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Probing Neutrino Mixing and Unitarity Violation at Neutrino Telescopes

TeV Particle Astrophysics, 24-28 September, 2008, Beijing, China. Shun Zhou. IHEP, CAS, Beijing. Based on our recent works: Z.Z. Xing and S. Zhou, PLB (2008); PRD (2006). Outline. UHE Neutrinos: Challenges and Opportunities Determination of the Initial Flavor Composition

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Probing Neutrino Mixing and Unitarity Violation at Neutrino Telescopes

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  1. TeV Particle Astrophysics, 24-28 September, 2008, Beijing, China Shun Zhou IHEP, CAS, Beijing Based on our recent works: Z.Z. Xing and S. Zhou, PLB (2008); PRD (2006). Outline • UHE Neutrinos: Challenges and Opportunities • Determination of the Initial Flavor Composition • Unitary versus Non-unitary Neutrino Mixing • Concluding Remarks Probing Neutrino Mixing and Unitarity ViolationatNeutrino Telescopes

  2. Ultrahigh-energy neutrinos: Astrophysical Sources “Grand Unified” Neutrino Spectrum UHE  ASPERA Roadmap Neutrino Astronomy • Solar neutrinos -Standard Solar Model -Neutrino Oscillations • SN neutrinos -Explosion Mechanism? -Mixing Parameters? • UHE neutrinos -Cosmic  Sources? -IntrinsicProperties?

  3. Ultrahigh-energy neutrinos: Astrophysical Sources Flux of Cosmic Rays Pierre Auger, PRL, 08 HiRes, PRL, 08 Observation of GZK cutoff ? Existence of UHE Neutrinos?

  4. Ultrahigh-energy neutrinos: Astrophysical Sources g GRB DM _ p c c e+ n AGN SNR

  5. Ultrahigh-energy neutrinos: Challenges and Opportunities Neutrino Telescope: AMANDA km3-scale NT: IceCube

  6. Ultrahigh-energy neutrinos: Challenges and Opportunities ANTARES La-Seyne-sur-Mer, France BAIKAL Russia NEMO Catania, Italy NESTOR Pylos, Greece AMANDA andIceCube South Pole, Antarctica KM3NeT

  7. Ultrahigh-energy neutrinos: Challenges and Opportunities 10 TeV 375 TeV 104 TeV • Distinct signals for different flavors: • Particle physics by using the flavors, given the sources • Probe sources by using the flavors, givenνproperties

  8. Ultrahigh-energy neutrinos: Unique Opportunity CMB Light absorbed (1e:1:1) Neutrino (1e:2) Proton scattered by magnetic field To explore extremely high energy region To locate distant astrophysical sources To study new scenarios in particle physics Conventional source:decays of charged ’s produced from UHEp +p or p +collisions. Naïve expectation:ultra-long-baseline UHE cosmic -oscillations (Learned, Pakvasa 95).

  9. Ultrahigh-energy neutrinos: Unique Opportunity ■ Learned, Pakvasa, APP (95) ★ Athar et al, PRD (00) ★ Bento et al, PLB (00) ★ Gounaris, Moultaka, hep-ph/0212110 ★ Barenboim, Quigg, PRD (03) ★ Beacom et al, PRD (03) ★ Keraenen et al, PLB (03) ★ Beacom et al, PRD (04) ★ Hooper et al, PLB (05) ★ Serpico, Kachelriess, PRL (05) ★ Bhattacharjee, Gupta, hep-ph/0501191 ★ Serpico, PRD (06) ★ Xing, PRD (06) ★ Xing, Zhou, PRD (06) ★ Winter, PRD (06) ★ Athar et al, MPLA (06) General sources and contaminations (Parametrization, Xing & Zhou 06) active-sterile neutrino mixing & oscillation ★ Rodejohann, JCAP (07) ★ Majumdar, Ghosal, PRD (07) ★ Xing, NPB (Proc. Suppl.) (07) ★ Blum, Nir, Waxman, arXiv:0706.2070 ★ Lipari et al, PRD (07) ★ Meloni, Ohlsson, PRD (07) ★ Awasthi, Choubey, PRD (07) ★ Hwang, Kim, arXiv:0711.3122 ★ Xing, NPB (Proc. Suppl.) (08) ★ Pakvasa et al, JHEP (08) ★ Choubey, Niro, Rodejohann, PRD (08) ★Pakvasa, arXiv:0803.1701 ★ Maltoni, Winter, JEHP (08) ★ Xing, Zhou, PLB (08) ★ …… - symmetry breaking effects and CP phase  -decays Test of CPT, Q-coherence, unitarity, … Can -telescopes (IceCube, KM3NeT) do …?

