TY - JOUR
T1 - Neutrino oscillation signatures of oxygen-neon-magnesium supernovae
AU - Lunardini, Cecilia
AU - Müller, B.
AU - Janka, H. Th
PY - 2008/7/23
Y1 - 2008/7/23
N2 - We discuss the flavor conversion of neutrinos from core-collapse supernovae that have oxygen-neon-magnesium (ONeMg) cores. Using the numerically calculated evolution of the star up to 650 ms post bounce, we find that, for the normal mass hierarchy, the electron neutrino flux in a detector shows signatures of two typical features of an ONeMg-core supernova: a sharp step in the density profile at the base of the He shell and a faster shock wave propagation compared to iron core supernovae. Before the shock hits the density step (t 150ms), the survival probability of electron neutrinos above ∼20MeV of energy is about ∼0.68, in contrast to values of ∼0.32 or less for an iron core supernova. The passage of the shock through the step and its subsequent propagation cause a decrease of the survival probability and a decrease of the amplitude of oscillations in the Earth, reflecting the transition to a more adiabatic propagation inside the star. These changes affect the lower energy neutrinos first; they are faster and more sizable for larger θ13. They are unique of ONeMg-core supernovae, and give the possibility to test the speed of the shock wave. The time modulation of the Earth effect and its negative sign at the neutronization peak are the most robust signatures in a detector.
AB - We discuss the flavor conversion of neutrinos from core-collapse supernovae that have oxygen-neon-magnesium (ONeMg) cores. Using the numerically calculated evolution of the star up to 650 ms post bounce, we find that, for the normal mass hierarchy, the electron neutrino flux in a detector shows signatures of two typical features of an ONeMg-core supernova: a sharp step in the density profile at the base of the He shell and a faster shock wave propagation compared to iron core supernovae. Before the shock hits the density step (t 150ms), the survival probability of electron neutrinos above ∼20MeV of energy is about ∼0.68, in contrast to values of ∼0.32 or less for an iron core supernova. The passage of the shock through the step and its subsequent propagation cause a decrease of the survival probability and a decrease of the amplitude of oscillations in the Earth, reflecting the transition to a more adiabatic propagation inside the star. These changes affect the lower energy neutrinos first; they are faster and more sizable for larger θ13. They are unique of ONeMg-core supernovae, and give the possibility to test the speed of the shock wave. The time modulation of the Earth effect and its negative sign at the neutronization peak are the most robust signatures in a detector.
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U2 - 10.1103/PhysRevD.78.023016
DO - 10.1103/PhysRevD.78.023016
M3 - Article
AN - SCOPUS:48349116086
SN - 1550-7998
VL - 78
JO - Physical Review D - Particles, Fields, Gravitation and Cosmology
JF - Physical Review D - Particles, Fields, Gravitation and Cosmology
IS - 2
M1 - 023016
ER -