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George M. Fuller Department of Physics & Center for Astrophysics and Space Science University of California, San Diego Supernova Physics and DUSEL UCLA/UCSD.

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Presentation on theme: "George M. Fuller Department of Physics & Center for Astrophysics and Space Science University of California, San Diego Supernova Physics and DUSEL UCLA/UCSD."— Presentation transcript:

1 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 Detectors experimental exploitation of spectral swaps experimental exploitation of spectral swaps George M. Fuller Department of Physics

2 We know the mass-squared differences: We do not know the absolute masses or the mass hierarchy: Neutrino Mass: what we know and don’t know

3 We know 2 of the 4 vacuum 3X3 mixing parameters and we have a good upper limit on a third. Neutrino energy (mass) states are not coincident with the weak interaction (flavor) states The unitary transformation that relates these states in vacuum has 4 parameters ( exclusive of Majorana phases )

4 4 parameters Maki-Nakagawa-Sakata matrix

5 Atmospheric Neutrinos “Solar”/KamLaND Neutrinos The key mixing angle

6 survival probability cosine of  trajectory angle wrt. normal to n.s. surface consequences of neutrino mass and quantum coherence in supernovae H. Duan, G. M. Fuller, J. Carlson, Y.-Z. Qian, Phys. Rev. Lett. 97, (2006) astro-ph/ normal mass hierarchy inverted mass hierarchy Spectral Swap

7 The e -  Spectral Swap - a mass hierarchy signal ? normal mass hierarchy inverted mass hierarchy cosine of neutrino emission angle survival probability P neutrino energy here spectral swap energy E C decreases with decreasing  V swap has its origin in nonlinear neutrino self-coupling

8 Radius where P drops below 0.9 The inverted mass hierarchy sets up instability in flavor evolution. Hence, even tiny   values can bring about a spectral swap!

9 ECEC swap energy swap normal mass hierarchy

10 Probably now need to re-think strategy for detecting the neutrino signal from a future Galactic supernova. Swap features that could tell us the neutrino mass hierarchy and are at relatively low energy, like solar neutrinos, and  13 are at relatively low energy, like solar neutrinos, at least for Fe-core collapse supernovae. Swap features might occur at late times post-core-bounce, when neutrino fluxes are low. Perhaps consider liquid scintillator and liquid noble gas detectors for. liquid noble gas detectors for DUSEL.

11 Nuclear Physics of Mass Charged current capture on 40 Ar : Minimum Gamow-Teller Threshold: 3.8 MeV to first 1 + state Gamow-Teller resonance: excitation energy E GT ~ 4.46 to 6 MeV GT-Res Threshold: ~ 6 to 8 MeV Neutral current excitation of 40 Ar : 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

12 1s1/2 1p3/2 1p1/2 1d5/2 1d3/2 2s1/2 1f7/2 2p3/2 2p1/2 1f5/ protonsneutrons xx xxoo 4 xxxo x protonsneutrons zero-order single particle shell model

13 Fermi resonance (IAS) Gamow-Teller resonance Charged current capture gives final state electron and lots of nuclear de-excitation photons Neutral current excitation gives lots of de-excitation photons Cline & Fuller 09


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