Stimulated neutrino transformation through turbulence on a changing density profile and application to supernovae

Abstract

We apply the model of stimulated neutrino transitions to neutrinos traveling through turbulence on a non-constant density profile. We describe a method to predict the location of large amplitude transitions and demonstrate the effectiveness of this method by comparing to numerical calculations using a model supernova (SN) profile. The important wavelength scales of turbulence, both those that stimulate neutrino transformations and those that suppress them, are presented and discussed. We then examine the effects of changing the parameters of the turbulent spectrum, specifically the root-mean-square amplitude and cutoff wavelength, and show how the stimulated transitions model offers an explanation for the increase in both the amplitude and number of transitions with large amplitude turbulence, as well as a suppression or absence of transitions for long cutoff wavelengths. The method can also be used to predict the location of transitions between antineutrino states which, in the normal hierarchy we are using, will not undergo Mikheev-Smirnov-Wolfenstein (MSW) transitions. Finally, the stimulated neutrino transitions method is applied to the turbulence derived found in a 2D supernova simulation and explains the minimal observed effect on neutrino oscillations in the simulation as as being due to excessive long wavelength modes suppressing transitions and the absence of modes that fulfill the parametric resonance condition.