Lepton photon 2007 August 17 2007 Neutrinos of

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

Solar neutrinos Solar 10 6 neutrinos 10 9 10 12 10 15 10 18 21 10 Energy (e. V)

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

Current status of solar neutrino oscillations 99. 73% Solar+Kam. LAND Expected e survival probability P( e e) Large Mixing Angle(LMA) solution ! Vacuum osc. dominant (at best fit param. ) P=1 - 0. 5・sin 22 q 12 matter osc. 95% P=sin 2 q 12 Kam. LAND SSM spectrum Solar global (Me. V) pp 7 Be pep 8 B Solar+Kam. LAND: Dm 2=(7. 9 +0. 4/-0. 3)X 10 -5 ev 2 sin 2 q=0. 30 +0. 04/-0. 025

What are not (well) known in solar neutrinos? • How large is 7 Be neutrino flux? – BOREXINO started from May 2007 and Kam. LAND is purifying liquid scintillator • Is 8 B 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 14 N(p, )15 O measured by LUNA decreased expected CNO neutrino flux by a factor of two. – Kam. LAND(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 51 Cr run 1, run 2, and SAGE 51 Cr and 37 Ar) • pp neutrino by real time experiments? – Future experiments (LENS, XMASS, CLEAN …).

What are not (well) known in solar neutrinos? • How large is 7 Be neutrino flux? – BOREXINO started from May 2007 and Kam. LAND is purifying liquid scintillator • Is 8 B 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 14 N(p, )15 O measured by LUNA decreased expected CNO neutrino flux by a factor of two. – Kam. LAND(future) and SNO+ plan to measure the CNO flux • Cross section of Gallium? pp 7 Be – The neutrino source runs with Gallium experiments give pep R(observed/expected) = 0. 88 +- 0. 05 (combined value of GALLEX 51 Cr run 1, 8 B run 2, and SAGE 51 Cr and 37 Ar) • pp neutrino by real time experiments? – Future experiments (LENS, XMASS, CLEAN …).

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 7 Be neutrino signal is ~30/day Figures from G. Bellini and G. Ranucci Detector is running successfully

Purification of scintillator at Kam. LAND So far, Kam. LAND could not measure 7 Be because of high (factor ~105) background rate from 85 Kr and 210 Pb. 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

What are not (well) known in solar neutrinos? • How large is 7 Be neutrino flux? – BOREXINO started from May 2007 and Kam. LAND is purifying liquid scintillator • Is 8 B 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 14 N(p, )15 O measured by LUNA decreased expected CNO neutrino flux by a factor of two. – Kam. LAND(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 51 Cr run 1, run 2, and SAGE 51 Cr and 37 Ar) • pp neutrino by real time experiments? – Future experiments (LENS, XMASS, CLEAN …).

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

SNO Phase I (D 2 O) Nov. 99 – May 01 n captures on 2 H(n, )3 H Phase II (salt) Phase III (3 He) July 01 – Sep. 03 2 t Na. Cl n captures on 35 Cl(n, )36 Cl Nov. 04 – Nov. 06 40 proportional counters 3 He(n, p)3 H Flux results of phase I and Phase II CC (SNO collab. , Phys. Rev. C 72: 055502, 2005) Stat + syst. NC SNO data taking is finished in November 2006 (D 2 O returned to the Canadian authority. ) Analyses of phase III and phase I+II(lower energy threshold) are going on. from A. W. P. Poon

What are not (well) known in solar neutrinos? • How large is 7 Be neutrino flux? – BOREXINO started from May 2007 and Kam. LAND is purifying liquid scintillator • Is 8 B 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 14 N(p, )15 O measured by LUNA decreased expected CNO neutrino flux by a factor of two. – Kam. LAND(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 51 Cr run 1, run 2, and SAGE 51 Cr and 37 Ar) • pp neutrino by real time experiments? – Future experiments (LENS, XMASS, CLEAN …).

Supernova Neutrinos SN 1987 A SN 10 6 neutrinos 10 9 10 12 10 15 10 18 21 10 Energy (e. V)

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

If a Galactic supernova happens in near future, # of events are for 10 kpc SN Super 32, 000 tons of water target. assuming Livermore spectrum. Kamiokande ~7300 ep e+n, ~300 e e scattering events. Precise e spectrum, directionality by e scattering. LVD 1000 ton liquid scintillator. 840 counters 1. 5 m 3 each. 4 Me. V thres. , ~50% eff. for tagging decayed signal. ~300 ep e+n events. Kam. LAND 1000 ton liquid scintillator, single volume. ~300 ep , several 10 CC on 12 C, ~60 NC , ~300 p p NC evts. p NC events can determine original x temperature. BOREXINO 300 ton liquid scintillator, single volume. ~100 ep , ~10 CC on 12 C, ~20 NC , ~100 p p NC evts. p NC events can determine original x temperature. ICECUBE Gigaton ice target. Observed as coherent increase of PMT dark noise. ~0. 75% statistical error at 0. 5 s and 100 ms bin for 10 kpc SN.

