Heidelberg, 9-12 November 2009 LAUNCH 09 Physics and astrophysics of SN neutrinos: What could we...

Heidelberg, 9-12 November 2009Heidelberg, 9-12 November 2009

LAUNCH 09

Physics and astrophysics of SN Physics and astrophysics of SN neutrinos: neutrinos:

What could we learn ?What could we learn ?

Alessandro MIRIZZI

(Hamburg Universität)

OUTLINE

New interpretations of SN 1987A ’s

Physics potential of current and future SN detectors

SN collective oscillations and possible signatures

Conclusions

Alessandro Mirizzi LAUNCH 09 Heidelberg, 12 November 2009

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.

SUPERNOVA NEUTRINOS

TIME SCALES: Neutrino emission lasts ~10 s

EXPECTED: 1-3 SN/century in

our galaxy (d O (10) kpc).

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


Results of neutrino emission based on the numerical simulations of SN explosion. [see, e.g., T. Totani, K.Sato, H.E. Dalhed, and J.R.

Wilson, Astrophys. J. 496, 216 (1998)].

NEUTRONIZATION BURST:e

• Duration: ~ 25 ms after the explosion

• Emitted energy : E~ 1051 erg

(1/100 of total energy)

• Accretion: ~ 0.5 s

• Cooling: ~ 10 s

• Emitted energy: E~ 1053 erg

THERMAL BURST (ACCRETION + COOLING): e , e , x , x

AC

CR

ET

ION

CO

OL

ING

NEUTRONIZATION

SN NEUTRINO FLUXES


Sanduleak Sanduleak 69 69 202202

Large Magellanic Cloud Large Magellanic Cloud Distance 50 kpcDistance 50 kpc (160.000 light years)(160.000 light years)

Tarantula NebulaTarantula Nebula

Supernova 1987ASupernova 1987A 23 February 198723 February 1987

SN1987A Neutrino Burst Observation : SN1987A Neutrino Burst Observation : First verification of stellar evolution mechanismFirst verification of stellar evolution mechanism


Energy Distribution of SN 1987A Neutrinos

Kamiokande-II (Japan)Water Cherenkov detector2140 tons

Irvine-Michigan-Brookhaven (US)Water Cherenkov detector6800 tons


[B. Jegerlehner, F. Neubig and G. Raffelt, PRD 54, 1194 (1996); A.M., and G. Raffelt, PRD 72, 063001 (2005)]

• Imposing thermal spectra, tension between the two experiments (marginal overlap between the two separate CL)

• Tension between the experiments and the theory.

To

tal

bin

din

g e

ner

gy

Average e energy

Theory

Interpreting SN1987A neutrinos

But….


NEW LONG-TERM COOLING CALCULATIONLower average energies…In agreement with SN 1987A data

Fischer et al. (Basel group), arXiv: 0908.1871

Possible to reconcile detection and theory… Still many open questions!

SN NEUTRINO SPECTRUM FROM SN1987A[Yuksel & Beacom, astro-ph/0702613]

Original SN energy spectra expected to be quasi-thermal

SN1987A inferred energy spectrum shows strong deviations from quasi-thermal distribution:

Possible effects of:

• neutrino mixing

• interactions

• decay

• nonstandard interactions

• additional channels of energy exchange among flavors

?Alessandro Mirizzi LAUNCH 09 Heidelberg, 12 November 2009

What could we see “tomorrow”?

What could we see “tomorrow”?

SN 20XXA !SN 20XXA !

Large Detectors for Supernova Neutrinos

Super-Kamiokande (10Super-Kamiokande (1044))KamLAND (330)KamLAND (330)

MiniBooNE (200)MiniBooNE (200)

In brackets eventsIn brackets eventsfor a “fiducial SN”for a “fiducial SN”at distance 10 kpcat distance 10 kpc

LVD (400)LVD (400)Borexino (80)Borexino (80)

IceCube (10IceCube (1066))

SEARCH FOR SN NEUTRINO BURSTS

SUPER-KAMIOKANDE MINIBOONE

Upper limit: 0.32 SN year-1 @ 90 % C.L.for d < 100 kpc[SK collaboration, arXiv: 0706.2283]

