Diapositiva 1

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Réunions plénières du GDR NEUTRINO
LPNHE-Paris, 27-28 Avril 2009
Future supernova neutrino observations What
could we learn ?
Alessandro MIRIZZI (MPI, Munich)
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OUTLINE
SN 1987A n detection
Physics potential of current and future SN n
detectors
Signatures of SN n oscillations
Conclusions
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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SUPERNOVA NEUTRINOS

• Core collapse SN corresponds to the terminal
  phase of a massive star M ? 8 M? which becomes
  instable at the end of its life. It collapses and
  ejects its outer mantle in a shock wave driven
  explosion.

• ENERGY SCALES 99 of the released energy ( 1053
  erg) is emitted by n and n of all flavors, with
  typical energies E O(15 MeV).

• TIME SCALES Neutrino emission lasts
  10 s
• EXPECTED 1-3 SN/century in our galaxy (d ?
  O (10) kpc).

Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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SN1987A Neutrino Burst Observation First
verification of stellar evolution mechanism
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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Energy Distribution of SN 1987A Neutrinos
Kamiokande-II (Japan) Water Cherenkov
detector 2140 tons
Irvine-Michigan-Brookhaven (US) Water Cherenkov
detector 6800 tons
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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SN NEUTRINO SPECTRUM FROM SN1987A
Yuksel Beacom, astro-ph/0702613
Original SN n energy spectra expected to be
quasi-thermal
SN1987A inferred n energy spectrum shows strong
deviations from quasi-thermal distribution
?
Possible effects of

• neutrino mixing
• n-n interactions
• n decay
• nonstandard n interactions
• additional channels of energy exchange among
  flavors

Still many open questions!
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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What could we see tomorrow?
SN 20XXA !
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Large Detectors for Supernova Neutrinos
Super-Kamiokande (104) KamLAND (330)
MiniBooNE (200)
In brackets events for a fiducial SN at
distance 10 kpc
IceCube
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Simulated Supernova Signal at Super-Kamiokande
Simulation for Super-Kamiokande SN signal at 10
kpc, based on a numerical Livermore
model Totani, Sato, Dalhed Wilson, ApJ 496
(1998) 216
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SHOCK-OSCILLATION MODULATED SN n SIGNAL
Marek, Janka, Mueller, arXiv0808.4136
Convective motions lead to large-amplitude
oscillations of the stalled shock with a period
of 10 ms
Necessary high statistics and high time resolution
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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SIGNALS OF QCD PHASE TRANSITION IN SN n
Sagert et al., arXiv0809.4225
If QCD phase transition happens in a SN ? second
peak in the neutrino signal. In contrast to the
first neutronization burst, second neutrino burst
dominated by the emission of anti-neutrinos
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Next generation Detectors for Supernova Neutrinos
Next-generation large volume detectors might open
a new era in SN neutrino detection

• 0.4 Mton WATER Cherenkov detectors
• 100 kton Liquid Ar TPC
• 50 kton scintillator

Mton Cherenkov
See LAGUNA Collaboration, Large underground,
liquid based detectors for astro-particle physics
in Europe Scientific case and prospects,
arXiV0705.0116 hep-ph
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0.4 Mton Water Cherenkov detector
Fogli, Lisi, A.M., Montanino, hep-ph/0412046
2.5105 events _at_ 10 kpc
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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• Next-generation detectors would assure a
  high-statistics measurement of galactic SN
  neutrinos.
• This would allow spectral studies
• in time
• in energy
• in different interaction channels

