### Abstract

We study the matter effects on oscillations of high-energy neutrinos in the Universe. A substantial effect can be produced by scattering of the neutrinos from cosmological sources (Formula presented) on the relic neutrino background, provided that the latter has large (Formula presented) asymmetry: (Formula presented) where (Formula presented) (Formula presented) and (Formula presented) are the concentrations of neutrinos, antineutrinos, and photons. We consider in detail the dynamics of conversion in the expanding neutrino background. Applications are given to the diffuse fluxes of neutrinos from gamma ray bursters, active galactic nuclei, and the decay of superheavy relics. We find that the vacuum oscillation probability can be modified by (Formula presented) and in extreme cases allowed by present bounds on (Formula presented) the effect can reach (Formula presented) The signatures of matter effects would consist (i) for both active-active and active-sterile conversion, in a deviation of the numbers of events produced in a detector by neutrinos of different flavors, (Formula presented) (Formula presented) and of their ratios from the values given by vacuum oscillations; such deviations can reach (Formula presented) and (ii) for active-sterile conversion, in a characteristic energy dependence of the ratios (Formula presented) Searches for these matter effects will probe large (Formula presented) and lepton asymmetries in the Universe.

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

Number of pages | 1 |

Journal | Physical Review D - Particles, Fields, Gravitation and Cosmology |

Volume | 64 |

Issue number | 7 |

DOIs | |

State | Published - Jan 1 2001 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Nuclear and High Energy Physics
- Physics and Astronomy (miscellaneous)

### Cite this

**High-energy neutrino conversion and the lepton asymmetry in the universe.** / Lunardini, Cecilia; Smirnov, A. Yu.

Research output: Contribution to journal › Article

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TY - JOUR

T1 - High-energy neutrino conversion and the lepton asymmetry in the universe

AU - Lunardini, Cecilia

AU - Smirnov, A. Yu

PY - 2001/1/1

Y1 - 2001/1/1

N2 - We study the matter effects on oscillations of high-energy neutrinos in the Universe. A substantial effect can be produced by scattering of the neutrinos from cosmological sources (Formula presented) on the relic neutrino background, provided that the latter has large (Formula presented) asymmetry: (Formula presented) where (Formula presented) (Formula presented) and (Formula presented) are the concentrations of neutrinos, antineutrinos, and photons. We consider in detail the dynamics of conversion in the expanding neutrino background. Applications are given to the diffuse fluxes of neutrinos from gamma ray bursters, active galactic nuclei, and the decay of superheavy relics. We find that the vacuum oscillation probability can be modified by (Formula presented) and in extreme cases allowed by present bounds on (Formula presented) the effect can reach (Formula presented) The signatures of matter effects would consist (i) for both active-active and active-sterile conversion, in a deviation of the numbers of events produced in a detector by neutrinos of different flavors, (Formula presented) (Formula presented) and of their ratios from the values given by vacuum oscillations; such deviations can reach (Formula presented) and (ii) for active-sterile conversion, in a characteristic energy dependence of the ratios (Formula presented) Searches for these matter effects will probe large (Formula presented) and lepton asymmetries in the Universe.

AB - We study the matter effects on oscillations of high-energy neutrinos in the Universe. A substantial effect can be produced by scattering of the neutrinos from cosmological sources (Formula presented) on the relic neutrino background, provided that the latter has large (Formula presented) asymmetry: (Formula presented) where (Formula presented) (Formula presented) and (Formula presented) are the concentrations of neutrinos, antineutrinos, and photons. We consider in detail the dynamics of conversion in the expanding neutrino background. Applications are given to the diffuse fluxes of neutrinos from gamma ray bursters, active galactic nuclei, and the decay of superheavy relics. We find that the vacuum oscillation probability can be modified by (Formula presented) and in extreme cases allowed by present bounds on (Formula presented) the effect can reach (Formula presented) The signatures of matter effects would consist (i) for both active-active and active-sterile conversion, in a deviation of the numbers of events produced in a detector by neutrinos of different flavors, (Formula presented) (Formula presented) and of their ratios from the values given by vacuum oscillations; such deviations can reach (Formula presented) and (ii) for active-sterile conversion, in a characteristic energy dependence of the ratios (Formula presented) Searches for these matter effects will probe large (Formula presented) and lepton asymmetries in the Universe.

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U2 - 10.1103/PhysRevD.64.073006

DO - 10.1103/PhysRevD.64.073006

M3 - Article

AN - SCOPUS:0345901251

VL - 64

JO - Physical review D: Particles and fields

JF - Physical review D: Particles and fields

SN - 1550-7998

IS - 7

ER -