Transcript Neutrinos: Ghostparticles of the Universe

Supernova Neutrinos
Supernova Neutrinos
Нейтрино от сверхновые
Georg Raffelt, 17th Lomonosov Conference, Moscow
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Core-Collapse Supernova Explosion
Collapse of
degenerate core
Neutrino
cooling by
diffusion
• Huge rate of low-E neutrinos
(tens of MeV) over few seconds
in large-volume detectors
• A few core-collapse SNe in our
galaxy per century
• Once-in-a-lifetime opportunity
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Three Distinct Phases of Neutrino Emission
Explosion
triggered
• Shock breakout
• De-leptonization of
outer core layers
Cooling on neutrino
diffusion time scale
Spherically symmetric Garching model (25 M⊙) with Boltzmann neutrino transport
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
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
Within clock uncertainties,
all signals are contemporaneous
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Operational Detectors for Supernova Neutrinos
SNO+
(300)
HALO
(tens)
LVD (400)
Borexino (100)
Baksan
(100)
Super-K (104)
KamLAND (400)
Daya Bay
(100)
IceCube (106)
Georg Raffelt, MPI Physics, Munich
In brackets events
for a “fiducial SN”
at distance 10 kpc
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
IceCube as a Supernova Neutrino Detector
SN signal at 10 kpc
10.8 Msun simulation
of Basel group
[arXiv:0908.1871]
Accretion
Cooling
Pryor, Roos & Webster, ApJ 329:355, 1988. Halzen, Jacobsen & Zas, astro-ph/9512080.
Demirörs, Ribordy & Salathe, arXiv:1106.1937.
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Next Generation Large-Scale Detectors (2020+)
IceCube Gen-2
- Dense infill (PINGU)
- Larger volume (statistics for high-E events)
Doubling the number of optical modules
Megaton water Cherenkov detector
Notably Hyper-Kamiokande
SN neutrino statistics comparable to IceCube,
but with event-by-event energy information
Scintillator detector (tens of kilotons)
- Original LENA concept 50 kt
- JUNO (20 kt) in China for reactor nus
- RENO-50 (20 kt) in Korea for reactor nus
- Baksan Large Vol. Scintillator Detector (20 kt)
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Local Group of Galaxies
With megatonne class (30 x SK)
60 events from Andromeda
Current and next-generation
neutrino detectors
sensitive out to few 100 kpc
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
SN Distance Distribution and Peak Count Rate
JUNO Yellow Book, in preparation (2014)
Peak count rate
in JUNO (20 kt)
depending on
SN distance
SN distance
probability
in Milky Way
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Crab Nebula
Core-Collapse Supernova
Explosion Mechanism
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Shock Revival by Neutrinos
Stalled shock wave must
receive energy to start
re-expansion against
ram pressure of
infalling stellar core
O
Si
n
n
Shock can receive
fresh energy from
neutrinos!
