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Supernova neutrinos production, propagation and oscillations Amol Dighe Tata Institute of Fundamental Research, Mumbai Neutrino 2004, College de France, Paris, June 19, 2004 Supernova neutrinos p.1/33 Production Neutrino emission during


  1. Supernova neutrinos production, propagation and oscillations Amol Dighe Tata Institute of Fundamental Research, Mumbai Neutrino 2004, College de France, Paris, June 19, 2004 Supernova neutrinos – p.1/33

  2. Production Neutrino emission during the core collapse and cooling Primary neutrino spectra and their model dependence Propagation Role of neutrinos in SN explosion Neutrino flavour conversions in SN mantle and envelope Neutrino mixing scenarios and observed neutrino spectra Oscillations Earth matter effects on neutrino spectra Identification of neutrino mixing scenario Learning about shock propagation Supernova neutrinos – p.2/33

  3. Neutrino production in core collapse SN Supernova neutrinos – p.3/33

  4. 10 g/cc. � � 10 Before the collapse Neutrinos trapped inside “neutrinospheres” around h E i < h E i < h E i � � � � e e x Escaping neutrinos: Supernova neutrinos – p.4/33

  5. � ; � � ; � ; � � ; � ; � � e e � � � � � capture enhanced During the core collapse ) e � � e emitted at the e neutrinosphere. � 10 ms Neutronization burst: Shock wave breaks up the nuclei Duration: The first Supernova neutrinos – p.5/33

  6. � capture enhanced During the core collapse ) e � � e emitted at the e neutrinosphere. � 10 ms Neutronization burst: Shock wave breaks up the nuclei � ; � � ; � ; � � ; � ; � � e e � � � � Duration: The first Cooling through neutrino emission: Duration: About 10 sec Emission of 99% of the SN energy in neutrinos Can be used for “pointing” to the SN in advance. (“Early warning”) A few hours before the explosion (SNEWS) Supernova neutrinos – p.5/33

  7. � � � � � 1+ � Initial neutrino spectra � (1 + � ) E E 0 0 F = exp � ( � + 1) � i E �(1 + � ) E E 0 0 0 Neutrino fluxes: E � : in general time dependent 0 , E ( � ) < E ( � � ) < E ( � ) 0 e 0 e 0 x � > 2 � i Known properties of the spectra: E ( � ) � 10 – 12 MeV 0 e Energy hierarchy: E ( � � ) � 13 – 16 MeV 0 e Spectral pinching: E ( � ) � 15 – 20 MeV 0 x � � 2 – 4 � i 0.07 0.06 0.05 0.04 0.03 0.02 G. G. Raffelt, M. T. Keil, R. Buras, H. T. Janka 0.01 E(MeV) and M. Rampp, astro-ph/0303226 10 20 30 40 Supernova neutrinos – p.6/33

  8. Model dependent neutrino fluxes 25 25 � � e 20 20 � � x 〈 E 〉 15 15 10 10 0 1 2 3 4 0 250 500 750 solid line: 6 − 6 ν dotted line: e L [10 52 erg s -1 ] − 5 5 ν x 4 4 3 3 � ( � ) � ( � � ) 0 e 0 e h E ( � ) i h E ( � � ) i h E ( � ) i e e x 0 0 0 2 2 � ( � ) � ( � ) 0 x 0 x 1 1 0 0 0 1 2 3 4 0 250 500 750 Time [s] Time [ms] Model Garching (G) 12 15 18 0.8 0.8 Livermore (L) 12 15 24 2.0 1.6 G. G. Raffelt, M. T. Keil, R. Buras, H. T. Janka and M. Rampp, astro-ph/0303226 T. Totani, K. Sato, H. E. Dalhed and J. R. Wilson, Astrophys. J. 496, 216 (1998) Supernova neutrinos – p.7/33

  9. Neutrino propagation inside SN Supernova neutrinos – p.8/33

  10. Role of neutrinos in explosion Neutrino heating Neutrino cooling ������� ������� ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� p ��������������� ��������������� ������� ������� Stalled Shock n ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� Proto−Neutron ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� Star (n,p) ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� e ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� ��������������� ��������������� ������� ������� dM/dt ��������������� ��������������� Neutrinosphere ��������������� ��������������� ��������������� ��������������� ��������������� ��������������� ��������������� ��������������� ��������������� ��������������� 20 km 70 km 200 km Neutrino heating essential, but not enough No spherically symmetric (1-D) simulations show robust explosions Supernova neutrinos – p.9/33

  11. Ingradients required for explosion R. Buras, H.-T. Janka, M. Rampp, K. Kifonidis, astro-ph/0303171 [ms] Neutrino heating: higher neutrino opacity Large scale convenction modes Stiffer equation of state for the core Rotation of the star O. E. Bronson Messer, S. Bruenn, C. Cardall, M. Liebendoerfer, .-K. Thielemann et al A. Mezzacappa, W. Raphael Hix, F Supernova neutrinos – p.10/33

  12. Propagation through matter SUPERNOVA EARTH VACUUM envelope ν core 14 10 ρ=10 g/cc 12 10 0.1 10 km kpc 10000 km 10 R sun Matter effects on neutrino mixing crucial Flavor conversions at resonances / level crossings Supernova neutrinos – p.11/33

  13. Level crossings during propagation Normal mass hierarchy Inverted mass hierarchy 2 3 g/cc H resonance: ( � m � � � 10 13 ), atm , � channel for normal hierarchy, � channel for inverted hierarchy � 2 L resonance: ( � m � � � 10 g/cc � ), � , � channel 2 hierarchy � m ) Independent dynamics at resonances In Always in Supernova neutrinos – p.12/33

  14. Conversion probability at resonance 1−P f P f 1−P f � � P � 1 � � 2 2 f � � m sin 2 � 1 dn e P � exp � � ; � � f Envelope Core 2 2 E os 2 � n dr e Vacuum � � 1 ) P � 1 ) Adiabatic resonance f L resonance always adiabatic 2 � 3 , > H resonance adiabatic for j U j 10 e 3 � 2 � 5 < Landau’1932, Zener’1932 j U j 10 e 3 � non-adiabatic for Supernova neutrinos – p.13/33

  15. 0 0 Fluxes arriving at the Earth F = pF + (1 � p ) F ; � e � � e x 0 0 F = pF � + (1 � p ) F � ; � � e � � � e x Mixture of initial fluxes: 0 0 0 4 F = (1 � p ) F + (1 � p ) F � + (2 + p + p ) F � : � x � � � � e e x 2 sin � p p � 13 2 os � � 2 Survival probabilities in different scenarios: sin � � 2 2 sin � os � � � Case Hierarchy A Normal large 0 2 2 � 3 , “Large”: � 3 . < > sin � 10 sin � 10 13 13 B Inverted � large � 0 C Any small “Small”: AD, A. Smirnov, PRD 62, 033007 (2000) Supernova neutrinos – p.14/33

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