LENA

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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 www.e15.physi
k.tu-muenchen.de/research/lena.htlm
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LENA 50 kt liquid scintillator detector
100m
30m
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 0.99 high self shielding
• high light yield low energy events
• low background level U, Th solar n, geo n,
  snr n

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LENA at CUPP

• 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 !

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Scintillator for LENA
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
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Physics goals

• Baryon number violation (Proton decay)
• Gravitational collapse (SN n detection)
• Star formation (diffuse SN n background)
• Thermonuclear fusion processes (low E solar
  neutrinos CNO, pep, 7Be)
• Geophysical models (U, Th n)
• Neutrino oscillations (Long baseline n)

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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
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Contribution to the signal as function of z
Ando et al., 2003
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Supernovae Relic ne
SRN Rate (between 9.5 and 30 MeV) 40 77 / (10
a) Background 21 / (10 a) Spectral shape
analysis possible Redshift z 2 Separation LL
vs. TBP possible (90 cl)
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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
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Supernova Neutrinos
Assumption Supernova II with 8 solar masses at
10 kpc distance
ne flux and spectrum
ne flux and spectrum
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Supernova Neutrinos
Total neutrino flux
Total energy spectrum
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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...
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Solar Neutrinos
LENA Fiducial Volume for solar n 18 x 103 m3

• High statistic ( 5.4 x 103 / day ) 7Be n
  e -gt 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/0506171)

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Test of MSW effect
7Be pep CNO
MSW effect
8B
8B via 13C
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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 Earths core (is
  there a breeder reactor ?)

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Rate of Geo-neutrinos in LENA
LENA _at_ 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/0401085
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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
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LENA and Proton Decay
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Event structure in LENA
K-gtm n
K
Background suppression 10(-4) Acceptance 60
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Background suppression in LENA
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Actual SK limit 2.3 x 1033 y after 10 years
40 events (lt 1 background event) 90cl
limit 4 x 1034 years
T. Marrodan et al., Phys. Rev. D 72, 075014 (2005)
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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