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Neutrinos and the stars
Supernova Neutrinos
Georg Raffelt, MPI for Physics
Lectures at the Topical Seminar
Neutrino Physics & Astrophysics
17-21 Sept 2008, Beijing, China
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Sanduleak -69 202
Supernova 1987A
23 February 1987
Tarantula Nebula
Large Magellanic Cloud
Distance 50 kpc
(160.000 light years)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Supernova Neutrinos 20 Jahre nach SN 1987A
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Crab Nebula
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Stellar Collapse and Supernova Explosion
Main-sequence
Onion structure
star
Degenerate iron core:
r  109 g cm-3
Hydrogen
Burning
T  1010 K
MFe  1.5 Msun
RFe  8000 km
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Collapse
Helium-burning
(implosion)
star
Helium
Burning
Hydrogen
Burning
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Stellar Collapse and Supernova Explosion
Newborn Neutron Star
Collapse
Explosion
(implosion)
~ 50 km
Neutrino
Cooling
Proto-Neutron Star
r  rnuc = 3 1014 g cm-3
T  30 MeV
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Stellar Collapse and Supernova Explosion
Newborn Neutron Star
~ 50 km
Gravitational binding energy
Eb  3  1053 erg  17% MSUN c2
Neutrino
Cooling
Proto-Neutron Star
r  rnuc = 3 1014 g cm-3
T  30 MeV
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
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
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
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
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
SN 1987A Event No.9 in Kamiokande
Kamiokande Detector
Hirata et al., PRD 38 (1988) 448
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Thermonuclear vs. Core-Collapse Supernovae
Thermonuclear (Type Ia)
• Carbon-oxygen white dwarf
(remnant of
low-mass star)
• Accretes matter
from companion
Core collapse (Type II, Ib/c)
• Degenerate iron core
of evolved massive star
• Accretes matter
by nuclear burning
at its surface
Chandrasekhar limit is reached - MCh  1.5 Msun (2Ye)2
C O LLAP S E
SETS IN
Nuclear burning of C and O ignites
 Nuclear deflagration
(“Fusion bomb” triggered by collapse)
Powered by nuclear binding energy
Gain of nuclear binding energy
~ 1 MeV per nucleon
Collapse to nuclear density
Bounce & shock
Implosion  Explosion
Powered by gravity
Gain of gravitational binding energy
~ 100 MeV per nucleon
99% into neutrinos
Comparable “visible” energy release of ~ 3  1051erg
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Supernova Neutrinos 20 Jahre nach SN 1987A
Explosion Mechanism
for Core-Collapse SNe
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Collapse and Prompt Explosion
Velocity
Density
Movies by J.A.Font, Numerical Hydrodynamics in General Relativity
http://www.livingreviews.org
Supernova explosion primarily a hydrodynamical phenomenon
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Why No Prompt Explosion?
• 0.1 Msun of iron has a
nuclear binding energy
 1.7  1051 erg
• Comparable to
explosion energy
Dissociated
Material
(n, p, e, n)
• Shock wave forms
within the iron core
• Dissipates its energy
by dissociating the
remaining layer of iron
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Neutrinos to the Rescue
Neutrino heating
increases pressure
behind shock front
Picture adapted from Janka, astro-ph/0008432
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Supernova Delayed Explosion Scenario
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Standing Accretion Shock Instability (SASI)
Mezzacappa et al., http://www.phy.ornl.gov/tsi/pages/simulations.html
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Gravitational Waves from Core-Collapse Supernovae
Müller, Rampp, Buras, Janka, & Shoemaker,
“Towards gravitational wave signals from
realistic core collapse supernova models,”
astro-ph/0309833
Asymmetric neutrino emission
Bounce
Convection
The gravitational-wave signal from convection
is a generic and dominating feature
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Supernova Neutrinos 20 Jahre nach SN 1987A
Some Particle-Physics
Lessons from SN 1987A
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Neutrino Mass Sensitivity by Signal Dispersion
Time-of-flight delay
of massive neutrinos
SN 1987A
(50 kpc)
 D   10 MeV 
 

t = 5.1 ms 
 10 kpc   En 
E  20 MeV, t  10 s
Simple estimate or detailed maximum
likelihood analysis give similar results
2
 mn 