We will mainly focus on the possibility to detect
signatures in the n signal for a typical galactic
SN explosion (d10 kpc unless otherwise noticed)
associated to
SN NEUTRINO OSCILLATIONS
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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SN n FLAVOR TRANSITIONS
The flavor evolution in matter is described by
the non-linear MSW equations
In the standard 3n framework
Kinematical mass-mixing term
Dynamical MSW term (in matter)
Neutrino-neutrino interactions term (non-linear)
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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VACUUM OSCILLATIONS 3n FRAMEWORK
Mixing parameters U U (q12, q13, q23)
as for CKM matrix
Mass-gap parameters
(see,e.g., Fogli et al., 0805.2517)
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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SN SELF-INTERACTION POTENTIAL AND MATTER POTENTIAL
r lt 200 km Self-induced collective oscillations
r gt 200 km Ordinary MSW effects
Recent review H.Duan J. Kneller
arXiv0904.0974 astro-ph.HE
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SYNCHRONIZED OSCILLATIONS BY NEUTRINO-NEUTRINO
INTERACTIONS
Example evolution of neutrino momenta with a
thermal distribution
If neutrino density dominates, synchronoized
oscillations with a characteristic common
oscillation frequency
Pastor, Raffelt, Semikoz, hep-ph/0109033
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BIPOLAR OSCILLATIONS
Hannestad, Raffelt, Sigl, Wong, astro-ph/0608695
Complete flavor conversions!
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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COLLECTIVE OSCILLATIONS IN IH _at_ q13? 0
Collective flavor conversions in inverted
hierarchy are expected also for q13?0, when
further MSW matter effects are negligible
Duan, Fuller, Carlson Qian, arXiv0707.0290 (as
tro-ph)
Effect logarithmically delayed when q13?0
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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SPECTRAL SPLIT
G.L.Fogli, E.Lisi, A. Marrone, A.M. , arXiV
0707.1998 hep-ph
Initial fluxes at neutrinosphere (r 10 km)
Inverted mass hierarchy
Fluxes at the end of collective effects (r 200
km)
The spectral split is a robust effect (also at
q13?0)
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USING EARTH EFFECT TO DIAGNOSE COLLECTIVE
OSCILLATIONS
Earth matter crossing induces additional n
conversions between n1 and n2 mass eigenstates.
The main signature of Earth matter effects
oscillatory modulations of the observed energy
spectra is unambiguous since it can not be
mimicked by known astrophysical phenomena
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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http//www.mppmu.mpg.de/supernova/shadowing
Mirizzi, Raffelt Serpico astro-ph/0604300
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MASS HIERARCHY DETERMINATION AT EXTREMELY SMALL
q13
Dasgupta, Dighe, A.M., arXiv0802.1481 hep-ph
Ratio of spectra in two water Cherenkov detectors
(0.4 Mton), one shadowed by the Earth, the other
not.
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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MSW EFFECTS AND SHOCK WAVE
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Neutrino oscillations as a camera for
shock-wave propagation
G.L. Fogli, E. Lisi, A.M., and D. Montanino,
hep-ph/0412046
without collective effects
fwd shock
fwdrev shock
sin2q1310-2
events/bin
In inverted hierarchy and for q13 not too small,
SN shock wave(s) induce non-monotonic time
spectra at sufficiently high energy.
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COMBINING COLLECTIVE MSW EFFECTS
Gava,Kneller, Volpe, McLaughlin, arXiv0902.0317
Collective oscillations swap the original spectra
E 20 MeV
E 15 MeV
Dips in the events rate associated to the shock
propagation, now become bumps and viceversa
E 29 MeV
E 10 MeV
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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STOCHASTIC DENSITY FLUCTUATIONS
Turbulent convective motions behind the shock
front create a fluctuating density field in the
post-shock region. A SN neutrino beam might
thus experience stochastic matter effects while
traversing the stellar envelope.
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009
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SHADOWING THE SHOCK-WAVE SIGNATURE
_at_ a Mton-class water Cherenkov detector
Fogli, Lisi, A.M. , Montanino, hep-ph/0603033
d-correlated noise, length-scale of order the
oscillation length (10 km), ampltitude 4.
Black no noise. Red noise
Choubey, Harries, Ross, hep-ph/0703092
Kolmogorov spectrum for turbulence.
Left no noise. Right noise
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CONCLUSIONS
Observing SN neutrinos is the next frontiers of
low-energy neutrino astronomy
The physics potential of next-generation
detectors in this context is enormous, both for
particle physics and astrophysics.
SN n physics program with next-generation
detectors is a no-loose project, and probably a
high-winner one.
Alessandro Mirizzi GDR Neutrino
Paris, 28/04/2009