Physik Kolloquium, 19. November 2007 RWTH Aachen Title Physik Kolloquium, 19. November 2007 RWTH Aachen Exzellenz Georg Raffelt, Max-Planck-Institut für Physik, München

Supernova Neutrinos 20 Years after SN 1987A Aachen Skyline Supernova Neutrinos 20 Years after SN 1987A

Sanduleak -69 202 Supernova 1987A 23 February 1987 Tarantula Nebula Large Magellanic Cloud Distance 50 kpc (160.000 light years) Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

Supernova Neutrinos 20 Jahre nach SN 1987A Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

Crab Nebula Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

Supernova 1054 Petrograph Hand signifies sacred place Crescent SN 1054 Moon 3 concentric circles, diameter  1 foot, with huge red flames trailing to the right. (Halley’s Comet ?) SN 1054 Hand signifies sacred place Possible SN 1054 Petrograph by the Anasazi people (Chaco Canyon, New Mexico)

SN 1987A Rings (Hubble Space Telescope 4/1994) Georg Raffelt, Max-Planck-Institut für Physik, München, Germany SN 1987A Rings (Hubble Space Telescope 4/1994) 500 Light-days Ring system consists of material ejected from the progenitor star, illuminated by UV flash from SN 1987A Foreground Star Supernova Remnant (SNR) 1987A

SN 1987A Explosion Hits Inner Ring

Stellar Collapse and Supernova Explosion Onion structure Main-sequence star Hydrogen Burning Collapse (implosion) Helium-burning star Helium Burning Hydrogen Degenerate iron core: r  109 g cm-3 T  1010 K MFe  1.5 Msun RFe  8000 km

Stellar Collapse and Supernova Explosion Newborn Neutron Star ~ 50 km Proto-Neutron Star r  rnuc = 3  1014 g cm-3 T  30 MeV Collapse (implosion) Neutrino Cooling

Stellar Collapse and Supernova Explosion Newborn Neutron Star ~ 50 km Proto-Neutron Star r  rnuc = 3  1014 g cm-3 T  30 MeV Neutrino Cooling Gravitational binding energy Eb  3  1053 erg  17% MSUN c2 This shows up as 99% Neutrinos 1% Kinetic energy of explosion (1% of this into cosmic rays) 0.01% Photons, outshine host galaxy Neutrino luminosity Ln  3  1053 erg / 3 sec  3  1019 LSUN While it lasts, outshines the entire visible universe

Periodic System of Elementary Particles Quarks Leptons Charm Top Gravitation Weak Interaction Strong Interaction (QCD) Electromagnetic Interaction (QED) Down Strange Bottom Electron Muon Tau e-Neutrino t-Neutrino 1st Family 2nd Family 3rd Family Charge +2/3 Charge -1/3 Charge -1 Charge 0 Up m-Neutrino nt ne e m t d s b c u nm Quarks Leptons Charge +2/3 Up Charge -1/3 Down Charge -1 Electron Charge 0 e-Neutrino ne e d u Neutron Proton

Where do Neutrinos Appear in Nature? Nuclear Reactors  Sun  Particle Accelerators  Supernovae (Stellar Collapse) SN 1987A  Earth Atmosphere (Cosmic Rays)  Astrophysical Accelerators Soon ? Earth Crust (Natural Radioactivity)  Cosmic Big Bang (Today 330 n/cm3) Indirect Evidence

Neutrinos from the Sun Helium Solar radiation: 98 % light Hans Bethe (1906-2005, Nobel prize 1967) Thermonuclear reaction chains (1938) Helium Reaction- chains Energy 26.7 MeV Solar radiation: 98 % light 2 % neutrinos At Earth 66 billion neutrinos/cm2 sec

Sun Glasses for Neutrinos? 8.3 light minutes Several light years of lead needed to shield solar neutrinos Bethe & Peierls 1934: “… this evidently means that one will never be able to observe a neutrino.”

