Physics of supernova neutrinos

I review the effects of flavor conversion of neutrinos from stellar collapse due to masses and mixing, and discuss the motivations for their study. I consider in detail the sensitivity of certain observables (characteristics of the energy spectra of ν_e and ν¯_e events) to the 13-mixing (sin² θ₁₃) and to the type of mass hierarchy/ordering (sign[∆m² ₁₃]). These observables are: the ratio of average energies of the spectra, r_E ≡ hEi/hĒi, the ratio of widths of the energy distributions, r_Γ ≡ Γ/Γ, ^¯ the ratios of total numbers of ν_e and ν¯_e events at low energies, S, and in the high energy tails, R_tail. I show that regions in the space of observables r_E, r_Γ, R_tail exist in which certain mass hierarchy and intervals of sin² θ₁₃ can be identified or discriminated. Finally, I discuss the potential of studying regeneration effects on ν_e and ν¯_e in the matter of the Earth and point out that both the observation or exclusion of these effects lead to model-independent information on sin² θ₁₃ and the mass hierarchy.