Decoherence and oscillations of supernova neutrinos

Understand

Supernova neutrinos have several exceptional features which can lead to interesting physical consequences.

• At the production point their wave packets have an extremely small size $\sigma_x \sim 10^{-11}$ cm; hence the energy uncertainty can be as large as the energy itself, $\sigma_E \sim E$, and the coherence length is short.
• On the way to the Earth the wave packets of mass eigenstates spread to macroscopic sizes and separate.
• Inside the Earth the mass eigenstates split into eigenstates in matter and oscillate again.