 1 eV 
mn r 20 eV
Rise-time of signal ~ 10 ms
(Totani, PRL 80:2040, 1998)
mn ~ 3 eV
Full signal
(Nardi & Zuluaga, NPB 731:140, 2005)
mn ~ 1 eV
With late
black-hole
formation
Cutoff “infinitely” fast
(Beacom et al., PRD 63:073011, 2001)
mn ~ 2 eV
Future SN in
Andromeda
(Megatonne)
D  750 kpc, t  10 s
few tens of events
Future
Galactic SN
at 10 kpc
(Super-K)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
2
mn ~ 1-2 eV
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Early Lightcurve of SN 1987A
Expected
bolometric
brightness
evolution
Expected
visual
brightness
evolution
Neutrinos several
hours before light
Adapted from
Arnett et al.,
ARAA 27 (1989)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
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
B U[r(t)] dt  1 - 5 months
tShapiro = -2A
Equal within ~ 1 - 4 10-3
Longo, PRL 60:173,1988
Krauss & Tremaine, PRL 60:176,1988
• Proves directly that neutrinos respond to gravity in the usual way
because for photons gravitational lensing already proves this point
• Cosmological limits Nn ≲ 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
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
The Energy-Loss Argument
Neutrino
sphere
Neutrino
diffusion
SN 1987A neutrino signal
Volume emission
of novel particles
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.)
Late-time signal most sensitive observable
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Axion Bounds
103
ma
106
keV
Experiments
109
eV
Tele
meV
CAST
scope
Too much hot dark matter
[GeV] fa
1012
meV
Direct
search
ADMX
Too much
cold dark matter
Globular clusters
(a-g-coupling)
Too many
events
Too much
energy loss
SN 1987A (a-N-coupling)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Sterile Neutrinos
Active-sterile
mixing
ns
e
W
p
n
Electron neutrino appears as sterile neutrino
in ½ sin2(2Qes) of all cases
s  21 sin2(2Q es ) L
Average scattering rate in SN core
involving ordinary left-handed neutrinos
L  1010 s-1
To avoid complete energy loss in ~ 1 s
1 sin2(2Q ) 1010 s -1  1s -1
es
2
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
sin2(2Qes) r 3  10-10
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Sterile Neutrino Limits
See also:
Maalampi & Peltoniemi:
Effects of the 17-keV
neutrino in supernovae
PLB 269:357,1991
Hidaka & Fuller:
Dark matter sterile
neutrinos in stellar
collapse: alteration of
energy/lepton number
transport and a
mechanism for
supernova explosion
enhancement
PRD 74:125015,2006
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Supernova 1987A Limit on Large Extra Dimensions
SN core emits large flux of
KK gravity modes by
nucleon-nucleon bremsstrahlung
-2
Rate  MPl
Large multiplicity of modes
RT ~ 1011
for R ~ 1 mm, T ~ 30 MeV
Rate 
(RT)n
2
MPl