  10. Ultrahigh-energy neutrinos: Flavor Transitions The transitional probability with unitary mixing matrix The typical distance for AGN: L~100 Mpc, while the oscillation length After many oscillations, the averaged transition probabilities given as The oscillatory terms disappear, also applicable to anti-neutrino oscillations

  11. Part I: Determination of the Initial Flavor Composition • Conventional (or standard) source: ’s are generated from ppor pcollisions. UHE ’s produced from the decays of ’s and the secondary ’s. • Postulated neutron source (Crocker et al 2005): UHE neutrinos are produced from the beta decay of neutrons. • Muon-damped source(Rachen, Meszaros 1998): Source is optically thick to ’s, not to ’s, different lifetimes. With the initial neutrino fluxes, the fluxes at the neutrino telescope:

  12. Part I: Determination of the Initial Flavor Composition Parametrization[Xing, Zhou, Phys. Rev. D 74, 013010 (2006)]: where characterizes the small amount of tau ’s at the source [e.g., from Ds- or B-meson decays (Learned, Pakvasa 1995)]. • Conventional (or standard) source: • Postulated neutron source: • Possible muon-damped source: Dominant contribution of charm at EHE: [Enberg, Reno, Sarcevic, arXiv:0808.2807[hep-ph]

  13. Part I: Determination of the Initial Flavor Composition Determination of the source parameters Define the working observables: Only two independent: Sources: Transition Probabilities

  14. Part I: Determination of the Initial Flavor Composition Question:Is it possible to determine the flavor distribution at sources? A global analysis of neutrino oscillation data: [Strumia &Vissani, 2006] Transition Probabilities [Xing, Zhou, PRD, 06]

  15. Part I: Determination of the Initial Flavor Composition Numerical Analysis: Large uncertainties from oscillation data: mixing angles and Dirac CP phase

  16. Part II: Unitary vs. Non-unitary Neutrino Mixing Matrix vs. CPC: CPV: Q:What are the sufficient and necessary conditions for flavor democracy? Given the conventional source A:The unique parametrization-independent conditions [Xing, Zhou, 08] In the standard parametrization: To measure the neutrino mixing parameters at neutrino telescopes

  17. Part II: Unitary vs. Non-unitary Neutrino Mixing Matrix Minimal Unitarity Violation(Antusch et al 07): -Only 3 light neutrino species are considered; -Sources of non-unitarity only in the SM Lagrangian which involves neutrinos. e.g., TeV Seesaw Models: Heavy Majorana fermions Neutrino mixing matrix is NON-unitary invarious neutrino mass models Constraints from experimental data: neutrino oscillations, W&Z decays, rare lepton-flavor-violating decays, lepton universality tests, …… Full parameterization of 3x3 non-unitary matrix: [Xing, PLB, 2008] A:~ Identity matrix V0:Unitary matrix

  18. Part II: Unitary vs. Non-unitary Neutrino Mixing Matrix Non-unitary deviation from TB Mixing: [Xing, Zhou, PLB, 08; Luo, PRD, 08] The non-unitary neutrino mixing matrix with additional 6 angles&6 phases The flavor distribution of neutrino fluxes at the detectors reads Conventional sources • Breaking of flavor democracy • TermsWi dominate over ReX • Effects at the percent level

  19. Part II: Unitary vs. Non-unitary Neutrino Mixing Matrix si4 ≤ 0.1 s14 s24 ≤ 7.0 x10-5 Free relative phase Experimental Constraints Working Observables Minimal scenario The total flux of cosmic neutrinos is not conserved Observable? Calibration by the flux of TeV photons

  20. Concluding Remarks 1. Neutrinos from the Sun and Supernova explosion have been observed, and have greatly improved our understanding of the stellar evolution and the properties of themselves. High energy neutrinos from other cosmic sources are promising to be discovered. 2. If neutrino mixing parameters are precisely measured in the terrestrial neutrino experiments, the flavor composition of cosmic neutrinos at the sources can be determined. It may help us locate the cosmic accelerators and learn more about the astrophysical processes at the sources. 3. On the other hand, if the sources are well known, UHE neutrinos may help us understand their intrinsic properties and test various scenarios of physics beyond the standard model. 4. The new generation of neutrino telescopes may serve as a powerful tool for us to go further both in astrophysics and particle physics. Thanks

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