Simulating fast time variations in the supernova neutrino flux in Hyper-Kamiokande

TL;DR

This paper explores the potential of Hyper-Kamiokande to detect supernova neutrino flux variations caused by SASI oscillations, using detailed simulations to account for detector effects and energy-dependent signals.

Contribution

It introduces a detailed simulation framework to evaluate Hyper-Kamiokande's ability to observe SASI-induced neutrino flux oscillations during a galactic supernova.

Findings

Simulation shows potential to detect SASI oscillations with Hyper-Kamiokande.

Energy-dependent oscillation amplitudes can be distinguished in the detector.

Detector effects like backgrounds and energy resolution are critical factors.

Abstract

Hyper-Kamiokande is a proposed next-generation water Cherenkov detector. If a galactic supernova happens, it will deliver a high event rate ($\mathcal{O}(10^5)$ neutrino events in total) as well as event-by-event energy information. Recent supernova simulations exhibit the Standing Accretion Shock Instability (SASI) which causes oscillations in the number flux and mean energy of neutrinos. The amplitude of these oscillations is energy-dependent, so the energy information available in Hyper-Kamiokande could be used to improve the detection prospects of these SASI oscillations. To determine whether this can be achieved in the presence of detector effects like backgrounds and finite energy uncertainty, we have started work on a detailed simulation of Hyper-Kamiokande's response to a supernova neutrino burst.