1. Neutrinos in Astrophysics and Cosmology
Title
TU Darmstadt, Physik Kolloquium, 23. November 2007
Neutrinos in
Astrophysics and Cosmology
Georg Raffelt, Max-Planck-Institut für Physik, München

2. Pauli’s Explanation of the Beta Decay Spectrum (1930)
Wolfgang Pauli
( )
Nobel Prize 1945
“Neutron”
(1930)
“Neutron”
(1930)
“Neutrino”
(E.Fermi)
Niels Bohr:
Energy not conserved
in the quantum domain?

3. Periodic System of Elementary Particles
Quarks
Leptons
Charm
Top
Gravitation
Weak Interaction
Strong Interaction (QCD)
Electromagnetic Interaction (QED)
Down
Strange
Bottom
Electron
Muon
Tau
e-Neutrino
t-Neutrino
1st Family
2nd Family
3rd Family
Charge /3
Charge -1/3
Charge
Charge Up
m-Neutrino nt ne e m t d s b c u nm
Quarks
Leptons
Charge /3 Up
Charge -1/3
Down
Charge
Electron
Charge
e-Neutrino ne e d u
Neutron
Proton

4. Where do Neutrinos Appear in Nature?
Nuclear Reactors 
Sun 
Particle Accelerators 
Supernovae
(Stellar Collapse)
SN 1987A 
Earth Atmosphere
(Cosmic Rays) 
Astrophysical
Accelerators Soon ?
Earth Crust
(Natural
Radioactivity) 
Cosmic Big Bang
(Today 330 n/cm3)
Indirect Evidence

5. Neutrinos from the Sun Helium Solar radiation: 98 % light
Hans Bethe ( , Nobel prize 1967)
Thermonuclear reaction chains (1938)
Helium
Reaction-
chains
Energy
26.7 MeV
Solar radiation: 98 % light
2 % neutrinos
At Earth 66 billion neutrinos/cm2 sec

6. Bethe’s Classic Paper on Nuclear Reactions in Stars
No neutrinos
from nuclear reactions
in 1938 …

7. Gamow & Schoenberg, Phys. Rev. 58:1117 (1940)

8. Sun Glasses for Neutrinos?
8.3 light minutes
Several light years of lead
needed to shield solar
neutrinos
Bethe & Peierls 1934:
“… this evidently means
that one will never be able
to observe a neutrino.”

9. First Detection (1954 - 1956) g p n Cd e+ e- Clyde Cowan (1919 – 1974)
Fred Reines
(1918 – 1998)
Nobel prize 1995
Detector prototype
Anti-Electron
Neutrinos
from
Hanford
Nuclear Reactor
3 Gammas
in coincidence p n Cd e+ e- g

10. First Measurement of Solar Neutrinos
Inverse beta decay
of chlorine
600 tons of
Perchloroethylene
Homestake solar neutrino
observatory ( )

11. Elastic scattering or CC reaction
Cherenkov Effect
Cherenkov Ring
Elastic scattering or CC reaction
Light
Electron or Muon
(Charged Particle)
Neutrino
Water
Georg Raffelt, Max-Planck-Institut für Physik, München
Physik Kolloquium, 23. November 2007, TU Darmstadt

12. Super-Kamiokande Neutrino Detector

13. Super-Kamiokande: Sun in the Light of Neutrinos
Georg Raffelt, Max-Planck-Institut für Physik, München
Physik Kolloquium, 23. November 2007, TU Darmstadt

14. Hydrogen burning: Proton-Proton Chains
< MeV
1.442 MeV
100%
0.24%
15%
85%
PPI
< 18.8 MeV
hep
90%
10%
0.02%
0.862 MeV
0.384 MeV
< 15 MeV
PPII
PPIII

