radio detection of uhe neutrinos e. zas, usc leeds july 23 rd 2004
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Radio detection of UHE neutrinos
E. Zas, USC
Leeds July 23rd 2004
EZ Leeds 2004 Radio Detection 2
Contents:
•Why UHE
•How does it work?
•What are the advantages?
•Which experiments
J. Alavarez-MuñizF. HalzenE. MarquesT. StanevR. VazquezE. Zas
EZ Leeds 2004 Radio Detection 3
Neutrino - Cosmic Ray connection
• CR knwn to exist with E>1020 eV
• UHECR mechanisms produce • By fragmentation [“Top Down” Z-burst ...]
• By interaction [Fermi]• With matter
• With radiationInteractions with CMB => GZK neutrinos
There must be UHE neutrinos!
EZ Leeds 2004 Radio Detection 4
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
+
pe e+
::e
2 : 4:2
( ) ( )
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•GZK neutrino flux depends on:
•Cosmic Ray spectrum
•Source distribution
•Maximum redshift
•Source evolution
Target: The GZK -spectrum
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CR
Flu
x / R
efer
ence
Flu
x
D.Gonzalez,RAV,EZ (in prep)
p-spectrum afterCMB interactions
ONE source onlyUniform Distribution UD + strong evolution
____________
E-2
EZ Leeds 2004 Radio Detection 7
CR
Flu
x / R
efer
ence
Flu
xE-2
D.Gonzalez,RAV,EZ (in prep)
_________U Dis+evol_________Unif Distr_________one source
EZ Leeds 2004 Radio Detection 8
P &
-F
lux
/ Ref
eren
ce F
lux
D.Gonzalez,RAV,EZ (in prep)
_________U Dis+evol_________Unif Distr_________one source
E-2
EZ Leeds 2004 Radio Detection 9
Radio pulses from showers: Why?
Coherent
Radiation
Radio wavelength Emission length
wl
• SIGNAL POWERElectric Field ~ Q
• STABILITYTo shower fluctuations
• INFORMATION• Spatial distribution
• Frequency Spectrum
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Cherenkov in radio (Askary’an 1960)
Wavelength (>> l,w e- and e+ cancel !!
But what about excess Ne--Ne+?
•e, interactions have charge symmetry•But matter only has electrons!!
•Interaction with matter electrons
Askary’an predicted ~10% charge excess
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Processes contributing to the excess charge
Compton e-
Annihilation
media electrons
e-
e+
Möller
e-
e-
Bhabha
e-
e+
e-
e+
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ZHS:FH,TS,EZ, PRD(91)
ICE
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)(
11)(
)()(
vki
eve
RiE
tvkiphaseoveralli
Calculate radio pulse interference
tn
tntv
)cos1(
)cos1(sin
tracklength
if =0 or =c
or t=0tv
(Fraunhofer limit)
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• |E| Ne-Ne+ Scaling
• Ne-Ne+ ESHOW
Signal Power
Radio Pulse Power |E|2 E2SHOW
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The slit diffraction analogy
If current is “thin”:
ikzezdzQR
iE )()(
cnk
)cos1(
Kind of FT with
EZ Leeds 2004 Radio Detection 22
• c
Stability
)(zdzQE
(because k=0)
EZ Leeds 2004 Radio Detection 23
•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?
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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
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Askary’an effect confirmed: SLAC
P.Gorham, D.Saltzberg et al. PRL (2000)
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Coherence! |E| Esh
|E()| spectral agreement
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• 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:
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Both Cosmic Ray & -detector
CR
Different geometries
EZ Leeds 2004 Radio Detection 33
EZ Leeds 2004 Radio Detection 34Complex acceptance geometry
MOONJAlvarez Muñiz
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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
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P. Gorham, et al. astro-ph/0310232
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GZ
K
-Flu
xE-2
D.Gonzalez,RAV,EZ (in prep)
_________U Dis+evol_________Unif Distr_________one source