[Paper Review] Supernova Neutrinos: Production, Oscillations and Detection

Alessandro Mirizzi, Irene Tamborra+6 more|arXiv (Cornell University)|Jul 31, 2015

Neutrino Physics ResearchPhysics and Astronomy453 references355 citations

TL;DR

This paper reviews the production, oscillations, and detection of supernova neutrinos, emphasizing their role as probes of core-collapse physics and neutrino properties. It highlights how future Galactic supernovae could yield high-statistics neutrino signals, revealing flavor-dependent dynamics through matter effects, self-induced oscillations, and shock-wave signatures, while also assessing prospects for detecting the diffuse supernova neutrino background (DSNB).

ABSTRACT

Neutrinos play a crucial role in the collapse and explosion of massive stars, governing the infall dynamics of the stellar core, triggering and fueling the explosion and driving the cooling and deleptonization of the newly formed neutron star. Due to their role neutrinos carry information from the heart of the explosion and, due to their weakly interacting nature, offer the only direct probe of the dynamics and thermodynamics at the center of a supernova. In this paper, we review the present status of modelling the neutrino physics and signal formation in collapsing and exploding stars. We assess the capability of current and planned large underground neutrino detectors to yield faithful information of the time and flavor dependent neutrino signal from a future Galactic supernova. We show how the observable neutrino burst would provide a benchmark for fundamental supernova physics with unprecedented richness of detail. Exploiting the treasure of the measured neutrino events requires a careful discrimination of source-generated properties from signal features that originate on the way to the detector. As for the latter, we discuss self-induced flavor conversions associated with neutrino-neutrino interactions that occur in the deepest stellar regions; matter effects that modify the pattern of flavor conversions in the dynamical stellar envelope; neutrino-oscillation signatures that result from structural features associated with the shock-wave propagation as well as turbulent mass motions in post-shock layers. Finally, we highlight our current understanding of the formation of the diffuse supernova neutrino background and we analyse the perspectives for a detection of this relic signal that integrates the contributions from all past core-collapse supernovae in the Universe.

Motivation & Objective

• To review the current state of modeling neutrino emission and flavor evolution in core-collapse supernovae.
• To assess the capability of current and future large underground detectors to extract detailed information from a Galactic supernova neutrino burst.
• To disentangle source-generated neutrino features from propagation effects such as matter-induced oscillations and self-induced flavor conversions.
• To evaluate the potential of supernova neutrinos as probes of the neutrino mass hierarchy and non-standard physics.
• To analyze the prospects for detecting the diffuse supernova neutrino background (DSNB) as a cosmological signal from all past core-collapse supernovae.

Proposed method

• Modeling neutrino emission from core-collapse supernovae using multi-dimensional hydrodynamic simulations and neutrino transport codes.
• Applying the neutrino light-bulb model and non-linear flavor evolution equations to study self-induced oscillations in high-density neutrino environments.
• Incorporating matter effects via the Mikheyev-Smirnov-Wolfenstein (MSW) mechanism to assess flavor conversion signatures in the stellar envelope.
• Simulating neutrino detection in various experimental configurations (e.g., water Cherenkov, liquid scintillator, LAr TPC) using event rate and energy spectrum calculations.
• Forecasting the DSNB flux using supernova simulation outputs and SN 1987A data, comparing with observational upper limits from Super-Kamiokande.
• Analyzing the impact of turbulence and shock dynamics on neutrino oscillation signatures through hydrodynamic simulations with neutrino feedback.

Experimental results

Research questions

• RQ1 How do self-induced flavor oscillations in dense neutrino media affect the observable neutrino signal from a Galactic supernova?
• RQ2 What signatures of the neutrino mass hierarchy can be extracted from the time- and flavor-dependent neutrino burst?
• RQ3 How do shock-wave propagation and post-shock turbulence imprint detectable features on the neutrino energy spectrum?
• RQ4 What is the expected detectability of the diffuse supernova neutrino background (DSNB) with current and next-generation detectors?
• RQ5 To what extent can neutrino oscillations in the supernova mantle distinguish between normal and inverted neutrino mass hierarchies?

Key findings

• Self-induced flavor oscillations in the dense core of a supernova lead to collective, non-linear neutrino flavor conversions that can significantly alter the final neutrino energy spectra.
• The neutrino mass hierarchy can be probed through matter-induced flavor conversions in the supernova mantle, with distinct signatures in the time- and flavor-resolved neutrino burst.
• Shock-wave propagation and SASI (Standing Accretion Shock Instability) can modulate neutrino energy spectra, offering a real-time probe of explosion dynamics.
• The diffuse supernova neutrino background (DSNB) is a guaranteed signal with a flux predicted to be within reach of current and next-generation detectors, such as Super-K-Gd and JUNO.
• The DSNB flux is estimated to be within a factor of ~2 of the current Super-Kamiokande upper limit, suggesting imminent detection within the next decade.
• The SN 1987A neutrino burst, though low in statistics, already provided strong constraints on exotic neutrino properties and non-standard cooling mechanisms, such as right-handed neutrinos and axions.