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Neutrinos of cosmic origin experiments

Lepton photon 2007, August 17, 2007. Solar. SN. Atmospheric. High energy. neutrinos. 9. 6. 15. 12. 21. 18. 10. 10. 10. 10. 10. 10. Energy (eV). Neutrinos of cosmic origin experiments. M.Nakahata. Kamioka observatory ICRR, Univ. of Tokyo. Solar neutrino Supernova neutrino

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Neutrinos of cosmic origin experiments

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  1. Lepton photon 2007, August 17, 2007 Solar SN Atmospheric High energy neutrinos 9 6 15 12 21 18 10 10 10 10 10 10 Energy (eV) Neutrinos of cosmic origin experiments M.Nakahata Kamioka observatory ICRR, Univ. of Tokyo Solar neutrino Supernova neutrino Atmospheric neutrino (Ultra-)High energy neutrino Conclusions

  2. 6 9 12 15 18 21 10 10 10 10 10 10 Energy (eV) Solar neutrinos Solar neutrinos

  3. Solar neutrino experiments, so far ne and (nm+nt) fluxes of 8B 71Ga 37Cl SK, SNO (real time) (radiochemical) pp 7Be pep 8B SSM(1s) SNO NC SNO CC SNO ES SK ES Direct evidence for neutrino oscillations by 8B n measurements by SK and SNO Deficit of measured fluxes except for SNO NC

  4. Current status of solar neutrino oscillations Large Mixing Angle(LMA) solution ! Expected nesurvival probability (at best fit param.) Vacuum osc. dominant P=1 - 0.5・sin22q12 P(ne ne) 99.73% Solar+KamLAND matter osc. P=sin2q12 95% KamLAND (MeV) SSM spectrum pp Solar global 7Be pep 8B Solar+KamLAND: Dm2=(7.9 +0.4/-0.3)X10-5 ev2 sin2q=0.30 +0.04/-0.025

  5. What are not (well) known in solar neutrinos? • How large is 7Be neutrino flux? • BOREXINO started from May 2007 and KamLAND is purifying liquid scintillator • Is 8B spectrum distorted as expected from LMA solution? • SK-III plan to measure with lower energy threshold • SNO data analysis with lower threshold • Flux of CNO cycle neutrinos? • The cross section of 14N(p,g)15O measured by LUNA decreased expected CNO neutrino flux by a factor of two. • KamLAND(future) and SNO+ plan to measure the CNO flux • Cross section of Gallium? • The neutrino source runs with Gallium experiments give R(observed/expected) = 0.88 +- 0.05 (combined value of GALLEX 51Cr run1, run2, and SAGE 51Cr and 37Ar) • pp neutrino by real time experiments? • Future experiments (LENS, XMASS, CLEAN …).

  6. What are not (well) known in solar neutrinos? pp 7Be pep 8B • How large is 7Be neutrino flux? • BOREXINO started from May 2007 and KamLAND is purifying liquid scintillator • Is 8B spectrum distorted as expected from LMA solution? • SK-III plan to measure with lower energy threshold • SNO data analysis with lower threshold • Flux of CNO cycle neutrinos? • The cross section of 14N(p,g)15O measured by LUNA decreased expected CNO neutrino flux by a factor of two. • KamLAND(future) and SNO+ plan to measure the CNO flux • Cross section of Gallium? • The neutrino source runs with Gallium experiments give R(observed/expected) = 0.88 +- 0.05 (combined value of GALLEX 51Cr run1, run2, and SAGE 51Cr and 37Ar) • pp neutrino by real time experiments? • Future experiments (LENS, XMASS, CLEAN …).