First Detection (1954 - 1956) g p n Cd e+ e- Clyde Cowan (1919 – 1974) Fred Reines (1918 – 1998) Nobel prize 1995 Detector prototype Anti-Electron Neutrinos from Hanford Nuclear Reactor 3 Gammas in coincidence p n Cd e+ e- g

First Measurement of Solar Neutrinos Inverse beta decay of chlorine 600 tons of Perchloroethylene Homestake solar neutrino observatory (1967-2002)

Elastic scattering or CC reaction Cherenkov Effect Cherenkov Ring Elastic scattering or CC reaction Light Electron or Muon (Charged Particle) Neutrino Water Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

Super-Kamiokande Neutrino Detector

Cherenkov Ring Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

Super-Kamiokande: Sun in the Light of Neutrinos Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

SN 1987A Event No.9 in Kamiokande-II Kamiokande-II detector 2140 tons of water fiducial volume for SN 1987A Hirata et al., PRD 38 (1988) 448

Neutrino Signal of Supernova 1987A Kamiokande-II (Japan) Water Cherenkov detector 2140 tons Clock uncertainty 1 min Irvine-Michigan-Brookhaven (US) Water Cherenkov detector 6800 tons Clock uncertainty 50 ms Baksan Scintillator Telescope (Soviet Union), 200 tons Random event cluster ~ 0.7/day Clock uncertainty +2/-54 s Within clock uncertainties, signals are contemporaneous

2002 Physics Nobel Prize for Neutrino Astronomy Ray Davis Jr. (1914 - 2006) Masatoshi Koshiba (*1926) “for pioneering contributions to astrophysics, in particular for the detection of cosmic neutrinos”

SN 1987A Neutrino Story as Told by the Pioneers

Supernova Neutrinos 20 Jahre nach SN 1987A Some Particle-Physics Lessons from SN 1987A Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

The Energy-Loss Argument Neutrino sphere SN 1987A neutrino signal Neutrino diffusion Late-time signal most sensitive observable Emission of very weakly interacting particles would “steal” energy from the neutrino burst and shorten it. (Early neutrino burst powered by accretion, not sensitive to volume energy loss.) Volume emission of novel particles

Astrophysical Axion Bounds 103 106 109 1012 [GeV] fa eV keV meV ma Experiments Tele scope CAST Direct search ADMX Hot dark matter limits (a-p-coupling) Cold Dark Matter Globular clusters (a-g-coupling) Too many events Too much energy loss SN 1987A (a-N-coupling)

Neutrino Limits by Intrinsic Signal Dispersion Time of flight delay by neutrino mass (G. Zatsepin, JETP Lett. 8:205, 1968) For “milli charged” neutrinos, path bent by galactic magnetic field, inducing a time delay mne ≲ 20 eV Loredo & Lamb Ann N.Y. Acad. Sci. 571 (1989) 601 find 23 eV (95% CL limit) from detailed maximum-likelihood analysis Barbiellini & Cocconi, Nature 329 (1987) 21 Bahcall, Neutrino Astrophysics (1989) At the time of SN 1987A competitive with tritium end-point Today mn < 2.2 eV from tritium Cosmological limit today mn ≲ 0.2 eV Assuming charge conservation in neutron decay yields a more restrictive limit of about 310-21 e

Do Neutrinos Gravitate? Neutrinos arrive a few hours earlier than photons  Early warning (SNEWS) SN 1987A: Transit time for photons and neutrinos equal to within ~ 3h Shapiro time delay for particles moving in a gravitational potential Longo, PRL 60:173,1988 Krauss & Tremaine, PRL 60:176,1988 Equal within ~ 1 - 4 10-3 Proves directly that neutrinos respond to gravity in the usual way because for photons gravitational lensing already proves this point Cosmological limits DNn ≲ 1 much worse test of neutrino gravitation Provides limits on parameters of certain non-GR theories of gravitation Photons likely obscured for next galactic SN, so this result probably unique to SN 1987A

Supernova Neutrinos 20 Jahre nach SN 1987A Core-Collapse Explosion Mechanism Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

Wilson, Proc. Univ. Illinois Meeting on Num. Astrophys.(1982) Delayed Explosion Wilson, Proc. Univ. Illinois Meeting on Num. Astrophys.(1982) Bethe & Wilson, ApJ 295 (1985) 14

Neutrino-Driven Delayed Explosion Neutrino heating increases pressure behind shock front Picture adapted from Janka, astro-ph/0008432

Exploding Models (8-10 Solar Masses) with O-Ne-Cores Kitaura, Janka & Hillebrandt: “Explosions of O-Ne-Mg cores, the Crab supernova, and subluminous type II-P supernovae”, astro-ph/0512065

