1. Low Energy Neutrino Astrophysics
LENA
LENA Delta
Low Energy Neutrino Astrophysics
L. Oberauer, F. von Feilitzsch, M. Göger-Neff, T. Marrodan, P. Pfahler, W. Potzel, M. Wurm
Technische Universität München

2. LENA 50 kt liquid scintillator detector Muon veto
30% coverage up to ~60% (light cones)
Scintillator solvent: PXE, or PXE/mineral oil mixture
non hazardous, flashpoint 160° C easy handling
density up to high self shielding
high light yield low energy events
low background level U, Th solar n, geo n, snr n

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

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

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

6. Supernovae Relic ne SRN Rate (between 9.5 and 30 MeV):
Background ~ 21 / (10 a)
Spectral shape analysis possible
Redshift z ~ 2
Separation LL vs. TBP possible (90% cl)

7. Supernovae Relic ne
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…

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

9. Supernova Neutrinos
Total neutrino flux
Total energy spectrum

10. Supernova and neutrino properties
„Wiggles“ in the ne spectrum observable
if spectra or fluxes of SN neutrino flavors differ
if neutrinos pass the Earth before entering LENA
yes no
Smirnov, Dighe, Raffelt...

11. LENA Fiducial Volume for solar n: 18 x 103 m3
Solar Neutrinos
LENA Fiducial Volume for solar n: 18 x 103 m3
High statistic ( ~ 5.4 x 103 / day ) 7Be n + e -> n + e
test of small flux fluctuations in time
CNO and pep – neutrinos ( ~ 3 x 102 / day )
solar neutrino luminosity
contribution of CNO cycle to solar energy release
Charged current ne (13C,13N) e- reaction ( ~ 103 / year )
spectroscopy of 8B-n at energies below 5 MeV
(A. Ianni et al., hep-ph/ )

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

13. 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 ?)

14. G. Fiorentini et al., hep-ph/0401085
Rate of Geo-neutrinos in LENA
Pyhäsalmi: ~ 1.5 x 103 events / year
TNU
(1 capture in 1032 protons per year)
Scaling KamLAND result to LENA:
between
3 x 102 and
3 x 103 events / year
G. Fiorentini et al., hep-ph/

15. Geo-neutrinos and LENA
Displacement n,e+ for directionality ?
e.g. 21 TW core model:
Indication (1 s) after a couple of years
zenith angle distribution in LENA
…thanks to E. Lisi & Baksan group

16. LENA and Proton Decay

17. Event structure in LENA
K->m n K
Background suppression ~ 10(-4)
Acceptance ~ 60%

18. T. Marrodan et al., Phys. Rev. D 72, 075014 (2005)
Actual SK limit 2.3 x 1033 y: after 10 years ~ 40 events (< 1 background event) %cl limit: 4 x 1034 years
T. Marrodan et al., Phys. Rev. D 72, (2005)

19. Conclusion LENA: a low energy neutrino observatory
Impact on astro- ,particle-, geophysics
Complementary to Neutrino Telescopes
Feasibility studies very promising
LENA is in the ApPEC roadmap
together with ~Mt Water Cherenkov and ~50 kt Liquid Argon Detectors
...thanks to Milla for the kind invitation to talk about LENA