Dissipative neutrino oscillations in randomly fluctuating matter

The generalized dynamics describing the propagation of neutrinos in randomly fluctuating media is analyzed: It takes into account matter-induced, decoherence phenomena that go beyond the standard Mikheyev-Smirnov-Wolfenstein (MSW) effect. A widely adopted density fluctuation pattern is found to be physically untenable: A more general model needs to be instead considered, leading to flavor changing effective neutrino-matter interactions. They induce new, dissipative effects that modify the neutrino oscillation pattern in a way amenable to a direct experimental analysis.

Figure 1

Behavior of electron neutrino mean survival probability ${\mathcal{P}}_{{\nu }_e\to {\nu }_e}$ as a function of the neutrino energy (through the ratio $A/A_R$), for ${sin}^{2}2\theta \simeq 0.8$, density dominated matter fluctuations, ${\lambda }_1,{\lambda }_2\gg {\lambda }_3$, and different correlation strengths, $\mathcal{W}/{\lambda }_2\simeq {10}^{-4}–{10}^{-3}$. The lower starting (black) curve corresponds to the case of noiseless matter (standard MSW effect), while the remaining (colored) ones show the effect of the stochastic fluctuations. The initial gap among the group of curves is due to the presence of the decoherence driven damping factor.