CURRENT HIGH ENERGY NEUTRINO DETECTION EFFORTS

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CURRENT HIGH ENERGY NEUTRINO DETECTION EFFORTS
BAIKAL
ANTARES
NESTOR
KAMCHATKA
SALSA
SADCO
GLUE
AUTEC
AMANDA/ICECUBE
RICE, ANITA
OPTICAL RADIO ACOUSTIC
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• HIGH ENERGY NEUTRINO DETECTION METHODS - II
• through
• radio emission
• acoustic emission

e, m, t
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RADIO DETECTION OF EM SHOWERS
EM cascades develop a 15-30 net negative charge
asymmetry (Askariyan effect) e
annihilations in the medium and Compton
knock-off of atomic e- Extended system ?
coherent emission Scale shower transverse
size, cm Cherenkov emission in the range
100 MHz-1GHz ( n c/l ) Radiated power
En2 Radio emission exceeds optical EM
radiation at 10 PeV Becomes completely dominant
at EeV energies

-
ns pulse, Ep-p 200 V/m!
Effect confirmed in 2000 in SLAC. gs on silica
sand target
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• RADIO DETECTION OF EM SHOWERS

• Natural salt shows good transparency
• to radio frequencies
• Existing mines provide easy access sites for
  deployment of antenna arrays
• Usable frequency range from few MHz to 10 GHz
• Natural salt mines can be turned into
  neutrino detectors!

radio frequency attenuation lengths (m)
Ice is also extremely RF transparent in
the interesting MHz -GHz range
Antarctica can be turned into a neutrino detector!
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• RADIO DETECTION OF EM SHOWERS RICE
• ( Radio Ice Cherenkov Experiment)

• 18 antennas deployed
• between 120-250 m at the
• South Pole (many using
• AMANDA holes)
• Taking data since 1999
• Attenuation length of radio
• in ice 1Km each antenna
• probes a big volume

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• RADIO DETECTION OF EM SHOWERS SALSA
• ( SALt dome Shower Array)

• Location Hockley mine, US
• Cluster of 6 antennas
• Insert into shallow boreholes within
• mine at 40 m separation
• Measurements compatible with
• gt200 m attenuation length
• Reach an effective volume of Km3
  at EeV energies
• Existing seismic system could provide fiber link
  to surface

Salt
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• RADIO DETECTION OF EM SHOWERS ANITA
• 
  (
  ANtarctic Impulsive Transient Antenna)

Go to high atmosphere to view a HUGE detection
area 1.5M Km2 Antenna system _at_ 37 km altitude
circumnavigating Antarctica Neutrino E
threshold EeV flight in dec 2006
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• RADIO DETECTION OF EM SHOWERS GLUE
• ( Goldstone Lunar Ultra high energy neutrino
  Experiment)

• Look for RF pulses from the Moon
• Utilize Deep Space NASA telecom 70m antenna
  (DSS14) for lunar RF pulse search-- fill gaps in
  antenna operations schedule
• First observations late 1998
• 1999 add 2nd 34 m fiber-linked
• antenna DSS13 in coincidence
• 2000 20 hours livetime acquired since July

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• ACOUSTIC DETECTION OF ELECTROMANETIC SHOWERS

• EM showers of particles produce localized heating
  in the medium
• Volume expansion generates pressure wave sound
• 1020 eV shower produces a pulse of mPa and ms
  duration
• perpendicular to the shower development axis
• Typical frequencies few kHz
• It can use water (as opposed to radio technique)
  cheap to
• instrument big volumes

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• ACOUSTIC DETECTION OF EM SHOWERS AUTEC

• Located at the Atlantic Undersea Test and
• Evaluation Center of the US navy in
• Bahamas
• Use existing military sonar equipment
• in parasite mode
• Existing array covers 250 km2
• 52 Hydrophones deployed between
• 1400-1600 m in a triangular lattice
• Bandwidths few kHz
• Accurate GPS time stamp
• Background noise studiessignal
• processing tested

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acoustic
underground water/ice
radio
Sensitive only to EM showers High energy
thresholds Cheap
Limited by absorption/ scattering of
Cherenkov photons Cost
Limited by physical size
Detect atmospheric Solar
Detect extragalactic
Detect extragalactic gt GKZ limit
logE/eV
6 9 12
15 18 21
(MeV GeV TeV
PeV EeV ZeV)
Detector size/eff. detection volume
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Neutrinos from dark matter
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• Neutrinos from dark matter in the Universe

• We know dark matter exists from
• Rotation curves of galaxies
• Motions of clusters of galaxies
• Gravitational lensing
• Studies of the cosmic microwave background
  temperature fluctuations

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Dark matter candidates

• Neutrinos we know they have mass, not much, but
  there are many of them. However, not enough to
  explain the missing mass.
• Things that do not shine MACHOs (Massive
  Compact Halo Objects), dead stars, unobserved
  planets, cold gas clouds
• ? baryonic matter (made of usual stuff p
  and n)
• Not enough big bang nucleosynthesis puts a very
  precise limit on how many baryons there are in
  the Universe. Otherwise the amount of observed
  primordial light elements (D, He, Li) can not be
  explained
• Solution Non-baryonic matter
• This solution has a problem non-baryonic matter
  has never been observed.
• The particles proposed as candidates are
  theoretical predictions of a model not yet
  verified, Supersymmetry.

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Supersymmetry

• An extension of the Standard Model
• Introduces (predicts) many new particles (one per
  existing elementary particles, differing in spin
  by 1/2)
• One has to be stable, with mgt40 GeV (from
  accelerator searches)
• and mlt300 TeV (from theoretical
  constrains)
• Is a good candidate for dark matter neutralino,
  c
• It is produced in the big bang and a sea of
  them remains as relics
• They interact only weakly and gravitationally
• Can be gravitationally bound in the halos of
  galaxies and be further trapped in heavy bodies
  Sun, Earth
• Increased concentration ? annihilation cc ?
  something ?ns

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Sun
interactions
ns as decay
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Neutrinos from cs

• Neutrinos from neutralino annihilation
• Would show strong directionality Sun, center of
  the Earth, or halo of the galaxy (uniform, with
  no connection to known objects)
• Would have energies of about the neutralino rest
  mass
• Searches (by AMANDA and Baikal) have given
  negative results so far

there are other searches direct, which look
for the recoil of a nucleus in a target from an
interactions with a c
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