Turbulence effects on supernova neutrinos

TL;DR

This paper investigates how turbulence in supernova environments affects neutrino flavor evolution, revealing sensitivity to tiny density fluctuations and novel multi-flavor effects beyond standard models.

Contribution

It models turbulence effects on supernova neutrinos using density fluctuations from multi-dimensional simulations, uncovering new flavor transition phenomena and sensitivities.

Findings

Turbulence effectively acts as two-flavor for fluctuations <~ 1% at high theta_13.

Sensitivity to density fluctuations as small as 0.001% in high resonance channels.

Discovery of new flavor transient effects at small theta_13 due to turbulence.

Abstract

Multi-dimensional core-collapse supernova simulations exhibit turbulence of large amplitude and over large scales. As neutrinos pass through the supernova mantle the turbulence is expected to modify their evolution compared to the case where the explosion is free of turbulence. In this paper we study this turbulence effect upon the neutrinos modelling the turbulence expected from multi-dimensional simulations by adding matter density fluctuations to density profiles taken from one-dimensional hydrodynamical simulations. We investigate the impact upon the supernova neutrino transition probabilities as a function of the neutrino mixing angle theta_13 and turbulence amplitude. In the high (H) resonant channel and with large theta_13 values we find that turbulence is effectively two flavor for fluctuation amplitudes <~ 1% and have identified a new effect due to the combination of turbulence and multiple H resonances that leads to a sensitivity to fluctuations amplitudes as small as ~ 0.001%. At small values of theta_13, beyond the range achievable in Earth based experiments, we find that turbulence leads to new flavor transient effects in the channel where the MSW H resonance occurs. Finally, we investigate large amplitude fluctuations which lead to three flavor effects due to broken HL factorization and significant non-resonant transitions and identify two non-resonant turbulence effects, one depending on the theta_13, and the other independent of this angle and due to the low (L) MSW resonance.