1. Prospects of supernova neutrino observation by large detectors Hisakazu Minakata Tokyo Metropolitan University Hisakazu Minakata Tokyo Metropolitan University

2. October 2-5, 2007NNN07@Hamamatsu Two attitudes Use SN data to learn about particle physics properties of neutrinos Use known particle physics properties of neutrinos to learn about physics inside SN core My personal view; 2nd viewpoint is becoming more and more important!

3. October 2-5, 2007NNN07@Hamamatsu oscillation has been seen! K2K SK MINOS 07 KamLAND 07

4. October 2-5, 2007NNN07@Hamamatsu 1st message; mass & mixing must be taken into account

5. October 2-5, 2007NNN07@Hamamatsu Matter profile of a progenitor star Nomoto et al. model of SN1987a

6. October 2-5, 2007NNN07@Hamamatsu level crossing diagram in SN Classification of SN spectrum pattern possible => next page; SN may distinguish mass hierarchy

7. October 2-5, 2007NNN07@Hamamatsu

8. October 2-5, 2007NNN07@Hamamatsu Classical picture

9. October 2-5, 2007NNN07@Hamamatsu Neutrino flux inside core 1st approximation = LTE Departure from LTE because strength of interactions different for e, e-bar, x (= e, e-bar, ,  -bar )  spectrum depends on flavor pinching of spectrum

10. October 2-5, 2007NNN07@Hamamatsu Neutrino energy spectra in SN core Garching flux Livermore flux Generally, but to what extent? Unlike the case of solar, we still do NOT have Standard SN model !

11. October 2-5, 2007NNN07@Hamamatsu Early era of optimism

12. October 2-5, 2007NNN07@Hamamatsu mass hierarchy from SN data? HM-H.Nunokawa 01, Lunardini-Smirnov 02- 04, Kachelriess et al. 0 ２ Beacom et al. 06 + many others Inverted mass hierarchy + measurable  13 => e-bar - x-bar swap obs. consequences if sizable spectrum difference between e-bar and x Inverted mass hierarchy + measurable  13 => e-bar - x-bar swap obs. consequences if sizable spectrum difference between e-bar and x

13. October 2-5, 2007NNN07@Hamamatsu Invitation to SN model independent methods

14. October 2-5, 2007NNN07@Hamamatsu Determining mass hierarchy by earth matter effect Use earth matter effect Suppose that  13 is so large that it can be measured by the next generation experiments => P H =0 (adiabatic H resonance) earth matter effect YES ＝＞ normal hierarchy earth matter effect NO ＝＞ inverted hierarchy SN simulation independent, it works even for very similar e -bar and x spectra

15. October 2-5, 2007NNN07@Hamamatsu Effect of a few % S/N=10 6 /10 7 Dighe et al. 03 It is a very good idea, but rather demanding …

16. October 2-5, 2007NNN07@Hamamatsu 2nd method for detecting earth matter effect; Detecting wiggles Dighe et al. 03

17. October 2-5, 2007NNN07@Hamamatsu In reality, however,..

18. October 2-5, 2007NNN07@Hamamatsu Does shock wave help ? R. Tomas et al. 04 How reliable is the estimation of shock wave strength?

19. October 2-5, 2007NNN07@Hamamatsu Neutronization burst Neutronization burst => robust signature of many SN simulations Normal mass hierarchy + measurable  13 => disappearance of neutronization peak Requires megaton detector + Gd 100% neutron tag assumed, Kachelriess et al 04

20. October 2-5, 2007NNN07@Hamamatsu Observatio nal diagnostics of SN core

21. October 2-5, 2007NNN07@Hamamatsu EuroConference on Neutrinos in the Universe, Lenggries 01 (HM) There have been some interests in flavor dependent reconstruction of SN fluxes since sometime ago Seminar@INT,Seattle 00 (JB)

22. October 2-5, 2007NNN07@Hamamatsu Flavor dependent reconstruction of fluxes; water Cherenkov only SN@10 kpc, 3 effective fluxes e, e -bar, x Parametrize the fluxes with (1) total energy (2) average energy (3) pinching parameter 3 parameters / flavor => 9 parameter fit  e -bar absorption reaction in water Cherenkov (HK with fiducial mass 720 kton assumed) What’s else in 2050?

