Low Multiplicity Burst Search at the Sudbury Neutrino Observatory

TL;DR

This paper reports a search for low-multiplicity neutrino bursts in the SNO detector, aiming to detect nearby supernovae, with no such bursts observed during the data collection periods.

Contribution

The study presents a blind analysis method for detecting low-multiplicity neutrino bursts in SNO data, setting new detection distance limits for supernovae.

Findings

No low-multiplicity neutrino bursts detected

Detection probability up to 70 kpc for Phase II

Analysis method effectively estimates background

Abstract

Results are reported from a search for low-multiplicity neutrino bursts in the Sudbury Neutrino Observatory (SNO). Such bursts could indicate detection of a nearby core-collapse supernova explosion. The data were taken from Phase I (November 1999 - May 2001), when the detector was filled with heavy water, and Phase II (July 2001 - August 2003), when NaCl was added to the target. The search was a blind analysis in which the potential backgrounds were estimated and analysis cuts were developed to eliminate such backgrounds with 90% confidence before the data were examined. The search maintained a greater than 50% detection probability for standard supernovae occurring at a distance of up to 60 kpc for Phase I and up to 70 kpc for Phase II. No low-multiplicity bursts were observed during the data-taking period.