15. Solar Neutrino Spectrum
7-Be line measured
by Borexino (2007)

16. BOREXINO Neutrino electron scattering Liquid scintillator technology
(~ 300 tons)
Low energy threshold
(~ 60 keV)
Online since 16 May 2007
Expected without flavor oscillations
75 ± c/100t/d
Expected with oscillations
49 ± c/100t/d
BOREXINO result (August 07)
47 ± 7stat ± 12sys c/100t/d

17. Neutrino Flavor Oscillations
Two-flavor mixing
Each mass eigenstate propagates as
with
Phase difference implies flavor oscillations
Probability ne  nm
sin2(2q)
Bruno Pontecorvo
(1913 – 1993)
Invented nu oscillations z
Oscillation
Length

18. Mixing of Neutrinos with Different Mass
mass m1
mass m2 n
Electron
neutrino
Mass m1
Mass m2 > m1
Mass m1
Mass m2 > m1
Mass m1
Mass m2 > m1
Mass m1
Mass m2 = m1
Mass m1
Mass m2 > m1
Neutrino propagation as a wave phenomenon
Georg Raffelt, Max-Planck-Institut für Physik, München
Physik Kolloquium, 23. November 2007, TU Darmstadt

19. Neutrino Oscillations
Mass m1
Mass m2 > m1
Oscillation length
Georg Raffelt, Max-Planck-Institut für Physik, München
Physik Kolloquium, 23. November 2007, TU Darmstadt

20. Neutrino Oscillations
Oscillation length
Georg Raffelt, Max-Planck-Institut für Physik, München
Physik Kolloquium, 23. November 2007, TU Darmstadt

21. Three-Flavor Neutrino Parameters
Solar
75-92
Atmospheric
CHOOZ
Solar/KamLAND
2s ranges
hep-ph/
Atmospheric/K2K
d CP-violating phase m e t 1
Sun
Normal 2 3
Atmosphere
Inverted
Tasks and Open Questions
Precision for q12 and q23
How large is q13 ?
CP-violating phase d ?
Mass ordering ?
(normal vs inverted)
Absolute masses ?
(hierarchical vs degenerate)
Dirac or Majorana ?

22. Sanduleak -69 202 Supernova 1987A 23 February 1987 Tarantula Nebula
Large Magellanic Cloud
Distance 50 kpc
( light years)
Georg Raffelt, Max-Planck-Institut für Physik, München
Physik Kolloquium, 23. November 2007, TU Darmstadt

23. Supernova Neutrinos 20 Jahre nach SN 1987A
Georg Raffelt, Max-Planck-Institut für Physik, München
Physik Kolloquium, 23. November 2007, TU Darmstadt

24. Crab Nebula Georg Raffelt, Max-Planck-Institut für Physik, München
Physik Kolloquium, 23. November 2007, TU Darmstadt

25. Stellar Collapse and Supernova Explosion
Onion structure
Main-sequence star
Hydrogen Burning
Collapse (implosion)
Helium-burning star
Helium
Burning
Hydrogen
Degenerate iron core:
r  109 g cm-3
T  K
MFe  1.5 Msun
RFe  8000 km

26. Stellar Collapse and Supernova Explosion
Newborn Neutron Star
~ 50 km
Proto-Neutron Star
r  rnuc = 3  g cm-3
T  30 MeV
Collapse (implosion)
Neutrino
Cooling

27. Stellar Collapse and Supernova Explosion
Newborn Neutron Star
~ 50 km
Proto-Neutron Star
r  rnuc = 3  g cm-3
T  30 MeV
Neutrino
Cooling
Gravitational binding energy
Eb  3  1053 erg  17% MSUN c2
This shows up as
99% Neutrinos
1% Kinetic energy of explosion
(1% of this into cosmic rays)
0.01% Photons, outshine host galaxy
Neutrino luminosity
Ln  3  1053 erg / 3 sec
 3  1019 LSUN
While it lasts, outshines the entire
visible universe

