2. Radio detection of UHE neutrinos E. Zas, USC Leeds July 23 rd 2004

3. EZ Leeds 2004Radio Detection2 Contents: Why UHE  How does it work? What are the advantages? Which experiments  J. Alavarez-Muñiz F. Halzen E. Marques T. Stanev R. Vazquez E. Zas

4. EZ Leeds 2004Radio Detection3 Neutrino - Cosmic Ray connection CR knwn to exist with E>10 20 eV UHECR mechanisms produce By fragmentation [“Top Down” Z-burst...] By interaction [Fermi] With matter With radiation Interactions with CMB => GZK neutrinos There must be UHE neutrinos!

5. EZ Leeds 2004Radio Detection4 The / p flux ratio: A step towards UHECR source origin Acceleration Fragmentation p+  p+p  +  0 p p :  :  0.09 : 2 : 6 p : 1 : 6 q q X p :  0 :  +/- 0.03 : 0.3 : 0.65    + p  e e +  :   :  e 2 : 4  :  2 ( )

6. EZ Leeds 2004Radio Detection5 GZK neutrino flux depends on: Cosmic Ray spectrum Source distribution Maximum redshift Source evolution Target: The GZK -spectrum

7. EZ Leeds 2004Radio Detection6 CR Flux / Reference Flux D.Gonzalez,RAV,EZ (in prep) p-spectrum after CMB interactions ONE source only Uniform Distribution UD + strong evolution ____ E -2

8. EZ Leeds 2004Radio Detection7 CR Flux / Reference Flux E -2 D.Gonzalez,RAV,EZ (in prep) _________ U Dis+evol _________ Unif Distr _________ one source

9. EZ Leeds 2004Radio Detection8 P & -Flux / Reference Flux D.Gonzalez,RAV,EZ (in prep) _________ U Dis+evol _________ Unif Distr _________ one source E -2

10. EZ Leeds 2004Radio Detection9 Radio pulses from showers: Why? Coherent Radiation Radio wavelength  Emission length w l SIGNAL POWER Electric Field ~ Q STABILITY To shower fluctuations INFORMATION Spatial distribution Frequency Spectrum

11. EZ Leeds 2004Radio Detection10 Cherenkov in radio (Askary’an 1960) Wavelength (  >> l,w e - and e + cancel !! But what about excess N e- -N e+ ? e,  interactions have charge symmetry But matter only has electrons!! Interaction with matter electrons Askary’an predicted ~10% charge excess

12. EZ Leeds 2004Radio Detection11 Processes contributing to the excess charge Compton e -  Annihilation media electrons e - e+e+ Möller e - e-e- Bhabha e - e+e+ e+e+

13. EZ Leeds 2004Radio Detection12 ZHS:FH,TS,EZ, PRD(91) ICE

14. EZ Leeds 2004Radio Detection13 Calculate radio pulse interference tracklength if  =0 or  =  c or  t=0 (Fraunhofer limit)

15. EZ Leeds 2004Radio Detection14

16. EZ Leeds 2004Radio Detection15

17. EZ Leeds 2004Radio Detection16 |E|  N e -N e+ Scaling N e -N e+  E SHOW Signal Power Radio Pulse Power  |E| 2  E 2 SHOW

18. EZ Leeds 2004Radio Detection17

19. EZ Leeds 2004Radio Detection18

20. EZ Leeds 2004Radio Detection19

21. EZ Leeds 2004Radio Detection20

22. EZ Leeds 2004Radio Detection21 The slit diffraction analogy If current is “thin”: Kind of FT with

23. EZ Leeds 2004Radio Detection22  c Stability (because k=0)

24. EZ Leeds 2004Radio Detection23 Calculations of UHE with hybrid code with LPM effect!! Electromagnetic showers  ~E -1/3 above 10 PeV Hadronic Showers hardly any elongation up to 100 EeV showers measure y?

25. EZ Leeds 2004Radio Detection24

26. EZ Leeds 2004Radio Detection25

27. EZ Leeds 2004Radio Detection26

28. EZ Leeds 2004Radio Detection27 Natural transparent media ICE: Antarctica –RICE (array buried) –ANITA (balloon) Greenland –FORTE (satellite) SALT: Domes explored –SALSA MOON REGOLITH: Radiotelescopes –GLUE Radiotelecope array –LUNASKA (ska) ATMOSPHERE: Antenna array –LOFAR Coherent radio detection: -experiments

29. EZ Leeds 2004Radio Detection28 Askary’an effect confirmed: SLAC P.Gorham, D.Saltzberg et al. PRL (2000)

30. EZ Leeds 2004Radio Detection29

31. EZ Leeds 2004Radio Detection30 Coherence! |E|  E sh |E(  )| spectral agreement

32. EZ Leeds 2004Radio Detection31 Radio Technique has an enormous potential To detect highest energy events To get detail about showers To cover large surfaces There are many projects under consideration It is worth pursuing them It is likely that radio provides the next step in the search for UHE radiation Summary and conclusion:

33. EZ Leeds 2004Radio Detection32 Both Cosmic Ray & -detector CR Different geometries

34. EZ Leeds 2004Radio Detection33

35. EZ Leeds 2004Radio Detection34 Complex acceptance geometry MOON JAlvarez Muñiz

36. EZ Leeds 2004Radio Detection35

37. EZ Leeds 2004Radio Detection36 FORTE low frequency search system for transients (weather measurements) central :20-300 MHz bandwith: 22 MHz 5 subbands coincidences Lehtinen, PG et al. astro-ph/0309656 Data Sep 97-Dec 99 2003 BOUND

38. EZ Leeds 2004Radio Detection37

39. EZ Leeds 2004Radio Detection38 P. Gorham, et al. astro-ph/0310232

40. EZ Leeds 2004Radio Detection39

41. EZ Leeds 2004Radio Detection40 NC & CC  or  flavor Hadronic showers (fewer particles) [Double showers (  flavor) ] CC (e-flavor) “Mixed showers” =0.2 => 20% Energy to hadronic shower 80% Energy to electromagnetic shower (Reno talk) ‘s can induce air showers

42. EZ Leeds 2004Radio Detection41 P & -Flux / Reference Flux UD & strong evolution Uniform Distribution ONE source ONLY ______

43. EZ Leeds 2004Radio Detection42 GZK -Flux 1 source injection uniform s. integral s. int. & evolution ______ -spectrum from p interactions with CMB E -2 D.Gonzalez,RAV,EZ (in prep)

44. EZ Leeds 2004Radio Detection43 GZK -Flux E -2 D.Gonzalez,RAV,EZ (in prep) _________ U Dis+evol _________ Unif Distr _________ one source