Tn
2n
MPl
Cullen & Perelstein, hep-ph/9904422
Hanhart et al., nucl-th/0007016
SN 1987A energy-loss argument:
R  1 mm, M > 9 TeV
(n = 2)
R  1 nm, M > 0.7 TeV (n = 3)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Originally the most restrictive
limit on such theories, except
for cosmological arguments
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Supernova Neutrinos 20 Jahre nach SN 1987A
Neutrinos from the
Next Galactic Supernova
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Local Group of Galaxies
Events in a detector with
30 x Super-K fiducial volume,
e.g. Hyper-Kamiokande
30
60
250
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Core-Collapse SN Rate in the Milky Way
SN statistics in
external galaxies
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)
0 1 2 3 4 5 6 7 8 9 10
Core-collapse SNe per century
References: van den Bergh & McClure, ApJ 425 (1994) 205. Cappellaro & Turatto, astroph/0012455. 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.
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Nearby Galaxies with Many Observed Supernovae
M83 (NGC 5236, Southern Pinwheel)
D = 4.5 Mpc
NGC 6946
D = (5.5 ± 1) Mpc
Observed Supernovae:
1923A, 1945B, 1950B, 1957D, 1968L,
1983N
Observed Supernovae:
1917A, 1939C, 1948B, 1968D, 1969P,
1980K, 2002hh, 2004et, 2008S
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Large Detectors for Supernova Neutrinos
MiniBooNE
(200)
LVD (400)
Borexino (100)
Baksan
(100)
IceCube (106)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Super-Kamiokande (104)
KamLAND (400)
In brackets events
for a “fiducial SN”
at distance 10 kpc
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
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
LVD
Supernova 1987A
Early Light Curve
Coincidence
Server
@ BNL
Alert
Others ?
http://snews.bnl.gov
astro-ph/0406214
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
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]
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Supernova Pointing with Neutrinos
n ep  ne 
95% CL half-cone opening angle
Neutron tagging efficiency
None
90 %
SK
7.8º
3.2º
SK  30
1.4º
0.6º
ne  ne
• Beacom & Vogel: Can a supernova be located by its neutrinos?
[astro-ph/9811350]
• Tomàs, Semikoz, Raffelt, Kachelriess & Dighe: Supernova pointing with
low- and high-energy neutrino detectors [hep-ph/0307050]
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
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
per OM
< 500 Hz
• Total of
4800 OMs
in IceCube
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
IceCube SN signal at 10 kpc, based
on a numerical Livermore model
[Dighe, Keil & Raffelt, hep-ph/0303210]
Method first discussed by
Halzen, Jacobsen & Zas
astro-ph/9512080
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
LAGUNA - Approved FP7 Design Study
Large Apparati for Grand Unification and Neutrino Astrophysics
(see also arXiv:0705.0116)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Supernova Neutrinos 20 Jahre nach SN 1987A
Neutrinos From
All Cosmic Supernovae
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Diffuse Background Flux of SN Neutrinos
1 SNu = 1 SN / 1010 Lsun,B / 100 years
Lsun,B = 0.54 Lsun = 2  1033 erg/s
En ~ 3  1053 erg per core-collapse SN
• Photons come from nuclear energy
• Neutrinos from gravitational energy
1 SNu ~ 4 Ln / Lg,B
Average neutrino
luminosity of galaxies
~ photon luminosity
For galaxies, average
nuclear & gravitational
energy release comparable
Present-day SN rate of ~ 1 SNu, extrapolated to the entire universe,
corresponds to ne flux of ~ 1 cm-2 s-1
Realistic flux is dominated by much larger early star-formation rate
 Upper limit ~ 54 cm-2 s-1
[Kaplinghat et al., astro-ph/9912391]
 “Realistic estimate” ~ 10 cm-2 s-1
[Hartmann & Woosley, Astropart. Phys. 7 (1997) 137]
Measurement would tell us about early history of star formation
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Experimental Limits on Relic Supernova Neutrinos
Super-K upper limit
29 cm-2 s-1 for
Kaplinghat et al. spectrum
[hep-ex/0209028]
Upper-limit flux of
Kaplinghat et al.,
astro-ph/9912391
Integrated 54 cm-2 s-1
Cline, astro-ph/0103138
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
DSNB Measurement with Neutron Tagging
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
Beacom & Vagins, hep-ph/0309300
[Phys. Rev. Lett., 93:171101, 2004]
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Supernova Neutrinos 20 Jahre nach SN 1987A
Oscillations of