  7. BOREXINO completely filled with scintillator (May 2007) • 300 tons (100 tons fiducial) liquid scintillator (PC + PPO (1.5 g/l) in inner vessel • Buffer liquid: PC + DMP (1040 ton) • Viewed by 2200 photomultipliers • Expected 7Be neutrino signal is ~30/day Detector is running successfully Figures from G.Bellini and G.Ranucci

  8. Purification of scintillator at KamLAND • So far, KamLAND could not measure 7Be n because of high (factor ~105) background rate from 85Kr and 210Pb. • Purification of scintillator is going on using distillation and pure nitrogen purge. Purified LS region Background vertex distribution on June 7, 2007 from Y.Kishimoto

  9. What are not (well) known in solar neutrinos? • How large is 7Be neutrino flux? • BOREXINO started from May 2007 and KamLAND is purifying liquid scintillator • Is 8B spectrum distorted as expected from LMA solution? • SK-III plan to measure with lower energy threshold • SNO data analysis with lower threshold • Flux of CNO cycle neutrinos? • The cross section of 14N(p,g)15O measured by LUNA decreased expected CNO neutrino flux by a factor of two. • KamLAND(future) and SNO+ plan to measure the CNO flux • Cross section of Gallium? • The neutrino source runs with Gallium experiments give R(observed/expected) = 0.88 +- 0.05 (combined value of GALLEX 51Cr run1, run2, and SAGE 51Cr and 37Ar) • pp neutrino by real time experiments? • Future experiments (LENS, XMASS, CLEAN …).

  10. Super-Kamiokande Aim to reduce background in SK-III SK-III running since July 2006 after the full reconstruction. Number of PMTs in the inner detector is now 11129 PMTs. ~70% reduction below 5.5MeV and lower threshold to 4MeV Expected spectrum distortion with 5 years SK-III data

  11. SNO Phase I (D2O) Nov.99 – May 01 n captures on 2H(n,g)3H Phase II (salt) July 01 – Sep.03 2t NaCl n captures on 35Cl(n,g)36Cl Phase III (3He) Nov.04 – Nov.06 40 proportional counters 3He(n,p)3H Flux results of phase I and Phase II (SNO collab.,Phys.Rev.C72:055502,2005) Stat. Stat + syst. NC CC SNO data taking is finished in November 2006 (D2O returned to the Canadian authority.) Analyses of phase III and phase I+II(lower energy threshold) are going on. from A.W.P.Poon

  12. What are not (well) known in solar neutrinos? • How large is 7Be neutrino flux? • BOREXINO started from May 2007 and KamLAND is purifying liquid scintillator • Is 8B spectrum distorted as expected from LMA solution? • SK-III plan to measure with lower energy threshold • SNO data analysis with lower threshold • Flux of CNO cycle neutrinos? • The cross section of 14N(p,g)15O measured by LUNA decreased expected CNO neutrino flux by a factor of two. • KamLAND(future) and SNO+ plan to measure the CNO flux • Cross section of Gallium? • The neutrino source runs with Gallium experiments give R(observed/expected) = 0.88 +- 0.05 (combined value of GALLEX 51Cr run1, run2, and SAGE 51Cr and 37Ar) • pp neutrino by real time experiments? • Future experiments (LENS, XMASS, CLEAN …).

  13. SN1987A 9 6 18 15 12 21 10 10 10 10 10 10 Energy (eV) Supernova Neutrinos SN neutrinos

  14. Twenty Years after SN1987A 95 % CL Contours Kam-II (11 evts.) Total Binding Energy IMB-3 (8 evts.) Baksan (5 evts.) _ Spectral ne Temperature Kamiokande-II IMB-3 BAKSAN Feb.23, 1987 at 7:35UT Theory from G.Raffelt

  15. If a Galactic supernova happens in near future, # of events are for 10kpc SN assuming Livermore spectrum.

  16. 6 9 12 21 18 15 10 10 10 10 10 10 Energy (eV) Atmospheric Neutrinos nm nt nm Atmospheric neutrinos

  17. Search for CC nt events (Super-Kamiokande) CC ntMC CC nt events nt hadrons t nt hadrons ● Many particles (hadrons) …. (But no big difference with the other (NC) events.) t-likelihood or NN analysis ● Upward going only Zenith angle Only ～ 1.0 CC ntFC events/kton・yr (BG (other n events) ～ 130 ev./kton・yr)

  18. Zenith angle of CC nt enhanced sample Likelihood analysis NN analysis Data scaled t-MC Number of events nm, ne, & NC background cosqzenith cosqzenith SK-collab. Phys.Rev.Lett.97:171801,2006 Fitted number of t events Exp’d number of t events Zero tau neutrino interaction is disfavored at 2.4s.