Atmospheric Neutrinos t Atmospheric 10 6 10 9 10 12 neutrinos 10 15 10 18 21 10 Energy (e. V)

Search for CC t events (Super-Kamiokande) CC t events t t t CC t MC hadrons ● Many particles (hadrons) …. (But no big difference with the other (NC) events. ) t-likelihood or NN analysis Only ～ 1. 0 CC t FC events/kton・yr ● Upward going only Zenith angle (BG (other events) ～ 130 ev. /kton・yr)

Zenith angle of CC t enhanced sample SK-collab. Phys. Rev. Lett. 97: 171801, 2006 Likelihood analysis Data Number of events scaled t-MC , e, & NC background cosqzenith Fitted number of t events Exp’d number of t events NN analysis cosqzenith 138± 48(stat) +15 / -32(syst) 134± 48(stat) +16 / -27(syst) 78± 26(syst) 78± 27 (syst) Zero tau neutrino interaction is disfavored at 2. 4 s.

High Energy Neutrinos SNR RX J 1713. 7 -3946 H. E. S. S. Chandra Cassiopeia A High energy 10 6 10 9 10 12 10 15 10 18 neutrinos 21 10 Energy (e. V)

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

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

Detectors for Cosmic High Energy Neutrinos Water(Ice) Cherenkov type Detector Location size Status Ice. Cube South Pole (1 km)3 (0. 2 kmf 0. 5 kmh) 22 strings (out of 80) are installed. Completed by 2011. (Amanda-II) Antares Mediterranean sea 0. 2 km x 0. 45 km 5 lines (out of 12) are installed. Completed by 2008. NT 200+ Lake Bikal 0. 2 km f x 0. 2 km h NT 200 and 3 outer strings placed at 100 m. Running since 2006. KM 3 Ne. T Mediterranean sea (1 km)3 Design study going on. Technical Design Report by 2009. (Antares, Nemo, Nestor) Extensive Air Shower type Auger Hi. Res TA Argentina 4 fluorescence and 1600 surface detectors in 3000 km 2. Utah, US 2 fluorescence detectors located 12. 6 km apart. Utah, US 3 fluorescence and 512 surface detectors in 700 km 2. 95% of deployment finished.

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

Diffuse flux limit and future prospects Water(Ice) Cherenkov type Ice. Cube 9 string 137 days AMANDA-II (2000 -2003) Waxman-Bahcall limit (estimate from high E cosmic rays) Full Ice. Cube 1 yr (prospect) K. Hoshina et al. (Ice. Cube collab. ), ICRC 2007

UHE neutrino search by Auger and Hi. Res Earth skimming neutrinos for tau neutrinos (at E=1018 e. V) Auger: Using data from Jan. ’ 04 till Dec. ‘ 06 (about 1 year of full surface detector) No candidate Hi. Res: HR 1 data May ’ 97 - Nov. ’ 05 HR 2 data Oct. ’ 99 – Nov. ’ 05 No candidate Hi. Res(e) exploits the Landau, Pomeranchuk, Migdal (LPM) effect for e induced electromagnetic showers. O. B. Bigas et al. (Auger collab. ) , ICRC 2007. K. Martens et al. (Hi. Res collab. ), astro-ph/0707. 4417

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 E 2 Peak Field Strength at Cherenkov angle Field strength increases with frequency Linearly polarized signal

Test of Askaryan effect in ice: SLAC T 486 SLAC 28. 5 Ge. V electron beam with ~109 particles Frequency Total energy The Askaryan effect was confirmed. (June 2006) Cherenkov angle ANITA collab. hep-ex/0611008

