CNNs for enhanced background discrimination in DSNB searches in large-scale water-Gd detectors

Abstract

Gadolinium-loading of large water Cherenkov detectors is a prime method for the detection of the Diffuse Supernova Neutrino Background (DSNB). While the enhanced neutron tagging capability greatly reduces single-event backgrounds, correlated events mimicking the IBD coincidence signature remain a potentially harmful background. Neutral-Current (NC) interactions of atmospheric neutrinos potentially dominate the DSNB signal especially in the low-energy range of the observation window that reaches from about 12 to 30 MeV. The present paper investigates a novel method for the discrimination of this background. Convolutional Neural Networks (CNNs) offer the possibility for a direct analysis and classification of the PMT hit patterns of the prompt events. Based on the events generated in a simplified SuperKamiokande-like detector setup, we find that a trained CNN can maintain a signal efficiency of 96 % while reducing the residual NC background to 2 % of the original rate. Comparing to recent predictions of the DSNB signal and measurements of the NC background levels in Super-Kamiokande, the corresponding signal-to-background ratio is about 4:1, providing excellent conditions for a DSNB discovery.

16 pages, 9 figures

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• The Diffuse Supernova Neutrino Background
• Stellar Collapse Diversity and the Diffuse Supernova Neutrino Background
• Neutrino Spectrum from SN 1987A and from Cosmic Supernovae
• Measurement of neutrino and antineutrino neutral-current quasielastic-like interactions on oxygen by detecting nuclear de-excitation $\gamma$-rays
• Measurement of neutrino-oxygen neutral-current quasi-elastic cross section using atmospheric neutrinos at Super-Kamiokande

Cited by in corpus (1)

• Prospects for the detection of the Diffuse Supernova Neutrino Background with the experiments SK-Gd and JUNO