Supernova Neutrinos
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Structure of Supernova Neutrino Signal
1. Collapse (infall phase)
2. Shock break out
3. Matter accretion
4. Kelvin-Helmholtz cooling
Traps
neutrinos
and
lepton
number
of outer
core
layers
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Neutronization Burst as a Standard Candle
Different Mass
Neutrino Transport
Nuclear EoS
If mixing
scenario is
known,
perhaps best
method to
determine
SN distance,
especially if
obscured
(better than
5-10%)
Kachelriess,
Tomàs, Buras,
Janka, Marek
& Rampp,
astro-ph
/0412082
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Flavor-Dependent Fluxes and Spectra
Prompt ne
deleptonization
burst
Broad characteristics
• Duration a few seconds
• En ~ 10-20 MeV
• En increases with time
• Hierarchy of energies
nx
_
ne
ne
Livermore numerical model
ApJ 496 (1998) 216
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
En e  E ne  En x
• Approximate equipartition
of energy between flavors
However, in traditional
simulations transport
of nm and nt schematic
• Incomplete microphysics
• Crude numerics to couple
neutrino transport with
hydro code
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Flavor-Dependent Neutrino Fluxes vs. Equation of State
Wolff & Hillebrandt nuclear EoS (stiff)
Lattimer & Swesty nuclear EoS (soft)
Kitaura, Janka & Hillebrandt, “Explosions of O-Ne-Mg cores, the Crab
supernova, and subluminous Type II-P supernovae”, astro-ph/0512065
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Level-Crossing Diagram in a SN Envelope
Normal mass hierarchy
Inverted mass hierarchy
Dighe & Smirnov, Identifying the neutrino mass spectrum from a supernova
neutrino burst, astro-ph/9907423
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Spectra Emerging from Supernovae
Primary fluxes
After leaving the
supernova envelope,
the fluxes are
partially swapped
Case
Mass ordering
A
Normal
B
Inverted
C
Any
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Fe0
for n e
Fe0
for n e
Fx0
for n m , nm , n t , n t
Fe0 = p Fe0  (1 - p) Fx0
Fe0 = p Fe0  (1 - p) Fx0
1 F = 2  p  p F0  1- p F0  1- p F0
x
e
e
4 x
4
4
4
sin2(2Q
13)
≳ 10-3
≲ 10-5
Survival probability
p (for n e )
p (for n e )
0
cos2(Q12)  0.7
sin2(Q12)  0.3
0
sin2(Q12)  0.3 cos2(Q12)  0.7
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Oscillation of Supernova Anti-Neutrinos
Measured n e spectrum at a detector like
Super-Kamiokande
Assumed flux parameters
Flux ratio n e : nm = 0.8 : 1
E(n e ) = 15 MeV
E(n x ) = 18 MeV
Mixing parameters
m2sun = 60 meV 2
sin2(2) = 0.9
No oscillations
Oscillations in SN envelope
Earth effects included
P(Dighe, Kachelriess, Keil, Raffelt, Semikoz, Tomàs),
hep-ph/0303210, hep-ph/0304150, hep-ph/0307050, hep-ph/0311172
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Model-Independent Strategies for Observing Earth Effects
One detector observes SN shadowed by Earth
Case 1:
• Another detector
observes SN directly
• Identify Earth effects
by comparing signals
Case2: Identify “wiggles” in signal of single detector
Problem: Smearing by limited energy resolution
If 13-mixing angle is
known to be “large”,
e.g. from Double Chooz,
observed “wiggles” in
energy spectrum signify
normal mass hierarchy
Scintillator detector
~ 2000 events
may be enough
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Water Cherenkov
Need megaton detector
with ~ 105 events
Dighe, Keil & Raffelt, “Identifying Earth matter
effects on supernova neutrinos at a single detector”
[hep-ph/0304150]
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Supernova Shock Propagation and Neutrino Oscillations
Schirato & Fuller:
Connection between
supernova shocks,
flavor transformation,
and the neutrino signal
[astro-ph/0205390]
Resonance
density for
2
matm
R. Tomàs, M. Kachelriess,
G. Raffelt, A. Dighe,
H.-T. Janka & L. Scheck:
Neutrino signatures of
supernova forward and
reverse shock propagation
[astro-ph/0407132]
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Shock-Wave Propagation in IceCube
Flux(n e )
= 0.8,
Flux(n x )
E ne = 15 MeV,
E n x = 18 MeV
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/0604300
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Supernova Neutrinos 20 Jahre nach SN 1987A
Collective Supernova
Neutrino Oscillations
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Neutrino Density Streaming off a Supernova Core
Typical luminosity in one
neutrino species
L n = 3  1052
erg
s
Corresponds to a neutrino
number density of
2
km


