Heidelberg, 9-12 November 2009 LAUNCH 09 Physics and astrophysics of SN neutrinos: 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 MirizziLAUNCH 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 (~ erg) is emitted by and of all flavors, with typical energies E ~ O(15 MeV). Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

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~ erg (1/100 of total energy) Accretion: ~ 0.5 s Cooling: ~ 10 s Emitted energy: E~ erg  THERMAL BURST (ACCRETION + COOLING): e, e, x, x ACCRETION COOLING NEUTRONIZATION SN NEUTRINO FLUXES Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

Sanduleak  Large Magellanic Cloud Distance 50 kpc ( light years) Tarantula Nebula Supernova 1987A 23 February 1987 Supernova 1987A 23 February 1987

SN1987A Neutrino Burst Observation : First verification of stellar evolution mechanism Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

Energy Distribution of SN 1987A Neutrinos Kamiokande-II (Japan) Water Cherenkov detector 2140 tons Irvine-Michigan-Brookhaven (US) Water Cherenkov detector 6800 tons Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

[ B. Jegerlehner, F. Neubig and G. Raffelt, PRD 54, 1194 (1996); A.M., and G. Raffelt, PRD 72, (2005) ] Imposing thermal spectra, tension between the two experiments (marginal overlap between the two separate CL) Tension between the experiments and the theory. Total binding energy Average e energy Theory Interpreting SN1987A neutrinos But…. Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

NEW LONG-TERM COOLING CALCULATION Lower average energies…In agreement with SN 1987A data Fischer et al. (Basel group), arXiv:

Possible to reconcile detection and theory… Still many open questions! SN NEUTRINO SPECTRUM FROM SN1987A [Yuksel & Beacom, astro-ph/ ] 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 MirizziLAUNCH 09 Heidelberg, 12 November 2009

What could we see “tomorrow”? SN 20XXA !

Large Detectors for Supernova Neutrinos Super-Kamiokande (10 4 ) KamLAND (330) MiniBooNE (200) In brackets events for a “fiducial SN” at distance 10 kpc LVD (400) Borexino (80) IceCube (10 6 )

SEARCH FOR SN NEUTRINO BURSTS SUPER-KAMIOKANDE MINIBOONE Upper limit: 0.32 SN year 90 % C.L. for d < 100 kpc [SK collaboration, arXiv: ] Upper limit: 0.69 SN year 90 % C.L. for d < 13.5 kpc [Miniboone collaboration, arXiv: ] Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

Accretion phase Cooling phase Simulation for Super-Kamiokande SN signal at 10 kpc, based on a numerical Livermore model [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/ ] LIVERMOREGARCHING Possible to reconstruct the SN lightcurve with current detectors. Discrimination btw different simulations.

Millisecond bounce time reconstruction Onset of neutrino emission Emission model adapted to Emission model adapted to measured SN 1987A data measured SN 1987A data “Pessimistic distance” of 20 kpc “Pessimistic distance” of 20 kpc Determine bounce time to within Determine bounce time to within a few tens of milliseconds a few tens of milliseconds SUPER-KAMIOKANDE ICE-CUBE [Pagliaroli, Vissani, Coccia & Fulgione arXiv: ] [Halzen & Raffelt, arXiv: ] External trigger for gravitational-wave search Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

SIGNALS OF QCD PHASE TRANSITION IN SN [Sagert et al., arXiv: ] 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-KAMIOKANDE ICE-CUBE Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

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: [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× kpc [ Fogli, Lisi, A.M., Montanino, hep-ph/ ] Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

SN FROM NEARBY GALAXIES The core-collpase SN rate in 10 Mpc is ̴ 1/ year. Detection of ̴ 1 per year in 1 Mton WC 1 Mton WC [ Ando, Beacom, Yuksel, astro-ph/ ] Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

COLLECTIVE SUPERNOVA NEUTRINO 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) Neutrino-neutrino interactions term (non-linear) Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

Mixing parameters: U = U (  12,  13,  23 ) as for CKM matrix Mass-gap parameters: M 2 = -, +, ±  m 2 m2m2 2 m2m2 2 “solar” “atmospheric” normal hierarchy inverted hierarchy m2/2m2/2 -m2/2-m2/2 m2m2  m 2 m2/2m2/2 -m2/2-m2/ VACUUM OSCILLATIONS: 3 FRAMEWORK (see,e.g., Fogli et al., ) Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

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: [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/ ] LARGE NEUTRINO DENSITY

PENDULAR OSCILLATIONS [ Hannestad, Raffelt, Sigl, Wong, astro-ph/ ] Equal densities of and INVERTED HIERARCHY + small θ LARGE 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! Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

Onset radius of collective conversions log 10  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: (astro-ph)] Effect logarithmically delayed when  13 → 0 COLLECTIVE OSCILLATIONS IN  13 → 0 Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

Accretion phase Cooling phase NEUTRINO FLUX NUMBERS Excess of e due to deleponization Moderate flavor hierarchy, possible excess of x [ Raffelt et al. (Garching group), astro-ph/ ] e e x

SPECTRAL SPLITS IN THE ACCRETION PHASE [ G.L.Fogli, E.Lisi, A. Marrone, A.M., arXiV: [hep-ph] ] Initial fluxes at neutrinosphere (r ~10 km) Fluxes at the end of collective effects (r ~200 km) Nothing happens in NH Inverted mass hierarchy (ratio typical of accretion phase)

MULTIPLE SPECTRAL SPLITS IN THE COOLING PHASE [ Dasgupta, Dighe, Raffelt & Smirnov, arXiv: [hep-ph] ] e (typical in cooling phase) Splits possible in both normal and inverted hierarchy, for &  Possible time-dependent signatures in the SN signal Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009 x

TERNARY LUMINOSITY DIAGRAM [ Fogli, Lisi, Marrone, Tamborra, arXiv: ] Equipartition of luminosities Moving from the equiparition point, double splits can occur for both and Phenomenology crucially dependent on the original neutrino fluxes Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

[ GARCHING astro-ph/ ] [BASEL ] COMPARING TWO SN SIMULATIONS COOLING PHASE BASEL (equipartition of luminosities) ACCRETION PHASE. Single split in and complete swap for  in IH. No effect in NH. Flux ordering robust consequence of the core deleptonization as in the accretion. GARCHING (deviation from equipartion) Multiple splits in NH & IH for both and

[Table by Amol Dighe] SN OSCILLATED SPECTRA Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

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 + Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

MASS HIERARCHY DETERMINATION AT EXTREMELY SMALL   [Dasgupta, Dighe, A.M., arXiv: [hep-ph]] Ratio of spectra in two water Cherenkov detectors (0.4 Mton), one shadowed by the Earth, the other not. (Accretion phase) Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009

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 Alessandro MirizziLAUNCH 09 Heidelberg, 12 November 2009 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 !!