S
PNS
n
Si
Georg Raffelt, MPI Physics, Munich
Shock
wave
17th Lomonosov
NOW
Conference,
2014, 7–14Moscow,
Sept 2014,
20–26
Otranto,
Aug 2015
Italy
Exploding 3D Garching Model (20 MSUN)
2D
3D
Neutrino opacity reduced (few 10%) by
strange quark contribution to nucleon spin
(thick lines)
“Standard” neutrino opacity
(thin lines)
Melson, Janka, Bollig, Hanke, Marek & Müller,
arXiv:1504.07631
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Exploding 3D Garching Model (20 MSUN)
Melson, Janka, Bollig, Hanke, Marek & Müller, arXiv:1504.07631
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Variability seen in Neutrinos (3D Model)
Tamborra, Hanke, Müller, Janka & Raffelt, arXiv:1307.7936
See also Lund, Marek, Lunardini, Janka & Raffelt, arXiv:1006.1889
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Sky Map of Lepton-Number Flux (11.2 MSUN Model)
Positive dipole
direction and
track on sky
Tamborra, Hanke, Janka, Müller, Raffelt & Marek, arXiv:1402.5418
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Growth of Lepton-Number Flux Dipole
Tamborra et al., arXiv:1402.5418
Monopole
Dipole
• Overall lepton-number flux (monopole) depends on accretion rate,
varies between models
• Maximum dipole similar for different models
• Dipole persists (and even grows) during SASI activity
• SASI and LESA dipoles uncorrelated
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Flavor Oscillations
Diffuse SN Neutrino Background
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Diffuse Supernova Neutrino Background (DSNB)
Beacom & Vagins,
PRL 93:171101,2004
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Experimental DSNB Limits
KamLand
SuperK IV
(with neutron tagging)
SuperK I-III
Super-K with
Gadolinium
enhancement
(neutron tagging)
will strongly improve
sensitivity
Super-Kamiokande Collaboration, arXiv:1311.3738
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
DSNB Sensitivity of JUNO 20 kt Scintillator Detector
JUNO detection
sensitivity (10 y)
Example for
typical parameters
JUNO 90% Exclusion
Sensitivity (10 y)
JUNO Collaboration, Yellow Book, arXiv:1507.05613
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Crab Nebula
Supernova Neutrino
Flavor Conversion
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Gribov and Pontecorvo 1968
Learning about
astrophysical sources
with neutrinos
Bruno Pontecorvo
(1913–1993)
Georg Raffelt, MPI Physics, Munich
Learning about
neutrinos from
astrophysics and
cosmology
Vladimir Gribov
(1930–1997)
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Flavor Oscillations in Core-Collapse Supernovae
Neutrino-neutrino
refraction causes
a flavor instability,
flavor exchange
between different
parts of spectrum
Flavor eigenstates are
propagation eigenstates
Neutrino flux
Neutrino
sphere
MSW region
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Self-Induced Flavor Conversion
No net flavor conversion of ensemble
(in contrast to MSW conversion)
Flavor content exchanged
between different momentum modes
(or nus and anti-nus changing together)
Interacting neutrino system: Coupled oscillators
- Collective harmonic oscillation modes
- Exponential run-away modes
Instability required to get started
- Exponentially growing off-diagonals in density matrix
- Linearized stability analysis to find growing modes
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
New Development: Spatial Symmetry Breaking
Time
Without flavor oscillations: free streaming
Mirizzi, Mangano & Saviano
arXiv:1503.03485
See also Duan et al,
arXiv:1412.7097, 1507.08992
Chakraborty et al., arXiv:1507.07569
Space coordinate along beam
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Instability Footprints
Axial-symmetry breaking (MAA)
instability (normal ordering NH)
is “more dangerous” to trigger
self-induced flavor conversion
Shock
wave
Traditional “bimodal” instability
(inverted mass ordering IH)
• Small-scale modes “fill in”
the stability footprint
for large neutrino density
• Largest-scale mode is
“most dangerous” to
cross SN density profile
Chakraborty, Hansen, Izaguirre & Raffelt, arXiv:1507.07569
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Status of Collective Flavor Conversion
Self-induced flavor conversion is an instability
in flavor space of the interacting neutrino ensemble
Space-time dependent phenomenon
(not simply stationary or homogeneous)
Solutions do not respect symmetries of initial system
Instabilities can occur on all scales
Essentially back
to the drawing board …
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Three Phases – Three Opportunities
Prompt ne burst
“Standard Candle”
•
•
•
•
SN theory
Distance
Flavor conversion
Multi-messenger
time of flight
Georg Raffelt, MPI Physics, Munich
Accretion
Cooling
Strong variations
(progenitor, 3D effects,
black hole formation, …)
• Testing astrophysics of
core collapse
• Flavor conversion has
strong impact on signal
EoS & mass dependence
• Testing Nuclear Physics
• Nucleosynthesis in
neutrino-driven wind
• Particle bounds from
cooling speed (axions …)
17th Lomonosov Conference, Moscow, 20–26 Aug 2015
Looking forward to the next galactic supernova
Neutrinos from next nearby supernova:
A once-in-a-lifetime opportunity: Do not miss it!
Georg Raffelt, MPI Physics, Munich
17th Lomonosov Conference, Moscow, 20–26 Aug 2015