Oscillation Effects and Time Variation of the Supernova Neutrino Signal

TL;DR

This paper investigates how supernova explosion dynamics influence the time-dependent neutrino signals detected on Earth, focusing on flavor oscillations and their impact on observable event rates in neutrino detectors.

Contribution

It introduces a detailed analysis of neutrino flavor transformation driven by density profile changes during supernova explosions using hydrodynamical simulations and Monte Carlo methods.

Findings

Neutrino flavor mixing varies significantly during the explosion.

Detector signals can reveal internal supernova dynamics.

Feasible to probe explosion features with current neutrino detectors.

Abstract

The neutrinos detected from the next Galactic core-collapse supernova will contain valuable information on the internal dynamics of the explosion. One mechanism leading to a temporal evolution of the neutrino signal is the variation of the induced neutrino flavor mixing driven by changes in the density profile. With one and two dimensional hydrodynamical simulations we identify the behavior and properties of prominent features of the explosion. Using these results we demonstrate the time variation of the neutrino crossing probabilities due to changes in the MSW neutrino transformations as the star explodes by using the S-matrix - Monte Carlo - approach to neutrino propagation. After adopting spectra for the neutrinos emitted from the proto-neutron star we calculate for a Galactic supernova the evolution of the positron spectra within a water Cerenkov detector and the ratio of charged current to neutral current event rates for a heavy water - SNO like - detector and find that these detector signals are feasible probes of a number of explosion features.