23. October 2-5, 2007NNN07@Hamamatsu Reduced analysis; only e -bar data + pinching parameter fixed  = E e-bar /E x HM, Nunokawa, Tomas, Valle 02  = L x /L e-bar

24. October 2-5, 2007NNN07@Hamamatsu A full analysis leads to an unexpected degeneracy !

25. October 2-5, 2007NNN07@Hamamatsu Continuous degeneracy in SN flux parameters pinching parameter fixed or varied 6 parameter fit, assume Case A or C; HM- Nunokawa-Tomas-Valle, to appear soon

26. October 2-5, 2007NNN07@Hamamatsu SN parameter degeneracy continued 1

27. October 2-5, 2007NNN07@Hamamatsu SN parameter degeneracy continued 2

28. October 2-5, 2007NNN07@Hamamatsu Simple reason for the degeneracy

29. October 2-5, 2007NNN07@Hamamatsu How to resolve degeneracy ?

30. October 2-5, 2007NNN07@Hamamatsu Possible ways out More reactions in water Cherenkov detector;  e + 16 O -> 16 F+e-, x + 16 O -> x + 16 O*, e +e -> e +e etc. Combine other detectors; Liquid scintillator etc. Resolution of degeneracy looks nontrivial because e -bar absorption reaction is statistically overwhelming Of course neutron tag (Gd) helps

31. October 2-5, 2007NNN07@Hamamatsu Supplement ary detector; an example

32. October 2-5, 2007NNN07@Hamamatsu Running ! K.Scholberg@Nu2006

33. October 2-5, 2007NNN07@Hamamatsu Philosophy - to produce a –Very low cost –Low maintenance –Low impact in terms of lab resources (space) –Long-term, high livetime dedicated supernova detector HALO - a Helium and Lead Observatory Slides taken/modified from:

34. October 2-5, 2007NNN07@Hamamatsu HALO – Phase 1 and 2 Phase 1: 80 tonnes of Pb from decommissioned Deep River Cosmic-ray station ~285 m 3 He proportional counter neutron detectors (NCDs) plus DAQ from SNO Phase2: Full ~700m of 3 He counters and possibly 130 m of 10 BF 3 counters Increased volume of lead

35. October 2-5, 2007NNN07@Hamamatsu Pb / 3 He ratio Tonnes of Pb Neutron Capture Efficiency (fid. volume) Length of NCDs used (m) Detected Neutrons (SN @ 10kpc) 14 kg/cm --- 1000 --- 55% --- 700 --- 372 8 kg/cm 80 560 31% 60% 95 700 22 246 4 kg/cm 80 280 48% 79% 190 700 31 167 2.7 kg/cm 80 189 57% 83% 285 700 36 127 HALO - Monte Carlo Studies F. Fleurot

36. October 2-5, 2007NNN07@Hamamatsu New developments;

37. October 2-5, 2007NNN07@Hamamatsu Collective transformation at high densities; long history Pantaleone 92 Samuel et al. 93-96 Fuller-Qian 95-96 Pastor-Raffelt-Semikoz 02 Duan-Fuller-Qian 05-07 Raffelt et al. 06-07 Fogli et al. 07 Raffelt-Smirnov 07, and more ? …

38. October 2-5, 2007NNN07@Hamamatsu Spin precession analogy  flavor oscillation/conversion can be cast into an analogous form with spin precession in magnetic field B=(sin2 , 0, -cos2  ) Mikheyev-Smirnov 86, Smirnov in ``New Era in Neutrino Physics’’@TMU, Tokyo 98

39. 9 Neutrino mass hierarchy (and  13 ) set initial conditions and fate.  13 sets initial misalignment with vertical. Specific value not much relevant (provided that  13 >0). Only for  13 =0 exactly, initial conditions are “ frozen ”. Normal hierarchy: Pendulum starts in ~downward (stable) position and stays nearby. No significant flavor change. Inverted hierarchy: Pendulum starts in ~upward (unstable) position and eventually falls down. Significant flavor changes. (( )) (( This slide taken from: Eligio Lisi@TAUP07

40. October 2-5, 2007NNN07@Hamamatsu Pee 1-Pee Inverted Normal

41. 11 Initial fluxes at the neutrinosphere (r~10 km) Final fluxes at the end of collective effects (r~200 km) [Single-angle approximation] Our results for the spectral split/swap (inv. hier.) This slide taken from: Eligio Lisi@TAUP07

42. October 2-5, 2007NNN07@Hamamatsu Conclusion If  13 extremely small, SN may contribute to determination of mass hierarchy and (if s 13 2 10 -3 ) But, SN flux model independent method required Collective transformation in high density region => good hope to distinguish hierarchy Flavor-dependent reconstruction of SN fluxes important but highly nontrivial what is the required minimal set of detectors that can run for a long time? Other methods for SN core diagnostics? G- wave?

43. October 2-5, 2007NNN07@Hamamatsu Supplement ary slides

44. October 2-5, 2007NNN07@Hamamatsu Garching vs pinched Fermi-Dirac Garching parametrization Keil et al. Pinched Fermi-Dirac parametrization