  19. 9 6 18 15 21 12 10 10 10 10 10 10 Energy (eV) High Energy Neutrinos SNR RX J1713.7-3946 Chandra Cassiopeia A H.E.S.S. High energy neutrinos

  20. High energy accelerators in the universe  We know cosmic rays(p, He, ..) exist. So, there much be cosmic high energy neutrinos. e Possible sources: AGN, supernova remnants, …. e+  + + sync p sync e- Black hole accretion disk

  21. Cosmic Ultra High Energy neutrinos galactic Extra- galactic Neutrinos Ultra High Energy Cosmic Ray(UHECR) exists. “Horizon” of UHECR is ~50Mpc. GZK neutrinos cosmic rays interact with the microwave background (due to n osc.)

  22. Detectors for Cosmic High Energy Neutrinos Water(Ice) Cherenkov type Extensive Air Shower type

  23. 22 strings 1320 digital modules 52 surface detectors From F.Halzen

  24. Diffuse n flux limit and future prospects Water(Ice) Cherenkov type IceCube 9string 137 days AMANDA-II (2000-2003) Waxman-Bahcall limit (estimate from high E cosmic rays) Full IceCube 1yr (prospect) K.Hoshina et al.(IceCube collab.), ICRC2007

  25. UHE neutrino search by Auger and HiRes Earth skimming neutrinos for tau neutrinos (at E=1018 eV) Auger: Using data from Jan.’04 till Dec. ‘06 (about 1 year of full surface detector)  No candidate HiRes: HR1 data May ’97 - Nov.’05 HR2 data Oct.’99 – Nov.’05  No candidate HiRes(e) exploits the Landau, Pomeranchuk, Migdal (LPM) effect for ne induced electromagnetic showers. O.B.Bigas et al.(Auger collab.) , ICRC2007. K.Martens et al.(HiRes collab.), astro-ph/0707.4417

  26. Radio Cherenkov: the Askaryan Effect High energy neutrino interactions produce particle shower in matter. The shower has ~20% excess negative charge due to • Compton scattering:  + e-(at rest)  + e- • Positron annihilation: e+ + e-(at rest)  +  Gurgen Askaryan (1928-1997) Excess Charge travels with v>c/n produce Radio Cherenkov radiation! (G. A. Askaryan, JETP 14, 441(1962).) Askaryan Signal Characteristics • Coherent in Radio Frequencies • Power goes as E2 • Peak Field Strength at Cherenkov angle • Field strength increases with frequency • Linearly polarized signal

  27. (June 2006) Test of Askaryan effect in ice: SLAC T486 SLAC 28.5GeV electron beam with ~109 particles Frequency Total energy Cherenkov angle The Askaryan effect was confirmed. ANITA collab.hep-ex/0611008

  28. Experiments using Askaryan effect Lunar regolith Antarctic ice Greenland ice

  29. ANITA Experiment Ice RF clarity: 1.2 km(!) attenuation Length @ 300 MHz ANITA ’06-07 flight • 35 days, 3.5 orbits from Dec.15, 2006 to Jan.19, 2007. • Stayed much further “west” than average • But still achieved ~1.7km average depth of ice From J.Nam

  30. UHE neutrino flux limit and prospects (Radio Cherenkov type) ANITA ’06-07 flight expected sensitivity ANITA projected sensitivity (2-3 flights). GZK neutrino expected range. From J.Nam

  31. Conclusions • More solar neutrino information is expected in near future (flux of 7Be, 8B spectrum, CNO, pp…) • If a galactic supernova occurs in near future, large number of neutrino events and detection by various methods are expected. • SK atmospheric analysis observed nt appearance with 2.4s level. • The sensitivity of high energy neutrino experiments are getting close to the interesting region where we can expect real neutrino signals. Fruitful results from cosmic origin neutrinos are expected in near future.

