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LENA

LENA. LENA Delta. Low Energy Neutrino Astrophysics. F. von Feilitzsch, L. Oberauer, W. Potzel Technische Universität München. LENA (Low Energy Neutrino Astrophysics). Idea: A large (~30 kt) liquid scintillator underground detector for. Relic supernovae neutrino detection.

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LENA

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  1. LENA LENA Delta Low Energy Neutrino Astrophysics F. von Feilitzsch, L. Oberauer, W. Potzel Technische Universität München

  2. LENA (Low Energy Neutrino Astrophysics) Idea: A large (~30 kt) liquid scintillator underground detector for Relic supernovae neutrino detection Search for Proton Decay Galactic supernova neutrino detection Neutrino properties Terrestrial neutrino detection Solar Neutrino Spectroscopy

  3. Npe ~ 100 / MeV beta ~ 12000 PMs (20 inch) P - decay event Scintillator: PXE , non hazardous, flashpoint 145° C, density 0.99, ultrapure (as proven in Borexino design studies)

  4. Possible locations for LENA ? Underground mine ~ 1450 m depth, low radioactivity, low reactor n-background ! Access via trucks

  5. LENA at CUPP • transport of 30 kt PXE via railway • loading of detector via pipeline • no fundamental security problem with PXE ! • no fundamental problem for excavation • standard technology (PM-encapsulation, electronics etc.) • LENA is feasible in Pyhäsalmi !

  6. Pylos (Nestor Institute) in Greece

  7. Galactic Supernova neutrino detection with Lena Electron Antineutrino spectroscopy ~7800 Electron n spectroscopy ~ 65 Neutral current interactions; info on all flavours ~ 4000 and ~ 2200 ~ 480 Event rates for a SN type IIa in the galactic center (10 kpc)

  8. Visible proton recoil spectrum in a liquid scintillator all flavors nm, nt and anti-particles dominate J. Beacom, astro-ph/0209136

  9. Relative size of the different luminosities is not well known: it depends on uncertainties of the explosion mechanism and the equation of state of hot neutron star matter Supernova neutrino luminosity (rough sketch) T. Janka, MPA

  10. SNN-detection and neutrino oscillations ne Water Cherenkov Scintillator good resolution Modulations in the energy spectrum due to matter effects in the Earth Dighe, Keil, Raffelt (2003)

  11. Preconditions for observation of those modulations • SN neutrino spectra ne and nm,t are different • distance L in Earth large enough • very good statistics (~ 5 kt minimum) • very good energy resolution (scintillator !)

  12. LENA and relic Supernovae Neutrinos ! • SuperK limit very close to theoretical expectations • Threshold reduction from ~19 MeV (SuperK) to ~ 9 MeV with LENA • Method: delayed coincidence of ne p -> e n • Low reactor neutrino background ! • Information about star formation in the early universe

  13. Reactor SK No background for LENA ! Reactor bg LENA ! LENA SNR rate: ~ 6 counts/y SRN Atmospheric neutrinos

  14. Low energyatmospheric neutrinosandLENA • LENA can measure the low energy part of atmospheric neutrinos, esp. ne • 30 MeV - 200 MeVne: • Losc ~ 103 km to 7 x 103 km • (Dm2 solar neutrinos!) • ne<-> nmatmospheric oscillations, but based on Dm2solar • observable ? • ...difficult (low statistics); needs further investigations

  15. Long baseline n - oscillations andLENA ? • To be investigated: • n spectrum • e, m - separation potential • potential in Q13 !

  16. Solar Neutrinos and LENA: Probes for Density Profile Fluctuations ! Balantekin, Yuksel TAUP 2003 hep-ph/0303169 7-Be ~200 / h LENA

  17. Geo - neutrinos and LENA • what is the source of the terrestrial heat flow ? • what is the contribution of natural radioactivity ? • how much of U, Th is in the mantle ? • (very low bg due to reactors!)

  18. Proton Decay and LENA • p K n • This decay mode is favoured in SUSY theories • The primary decay particle K is invisible in Water Cherenkov detectors • It and the K-decay particles are visible in scintillation detectors • Better energy solution further reduces background See also R. Swoboda (Taup 03)

  19. P -> K+ nevent structure: T (K+) = 105 MeV t (K+) = 12.8 nsec K+-> m+ n (63.5 %) K+-> p+ p0 (21.2 %) T (m+) = 152 MeV T (p+) = 108 MeV electromagnetic shower E = 135 MeV m+ -> e+n n (t = 2.2 ms) p+ -> m+ n(T = 4 MeV) m+ -> e+n n (t = 2.2 ms)

  20. Signal in LENA m m K K time (nsec) P decay into K and n

  21. Background • Rejection: • monoenergetic K- and m-signal! • position correlation • pulse-shape analysis • (after correction on • reconstructed position)

  22. Sensitivity of LENA ? • SuperKamiokande has 170 background events in 1489 days (efficiency 33% ) • In LENA, this would scale down to a background of ~ 5 / y and after PSD-analysis this could be suppressed in LENA to • ~ 0.25 / y ! (efficiency ~ 70% ) • A 30 kt detector (~ 1034 protons as target) would have a sensitivity of t < a few 1034 years for the K-decay after ~10 years measuring time • The minimal SUSY SU(5) model predicts the K-decay mode to be dominantwith a partial lifetime varying from 1029y to 1035 y ! • actual best limit from SK: t > 6.7 x 1032 y (90% cl)

  23. Conclusions • LENA a new observatory • complemntary to high energy neutrino astrophysics • fundamental impact on e.g. geophysics, astrophysics, neutrino physics, proton decay • feasibiluty studies very promising (Pyhäsalmi) • costs ca. 100 - 200 M€

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