Three flavor neutrino conversions in supernovae: Slow $\mathrm{\&}$ Fast instabilities

Self induced neutrino flavor conversions in the dense regions of stellar core collapse are almost exclusively studied in the standard two flavor scenario. Linear stability analysis has been successfully used to understand these flavor conversions. This is the first linearized study of $\mathit{\text{three}}\mathit{\text{flavor}}$ fast instabilities. The fast' conversions are fascinating distinctions of the dense neutrino systems. In the fast modes the collective oscillation dynamics are independent of the neutrino mass, growing at the scale of the large neutrino-neutrino interaction strength ($10^5$ km$^{-1}$) of the dense core. This is extremely fast, in comparison to the usual slow’ collective modes driven by much smaller vacuum oscillation frequencies (${10}^0$ km${}^{-1}$). The three flavor analysis shows distinctive characteristics for both the slow and the fast conversions. The slow oscillation results are in qualitative agreement with the existing nonlinear three flavor studies. For the fast modes, addition of the third flavor opens up possibilities of influencing the growth rates of flavor instabilities when compared to a two flavor scenario.