1. Earth-skimming UHE  at the Fluorescence Detector of Pierre Auger Observatory astro-ph/0407638 in collaboration with C. Aramo, A. Insolia, A. Leonardi, L. Perrone, O. Pisanti and D.V. Semikoz Now2004 G. Miele Università di Napoli “Federico II”

3. Terra Incognita II - Landscape & habitants Pampa Amarilla (Argentina)– Auger site

4. High Energy Neutrino Physics The Pierre Auger Giant Array Observatory

5. 5

7. Auger numbers 3000 km 2 area at an altitude of  1300 m a.s.l (Mendoza, Argentina); SD detector: 1600 Čerenkov light detectors with a 1.5 km spacing – (more than 400 already operating); FD detector: 13000 photomultipliers for 24 fluorescence telescopes located in 4 sites (duty cycle of 10%) – 12 already operating ; 3000 events yr -1 expected with energies above 10 19 eV and 30 events yr -1 above 10 20 eV; http://www.auger.org

8. Neutrino detection in Auger N eutrino initiated showers (HAS) have in principle different signatures from the hadronic ones. But... Are fluxes really detectable in Auger? Travelling an atmospheric depth up to 360 m water equivalent less than 1/1000 of crossing neutrinos will interact. Thus atmosphere is almost transparent for them. X. Bertou, P. Billoir, and S. Coutu 01

9. Fargion astro-ph/9704205, Halzen, Saltzberg 98 Becattini, Bottai 99,00 Iyer Dutta, Reno, Sarcevic 00 Bertou et al. astro-ph/0104452, Guerard ICRC01 Kusenko and Weiler, hep-ph/0106071 Feng et al. hep-ph/0105067 Beacom, Crotty, Kolb PRD66 021302 (2002) Tau neutrinos may have a chance! e ± and  ± are absorbed  ± can emerge

10. Earth-Skimming + Regenerated UHE  UHE  from mountains The  chances 10

11. Earth-skimming UHE   travelling chords ~ interaction lenght EeV neutrinos have interaction lenght ~ 500 Km water equivalent in rock J.L. Feng et al. hep-ph/0105067

12. Upgoing  shower (seen by Los Leones telescope)

13. Neutrino propagation in the Earth Iyer Dutta, Reno, Sarcevic PRD66 077302 (2002) One can expand the above set of equations in G F 2

14. The kernel K(E, E ,  ) gives the probability that: 1. the  survives for some distance z in the Earth ( P a ) 2.    in z, z+d z ( P b ) 3. the  comes out from the Earth before decaying ( P c ) 4. the energy of  be E  for a given E ( P d ) 5. the  decays producing a detectable shower ( P e ) The number of Up-going  -induced showers in unit of t

15. Regenerated UHE  Second order contribution, not relevant for final  above the FD threshold (10 18 eV) J.F. Beacom, P. Crotty, and E.W. Kolb 15

16. But we need: Neutrino fluxes Neutrino-Nucleon cross sections (   ) Inelasticity parameter A reliable parameterization of  energy loss in rock Two kinds of approach: Monte Carlo simulations (complex tool) Transport equations (perturbative but average approach)

17. Cosmogenic Neutrinos (Bottom-Up) (surely there!) Z-burst (quite unlikely!) Neutrinos from decay of massive relics (Top- Down) (still not excluded by experiment) Exotic Hadrons (we hope so!) Several kinds of models Neutrino Fluxes

18. Transport equations which evolve the spectra of nucleons, , e, neutrinos and antineutrinos, assuming for proton the following injection spectrum per comoving volume Kalashev et al. 01, 02 Semikoz & Sigl, hep-ph/0309328 Cosmogenic Neutrinos

19. Cosmogenic neutrino flux per flavour (red thick line) produced by primary proton flux normalized with AGASA and HiRes data. The UHECR sources are assumed to inject a proton spectrum  E -1 up to 2·10 22 eV with luminosity  (1 + z) 3 up to z = 2. Bottom-up Kalashev et al. 01, 02 Semikoz & Sigl, hep-ph/0309328

20. Kalashev, Kuzmin & Semikoz, 99 and 00 In this analysis 20

21. Predictions for a top-down model with m X = 2·10 13 GeV Top-down Kalashev et al. 01, 02 Semikoz & Sigl, hep-ph/0309328

22. Top-Down and New hadrons Neutrinos

23. In the cross-section the parton distribution functions (PDF’s) enter as unknown quantities, which have to be measured from deep-inelastic experiments. For x < 10 -5 the uncertainty is dominated by the lack of knowledge of PDF. Neutrino-Nucleon cross section Gandhi, Quigg, Reno & Sarcevic ’98 approach, but updated PDF’s

24. the different approaches give very similar cross- sections for the interesting energy range For E =10 18 eV KSM 1.04 10 -32 cm 2 GRV98 1.16 10 -32 cm 2 CTEQ4 –DIS 1.02 10 -32 cm 2 Let us consider for example  CC ( N) For E =10 21 eV KSM 1.17 10 -31 cm 2 GRV98 1.51 10 -31 cm 2 CTEQ4 –DIS 1.26 10 -31 cm 2

25. CTEQ6 CTEQ4 Log 10 E (GeV ) A good new ! 25

26. Inelasticity parameter y CC =1 -E  /E is a function of energy

27. Tau energy loss Koukolin & Petrukhin 71 Andreev & Bugaev 97 Bugaev & Shlepin 03

29. By using the previous results one gets A(E ) is the effective aperture

30. Not far from X. Bertou, P. Billoir, and S. Coutu 01 30

32.  max is the angle with respect to the horizontal for which is maximum the number of events

33. Numerical Results for PAO-FD # of events per year for  CC ( N) ( CTEQ6 – DIS) GZK-WB 0.02 GZK-L 0.04 GZK-H 0.09 TD0.11 NH0.25 2 x  CC ( N) 0.13 0.5 x  CC ( N) 0.5 If Auger South + North in 5 years one gains a factor 10. So we could be just at threshold! What about SD?

34. Conclusions The prediction for the # of events is strongly dependent on the -flux. Unavoidable! The computation of Earth-skimming events, seen by FD detector, seems to confirm the critical dependence on  CC ( N). The available DEM of a large area around Malargüe allows for a realistic Montecarlo simulation of  -induced events coming from mountains, but in order to perform a reliable simulation we need a good knowledge of very inclined showers and a their detectability by FD and/or SD.