28. Neutrino Signal of Supernova 1987A
Kamiokande-II (Japan)
Water Cherenkov detector
2140 tons
Clock uncertainty 1 min
Irvine-Michigan-Brookhaven (US)
Water Cherenkov detector
6800 tons
Clock uncertainty 50 ms
Baksan Scintillator Telescope
(Soviet Union), 200 tons
Random event cluster ~ 0.7/day
Clock uncertainty +2/-54 s
Within clock uncertainties,
signals are contemporaneous

29. SN 1987A Event No.9 in Kamiokande-II
Kamiokande-II detector
2140 tons of water fiducial volume
for SN 1987A
Hirata et al., PRD 38 (1988) 448

30. 2002 Physics Nobel Prize for Neutrino Astronomy
Ray Davis Jr.
( )
Masatoshi Koshiba
(*1926)
“for pioneering contributions to astrophysics, in
particular for the detection of cosmic neutrinos”

31. Neutrino-Driven Delayed Explosion
Neutrino heating
increases pressure
behind shock front
Picture adapted from Janka, astro-ph/

32. Standing Accretion Shock Instability (SASI)
Mezzacappa et al.,
Georg Raffelt, Max-Planck-Institut für Physik, München
Physik Kolloquium, 23. November 2007, TU Darmstadt

33. The Energy-Loss Argument
Neutrino
sphere
SN 1987A neutrino signal
Neutrino
diffusion
Emission of very weakly interacting
particles would “steal” energy from the
neutrino burst and shorten it.
(Early neutrino burst powered by accretion,
not sensitive to volume energy loss.)
Volume emission
of novel particles
Late-time signal most sensitive observable

34. Do Neutrinos Gravitate?
Neutrinos arrive a few hours earlier than photons  Early warning (SNEWS)
SN 1987A: Transit time for photons and neutrinos equal to within ~ 3h
Shapiro time delay for particles moving in a
gravitational potential
Longo, PRL 60:173,1988
Krauss & Tremaine, PRL 60:176,1988
Equal within ~ 10-3
Proves directly that neutrinos respond to gravity in the usual way
because for photons gravitational lensing already proves this point
Cosmological limits DNn ≲ 1 much worse test of neutrino gravitation
Provides limits on parameters of certain non-GR theories of gravitation
Photons likely obscured for next galactic SN, so this result probably
unique to SN 1987A

35. Large Detectors for Supernova Neutrinos
MiniBooNE
(200)
LVD (400)
Borexino (100)
Baksan
(100)
Super-Kamiokande (104)
KamLAND (400)
In brackets events
for a “fiducial SN”
at distance 10 kpc
IceCube (106)

36. Simulated Supernova Signal at Super-Kamiokande
Accretion
Phase
Kelvin-Helmholtz
Cooling Phase
Simulation for Super-Kamiokande SN signal at 10 kpc,
based on a numerical Livermore model
[Totani, Sato, Dalhed & Wilson, ApJ 496 (1998) 216]

37. IceCube Neutrino Telescope at the South Pole
1 km3 antarctic ice, instrumented
with 4800 photomultipliers
22 of 80 strings installed (2007)
Completion until 2011 foreseen

38. Global Cosmic Ray Spectrum

39. Core of the Galaxy NGC 4261
Georg Raffelt, Max-Planck-Institut für Physik, München
Physik Kolloquium, 23. November 2007, TU Darmstadt

40. Neutrino Beams: Heaven and Earth
Target:
Protons or Photons
Approx. equal fluxes of
photons & neutrinos
Equal neutrino fluxes
in all flavors due to
oscillations
F. Halzen (2002)

41. 3369 events from northern hemisphere
AMANDA Skyplot
3369 events from northern hemisphere

42. IceCube as a Supernova Neutrino Detector
Each optical module (OM) picks up
Cherenkov light from its neighborhood.
SN appears as “correlated noise”.
About 300
Cherenkov
photons
per OM
from a SN
at 10 kpc
Noise
< 260 Hz
Total of
4800 OMs
in IceCube
IceCube SN signal at 10 kpc, based
on a numerical Livermore model
[Dighe, Keil & Raffelt, hep-ph/ ]
Method first discussed by
Pryor, Roos & Webster,
ApJ 329:355 (1988)
Halzen, Jacobsen & Zas
astro-ph/

