George M. Fuller Department of Physics &Center for Astrophysics and Space Science University of California, San Diego

Supernova Physics and DUSEL UCLA/UCSD Workshop UCLA, September 16, 2009

Supernova Neutrino Detection with Liquid Argon DetectorsSupernova Neutrino Detection with Liquid Argon Detectors experimental exploitation of spectral swapsexperimental exploitation of spectral swaps

George M. Fuller Department of Physics

We know the mass-squared differences:

We do not know the absolute masses or the mass hierarchy:

Neutrino Mass: Neutrino Mass: what we know and don’t knowwhat we know and don’t know

We know We know 22 of the of the 4 4 vacuum 3X3 mixing parametersvacuum 3X3 mixing parametersand we have a good upper limit on a and we have a good upper limit on a thirdthird..

Neutrino energy (mass) states are Neutrino energy (mass) states are notnot coincident coincidentwith the weak interaction (flavor) stateswith the weak interaction (flavor) states

The unitary transformation that relates these statesThe unitary transformation that relates these statesin vacuum has 4 parameters (in vacuum has 4 parameters (exclusive of Majorana phasesexclusive of Majorana phases))

4 parameters

Maki-Nakagawa-Sakata matrix

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δm232 ≈ 2.4 ×10−3 eV2

sin2θ23 ≈ 0.50Atmospheric Neutrinos

“Solar”/KamLaND Neutrinos

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δmsol2 ≈ 7.6 ×10−5 eV2

sin2θ12 ≈ 0.31

The key mixing angle

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limit on θ13 ⇒

sin2θ13 < 0.040 ( 2σ )

survival probability

cosi

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consequences of neutrino mass and quantum coherence in supernovaeH. Duan, G. M. Fuller, J. Carlson, Y.-Z. Qian, Phys. Rev. Lett. 97, 241101 (2006) astro-ph/0606616

no

rma

l ma

ss

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rarc

hy

inv

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d m

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iera

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Spectral SwapSpectral Swap

The The e e - - Spectral Swap - Spectral Swap - a mass hierarchy signal ?a mass hierarchy signal ?

normal mass hierarchy inverted mass hierarchy

cosi

ne o

f n

eu

trin

o e

mis

sion a

ngle

survival probability P

neutrino energy neutrino energy

here spectral swap energy ECdecreases with decreasing V

swap has its origin in nonlinear neutrino self-couplingswap has its origin in nonlinear neutrino self-coupling

Radiu

s w

here

P d

rops

belo

w 0

.9

The inverted mass hierarchy sets upinstability in flavor evolution. Hence, even tiny values can

bring about a spectral swap!

ECswap energy

swapnormal mass hierarchy

Probably now need to re-think strategy forProbably now need to re-think strategy fordetecting the neutrino signal from a futuredetecting the neutrino signal from a futureGalactic supernova.Galactic supernova.

Swap features that could tell us the Swap features that could tell us the neutrino mass hierarchyneutrino mass hierarchyand and 13 are at relatively low energy, like solar neutrinos,are at relatively low energy, like solar neutrinos,at least for Fe-core collapse supernovae.at least for Fe-core collapse supernovae.

Swap features Swap features mightmight occur at late times post-core-bounce, occur at late times post-core-bounce, when when neutrino fluxes are low.neutrino fluxes are low.

Perhaps consider Perhaps consider liquid scintillatorliquid scintillator and and liquid noble gasliquid noble gas detectors for detectors for DUSEL..

Nuclear Physics of Mass 40

18

Charged current capture on 40Ar : Minimum Gamow-Teller Threshold: 3.8 MeV to first 1+ state

Gamow-Teller resonance: excitation energy EGT ~ 4.46 to 6 MeV GT-Res Threshold: ~ 6 to 8 MeV

Neutral current excitation of 40Ar :

Minimum allowed weak threshold: to first 0+ excited state at 2.12 MeV

sensitive to neutrino energy- electron flavor only

from all flavors-normalizes flux

1s1/2

1p3/2

1p1/2

1d5/2

1d3/2

2s1/2

1f7/2

2p3/2

2p1/2

1f5/2

2

4

2

6

2

4

2

4

2

6

2

protons neutrons

xx

xxoo 4xxxo

x

protons neutrons

zero-order single particle shell model

Fermi resonance(IAS)

Gamow-Teller resonanceCharged current capturegives final state electronand lots of nuclear de-excitation photons

Neutral current excitation giveslots of de-excitation photons

Cline & Fuller 09