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LENA

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LENA and long baseline accelerator experiments. Search for Q13 ... LENA: a low energy neutrino observatory. Impact on astro- ,particle-, geophysics ... – PowerPoint PPT presentation

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Title: LENA


1
LENA
LENA Delta
  • Low Energy Neutrino Astrophysics

EL SUD Meeting Garching, April 24th
L. Oberauer, Technische Universität
München www.e15.physik.tu-muenchen.de/research/len
a.htlm
2
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 145 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

3
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 !

4
Scintillator for LENA
CTF at Gran Sasso (BOREXINO) Absorption- and
Scattering lengths at TU München (M. Wurm
Diploma thesis)
Coverage 30
100 pe / MeV for an event at the center up to
200 pe / MeV with light cones should be
possible
5
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)

6
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
7
Contribution to the signal as function of z
Ando et al., 2003
8
Supernovae Relic ne
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)
M. Wurm Diploma thesis
9
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
10
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11
Supernova Neutrinos
Assumption Supernova II with 8 solar masses at
10 kpc distance
ne flux and spectrum
ne flux and spectrum
12
Supernova Neutrinos
Total neutrino flux
Total energy spectrum
13
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...
14
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)

15
Test of MSW effect
7Be pep CNO
MSW effect
8B
8B via 13C
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 Earths core (is
    there a breeder reactor ?)

17
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18
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
19
Distinction potential between U- and Th-series
20
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
K. Hochmuth Diploma thesis
21
LENA and Proton Decay
22
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23
Event structure in LENA
K-gtm n
Background suppression 5 x10(-5) Acceptance
65
K
24
Background suppression in LENA
25
T. Marrodan Undagoitia Diploma thesis
26
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)
27
LENA and long baseline accelerator experiments
  • Search for Q13
  • e.g. at a Betabeam (nm 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 gt 400 MeV and
    successive decay into muon

28
Muon
Electron
Muon (800 MeV) Tau 8 ns (risetime 15 - 85)
Electron (800 MeV) Tau 4 ns
Time (ns)
29
Conclusion
  • LENA a low energy neutrino observatory
  • Impact on astro- ,particle-, geophysics
  • Complementary to Neutrino Telescopes
  • Feasibility studies very promising
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