  32. Backup

  33. The source experiments with Ga Item GALLEX Cr1 GALLEX Cr2 SAGE 51Cr SAGE 37Ar Source production Mass of reactor target (kg) Target isotopic purity   Source activity (kCi)   Specific activity (kCi/g) Gallium exposure   Gallium mass (tones) Gallium density (1021 71Ga/cm3) Measured production rate ρ (71Ge/d) R=P(measured)/Ρ(predicted) 330 96.94% 40Ca 409 ±2 92.7 13.1 (Ga metal) 21.001 11.0 +1.0-0.9 ±0.6 0.79 +0.09-0.10 35.5 38.6% 50Cr 1714 +30-43 0.048 30.4 (GaCl3:HCl) 1.946 11.9 ±1.1 ±0.7 1.00 +0.11-0.10 35.6 38.6% 50Cr 1868 +89-57 0.052 30.4 (GaCl3:HCl) 1.946 10.7 ±1.2 ±0.7 0.81 ±0.10 0.512 92.4% 50Cr 516.6 ± 6.0 1.01 13.1 (Ga metal) 21.001 14.0 ±1.5 ±0.8 0.95 ±0.12 GALLEX Cr1 1.00+0.11-0.10 SAGE Cr 0.95 ± 0.12 GALLEX Cr2 0.81 ± 0.10 SAGE Ar 0.79+0.09-0.10 The weighted average value of Ris 0.88 ± 0.05, more thantwo SD less than unity. The most likely hypothesis is that cross sections for neutrino capture have been overestimated. A new experiment with a considerably higher rate from the neutrino source is planned now to settle this question. From V.Gavrin

  34. BOREXINO performance Expected signal and designed background level Known 14C background is measured as expected 14C spectrum 7Be data from BOREXINO will come in near future. From G.Ranucci

  35. L/E distribution from atmospheric neutrinos L Pmm = 1 – sin22qsin2(1.27 Dm2 ) En SK-I+II (141 kton・yr) n oscillation: MC (no osc.) Decoh. Decay MC (osc.) Mostly down-going Mostly up-going Osc. c2(osc)=83.9/83dof c2(decay)=107.1/83dof c2(decoherence)=112.5/83dof Oscillation gives the best fit to the data. Decay and decoherence models disfavored by 4.8 and 5.3 s, resp. Also, strong constraint on the oscillation param.

  36. Antares status Downward going cosmic ray muons number of events Upward going neutrinos cos q 2400m 12 lines 25 storeys / line 3 PMT / storey 450 m Since Jan.2007, 5 lines in operation. 40 km to shore Construction will be completed by 2008. Junction box Zenith angle distribution 60 m Readout cables From J.Carr

  37. Expectation at Super-Kamiokande SN at 10kpc Expected number of events in parentheses Visible energy spectrum Time profile Neutrino flux and spectrum from Livermore simulation Neutrino oscillations are not taken into account here.

  38. Sensitivity of SK for time variation measurement Assuming a supernova at 10kpc, expected statistical error is plotted. Time variation of event rate Time variation of mean energy Enough statistics to test those models

  39. nmnmntnt Solid: sum of all ne Determine original nm, nm, nt, nt temperature with ~10% accuracy. (free from neutrino oscillation.） ne n+p elastic signal（ n+p→ n+p） at KamLAND Beacom, Farr, and Vogel, PRD66, 033001(2002) Expected spectrum Temperature sensitivity ~300 events above 200keV ~150 events above 500keV

  40. IceCube as MeV  detector L.Koepke IceCube 10 kpc • Disadvantage: • no pointing • no energy •  intrinsic noise • Advantage: •  high statistics • (0.75% stat. error • @ 0.5s and 100ms bins) • Good for fine time • structures (noise low)! accretion phase Helmholtz cooling phase Simulation based on a numerical Livermore model at 10 kpc (normalization to SN1987A would give flux 1/3 lower) Totani, Sato, Dalhed & Wilson, ApJ 496 (1998) 216 See also Dighe, Keil & Raffelt, hep-ph/0303210 for pointing out IceCube’s capabilities

  41. UHE neutrino flux limit and prospects ARIANNA (proposed) ANITA ’06-07 flight expected sensitivity

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