Standing Accretion Shock Instability (SASI) Mezzacappa et al., http://www.phy.ornl.gov/tsi/pages/simulations.html Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

Gravitational Waves from Core-Collapse Supernovae Müller, Rampp, Buras, Janka, & Shoemaker, “Towards gravitational wave signals from realistic core collapse supernova models,” astro-ph/0309833 Asymmetric neutrino emission Bounce Convection The gravitational-wave signal from convection is a generic and dominating feature

Supernova Neutrinos 20 Jahre nach SN 1987A Galactic Supernova Rate Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

Core-Collapse SN Rate in the Milky Way SN statistics in external galaxies Core-collapse SNe per century 1 2 3 4 5 6 7 8 9 10 van den Bergh & McClure (1994) Cappellaro & Turatto (2000) Gamma rays from 26Al (Milky Way) Diehl et al. (2006) Historical galactic SNe (all types) Strom (1994) Tammann et al. (1994) No galactic neutrino burst 90 % CL (25 y obserservation) Alekseev et al. (1993) References: van den Bergh & McClure, ApJ 425 (1994) 205. Cappellaro & Turatto, astro-ph/0012455. Diehl et al., Nature 439 (2006) 45. Strom, Astron. Astrophys. 288 (1994) L1. Tammann et al., ApJ 92 (1994) 487. Alekeseev et al., JETP 77 (1993) 339 and my update.

Local Group of Galaxies Events in a detector with 30 x Super-K fiducial volume, e.g. Hyper-Kamiokande 30 60 250

Nearby Galaxies with Many Observed Supernovae M83 (NGC 5236, Southern Pinwheel) D = 4.5 Mpc NGC 6946 D = (5.5 ± 1) Mpc Observed Supernovae: 1923A, 1945B, 1950B, 1957D, 1968L, 1983N Observed Supernovae: 1917A, 1939C, 1948B, 1968D, 1969P, 1980K, 2002hh, 2004et

Supernova Neutrinos 20 Jahre nach SN 1987A Future Supernova Neutrino Observations Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

Large Detectors for Supernova Neutrinos MiniBooNE (200) LVD (400) Borexino (100) Baksan (100) Super-Kamiokande (104) KamLAND (400) In brackets events for a “fiducial SN” at distance 10 kpc IceCube (106)

SuperNova Early Warning System (SNEWS) Neutrino observation can alert astronomers several hours in advance to a supernova. To avoid false alarms, require alarm from at least two experiments. Super-K IceCube Coincidence Server @ BNL Alert LVD Supernova 1987A Early Light Curve Others ? http://snews.bnl.gov astro-ph/0406214

Simulated Supernova Signal at Super-Kamiokande Accretion Phase Kelvin-Helmholtz 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]

IceCube Neutrino Telescope at the South Pole 1 km3 antarctic ice, instrumented with 4800 photomultipliers 22 of 80 strings installed (2007) Completion until 2011 foreseen

IceCube as a Supernova Neutrino Detector Each optical module (OM) picks up Cherenkov light from its neighborhood. SN appears as “correlated noise”. About 300 Cherenkov photons per OM from a SN at 10 kpc Noise < 260 Hz Total of 4800 OMs in IceCube IceCube SN signal at 10 kpc, based on a numerical Livermore model [Dighe, Keil & Raffelt, hep-ph/0303210] Method first discussed by Pryor, Roos & Webster, ApJ 329:355 (1988) Halzen, Jacobsen & Zas astro-ph/9512080

LAGUNA - Funded FP7 Design Study Large Apparati for Grand Unification and Neutrino Astrophysics (see also arXiv:0705.0116)

Supernova Neutrinos 20 Jahre nach SN 1987A Neutrino Oscillations Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

Neutrino Flavor Oscillations Two-flavor mixing Each mass eigenstate propagates as with Phase difference implies flavor oscillations Probability ne  nm sin2(2q) Bruno Pontecorvo (1913 – 1993) Invented nu oscillations z Oscillation Length

Mixing of Neutrinos with Different Mass mass m1 mass m2 n Electron neutrino Mass m1 Mass m2 > m1 Mass m1 Mass m2 > m1 Mass m1 Mass m2 > m1 Mass m1 Mass m2 = m1 Mass m1 Mass m2 > m1 Neutrino propagation as a wave phenomenon Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

