Detecting the Diffuse Supernova Neutrino Background in the future Water-based Liquid Scintillator Detector Theia

Abstract

A large-scale neutrino observatory based on Water-based Liquid Scintillator (WbLS) will be excellently suited for a measurement of the Diffuse Supernova Neutrino Background (DSNB). The WbLS technique offers high signal efficiency and effective suppression of the otherwise overwhelming background from neutral-current interactions of atmospheric neutrinos. To illustrate this, we investigate the DSNB sensitivity for two configurations of the future Theia detector by developing the expected signal and background rejection efficiencies along a full analysis chain. Based on a statistical analysis of the remaining signal and background rates, we find that a rather moderate exposure of 150 kt•yrs will be sufficient to claim a (5σ) discovery of the faint DSNB signal for standard model assumptions. We conclude that, in comparison with other experimental techniques, WbLS offers the highest signal efficiency of more than 80 % and best signal significance over background.

Stellar Collapse Diversity and the Diffuse Supernova Neutrino Background

“…Intriguingly, the Super-Kamiokande (SK) experiment set upper flux limits on the DSNB (Malek et al 2003;Bays et al 2012;Zhang et al 2015) which are already close to theoretical predictions. This indicates the excellent discovery prospect within the next decade in the gadolinium-loaded SK detector and the forthcoming JUNO experiment (see, e.g., Beacom & Vagins 2004;Yüksel et al 2006;Horiuchi et al 2009;An et al 2016;Priya & Lunardini 2017;Møller et al 2018), as well as, in the longer term, with the Hyper-Kamiokande detector (Abe et al 2011) or with the proposed Theia detector (Askins et al 2020;Sawatzki et al 2020).…”