43. H- and L-Resonance for MSW Oscillations
R. Tomàs, M. Kachelriess,
G. Raffelt, A. Dighe,
H.-T. Janka & L. Scheck: Neutrino signatures of
supernova forward and
reverse shock propagation [astro-ph/ ]
Resonance
density for
Resonance
density for

44. Shock-Wave Propagation in IceCube
Inverted Hierarchy
No shockwave
Inverted Hierarchy
Forward & reverse shock
Inverted Hierarchy
Forward shock
Normal Hierarchy
Choubey, Harries & Ross, “Probing neutrino oscillations from supernovae shock
waves via the IceCube detector”, astro-ph/

45. Core-Collapse SN Rate in the Milky Way
SN statistics in
external galaxies
Core-collapse SNe per century 1 2 3 4 5 6 7 8 9 10
van den Bergh & McClure (1994)
Cappellaro & Turatto (2000)
Gamma rays from
26Al (Milky Way)
Diehl et al. (2006)
Historical galactic
SNe (all types)
Strom (1994)
Tammann et al. (1994)
No galactic
neutrino burst
90 % CL (25 y obserservation)
Alekseev et al. (1993)
References: van den Bergh & McClure, ApJ 425 (1994) 205. Cappellaro & Turatto, astro-ph/ Diehl et al., Nature 439 (2006) 45. Strom, Astron. Astrophys. 288 (1994) L1. Tammann et al., ApJ 92 (1994) 487. Alekeseev et al., JETP 77 (1993) 339 and my update.

46. SuperNova Early Warning System (SNEWS)
Neutrino observation can alert astronomers
several hours in advance to a supernova.
To avoid false alarms, require alarm from at
least two experiments.
Super-K
IceCube
Coincidence
Server
@ BNL
Alert
LVD
Supernova 1987A
Early Light Curve
Others ?
astro-ph/

47. The Red Supergiant Betelgeuse (Alpha Orionis)
First resolved
image of a star
other than Sun
Distance
(Hipparcos)
130 pc (425 lyr)
If Betelgeuse goes Supernova:
6 107 neutrino events in Super-Kamiokande
2.4 103 neutron events per day from Silicon-burning phase
(few days warning!), need neutron tagging
[Odrzywolek, Misiaszek & Kutschera, astro-ph/ ]

48. LAGUNA - Funded FP7 Design Study
Large Apparati for Grand Unification and Neutrino Astrophysics
(see also arXiv: )

49. Title Dark Energy 73% (Cosmological Constant) Neutrinos 0.1-2%
Matter 23%
Normal Matter 4%
(of this about 10%
luminous)
Georg Raffelt, Max-Planck-Institut für Physik, München
Physik Kolloquium, 23. November 2007, TU Darmstadt

50. “Weighing” Neutrinos with KATRIN
Sensitive to common mass scale m
for all flavors because of small mass
differences from oscillations
Best limit from Mainz und Troitsk
m < 2.2 eV (95% CL)
KATRIN can reach 0.2 eV
Under construction
Data taking foreseen to begin in 2009

51. “KATRIN Approaching” (25 Nov 2006)

52. Cosmological Limit on Neutrino Masses
Cosmic neutrino “sea” ~ 112 cm-3 neutrinos + anti-neutrinos per flavor
mn < 40 eV
For all
stable flavors
A classic paper:
Gershtein & Zeldovich
JETP Lett. 4 (1966) 120

53. Strukturbildung im Universum
Smooth
Structured
Structure forms by
gravitational instability
of primordial
density fluctuations
A fraction of hot dark matter
suppresses small-scale structure