nn = 3  10 35 cm-3 

 R 
Current-current structure
of weak interaction
causes suppression of
effective potential for
collinear-moving particles
Vweak  GF (1 - cos )
Nu-nu refractive effect
decreases as
Vnn  R - 4
Appears to be negligible
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Collective Effects in Neutrino Flavor Oscillations
Collapsed supernova core or accretion torus of
merging neutron stars:
• Neutrino flux very dense: Up to 1035 cm-3
• Neutrino-neutrino interaction energy
much larger than vacuum oscillation frequency
• Large “matter effect” of neutrinos on each
other
• Non-linear oscillation effects
• 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)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Self-Induced Flavor Oscillations of SN Neutrinos
Survival probability ne
Survival probability ne
Normal
Hierarchy
atm m2
MSW
effect
Realistic
nu-nu effect
Q13 close
to Chooz
limit
Inverted
Hierarchy
No
nu-nu effect
Bipolar
collective
oscillations
(single-angle
approximation)
MSW
Realistic
nu-nu effect
No
nu-nu effect
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Mass Hierarchy at Extremely Small Theta-13
Using Earth matter effects to diagnose transformations
Ratio of spectra in
two water Cherenkov
detectors (0.4 Mton),
one shadowed by the
Earth, the other not
Dasgupta, Dighe & Mirizzi, arXiv:0802.1481
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Collective SN neutrino oscillations 2006-2008 (I)
“Bipolar” collective transformations
important, even for dense matter
• Duan, Fuller & Qian
astro-ph/0511275
Numerical simulations
• Including multi-angle effects
• Discovery of “spectral splits”
• Duan, Fuller, Carlson & Qian
astro-ph/0606616, 0608050
• Pendulum in flavor space
• Collective pair annihilation
• Pure precession mode
• Hannestad, Raffelt, Sigl & Wong
astro-ph/0608695
• Duan, Fuller, Carlson & Qian
astro-ph/0703776
Self-maintained coherence
vs. self-induced decoherence
caused by multi-angle effects
• Sawyer, hep-ph/0408265, 0503013
• Raffelt & Sigl, hep-ph/0701182
• Esteban-Pretel, Pastor, Tomàs,
Raffelt & Sigl, arXiv:0706.2498
Theory of “spectral splits”
in terms of adiabatic evolution in
rotating frame
• Raffelt & Smirnov,
arXiv:0705.1830, 0709.4641
• Duan, Fuller, Carlson & Qian
arXiv:0706.4293, 0707.0290
Independent numerical simulations
• Fogli, Lisi, Marrone & Mirizzi
arXiv:0707.1998
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Collective SN neutrino oscillations 2006-2008 (II)
Three-flavor effects in O-Ne-Mg SNe
on neutronization burst
(MSW-prepared spectral double split)
• Duan, Fuller, Carlson & Qian,
arXiv:0710.1271
• Dasgupta, Dighe, Mirrizzi & Raffelt,
arXiv:0801.1660
Theory of three-flavor collective
oscillations
• Dasgupta & Dighe,
arXiv:0712.3798
Identifying the neutrino mass hierarchy
at extremely small Theta-13
• Dasgupta, Dighe & Mirizzi,
arXiv:0802.1481
Second-order mu-tau refractive effect
important in three-flavor context
• Esteban-Pretel, Pastor, Tomàs,
Raffelt & Sigl, arXiv:0712.1137
But for high density, conversions
suppressed by geometric effect
• Esteban-Pretel, Mirizzi, Pastor,
Tomàs, Raffelt, Serpico & Sigl,
arXiv:0807.0659
Collective oscillations along flux lines
for non-spherical geometry
• Dasgupta, Dighe, Mirizzi & Raffelt,
arXiv:0805.3300
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Neutrino Oscillations in a Neutrino Background
Neutrinos in a medium
suffer flavor-dependent
refraction
(Wolfenstein,
PRD 17:2369, 1978)
If neutrinos form the
background, the
refractive index has
“offdiagonal elements”
(Pantaleone,
PLB 287:128, 1992)
f
W, Z
n
f
n
Z
n
 ne - 1 nn
  ne   M2
2
i   = 
 2GF 

