1. Probing the Broken - Symmetry with Neutrino Telescopes
Zhi-zhong Xing
(IHEP, Beijing)
NOW 2006
Conca Specchiulla, September , 2006
Z.Z.X. hep-ph/ Phys. Rev. D 74 (2006)

2. Outline 1. UHE Neutrinos: the Oscillating Messenger
2. -Telescope as a Probe of - Symmetry
3. Further Discussion and Concluding Remarks

3. UHE Neutrinos

4. High-energy Cosmic Messengers
Neutrino (1e:2)
Light absorbed
Proton scattered
by magnetic field
(1e:1:1)
CMB
neutrino
proton
photon
Log E (GeV)
TeV
PeV
EeV
ZeV
“somebody really really wise” (Tom Weiler at Neutrino 2006)
straight-line propagation, unabsorbed, but difficult to detect
a sufficiently large neutrino detector --- neutrino telescopes

5. Optical Cherencov -Telescopes
NESTOR
Pylos, Greece
ANTARES
La-Seyne-sur-Mer, France
NEMO
Catania, Italy
BAIKAL
Russia
AMANDA and IceCube
South Pole, Antarctica

6. How to identify Neutrino Flavors?
Halzen, astro-ph/
Learned & Pakvasa 95
17m

7. The Starting Point of View
Point Two
Point One
First of all, discover something
Next, measure it precisely
Our concern: Initial flavor composition of UHE neutrino fluxes and their oscillations

8. Incomplete List of Relevant Works
■ Learned & Pakvasa, APP 3, 267 (1995)
★ Athar et al, PRD 62, (2000)
★ Bento et al, PLB 476, 205 (2000)
★ Gounaris & Moultaka, hep-ph/
★ Barenboim & Quigg, PRD 67, (2003)
★ Beacom et al, PRD 68, (2003)
★ Keraenen et al, PLB 574, 162 (2003)
★ Beacom et al, PRD 69, (2004)
★ Serpico & Kachelriess, PRL 94, (2005)
★ Bhattacharjee & Gupta, hep-ph/
★ Serpico, PRD 73, (2006)
● Xing, PRD 74, (2006)
● Xing & Zhou, PRD 74, (2006)
★ Winter, PRD 74, (2006)
■ Fogli et al, hep-ph/
★ Majumdar & Ghosal, hep-ph/

9. UHE Neutrino Oscillations
The transition probability:
For
, the oscillation length in vacuum
The expected sources (AGNs etc) at typical distances: ~100 Mpc
So after many oscillations, the averaged transition probability of UHE neutrinos is
atmosphere

10. Data and Approximation
A global analysis of current neutrino oscillation data yields
- symmetry
at 99% C.L.
(Strumia & Vissani 06)

11. Broken - Symmetry

12. Conventional UHE Neutrino Source
 High-energy pp collisions:
 charged poins
 muon and electron neutrinos
 High-energy p collisions:
There is no production of electron antineutrino, because the produced neutrons can escape the source before decaying (M. Ahlers et al, 05)
In either case, the sum of neutrinos and antineutrinos

13. Effect of - Symmetry Breaking
At the detectors of neutrino telescopes:
Two small parameters to measure tiny - symmetry breaking:

14. Correction to the Naïve Ratio 1:1:1
The allowed range of  :
ZZX: hep-ph/
The bound appears when two small - symmetry breaking parameters turn to take their maximal (upper limit) values

15. Signals at Neutrino Telescopes
Yes, if the following relation is
by accident satisfied:
Can =0 nontrivially hold?
A signal of   0 is in general expected, however.
The working observables:
It makes sense to consider the complementarity between neutrino telescopes and terrestrial neutrino oscillation experiments, in order to finally pin down the parameters of neutrino mixing and CP violation.
(Winter, hep-ph/ )

16. Glashow Resonance
A novel possibility to detect the UHE electron anti-neutrino flux from distant astrophysical sources (S.L. Glashow 60):
A neutrino telescope may measure: (a) the GR-mediated electron anti-neutrino events; (b) the muon neutrino  muon anti-neutrino charged-current interaction events in the vicinity, to extract
Comment 1: it is possible to probe the - symmetry breaking;
Comment 2: it is likely to probe the solar neutrino mixing angle.

17. Concluding Remarks

18. Do Flavor Physics with -Telescopes
The astrophysical sources of UHE neutrinos: puzzles
Do ultra-long baseline & ultra-high energy neutrino oscillation experiments with ultra-large -telescopes?
Neutrino telescopes can do this, at least in principle
The initial flavor composition of UHE neutrino fluxes should be determined experimentally
Z.Z.X. & S.Zhou: Phys. Rev. D 74 (2006)
Given a well-understood source, a neutrino telescope can help determine the neutrino mixing parameters
There is a lot of important complementarity between terrestrial neutrino experiments & neutrino telescopes

19. Search for ’s at Wonderful Places
The South Pole
The Mediterranean Sea

20. Thanks a lot Last but not Least Source Detector
Unless there is an exact - flavor symmetry!
Thanks a lot