1. LENA Low Energy Neutrino Astrophysics L. Oberauer, Technische Universität München www.e15.physik.tu-muenchen.de/research/lena.htlm LENA Delta EL SUD Meeting Garching, April 24th

2. Scintillator solvent: PXE, or PXE/mineral oil mixture non hazardous, flashpoint 145° C easy handling non hazardous, flashpoint 145° C easy handling density up to 0.99high self shielding density up to 0.99high self shielding high light yield low energy events high light yield low energy events low background level U, Th solar  geo, snr low background level U, Th solar  geo, snr Muon veto 30% coverage up to ~60% (light cones) LENA 50 kt liquid scintillator detector 100m 30m

3. transport railway transport of PXE via railway loading pipeline loading of detector via direct pipeline no fundamental security problem with PXE excavation no fundamental problem for excavation LENA is feasible in Pyhäsalmi ! LENA at CUPP

4. Scintillator for LENA CTF at Gran Sasso (BOREXINO) Absorption- and Scattering lengths at TU München (M. Wurm – Diploma thesis) ~ 100 pe / MeV for an event at the center up to ~ 200 pe / MeV with light cones should be possible Coverage 30%

5. Physics goals Baryon number violation (Proton decay) Gravitational collapse (SN detection) Star formation (diffuse SN  background) Thermonuclear fusion processes (low E solar neutrinos CNO, pep, 7 Be) Geophysical models (U, Th –  Neutrino oscillations (Long baseline – 

6. Supernovae Relic e 3 models (different spectral shapes): Lawrence Livermore – LL Keil, Raffelt, Janka – KRJ Thompson, Burrows, Pinto - TBP Large systematic uncertainties UV (blue), H  (green) and FIR (red) are impeded by dust extinction

7. Contribution to the signal as function of z Ando et al., 2003

8. SRN Rate (between 9.8 and 30 MeV): 28 – 55 / (10 a) Background ~ 8 / (10 a) Spectral shape analysis possible Redshift z ~ 2 Separation LL vs. TBP possible (90% cl) Supernovae Relic e M. Wurm – Diploma thesis

9. Supernovae Relic e Threshold at Kamioka ~ 12 MeV (for water Cherenkov detectors) Redshift z ~ 1 Between 21% and 37% lower rate (compared to Pyhäsalmi) Best locations: Hawaii, Australia…

11. Supernova Neutrinos Assumption: Supernova II with 8 solar masses at 10 kpc distance e flux and spectrum

12. Supernova Neutrinos Total neutrino flux Total energy spectrum

13. Supernova and neutrino properties „Wiggles“ in the e spectrum observable if spectra or fluxes of SN neutrino flavors differ if neutrinos pass the Earth before entering LENA yesno Smirnov, Dighe, Raffelt...

14. Solar Neutrinos High statistic ( ~ 5.4 x 10 3 / day ) 7 Be + e  + e test of small flux fluctuations in time CNO and pep – neutrinos ( ~ 3 x 10 2 / day ) solar neutrino luminosity contribution of CNO cycle to solar energy release Charged current e ( 13 C, 13 N) e - reaction ( ~ 10 3 / year ) spectroscopy of 8 B- at energies below 5 MeV (A. Ianni et al., hep-ph/0506171) LENA Fiducial Volume for solar : 18 x 10 3 m 3

15. Test of MSW effect 7 Be pep CNO 8B8B 8 B via 13 C MSW effect

16. Geo Neutrinos Detection via inverse beta decay measurement of radiogenic contribution to terrestrial heat (~ 40 TW) test of the Bulk Silicate Earth model test of unorthodox models of Earth‘s core (is there a breeder reactor ?)

18. LENA @ Pyhäsalmi: ~ 1.5 x 10 3 events / year TNU (1 capture in 10 32 protons per year) Scaling KamLAND result to LENA: between 3 x 10 2 and 3 x 10 3 events / year Rate of Geo-neutrinos in LENA G. Fiorentini et al., hep-ph/0401085

19. Distinction potential between U- and Th-series

20. Geo-neutrinos and LENA Displacement n,e + for directionality ? zenith angle distribution in LENA e.g. 21 TW core model: Indication (1  ) after a couple of years K. Hochmuth – Diploma thesis

21. LENA and Proton Decay

23. K  K Event structure in LENA Background suppression ~ 5 x10(-5) Acceptance ~ 65%

24. Background suppression in LENA

25. T. Marrodan Undagoitia – Diploma thesis

26. Actual SK limit 2.3 x 10 33 y: after 10 years ~ 40 events (< 1 background event) 90%cl limit: 4 x 10 34 years T. Marrodan et al., Phys. Rev. D 72, 075014 (2005)

27. LENA and long baseline accelerator experiments Search for  13 e.g. at a Betabeam (  appearance experiment) Separation between muon- and electron like events ? Two methods under investigation: pulse shape discrimination (works fine for HE) muon decay (delayed coincidence) problem: pion production E > 400 MeV and successive decay into muon

28. Muon (800 MeV) Tau = 8 ns (risetime 15% - 85%) Electron (800 MeV) Tau = 4 ns Time (ns) Muon Electron

29. Conclusion LENA: a low energy neutrino observatory Impact on astro-,particle-, geophysics Complementary to Neutrino Telescopes Feasibility studies very promising