High-Energy Neutrino Astrophysics

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High-Energy Neutrino Astrophysics

• Tom Weiler
• Vanderbilt University

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The Cosmic Ray Timeline
 
 
1912 Hess (Austrian) balloons to 5km, his sparks
increase also sees no change during solar
eclipse 1929 Cloud chambers, and the birth of
particle physics   1933 Andersons
positron Kunzes muon (Rostock)   1937 Andersons
muon   1938 Augers remarkable PeV
air-shower   1949-54 Fermis Doppler
acceleration via magnetized shocks   1966 3K CMB
discovered GZK predict cutoff at 5x1019
eV (But Linsley already reported (PRL) event at
1020 eV)   1987 IMB/Kamiokande neutrinos from
SN87a  
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AUGERs key discovery
      Auger, in 1938, separated two particle
counters by a km high in the Swiss Alps
(Jungfrau, near Bern), he discovered coincident
signals.   He calculated ETOT to be about 1015
eV. His inference was correct.   His energy was
107 times the prior record event, And now thought
to be typical of emission from a SN remnant.
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1991 Flys Eye reports 3x1020 eV, with
proton-like profile Akeno/AGASA Xpt
begins  mid-90s DUMAND taken off life-support
Baikal continues  90s SuperK neutrinos from the
sun (directional astro)  1996 AGASA reports event
clustering within 2.50 ang. resn and F(E ?
1020 eV) 1/km2/century, with shower diameter
5km, N(e?) 1011  2000 20 events at and above
1020 eV  2001 HiRes withdraws 7 events AGASA
adds 6 (from ?z gt 45o) And the controversy has
begun! Importantly, Auger gets first
light  2002 AMANDA pushes to 1014 eV thru-Earth
neutrinos   2005 Auger Observatory data
expected  2008 Extreme Universe Space
Observatory (EUSO) ?
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CR Spectrum above a TeV
from Tom Gaisser
VLHC (100 TeV)2
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Highest Energy Event
The CR record energy is 3x1020 eV (0.3
ZeV).   Found by Flys Eye a decade ago (they got
lucky!).   This is truly a macroscopic
energy   3x1020 eV 50 Joules   equivalent to a
Roger Clemens fastball, a Tiger Woods tee
shot, a Pete Sampras tennis serve, Or a
speeding bullet.   (Also to 12 Calories, which
heats a gram of water by 12oC)
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3 x1020 eV macroscopic 50 Joules
Clemens does this with 1027 nucleons Nature does
this with one nucleon, 1027 times more efficient
!
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Flys Eye 3x1020 eV event (1992)
100 billion ee- pairs at xmax 800 g/cm2
This longitudinal profile is consistent with a
primary proton, but not with a primary photon
Disfavors local top-down sources such as
massive Particle DK, topo-defects, Z-bursts, etc.
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EE Neutrinos are young
Liberated at TMev, t 1 sec Depends on energy
(Lorentz boost)
Consider a 1020 eV neutrino. Lorentz factor
1021 for mn 0.1 eV. Age of Uni is 1018
sec, But age of n is 1018/1021 sec 1
millisecond ! And it doesnt even see the stream
of radiation rushing past it untouched !
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Hillas Plot -- coherence length B x L
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Size matters
EUSO 300 x AGASA 10 x Auger EUSO
(Instantaneous) 3000 x AGASA 100 x Auger
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Extreme Universe Space Observatory

• EUSO onboard the ISS (Or Not!)
• 2012 Hundredth anniversary of Hess
• EUSO finishes three-year data-taking

 

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clear moonless nights
Or New York State power blackout
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Orbiting Wide-angle Lens (OWL)
3000 events/year above 1020eV and UHE
Neutrinos!
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n HAS event rate is small
e.g. FCR at 1020 eV implies 10-2 events/yr
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AGASA Spectrum EeV to ZeV
AGASA, July 2002
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Greisen-Zatsepin-Kuzmin and the Cosmic-Ray Wall
Photo-pion production off CMB p?cmb? ? ?p/n?
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HiRes vs. AGASA UHE spectrum
FlysEye event goes here
discovery
opportunity
GZK recovery ? Z-burst uncovery ?
EUSO reach x 103 better
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AGASA hot-spots -- Data
red E gt 4 1019 eV green E gt 1020 eV
Cluster Component E -1.80.5
Neutrinos will point better
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AGASA hot-spots -- numbers
Within 2.5 degree circles, AGASA identifies six
doublet, one triplet, Out of 57 events Opening
the angle to just 2.6 degrees, AGASA identifies
seven doublets, two triplets Haverah Park
contributes two more paired events in AGASA
directions. NOT corroborated by HiRes.

• Source number N12/2N2 270 to 50,
• weighting with GZK suppression,
• 10-5 /Mpc3 for source density

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Berezinsky et al Xgal proton flux
Mass-composition data (HiRes 2002)
Theory threshold for pg2.7K?pee- and data
(knee) are at 1017.6 eV.