54. Structure Formation with Hot Dark Matter
Standard LCDM Model
Neutrinos with Smn = 6.9 eV
Structure fromation simulated with Gadget code
Cube size 256 Mpc at zero redshift
Troels Haugbølle,

55. Power Spectrum of Cosmic Density Fluctuations

56. Some Recent Cosmological Limits on Neutrino Masses
Smn/eV
(limit 95%CL)
Data / Priors
Hannestad 2003
[astro-ph/ ]
1.01
WMAP-1, CMB, 2dF, HST
Spergel et al. (WMAP) 2003
[astro-ph/ ]
0.69
WMAP-1, 2dF, HST, s8
Crotty et al. 2004
[hep-ph/ ]
1.0
0.6
WMAP-1, CMB, 2dF, SDSS
& HST, SN
Hannestad 2004
[hep-ph/ ]
0.65
WMAP-1, SDSS, SN Ia gold sample,
Ly-a data from Keck sample
Seljak et al. 2004
[astro-ph/ ]
0.42
WMAP-1, SDSS, Bias,
Ly-a data from SDSS sample
Hannestad et al. 2006
[hep-ph/ ]
0.30
WMAP-1, CMB-small, SDSS, 2dF,
SN Ia, BAO (SDSS), Ly-a (SDSS)
Spergel et al. 2006
[hep-ph/ ]
0.68
WMAP-3, SDSS, 2dF, SN Ia, s8
Seljak et al. 2006
[astro-ph/ ]
0.14
WMAP-3, CMB-small, SDSS, 2dF,
SN Ia, BAO (SDSS), Ly-a (SDSS)

57. Weak Lensing - A Powerful Probe for the Future
Distortion of background images by foreground matter
Unlensed
Lensed

58. Sensitivity Forecasts for Future LSS Observations
Lesgourgues, Pastor
& Perotto,
hep-ph/
Planck & SDSS
Smn > 0.21 eV detectable
at 2s
Smn > 0.13 eV detectable
Ideal CMB & 40 x SDSS
Abazajian & Dodelson
astro-ph/
Future weak lensing
survey 4000 deg2
σ(mν) ~ 0.1 eV
Kaplinghat, Knox & Song,
astro-ph/
σ(mν) ~ 0.15 eV (Planck)
σ(mν) ~ eV (CMBpol)
CMB lensing
Wang, Haiman, Hu,
Khoury & May,
astro-ph/
Weak-lensing selected
sample of > 105 clusters
σ(mν) ~ 0.03 eV

59. Fermion Mass Spectrum 10 100 1 meV eV keV MeV GeV TeV d s b
Quarks (Q = -1/3) u c t
Quarks (Q = +2/3)
Charged Leptons (Q = -1) e m t
All flavors n3
Neutrinos

60. Periodic System of Elementary Particles
Matter
Anti-Quarks
Anti-Leptons
-2/3
+1/3 +1
Strong Int’n
Electromagnetic Int’n
Antimatter
Leptons
Anti-Leptons
„Majorana Neutrinos”
are their own
antiparticles
Can explain baryogenesis
by leptogenesis
Why is there no antimatter
in the Universe?
(Problem of „Baryogenesis”)
Quarks
Leptons
+2/3 c t
Gravitation
Weak Interaction
Strong Int’n
Electromagnetic Int’n
-1/3 s b -1 m
1st Family
2nd Family
3rd Family u d e
Charge

61. See-Saw Model for Neutrino Masses
Neutrinos
Charged Leptons
Dirac masses
from coupling
to standard
Higgs field f
Heavy
Majorana
masses
Mj > 1010 GeV
Lagrangian for
particle masses
Light Majorana mass
Diagonalize

62. See-Saw Model for Neutrino Massesℓ
1010 GeV
1 GeV
10-10 GeV
Charged
leptons
Ordinary
neutrinos
Heavy
“right-handed”
(no gauge
interactions)
Light Majorana mass