Upper limit: 0.69 SN year-1 @ 90 % C.L.for d < 13.5 kpc

[Miniboone collaboration, arXiv: 0910.3182]


Accretion phase

Cooling phase

Simulation for Super-Kamiokande SN signal at 10 kpc,Simulation for Super-Kamiokande SN signal at 10 kpc,based on a numerical Livermore modelbased on a numerical Livermore model[Totani, Sato, Dalhed & Wilson, ApJ 496 (1998) 216][Totani, Sato, Dalhed & Wilson, ApJ 496 (1998) 216]

Simulated Supernova Signal at Super-Kamiokande

Simulated Supernova Signal at Ice-Cube[Dighe, Keil and Raffelt, hep-ph/0303210]

LIVERMORE GARCHING

Possible to reconstruct the SN lightcurve with current detectors. Discrimination btw different simulations.

Millisecond bounce time reconstruction

Onset of neutrinoOnset of neutrinoemissionemission

• Emission model adapted toEmission model adapted to measured SN 1987A datameasured SN 1987A data

• “ “Pessimistic distance” of 20 kpcPessimistic distance” of 20 kpc

• Determine bounce time to withinDetermine bounce time to within a few tens of millisecondsa few tens of milliseconds

SUPER-KAMIOKANDE ICE-CUBE

[Pagliaroli, Vissani, Coccia & Fulgione arXiv:0903.1191]

[Halzen & Raffelt, arXiv:0908.2317]

External trigger for gravitational-wave search


SIGNALS OF QCD PHASE TRANSITION IN SN [Sagert et al., arXiv:0809.4225]

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

PROBING QCD PHASE TRANSITION IN SN DETECTORS

[Dasgupta, Fischer, Horiuchi, Liebendoerfer, A.M., in preparation]

While the standard e neutronization burst is difficult to detect with current detectors, the QCD-induced e peak would be successfully tracked by IBD reactions.

SUPER-KAMIOKANDEICE-CUBE


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

UNO, MEMPHYS, HYPER-K

Mton Cherenkov

LENA

Scintillator

See LAGUNA Collaboration, “Large underground, liquid based detectors for astro-particle physics in Europe: Scientific case and prospects,” arXiV:0705.0116 [hep-ph]

Next generation Detectors for Supernova Neutrinos

GLACIER

LAr TPC

0.4 Mton Water Cherenkov detector

Golden channel: Inverse beta decay (IBD) of e

~2.5×105 events @ 10 kpc

[ Fogli, Lisi, A.M., Montanino, hep-ph/0412046]


SN FROM NEARBY GALAXIES

The core-collpase SN rate in 10 Mpc is R 1/ year. Detection of R 1 per year in 1 Mton WC detector

@ 1 Mton WC

[Ando, Beacom, Yuksel, astro-ph/0503321]


COLLECTIVE SUPERNOVA COLLECTIVE SUPERNOVA NEUTRINO OSCILLATIONSNEUTRINO OSCILLATIONS

SN FLAVOR TRANSITIONS

The flavor evolution in matter is described by the non-linear MSW equations:

In the standard 3 framework

Kinematical mass-mixing term

Dynamical MSW term (in matter)

vac e

di H H Hdx

2 (1 cos ) F pq q qH G dq

2 †

2vac

U M UH

E

2 diag( ,0,0)e F eH G N

Neutrino-neutrino interactions term (non-linear)


Mixing parameters: U = U (12, 13, 23) as for CKM matrix

Mass-gap parameters:M2 = - , + , ±

m2m2

2m2

2

“solar” “atmospheric”

normal hierarchy

inverted hierarchy

m2/2-m2/2

m2

m2

m2/2-m2/2

1 12 2

3

3

VACUUM OSCILLATIONS: 3 FRAMEWORK

(see,e.g., Fogli et al., 0805.2517)

2 3 2

2 5 2

12

23

13

2.4 10 eV

8. 10 eV

0.6

/ 4

0.1

m

m


SN SELF-INTERACTION POTENTIAL AND MATTER POTENTIAL

r < 200 km : Self-induced collective oscillations

r > 200 km : Ordinary MSW effects

Recent review: A. Dighe: arXiv:0809.2977 [hep-ph]

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]

LARGE NEUTRINO DENSITY

PENDULAR OSCILLATIONS

[Hannestad, Raffelt, Sigl, Wong, astro-ph/0608695]

Equal densities of and INVERTED HIERARCHY + small θLARGE flavour transformations:

Periodic if density constant

Non-periodic if density decreases (SUPERNOVA!)