Neutrino Oscillations Mass m1 Mass m2 > m1 Oscillation length Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

Neutrino Oscillations Oscillation length Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

Three-Flavor Neutrino Parameters Solar 75-92 Atmospheric 1400-3000 CHOOZ Solar/KamLAND 2s ranges hep-ph/0405172 Atmospheric/K2K d CP-violating phase m e t 1 Sun Normal 2 3 Atmosphere Inverted Tasks and Open Questions Precision for q12 and q23 How large is q13 ? CP-violating phase d ? Mass ordering ? (normal vs inverted) Absolute masses ? (hierarchical vs degenerate) Dirac or Majorana ?

Long-Baseline Experiment K2K K2K Experiment (KEK to Kamiokande) has confirmed neutrino oscillations, to be followed by T2K (2009)

The Future: A Megatonne Detector? Megatonne detector motivated by Long baseline neutrino oscillations Proton decay Atmospheric neutrinos Solar neutrinos Supernova neutrinos (~105 events for SN at 10 kpc) Similar discussions in US (UNO project) Europe (MEMPHYS project)

Neutrino Oscillations in Matter Lincoln Wolfenstein n f Z W, Z Neutrinos in a medium suffer flavor-dependent refraction (PRD 17:2369, 1978) In Earth or Sun weak potential of order 10-13 eV “Level crossing” possible in a medium with a gradient (MSW effect) - For solar nus large flavor conversion anyway due to large mixing - Still important for 13-oscillations in supernova envelope Breaks degeneracy between Q and p/2 - Q (dark vs light side) - 12 mass ordering for solar nus established - 13 mass ordering (normal vs inverted) at future LBL or SN Discriminates against sterile nus in atmospheric oscillations CP asymmetry in LBL, to be distinguished from intrinsic CP violation Prevents flavor conversion in a SN core and within shock wave Strongly affects sterile nu production in SN or early universe

H- and L-Resonance for MSW Oscillations R. Tomàs, M. Kachelriess, G. Raffelt, A. Dighe, H.-T. Janka & L. Scheck: Neutrino signatures of supernova forward and reverse shock propagation [astro-ph/0407132] Resonance density for Resonance density for

Shock-Wave Propagation in IceCube Inverted Hierarchy No shockwave Inverted Hierarchy Forward & reverse shock Inverted Hierarchy Forward shock Normal Hierarchy Choubey, Harries & Ross, “Probing neutrino oscillations from supernovae shock waves via the IceCube detector”, astro-ph/0604300

Matrices of Density in Flavor Space Neutrino quantum field Spinors in flavor space Destruction operators for (anti)neutrinos Variables for discussing neutrino flavor oscillations Quantum states (amplitudes) “Matrices of densities” (analogous to occupation numbers) Neutrinos Anti- neutrinos Sufficient for “beam experiments,” but confusing “wave packet debates” for quantifying decoherence effects “Quadratic” quantities, required for dealing with decoherence, collisions, Pauli-blocking, nu-nu-refraction, etc.

General Equations of Motion Vacuum oscillations M is neutrino mass matrix Note opposite sign between neutrinos and antineutrinos Usual matter effect with Nonlinear nu-nu effects are important when nu-nu interaction energy exceeds typical vacuum oscillation frequency (Do not compare with matter effect!)

Toy Supernova in “Single-Angle” Approximation Assume 80% anti-neutrinos Vacuum oscillation frequency w = 0.3 km-1 Neutrino-neutrino interaction energy at nu sphere (r = 10 km) m = 0.3105 km-1 Falls off approximately as r-4 (geometric flux dilution and nus become more co-linear) Bipolar Oscillations Decline of oscillation amplitude explained in pendulum analogy by inreasing moment of inertia (Hannestad, Raffelt, Sigl & Wong astro-ph/0608695)