t  n m   2E
0


n
 n e 
 
- 1 nn  n m 
2

0
n
n
Z
n

 2nn e  nnm
  ne   M2
i   =
 2GF 
 n
t  n m   2E
nm n e


nn n

e m  n e 
 

nn e  2nnm  n m 

• One can not operationally distinguish between
“beam” and “background”
• Problem is fundamentally nonlinear
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Matrices of Density in Flavor Space
Neutrino quantum field

 
 d3p 



†
i
p
  b t,-p  v  e  x


(t, x) = 
a
t
,
p
u
p
-p 
3

 2  
Spinors in flavor space
 1 


 =  2 
 
 3
 a1 
 b1 
 
 
a =  a 2  b =  b2 
a 
b 
 3
 3
Destruction
operators for
(anti)neutrinos
Variables for discussing neutrino flavor oscillations
Quantum states (amplitudes)

 †
 a1t, p  
n1t, p 


 
n 2 t, p  =  a 2 t, p   0


 
n 3 t, p 
a
 3t,p  
Sufficient for “beam experiments”
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
“Matrices of densities”
(analogous to occupation numbers)


† 
r ijt, p  = a j t, p a i t, p



r ijt, p  = b †i t, p bj t, p
Neutrinos
Antineutrinos
“Quadratic” quantities, required for
dealing with decoherence, collisions,
Pauli-blocking, nu-nu-refraction, etc.
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
General Equations of Motion
n
3
 M2


d
q
i trp =  
, rp   2GF [L, rp ]  2GF 
(1 - cos p q )[(rq - rq ), rp ]
3
 2p

 2 
n
3
 M2


d
q
i t rp = - 
, rp   2GF [L, rp ]  2GF 
(1 - cos p q )[(rq - rq ), rp ]
3
 2 
 2p

• Vacuum oscillations
M is neutrino mass matrix
• Note opposite sign between
neutrinos and antineutrinos
Usual matter effect with
0
0 
 ne - n e


L= 0
nm - nm
0 
 0
0
nt - nt 

Nonlinear nu-nu effects are important
when nu-nu interaction energy exceeds
typical vacuum oscillation frequency
(Do not compare with matter effect!)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
m2
wosc =
 m = 2 GFnn 1 - cos 
2E
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Oscillations of Neutrinos plus Antineutrinos in a Box
m2
Equal n e and n e densities, single energy E, with m = 2 GFnn e ≫
>w=
2E
(n)
 tP = wB  P  m (P - P)  P
 t P = -wB  P  m (P - P)  P




 
Opposite vacuum Equal
oscillations self terms
(n)
w
-w
B
B
P
P
P
P
 = wm
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
“Pendulum in flavor space”
• Inverted mass hierarchy
 Inverted pendulum
 Unstable even for small mixing angle
• Normal mass hierarchy
 Small-amplitude oscillations
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Flavor Conversion Without Flavor Mixing?
Equal ne and ne densities in a box
(inverted hierarchy)
_
Inverted pendulum:
• Time to fall depends
logarithmically on
small initial angle Q
• Stays up forever only
for Q = 0
• Unstable by quantum
uncertainty relation
(“How long can a pencil
stand on its tip?”)
• This is no real “flavor conversion”,
rather a “coherent pair conversion”
n e n e  n m nm
• Occurs anyway at second order GF
• Coherent “speed-up effect” (Sawyer)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Not clear (to me) if coherent
transformations can be triggered
by quantum fluctuations alone
(mixing angle Q = 0)
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Supernova Neutrino Conversion
Permanent pendular
oscillations
Neutrinos
in a box
Neutrinos
streaming
off a
supernova
core
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Envelope declines
as ∝ m1/2 ∝ r -2
Complete conversion
• Nu-nu interaction energy
m = 2GFnn decreases
• Pendulum’s moment of
inertia m-1 increases
• Conservation of angular
momentum
 kinetic energy decreases
 amplitude decreases ∝ m1/2
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Flavor Conversion in Toy Supernova
• 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)
Pendular
Oscillations
Decline of oscillation amplitude
explained in pendulum analogy
by inreasing moment of inertia
(Hannestad, Raffelt, Sigl & Wong
astro-ph/0608695)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Synchronized vs. Pendular Oscillations
• Ensemble of unequal densities nne = a nn e (antineutrino fraction a < 1)
• Equal energies (equal oscillation frequency w = m2/2E)
• Interaction energy m = 2GFnn e