Experiments using Askaryan effect Lunar regolith Antarctic ice Greenland ice Parkes 64 m radio Hankins, Ekers, O’Sullivan, 1996 telescope 10 hours looking for impulses from Lunar regolith, >1020 e. V (Australia) (C. W. James et al. , Mon. Not. R. Astron. Soc. 379: 1037, 2007) RICE Radio Ice Cherenkov Experiment, late 1990’s-present AMANDA boreholes with antennas at South Pole, >1017 e. V (L. Kravchenko et al. , Astropart. Phys. 20, 195(2003). ) GLUE Goldstone lunar ultrahigh energy experiment, 1998 -2002, 120 hrs on lunar regolith with 70 m+34 m radio telescopes, >1020 e. V. (P. W. Gorham et al. , Phys. Rev. Lett. 93: 041101(2004)) 64 m Karyazin 64 m Kalyazin Radio Astronomical observatory of the Astro telescope(Russia) Space Center, radio emission from lunar regolith, > 1020 e. V (A. R. Beresnyak et al. , Astronomy Reports 49, 127(2005). ) FORTE Fast On-orbit Recording of Transient Events. Satellite for lightning, set limits based on Greenland ice observ. >1022 e. V (N. G. Lehtinen et al. , Phys. Rev. D 69, 013008(2004). ) ANITA Antarctic Impulsive Transient Antenna. Long duration balloon

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. 7 km average depth of ice From J. Nam

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

Conclusions • More solar neutrino information is expected in near future (flux of 7 Be, 8 B 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 t appearance with 2. 4 s 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.

Backup

The source experiments with Ga Item GALLEX Cr 1 GALLEX Cr 2 SAGE 51 Cr SAGE 37 Ar Source production Mass of reactor target (kg) Target isotopic purity Source activity (k. Ci) Specific activity (k. Ci/g) 35. 5 38. 6% 50 Cr 1714 +30 -43 0. 048 35. 6 38. 6% 50 Cr 1868 +89 -57 0. 052 0. 512 92. 4% 50 Cr 516. 6 ± 6. 0 1. 01 330 96. 94% 40 Ca 409 ± 2 92. 7 Gallium exposure Gallium mass (tones) Gallium density (1021 71 Ga/cm 3) Measured production rate ρ (71 Ge/d) 30. 4 (Ga. Cl 3: HCl) 1. 946 11. 9 ± 1. 1 ± 0. 7 30. 4 (Ga. Cl 3: HCl) 1. 946 10. 7 ± 1. 2 ± 0. 7 13. 1 (Ga metal) 21. 001 14. 0 ± 1. 5 ± 0. 8 13. 1 (Ga metal) 21. 001 11. 0 +1. 0 -0. 9 ± 0. 6 1. 00 +0. 11 -0. 10 0. 81 ± 0. 10 0. 95 ± 0. 12 0. 79 +0. 09 -0. 10 R=P(measured)/Ρ(predicted) The weighted average value of R is 0. 88 ± 0. 05, 05 more than two 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 GALLEX Cr 1 1. 00+0. 11 -0. 10 SAGE Cr 0. 95 ± 0. 12 GALLEX Cr 2 0. 81 ± 0. 10 SAGE Ar 0. 79+0. 09 -0. 10

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

L/E distribution from atmospheric neutrinos oscillation: P = 1 – sin 22 qsin 2(1. 27 Dm 2 L ) E SK-I+II (141 kton・yr) MC (no osc. ) Decoh. Decay MC (osc. ) Mostly down -going Mostly up -going Osc. c 2(osc)=83. 9/83 dof Oscillation gives the best fit to the data. c 2(decay)=107. 1/83 dof Decay and decoherence models disfavored by 4. 8 and 5. 3 s, resp. Also, strong constraint on the oscillation param. c 2(decoherence)=112. 5/83 dof

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

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

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

+p elastic signal（ +p→ +p） at Kam. LAND Beacom, Farr, and Vogel, PRD 66, 033001(2002) Expected spectrum e e t t Solid: sum of Temperature sensitivity all ~300 events above 200 ke. V ~150 events above 500 ke. V Determine original , , t temperature with ~10% accuracy. (free from neutrino oscillation. ）

L. Koepke Ice. Cube as Me. V detector Ice. Cube 10 kpc Disadvantage: no pointing no energy intrinsic noise accretion phase Helmholtz cooling phase Advantage: high statistics (0. 75% stat. error @ 0. 5 s and 100 ms bins) Good for fine time structures (noise low)! Simulation based on a numerical Livermore model at 10 kpc (normalization to SN 1987 A would give flux 1/3 lower) Totani, Sato, Dalhed & Wilson, Ap. J 496 (1998) 216 See also Dighe, Keil & Raffelt, hep-ph/0303210 for pointing out Ice. Cube

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