• Xgal proton dominance
• begins at 1018 eV, not 1019 eV !
• Fn 50 x Waxman-Bahcall
• AMANDA/RICE/EAS-sensitive !!
• (AGHW, 2004)

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AMANDA to 100 TeV
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AMANDA/IceCube nm event
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Xgal proton fit ? huge n flux
low Xgal dominance flux, with no evolution
WB fluxes
AGHW, hep-ph/04010003
xp is pion energy/CR energy at source (1 for WB
limit) xz is cosmic evolution factor, 0.6
(no) to 3.0 (SFR)
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Neutrinos versus Cosmic-Rays and Photons
ns come from central engines - near Rs of
massive BHs - even from dense hidden sources
cf. ns vs. gs from the sun ns not affected by
cosmic radiation (except for annihilation
resonance) ns not bent by magnetic fields -
enables neutrino astronomy
Also, besides Energy and Direction, ns carry
flavor
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n diagnostic of astro-enginespp?p vs. pg? p
The process nee-- ? W-- is resonant at 6.4
PeV IceCube will have flavor ID, and DE/E of
25, and so can measure On-Res/Off-Res ratio. pp
make nearly equal pp- ? nmnmnene
2211 ? flavor democracy, ne 1/6 total pg
via D make p ? nmnmne 111 (no ne) ? ne
1/15 total IceCube can resolve this (AGHW,
ArXiv this week)
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The cosmic n flavor-mixing theorem
If theta32 is maximal (it is), And if Re(Ue3) is
minimal (it is), Then nm and nt
equilibrate Further, if initial ne flux is
1/3 (as from pion-muon decay chain), Then all
three flavors equilibrate.
nenmnt 1 1 1 at Earth
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Democracy Broken

• 1. n decay (15 minutes of fame)
• 2. Vacuum resonance
• (MaVaNs, LIV vector)
• 3. Pseudo-Dirac n oscillations
• 4. Source dynamics (w/ Farzan)

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Neutrino Decay -- Models, Signatures, and Reach
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Essentially Guaranteed Xgal n Flux
HiRes 2004 fit Green galactic component Red
Xgal component Evolution parameter 2.8 /- 0.3
Cosmogenic ns Fn(Ep/5/4) Fp(Egt5 1019) x 20
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Essentially GuaranteedXgal Cosmogenic n Flux
Cosmogenic ns Fn(Ep/5/4) Fp(Egt5 1019) x 20
graphs from Semikoz and Sigl
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Essentially Guaranteed High-Energy Galactic
Neutrino Flux
ctn 10 kpc (En / EeV) and En / En Q / mn
0.8 x 10-3 ? En PeV, for En EeV
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More Guaranteed
Comparing to guaranteed cosmogenic flux,
Galactic beam (here) is higher !
Icecube atmos background in 1o circle is just
1.5events/yr, ? 3.5 events offers 95 CL
detection in 1 yr Calculated signal is 4 nm /yr
and 16 nent showers/yr. Conclude that in a few
years, IceCube attains 5s discovery sensitivity
for Fe ? n ? ne ? nm, Providing smoking ice for
GP neutron hypothesis.
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Relic Neutrino density meV astrophysics
Neutrino density from CMB density
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Resonant Neutrino Annihilation Mean-Free-Path
From Fargion, Mele, Salis
l(nn sn)-1 40 DH/h70 (neglecting higher
densities at earlier times)
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Eschers Angels and Devils
 
Looking back, nn(1z)3, And so the absorption is
greatly Enhanced for ns from high-z sources
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Neutrino mass-spectroscopy absorption and
emission
The only possibility to directly infer the relic
n density
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n-mass spectroscopy
zmax2, 5, 20 (top to bottom), n-a2 (bottom-up
acceleration) Eberle, Ringwald, Song, TJW, 2004
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Dips sobering realism

• hidden MX4 1014 and 1016 GeV,
• to explain gtGZK w/ Z-bursts
• mass 0.2 (0.4) eV - dashed (solid)
• Error bars per energy decade, by 2013,
• for flux saturating present limits

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Z-bursts
TJW, 1982 Revival 1997
50 Mpc
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Fitted Z-burst (Emission) Flux


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Nu-mass limit for Z-burst fitted to EECRs

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HiRes vs. AGASA UHE spectrum
FlysEye event goes here
discovery
opportunity
GZK recovery ? Z-burst uncovery ? EUSO reach x 103
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Model Neutrino Fluxes and Future Limits
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View (Japanese) of Earth-Moon System
n
radio Cherenkov
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Summary

• Neutrino Astrophysics
• now in the hands of theorists (speculation) and
  engineers (construction)
• -- soon in the hands of experimenters (real data)
• Promise to reveal
• -- neutrino physics (cross-section, lifetime,
  pseudoDirac)
• -- extreme astrophysics (source dynamics, source
  environment)
• -- cosmology (CnB, Omegas)
• Next ten years will be critical, and, the deities
  willing, fruitful !