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ICTP Summer School on Particle Physics, Trieste, Italy, June 2005John Beacom, The Ohio State University

Lecture 3: Supernova NeutrinosLecture 3: Supernova NeutrinosJohnJohn BeacomBeacom, The Ohio State University, The Ohio State University


Elevator PitchElevator PitchWe need complementary searches for new physics

Type II SN: iron white dwarf in core of star;neutrinos reveal (gravitational) explosion energy;hot + dense --> nu + nubar

Type Ia SN: carbon-oxygen white dwarf in binary;gammas reveal (thermonuclear) explosion energy;56Ni --> 56Co --> 56Fe with gammas

“nearby” supernovae are rare

diffuse neutrino background: not seen, is SNII (!?)

diffuse gamma background: is seen, not SNIa (?!)


Main Sequence

t ~ 10-100 Myr

Core-Collapse, Neutrino Emission

Massive Stars (> 8 Solar Mass)

Optical SNII (+Fe)

Black Hole

t ~ sec

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Intermediate Mass Stars (3-8 Solar Mass)

Main Sequence, Binary

t ~ Gyr

Accreting White Dwarf

t ~ Gyr

SNIa (+Fe)

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Two Types of SupernovaeTwo Types of Supernovae


Core Collapse SupernovaeCore Collapse Supernovae


SupernovaeSupernovae

SN1999dk, z = 0.015Modeling (1d, 2d, 3d)

Mezzacappa et al, PRL 86, 1935 (2001)


SupernovaSupernova EnergeticsEnergetics


Supernova Neutrino EmissionSupernova Neutrino Emission


Galactic SupernovaeGalactic Supernovae


Supernova Neutrino DetectionSupernova Neutrino Detection

Supernova physics (models, black holes, progenitors…)

Particle physics (neutrino properties, new particles, …)

IMB

KamII


Super-KamiokandeSuper-Kamiokandee- , e+ , �convert to Cerenkov light


Detection YieldsDetection YieldsAssume a Galactic supernova at 10 kpc

Yields in 22.5 kton Super-Kamiokande:

~ 1 kton detectors: SNO, KamLAND, MiniBooNE~ 1 Gton (but very noisy) detector: IceCube


Waiting Is BoringWaiting Is Boring

“Everybody complains about the supernovarate, but nobody does anything about it.”


Nearby SupernovaeNearby Supernovae


Nearby Star Formation RateNearby Star Formation Rate

Ando, Beacom, and Yüksel, astro-ph/0503321


Supernova DiscoveriesSupernova Discoveries

(Hasan Yüksel)


NearbyNearby SupernovaeSupernovae


More Than a SnowballMore Than a Snowball’’s Chances Chance



Nearby SupernovaNearby Supernova DetectionDetection



DSNB, Take 1: First Good LimitDSNB, Take 1: First Good Limit


Supernova Neutrino BackgroundSupernova Neutrino Background

Ando, Sato, and Totani, Astropart. Phys. 18, 307 (2003)


Relative SpectraRelative Spectra

(M. Malek)


SK Data LimitSK Data Limit

Malek et al. (SK), PRL 90, 061101 (2003)

•4.1 years of SK data

•Background limited

•Some improvementis possible


DSNB Flux LimitDSNB Flux Limit•Predictions roughly agree on spectrum shape

•Main question is normalization of

1.0 Strigari, Kaplinghat, Steigman, Walker, JCAP 0403, 007 (2004)


SK +SK + Gadolinium: DSNB DetectionGadolinium: DSNB Detection


Inverse Beta DecayInverse Beta Decay

•Cross section is “large” and “spectral”

Corrections in Vogel and Beacom, PRD 60, 053003 (1999)

•We must detect the neutron, but how?


Add Gadolinium to SK?Add Gadolinium to SK?

GadoliniumAntineutrinoDetectorZealouslyOutperformingOldKamiokande,Super!

Beacom and Vagins, PRL (2004)


Neutron CaptureNeutron Capture

Capture on H: sigma = 0.3 barnsEgamma = 2.2 MeV

Capture on Gd: sigma = 49100 barnsEgamma = 8 MeV(Equivalent Ee ~ 5 MeV)

At 0.2% GdCl3:


Cost ofCost of GdGd

1984: $4,000/kg $400,000,000/SK

1993: $485/kg $48,500,000/SK

1999: $115/kg $11,500,000/SK

2002: $3/kg $300,000/SK

Based on 100 tons of GdCl3 in SK (0.2% by mass)


Important GdClImportant GdCl33 PropertiesProperties•Soluble in water (unlike mineral oil)

•Initial chemical and radiological purity excellent

•Initial water transparency tests excellent

•100 tons? No problem

•Used in MRI contrasting agents

You could drink 12 liters ofGADZOOKS! water every day


Gadolinium SupplementsGadolinium Supplements

Try “gadolinium health buy” in Google

1.25 ng/liter Gadolinium

“Supports healthy cellular functions”

“Not carcinogenic”

Note: sea water is 0.7 ng/liter Gadolinium

But it doesn’t come in raspberry flavor


Spectrum With GADZOOKS!Spectrum With GADZOOKS!

Beacom and Vagins, PRL (2004) [hep-ph/0309300]


Neutron Backgrounds in SKNeutron Backgrounds in SKDon’t want captures on Gdto dilute the solar signal

How many neutrons are inSK anyway?

•Spallation ~ 105/daybut can be easily cut

•Reactor ~ 20/day (more likely a signal!)

•152Gd decay 1010 alpha/day, P(alpha,n) on 17O is 10-10

•U/Th contamination in GdCl3 must be controlled


Correlated BackgroundsCorrelated Backgrounds•Singles event rate above 5 MeV is ~ 1/ton/yearso accidental background rate is vanishing

•8He/9Li/11Li produced by spallationBeta decay followed by neutron emissionRare, controlled by timing and energy cuts


Galactic Supernova DetectionGalactic Supernova Detection

With GADZOOKS!, we can separate reactions

Real chance to see CC reactions on 16OHaxton, PRD 36, 2283 (1987)Oscillations can increase those yields by ~ 10


IsIs There an Easier Route?There an Easier Route?

Photo thanks to Alex Kusenko


DSNB, Take 2: AstrophysicsDSNB, Take 2: Astrophysics


Star Formation Rate Constraints (?)Star Formation Rate Constraints (?)

Fukugita and Kawasaki, MNRAS 340, L7 (2003)


New Constraint on SFRNew Constraint on SFR

Strigari, Beacom, Walker, Zhang, astro-ph/0502150


Corresponding SupernovaCorresponding Supernova RatesRates



Supernova Gamma-ray BackgroundSupernova Gamma-ray Background



ConclusionsConclusions

Understanding supernovae is essential for:

particle physics: SNII energy loss channelsneutrino properties

nuclear physics: production of the elementsneutron star equation of state

astrophysics: cycle of stellar birth, life, deathconstraints on new sources

cosmology: supernova distance indicatorsdark matter decay, annihilation


Further ReadingFurther Reading

• Georg Raffelt’s online talks:http://wwwth.mppmu.mpg.de/members/raffelt/

• “Identifying the Neutrino Mass Spectrum from the NeutrinoBurst from a Supernova,” Dighe & Smirnov, PRD 62, 033007 (2000)

• “Neutrinos as Astrophysical Probes,” Cavanna, Costantini,Palamara, Vissani, astro-ph/0311256

• Mark Vagins’ talk at Neutrino 2004 (video)http://neutrino2004.in2p3.fr/

• “APS Neutrino Study: Report of the Neutrino Astrophysics andCosmology Working Group,'’ Barwick et al., astro-ph/0412544

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