kt liquid scintillator detector. Its large target mass allows to search for the Diffuse Supernova Neutrino Background (DSNB), which was generated by the cumulative emissions of all core-collapse supernovae throughout the universe. Indistinguishable background from reactor and atmospheric electron antineutrinos limits the detection window to the energy range between 9.5 MeV and 25 MeV. Depending on the mean supernova neutrino energy, about 5 to 10 events per year are expected in this energy window. The background from neutral current reactions of atmospheric neutrinos surpasses the DSNB by more than one order magnitude, but can be suppressed by pulse shape discrimination. Assuming that the residual background is known with 5% uncertainty, the DSNB can be detected with 2 sigma significance after 10 years of data taking. In case that no hint for a signal is seen, current standard DSNB models would be ruled out with more than 90% C.L.