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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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slide1

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

slide2

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?

slide3

Ultrahigh-energy neutrinos: Astrophysical Sources

Flux of Cosmic Rays

Pierre Auger, PRL, 08

HiRes, PRL, 08

Observation of GZK cutoff ?

Existence of UHE Neutrinos?

slide5

Ultrahigh-energy neutrinos: Challenges and Opportunities

Neutrino Telescope: AMANDA

km3-scale NT: IceCube

slide6

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

slide7

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
slide8

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).

slide9

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 …?

slide10

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

slide11

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:

slide12

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]

slide13

Part I: Determination of the Initial Flavor Composition

Determination of the source parameters

Define the working observables:

Only two independent:

Sources:

Transition Probabilities

slide14

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]

slide15

Part I: Determination of the Initial Flavor Composition

Numerical Analysis:

Large uncertainties from oscillation data: mixing angles and Dirac CP phase

slide16

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

slide17

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

slide18

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
slide19

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

slide20

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