63. Leptogenesis by Out-of-Equilibrium Decay
abundance of
heavy Majorana
neutrinos
Created
lepton-number
abundance
Equilibrium
abundance of
heavy Majorana
neutrinos
Real abundance
determined by
decay rate
CP-violating decays by
interference of tree-level
with one-loop diagram
Equilibrium
abundance of
heavy Majorana
neutrinos
Real abundance
determined by
decay rate
M. Fukugita & T. Yanagida:
Baryogenesis without Grand
Unification
Phys. Lett. B 174 (1986) 45
W. Buchmüller & M. Plümacher: Neutrino masses and the baryon asymmetry
Int. J. Mod. Phys. A15 (2000)

64. Leptogenesis by Majorana Neutrino Decays
In see-saw models for neutrino masses, out-of-equilibrium
decays of right-handed heavy Majorana neutrinos provide
source for CP- and L-violation
Cosmological evolution
B = L = 0 early on
Thermal freeze-out of heavy Majorana neutrinos
Out-of-equilibrium CP-violating decay creates net L
Shift L excess into B by sphaleron effects
Sufficient deviation from equilibrium distribution of heavy Majorana neutrinos at freeze-out
Limits on
Yukawa
couplings
Limits on
masses of
ordinary
neutrinos
Requires Majorana neutrino masses below 0.1 eV
Buchmüller, Di Bari & Plümacher, hep-ph/ & hep-ph/

65. Title Dark Energy 73% (Cosmological Constant) Neutrinos 0.1-2%
Matter 23%
Normal Matter 4%
(of this about 10%
luminous)
Massive neutrinos can
explain presence of matter
by leptogenesis mechanism
Georg Raffelt, Max-Planck-Institut für Physik, München
Physik Kolloquium, 23. November 2007, TU Darmstadt

66. Killing Two Birds with One Stone
See-Saw mechanism explains
Small neutrino masses
Baryon asymmetry of the
universe by leptogenesis

67. Leptogenesis by Majorana Neutrino Decays
A classic paper

68. Leptogenesis as a Research Topic
Citation of Fukugita & Yanagida, PLB 174 (1986) 45
or “leptogenesis” in title (SPIRES data base)

69. Neutrinoless bb Decay 0n mode, enabled Standard 2n mode
by Majorana mass
Measured
quantity
Best limit
from 76Ge

70. Portion of the Hubble Ultra Deep Field
Astrophysics & Cosmology
Elementary Particle Physics n
Cosmic Rays
Georg Raffelt, Max-Planck-Institut für Physik, München
Physik Kolloquium, 23. November 2007, TU Darmstadt

72. Gamow & Schoenberg 2

73. Long-Baseline Experiment K2K
K2K Experiment
(KEK to
Kamiokande)
has confirmed
neutrino
oscillations,
to be followed
by T2K (2009)

74. Geo Neutrinos Predicted geo neutrino flux
KamLAND scintillator detector (1 kton)
Reactor background

75. Matrices of Density in Flavor Space
Neutrino quantum field
Spinors in flavor space
Destruction
operators for
(anti)neutrinos
Variables for discussing neutrino flavor oscillations
Quantum states (amplitudes)
“Matrices of densities”
(analogous to occupation numbers)
Neutrinos
Anti-
neutrinos
Sufficient for “beam experiments,”
but confusing “wave packet debates”
for quantifying decoherence effects
“Quadratic” quantities, required for
dealing with decoherence, collisions,
Pauli-blocking, nu-nu-refraction, etc.

76. General Equations of Motion
Vacuum oscillations
M is neutrino mass matrix
Note opposite sign between
neutrinos and antineutrinos
Usual matter effect with
Nonlinear nu-nu effects are important
when nu-nu interaction energy exceeds
typical vacuum oscillation frequency
(Do not compare with matter effect!)

