1. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 Probing Neutrino Mixing and Unitarity Violation at Neutrino Telescopes Shun Zhou IHEP, CAS, Beijing TeV Particle Astrophysics, 24-28 September, 2008, Beijing, China Based on our recent works: Z.Z. Xing and S. Zhou, PLB (2008); PRD (2006). 1.UHE Neutrinos: Challenges and Opportunities 2.Determination of the Initial Flavor Composition 3.Unitary versus Non-unitary Neutrino Mixing 4.Concluding Remarks Outline

2. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 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? - Intrinsic Properties?

3. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 Ultrahigh-energy neutrinos: Astrophysical Sources HiRes, PRL, 08 Pierre Auger, PRL, 08 Flux of Cosmic Rays Observation of GZK cutoff ? Existence of UHE Neutrinos?

4. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 Ultrahigh-energy neutrinos: Astrophysical Sources AGN GRB SNR  p e+e+  _ DM

5. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 Ultrahigh-energy neutrinos: Challenges and Opportunities Neutrino Telescope: AMANDAkm 3 -scale NT: IceCube

6. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 BAIKAL Russia NESTOR Pylos, Greece ANTARES La-Seyne-sur-Mer, France NEMO Catania, Italy AMANDA and IceCube South Pole, Antarctica Ultrahigh-energy neutrinos: Challenges and Opportunities KM3NeT

7. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 Ultrahigh-energy neutrinos: Challenges and Opportunities 375 TeV10 TeV 10 4 TeV Distinct signals for different flavors: 1.Particle physics by using the flavors, given the sources 2.Probe sources by using the flavors, given ν properties

8. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 Ultrahigh-energy neutrinos: Unique Opportunity Neutrino (1 e :2  ) Light absorbed Proton scattered by magnetic field (1 e :1  :1  ) CMB 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 UHE p +p or p +  collisions. Naïve expectation: ultra-long-baseline UHE cosmic -oscillations (Learned, Pakvasa 95).

9. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 ■ 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) Ultrahigh-energy neutrinos: Unique Opportunity ★ 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) ★ …… General sources and contaminations (Parametrization, Xing & Zhou 06) active-sterile neutrino mixing & oscillation  -  symmetry breaking effects and CP phase  Test of CPT, Q-coherence, unitarity, … -decays Can -telescopes (IceCube, KM3NeT) do …?

10. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 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. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 Part I: Determination of the Initial Flavor Composition Conventional (or standard) source:  ’s are generated from pp or 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. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 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 D s - 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. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 Part I: Determination of the Initial Flavor Composition Define the working observables: Only two independent: Determination of the source parameters Sources: Transition Probabilities

14. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 Part I: Determination of the Initial Flavor Composition Question: Is it possible to determine the flavor distribution at sources? Transition Probabilities [Xing, Zhou, PRD, 06] A global analysis of neutrino oscillation data: [Strumia & Vissani, 2006]

15. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 Part I: Determination of the Initial Flavor Composition Numerical Analysis: Large uncertainties from oscillation data: mixing angles and Dirac CP phase

16. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 Part II: Unitary vs. Non-unitary Neutrino Mixing Matrix Given the conventional source Q: What are the sufficient and necessary conditions for flavor democracy? vs. A: The unique parametrization-independent conditions [Xing, Zhou, 08] CPC : CPV : In the standard parametrization: To measure the neutrino mixing parameters at neutrino telescopes

17. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 Part II: Unitary vs. Non-unitary Neutrino Mixing Matrix Neutrino mixing matrix is NON-unitary in various neutrino mass models 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 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 V 0 : Unitary matrix

18. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 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 1.Breaking of flavor democracy 2.Terms W i dominate over ReX 3.Effects at the percent level Conventional sources

19. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 Part II: Unitary vs. Non-unitary Neutrino Mixing Matrix Experimental Constraints Minimal scenario Working Observables The total flux of cosmic neutrinos is not conserved s i4 ≤ 0.1 s 14 s 24 ≤ 7.0 x10 -5 Free relative phase Observable? Calibration by the flux of TeV photons

20. Shun Zhou, IHEP, Beijing, China TeVPA, 24-28 September, 2008 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