Probing the Broken - Symmetry with Neutrino Telescopes Zhi-zhong Xing (IHEP, Beijing) NOW 2006 Conca Specchiulla, September 9 - 16, 2006 Z.Z.X. hep-ph/0605219 Phys. Rev. D 74 (2006) 013009

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

UHE Neutrinos

High-energy Cosmic Messengers Neutrino (1e:2) Light absorbed Proton scattered by magnetic field (1e:1:1) CMB 1 2 3 4 5 6 7 8 9 10 11 12 13 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

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

How to identify Neutrino Flavors? Halzen, astro-ph/0602132 Learned & Pakvasa 95 17m

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

Incomplete List of Relevant Works ■ Learned & Pakvasa, APP 3, 267 (1995) ★ Athar et al, PRD 62, 103007 (2000) ★ Bento et al, PLB 476, 205 (2000) ★ Gounaris & Moultaka, hep-ph/0212110 ★ Barenboim & Quigg, PRD 67, 073024 (2003) ★ Beacom et al, PRD 68, 093005 (2003) ★ Keraenen et al, PLB 574, 162 (2003) ★ Beacom et al, PRD 69, 017303 (2004) ★ Serpico & Kachelriess, PRL 94, 211102 (2005) ★ Bhattacharjee & Gupta, hep-ph/0501191 ★ Serpico, PRD 73, 047301 (2006) ● Xing, PRD 74, 013009 (2006) ● Xing & Zhou, PRD 74, 013010 (2006) ★ Winter, PRD 74, 033015 (2006) ■ Fogli et al, hep-ph/0608321 ★ Majumdar & Ghosal, hep-ph/0608334

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

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

Broken - Symmetry

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

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

Correction to the Naïve Ratio 1:1:1 The allowed range of  : ZZX: hep-ph/0605219 The bound appears when two small - symmetry breaking parameters turn to take their maximal (upper limit) values

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/0604191)

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.

Concluding Remarks

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) 013010 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

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

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