### Abstract

We consider in detail the effects of the 13-mixing (sin^{2} θ_{13}) and of the type of mass hierarchy/ordering (sign[Δm_{13}
^{2}]) on neutrino signals from the gravitational collapses of stars. The observables (characteristics of the energy spectra of v_{e} and v̄_{e} events) sensitive to sin ^{2} θ_{13} and sign[Δ_{13}
^{2}] have been calculated. They include the ratio of average energies of the spectra, r _{E} ≡ 〈E〉 /〈Ē〉, the ratio of widths of the energy distributions, r_{Γ} ≡ Γ/Γ̄, the ratios of total numbers of v_{e} and v̄_{e} events at low energies, S, and in the high energy tails, R_{tail}. We construct and analyse scatter plots which show the predictions for the observables for different intervals of sin^{2} θ_{13} and signs of Δm_{13}
^{2}, taking into account uncertainties in the original neutrino spectra, the star density profile, etc. Regions in the space of observables r_{E}, r_{Γ}, S, R_{tail} exist in which certain mass hierarchy and intervals of sin^{2} θ_{13} can be identified or discriminated. We elaborate on the method of the high energy tails in the spectra of events. The conditions are formulated for which sin^{2} θ_{13} can be (i) measured, (ii) restricted from below, (iii) restricted from above. We comment on the possibility to determine sin^{2} θ_{13} using the time dependence of the signals due to the propagation of the shock wave through the resonance layers of the star. We show that the appearance of the delayed Earth matter effect in one of the channels (v_{e} or v̄_{e}) in combination with the undelayed effect in the other channel will allow us to identify the shock wave appeareance and determine the mass hierarchy.

Original language | English (US) |
---|---|

Pages (from-to) | 121-168 |

Number of pages | 48 |

Journal | Journal of Cosmology and Astroparticle Physics |

Issue number | 6 |

State | Published - Jun 2003 |

Externally published | Yes |

### Fingerprint

### Keywords

- Neutrino properties
- Supernova neutrinos

### ASJC Scopus subject areas

- Physics and Astronomy(all)

### Cite this

*Journal of Cosmology and Astroparticle Physics*, (6), 121-168.

**Probing the neutrino mass hierarchy and the 13-mixing with supernovae.** / Lunardini, Cecilia; Smirnov, Alexei Yu.

Research output: Contribution to journal › Article

*Journal of Cosmology and Astroparticle Physics*, no. 6, pp. 121-168.

}

TY - JOUR

T1 - Probing the neutrino mass hierarchy and the 13-mixing with supernovae

AU - Lunardini, Cecilia

AU - Smirnov, Alexei Yu

PY - 2003/6

Y1 - 2003/6

N2 - We consider in detail the effects of the 13-mixing (sin2 θ13) and of the type of mass hierarchy/ordering (sign[Δm13 2]) on neutrino signals from the gravitational collapses of stars. The observables (characteristics of the energy spectra of ve and v̄e events) sensitive to sin 2 θ13 and sign[Δ13 2] have been calculated. They include the ratio of average energies of the spectra, r E ≡ 〈E〉 /〈Ē〉, the ratio of widths of the energy distributions, rΓ ≡ Γ/Γ̄, the ratios of total numbers of ve and v̄e events at low energies, S, and in the high energy tails, Rtail. We construct and analyse scatter plots which show the predictions for the observables for different intervals of sin2 θ13 and signs of Δm13 2, taking into account uncertainties in the original neutrino spectra, the star density profile, etc. Regions in the space of observables rE, rΓ, S, Rtail exist in which certain mass hierarchy and intervals of sin2 θ13 can be identified or discriminated. We elaborate on the method of the high energy tails in the spectra of events. The conditions are formulated for which sin2 θ13 can be (i) measured, (ii) restricted from below, (iii) restricted from above. We comment on the possibility to determine sin2 θ13 using the time dependence of the signals due to the propagation of the shock wave through the resonance layers of the star. We show that the appearance of the delayed Earth matter effect in one of the channels (ve or v̄e) in combination with the undelayed effect in the other channel will allow us to identify the shock wave appeareance and determine the mass hierarchy.

AB - We consider in detail the effects of the 13-mixing (sin2 θ13) and of the type of mass hierarchy/ordering (sign[Δm13 2]) on neutrino signals from the gravitational collapses of stars. The observables (characteristics of the energy spectra of ve and v̄e events) sensitive to sin 2 θ13 and sign[Δ13 2] have been calculated. They include the ratio of average energies of the spectra, r E ≡ 〈E〉 /〈Ē〉, the ratio of widths of the energy distributions, rΓ ≡ Γ/Γ̄, the ratios of total numbers of ve and v̄e events at low energies, S, and in the high energy tails, Rtail. We construct and analyse scatter plots which show the predictions for the observables for different intervals of sin2 θ13 and signs of Δm13 2, taking into account uncertainties in the original neutrino spectra, the star density profile, etc. Regions in the space of observables rE, rΓ, S, Rtail exist in which certain mass hierarchy and intervals of sin2 θ13 can be identified or discriminated. We elaborate on the method of the high energy tails in the spectra of events. The conditions are formulated for which sin2 θ13 can be (i) measured, (ii) restricted from below, (iii) restricted from above. We comment on the possibility to determine sin2 θ13 using the time dependence of the signals due to the propagation of the shock wave through the resonance layers of the star. We show that the appearance of the delayed Earth matter effect in one of the channels (ve or v̄e) in combination with the undelayed effect in the other channel will allow us to identify the shock wave appeareance and determine the mass hierarchy.

KW - Neutrino properties

KW - Supernova neutrinos

UR - http://www.scopus.com/inward/record.url?scp=23244435766&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=23244435766&partnerID=8YFLogxK

M3 - Article

AN - SCOPUS:23244435766

SP - 121

EP - 168

JO - Journal of Cosmology and Astroparticle Physics

JF - Journal of Cosmology and Astroparticle Physics

SN - 1475-7516

IS - 6

ER -