B

B

P

P

B

P

P
1 a
wsynch =
w
1- a
 = (1  a)wm
Synchronized oscillations
1 a
w≪
m
2
(1 - a)
Pendular oscillations
1 a
w≪
 m≪

w
2
(1 - a)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
w

P
-w

P
Free oscillations
m≪
w
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Synchronized vs. Pendular Oscillations
Supernova
Core
R  200 km
R = 40-60 km

B

B

P

P

B

P

P
1 a
wsynch =
w
1- a
 = (1  a)wm
Synchronized oscillations
1 a
w≪
m
2
(1 - a)
Pendular oscillations
1 a
w≪
 m≪

w
2
(1 - a)
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
w

P
-w

P
Free oscillations
m≪
w
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Pendulum in Flavor Space
Polarization vector
for neutrinos plus
antineutrinos
Precession
(synchronized oscillation)
Nutation
(pendular
oscillation)
• Very asymmetric system
- Large spin
- Almost pure precession
nn ≫
> nn
- Fully synchronized oscillations
Spin
(Lepton Asymmetry)
• Perfectly symmetric system
- No spin
- Simple spherical pendulum
n = nn
- Fully pendular oscillation n
[Hannestad, Raffelt, Sigl, Wong:
astro-ph/0608695]
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Mass direction
in flavor space
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Multi-Energy and Multi-Angle Effects
(n)
(n)
 d3q
m2
 tPp = 
B  Pp  L  Pp  2GF 
(1 - cos pq)(Pq - Pq)  Pp
3
2p
 2 
 d3q
m2
 t Pp = B  Pp  L  Pp  2GF 
(1 - cos pq)(Pq - Pq)  Pp
3
2p
 2 
• Different modes oscillate
with different frequencies
 kinematical decoherence
• Self-maintained coherence
by nu-nu interactions
Multi-angle effects for non-isotropic
nu distribution (streaming from SN):
Different modes should oscillate
differently  kinematical decoherence
However, nu-nu interaction can lead to
• Can lead to “spectral split”
• “Angular synchronization”
(quasi-single angle behavior)
Isotropic matter background
affects all modes the same
• Self-accelerated multi-angle
decoherence
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Spectral Split (Stepwise Spectral Swapping)
Initial fluxes
at nu sphere
For explanation see
After
collective
transformation
Raffelt & Smirnov
arXiv:0705.1830
0709.4641
Duan, Fuller,
Carlson & Qian
arXiv:0706.4293
0707.0290
Fogli, Lisi, Marrone & Mirizzi, arXiv:0707.1998
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
Spectral split in terms of the w variable
_
Collective conversion of thermal spectra of ne and ne as in a supernova
Energy spectrum
n initial
n initial
n final
Spectrum in terms of w = m2/2E
n initial
n final
n initial
n final
n final
Flavor lepton number conservation:
Equal integrals
Raffelt & Smirnov, arXiv:0709.4641
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China
SN 1006
Looking Lots
forward
of
May
theoretical
to
take
Nothe
problem
anext
long
work
galactic
timeto do!
supernova
Georg Raffelt, Max-Planck-Institut für Physik, München, Germany
http://antwrp.gsfc.nasa.gov/apod/ap060430.html
Neutrino Physics & Astrophysics, 17-21 Sept 2008, Beijing, China