Excess of e over e

• Occurs for very small mixing angles• Almost independent of the presence of

dense normal matter

Complete flavor conversions!


Ons

et r

adiu

s of

col

lect

ive

conv

ersi

ons

log10 13

Collective flavor conversions in inverted hierarchy are expected also for 13→0, when further MSW matter effects are negligible

[Duan, Fuller, Carlson & Qian, arXiv:0707.0290 (astro-ph)]

Effect logarithmically delayed when 13→0

COLLECTIVE OSCILLATIONS IN IH @ 13→ 0


Accretion phase Cooling phase

xee FFF

xee FFF

eex FFF

eex FFF

NEUTRINO FLUX NUMBERS

Excess of e due to deleponization

Moderate flavor hierarchy, possible excess of x

[Raffelt et al. (Garching group), astro-ph/0303226]

e

e

x

SPECTRAL SPLITS IN THE ACCRETION PHASE[G.L.Fogli, E.Lisi, A. Marrone, A.M. , arXiV: 0707.1998 [hep-ph]]

Initial fluxes at neutrinosphere (r ~10 km)

Fluxes at the end of collective effects (r ~200 km)Nothing happens in NH

Inve

rted

mas

s h

iera

rch

y

: : 2.4 :1.6 :1.0e e xF F F

(ratio typical of accretion phase)

MULTIPLE SPECTRAL SPLITS IN THE COOLING PHASE[Dasgupta, Dighe, Raffelt & Smirnov, arXiv:0904.3542 [hep-ph] ]

: : 0.85 : 0.75 :1.00e e xF F F

e (typical in cooling phase)

Splits possible in both normal and inverted hierarchy, for &

Possible time-dependent signatures in the SN signal


x

TERNARY LUMINOSITY DIAGRAM[Fogli, Lisi, Marrone, Tamborra, arXiv:0907.5115]

Equipartition of luminosities

)6/4,6/1,6/1()4,,( xee LLL

Moving from the equiparition point, double splits can occur for both and

Phenomenology crucially dependent on the original neutrino fluxes


[GARCHING astro-ph/0303226] [BASEL 0908.1871]

COMPARING TWO SN SIMULATIONS

COOLING PHASE BASEL (equipartition of luminosities)

xee FFF ACCRETION PHASE . Single split in and complete swap for in IH. No effect in NH. Flux ordering robust consequence of the core deleptonization

xee FFF as in the accretion. GARCHING (deviation from equipartion) eex FFF Multiple splits in NH & IH for both and

[Table by Amol Dighe]

SN OSCILLATED SPECTRA

00

00

)1(

)1(

xee

xee

FpFpF

FpFpF


USING EARTH EFFECT TO DIAGNOSE COLLECTIVE OSCILLATIONS

Earth matter crossing induces additional conversions between 1 and 2 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

e + p → n + e+


MASS HIERARCHY DETERMINATION AT EXTREMELY SMALL

[Dasgupta, Dighe, A.M., arXiv:0802.1481 [hep-ph]]

Ratio of spectra in two water Cherenkov detectors (0.4 Mton), one shadowed by the Earth, the other not.

shadowed unshadowede e

unshadowede

F FR

F

(Accretion phase)


Observing SN neutrinos is the next frontier of low-energy neutrino astronomy

The physics potential of current and next-generation detectors in this context is enormous, both for particle physics and astrophysics.

CONCLUSIONS


SN provide very extreme conditions, where neutrino-neutrino interactions prove to be surprisingly important

Lot of theoretical work still needed to understand neutrino flavor conversions during a stellar collapse

Difficult to make robust predictions at the moment: Necessary more reliable predictions of primary fluxes. Next SN burst will “calibrate” the simulations.

SUCCESS IS GUARANTEED !!

Heidelberg, 9-12 November 2009 LAUNCH 09 Physics and astrophysics of SN neutrinos: What could we...

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