77. Toy Supernova in “Single-Angle” Approximation
Assume 80% anti-neutrinos
Vacuum oscillation frequency
w = 0.3 km-1
Neutrino-neutrino interaction
energy at nu sphere (r = 10 km)
m = 0.3105 km-1
Falls off approximately as r-4
(geometric flux dilution and nus
become more co-linear)
Bipolar
Oscillations
Decline of oscillation amplitude
explained in pendulum analogy
by inreasing moment of inertia
(Hannestad, Raffelt, Sigl & Wong
astro-ph/ )

78. Collective SN neutrino oscillations 2006-2007
“Bipolar” collective transformations
important, even for dense matter
Duan, Fuller & Qian
astro-ph/
Numerical simulations
Including multi-angle effects
Discovery of “spectral splits”
Duan, Fuller, Carlson & Qian
astro-ph/ ,
Pendulum in flavor space
Collective pair annihilation
Pure precession mode
Hannestad, Raffelt, Sigl & Wong
astro-ph/
Duan, Fuller, Carlson & Qian
astro-ph/
Self-maintained coherence
vs. self-induced decoherence
caused by multi-angle effects
Raffelt & Sigl, hep-ph/
Esteban-Pretel, Pastor, Tomas,
Raffelt & Sigl, arXiv:
Theory of “spectral splits”
in terms of adiabatic evolution in
rotating frame
Raffelt & Smirnov,
arXiv: ,
Duan, Fuller, Carlson & Qian
arXiv: ,
Independent numerical simulations
Fogli, Lisi, Marrone & Mirizzi
arXiv:

79. Looking forward to the next galactic supernova
SN 1006
Looking forward to the next galactic supernova

80. Wilson, Proc. Univ. Illinois Meeting on Num. Astrophys.(1982)
Delayed Explosion
Wilson, Proc. Univ. Illinois Meeting on Num. Astrophys.(1982)
Bethe & Wilson, ApJ 295 (1985) 14

81. Experimental Limits on Relic Supernova Neutrinos
Super-K upper limit
29 cm-2 s-1 for
Kaplinghat et al. spectrum
[hep-ex/ ]
Upper-limit flux of
Kaplinghat et al.,
astro-ph/
Integrated 54 cm-2 s-1
Cline, astro-ph/

82. DSNB Measurement with Neutron Tagging
Beacom & Vagins, hep-ph/
[Phys. Rev. Lett., 93:171101, 2004]
Future large-scale scintillator
detectors (e.g. LENA with 50 kt)
Inverse beta decay reaction tagged
Location with smaller reactor flux
(e.g. Pyhäsalmi in Finland) could
allow for lower threshold
Pushing the boundaries of neutrino
astronomy to cosmological distances

83. Neutrinos in Astrophysics and Cosmology
responsible
for ordinary
astrophysical
and
cosmological
phenomena
Dominant radiation component in the early universe
Crucial role in big-bang nucleosynthesis
Dark-matter component (but subdominant)
May be responsible for baryonic matter in the
universe (leptogenesis)
Important (sometimes dominant) cooling agent of stars
May trigger supernova explosions
May be crucial for r-process nucleosynthesis
Heavenly
laboratories
for new
particle
physics
phenomena
Cosmological limit (future detection?) of nu mass scale
Flavor oscillations of solar and atmospheric neutrinos
Neutrino oscillations from a future galactic supernova
Limits on “exotic” neutrino properties
(dipole moments, right-handed interactions, decays,
flavor-violating neutral currents, sterile nus, …)
Neutrinos as
astrophysical
messengers
Look into the solar interior (“measure” temperature)
Watch stellar collapse directly
Neutrinos from all cosmological supernovae
Astrophysical accelerators for cosmic rays
Annihilation signature for neutralino dark matter

84. Hot dark matter ruled out in 1983
1000 particle simulation [Frenk, White & Davis, ApJ 271 (1983) 417]
The coherence length of the neutrino distribution […] is too large
to be consistent with the observed clustering scale of galaxies […]
The conventional neutrino-dominated picture appears to be ruled
out White, Frenk & Davis, ApJ 274 (1983) L1.