Collective SN neutrino oscillations 2006-2007 “Bipolar” collective transformations important, even for dense matter Duan, Fuller & Qian astro-ph/0511275 Numerical simulations Including multi-angle effects Discovery of “spectral splits” Duan, Fuller, Carlson & Qian astro-ph/0606616, 0608050 Pendulum in flavor space Collective pair annihilation Pure precession mode Hannestad, Raffelt, Sigl & Wong astro-ph/0608695 Duan, Fuller, Carlson & Qian astro-ph/0703776 Self-maintained coherence vs. self-induced decoherence caused by multi-angle effects Raffelt & Sigl, hep-ph/0701182 Esteban-Pretel, Pastor, Tomas, Raffelt & Sigl, arXiv:0706.2498 Theory of “spectral splits” in terms of adiabatic evolution in rotating frame Raffelt & Smirnov, arXiv:0705.1830, 0709.4641 Duan, Fuller, Carlson & Qian arXiv:0706.4293, 0707.0290 Independent numerical simulations Fogli, Lisi, Marrone & Mirizzi arXiv:0707.1998

Supernova Neutrinos 20 Jahre nach SN 1987A Cosmic Diffuse Supernova Neutrino Background (DSNB) Georg Raffelt, Max-Planck-Institut für Physik, München Physik Kolloquium, 19. November 2007, RWTH Aachen

Diffuse Background Flux of SN Neutrinos 1 SNu = 1 SN / 1010 Lsun,B / 100 years Lsun,B = 0.54 Lsun = 2  1033 erg/s En ~ 3  1053 erg per core-collapse SN 1 SNu ~ 4 Ln / Lg,B Average neutrino luminosity of galaxies ~ photon luminosity Photons come from nuclear energy Neutrinos from gravitational energy For galaxies, average nuclear & gravitational energy release comparable Present-day SN rate of ~ 1 SNu, extrapolated to the entire universe, corresponds to ne flux of ~ 1 cm-2 s-1 Realistic flux is dominated by much larger early star-formation rate  Upper limit ~ 54 cm-2 s-1 [Kaplinghat et al., astro-ph/9912391]  “Realistic estimate” ~ 10 cm-2 s-1 [Hartmann & Woosley, Astropart. Phys. 7 (1997) 137] Measurement would tell us about early history of star formation

Experimental Limits on Relic Supernova Neutrinos Super-K upper limit 29 cm-2 s-1 for Kaplinghat et al. spectrum [hep-ex/0209028] Upper-limit flux of Kaplinghat et al., astro-ph/9912391 Integrated 54 cm-2 s-1 Cline, astro-ph/0103138

Improved Sensitivity with Neutron Tagging Beacom & Vagins, hep-ph/0309300 [Phys. Rev. Lett., 93 (2004) 171101] Status of R & D (04/2006) [Mark Vagins, private communication] Detection of DSNB limited by Solar neutrinos for En ≲ 18 MeV Sub-Cherenkov muons from atm nus Solution: neutron tagging from 2.2 MeV gamma from n + p  d invisible in water Cherenkov detector Nov 05: Gd Cl3 added to K2K test tank (kiloton or KT detector) Gd Cl3 is easy to dissolve Gd Cl3 does not significantly affect the light collection Choice of detector materials critical (old rust in KT with Gd Cl3 badly affected transparency) The 20 inch Super-K PMT's operate well in conductive water Gd filtration works as designed at 3.6 tons/h, can easily be scaled up Add gadolinium to Super-Kamiokande Efficient neutron capture on Gd 8 MeV gamma cascade easily visible 0.1% (100 tons of Gd Cl3) achieves > 90% tagging efficiency Diffuse SN nu background (DSNB): a few events per year in Super-K with no background at all Looks promising for Super-K, conceivable within next few years Capital cost negligible for future megatonne-class detectors

DSNB Measurement with Neutron Tagging Beacom & Vagins, hep-ph/0309300 [Phys. Rev. Lett., 93:171101, 2004] Future large-scale scintillator detectors (e.g. LENA with 50 kt) Inverse beta decay reaction tagged Location with smaller reactor flux (e.g. Pyhäsalmi in Finland) could allow for lower threshold Pushing the boundaries of neutrino astronomy to cosmological distances

The Red Supergiant Betelgeuse (Alpha Orionis) First resolved image of a star other than Sun Distance (Hipparcos) 130 pc (425 lyr) If Betelgeuse goes Supernova: 6 107 neutrino events in Super-Kamiokande 2.4 103 neutron events per day from Silicon-burning phase (few days warning!), need neutron tagging [Odrzywolek, Misiaszek & Kutschera, astro-ph/0311012]

Looking forward to the next galactic supernova! Aachen Skyline Looking forward to the next galactic supernova!