1. Neutrinoastrophysik bei niedrigen Energien BOREXINO and LAGUNA
Astroteilchenphysik in Deutschland, February 2010
Zeuthen DESY
Lothar Oberauer, TUM, Physik-Department
Forschungsbereich Kern- Teilchen- Astrophysik
Institut für experimentelle Astroteilchenphysik

2. Content New results from BOREXINO
Prospects for solar neutrino spectroscopy
Prospects for low energy neutrino astronomy
Status of LAGUNA and LENA

3. The dominating solar pp - cycle
H. Bethe
W. Fowler
pp - 1
pp -2
pp -3

4. The sub-dominant solar CNO - cycle
…dominates in stars with more mass as our sun…
=>Large astrophysical relevance
Measurement of CNO neutrinos = determination of inner solar metallicity

5. Solar Neutrinos Neutrino Energy in MeV Scintillator BOREXINO
Water Cherenkov
L. Oberauer, TUM

6. BOREXINO Neutrino electron scattering n e -> n e
Liquid scintillator technology (~300t):
Low energy threshold (~60 keV)
Good energy resolution (~ 1 MeV)
very low background
Sensitivity on sub-MeV neutrinos
Online since May 16th, 2007
L. Oberauer, TUM

7. Neutrino elastic scattering off electrons
Cross section for ne is larger (factor ~5) as for nm,t
Expected rate without neutrino mixing ~ 74 counts per day and 100t target
Expected rate with neutrino mixing (MSW-LMA) ~ 48 c/(d 100 t)
L. Oberauer, TUM

8. BOREXINO in the Italian Gran Sasso Underground Laboratory in the mountains of Abruzzo, Italy,
~120 km from Rome
Laboratori
Nazionali del
Gran Sasso
LNGS
Shielding
~3500 m.w.e
External Labs
Borexino Detector and Plants

9. BOREXINO Detector layout
Stainless Steel Sphere:
2212 PMTs + concentrators
1350 m3
Scintillator:
270 t PC+PPO in a 150 mm
thick nylon vessel
Water Tank:
g and n shield
m water Č detector
208 PMTs in water
2100 m3
Nylon vessels:
Inner: 4.25 m
Outer: 5.50 m
Excellent shielding of external background
Increasing purity from outside to the central region
Carbon steel plates
L. Oberauer, TUM

10. Results on solar 7Be neutrinos
Counting rate on solar 7Be-neutrinos: 49 ± 3stat ± 4sys /(d 100t)
L. Oberauer, TUM

11. Results on solar 8B - neutrinos
No neutrino mixing
neutrino mixing plus (MSW) effect
New data for solar 8B neutrinos
L. Oberauer, TUM

12. Systematic uncertainties
Calibration with radioactive sources
(completed in 2009)
Study of response function
(e.g. gamma quenching, kb – parameter…)
Final systematic uncertainty on 7Be neutrino flux ~ 5%
L. Oberauer, TUM

13. Implications of solar 7Be neutrino result
Borexino exp. result:
49 ± 3stat ± 4sys / (d 100t)
Solar model (high metallicity, neutrino mixing, MSW): 48 ± 4 / (d 100t)
Solar model (low metallicity, neutrino mixing, MSW): 44 ± 4 / (d 100t)
Solar model, but no neutrino mixing:
74 ± 4 / (d 100t)
Clear confirmation of neutrino mixing and MSW
L. Oberauer, TUM

14. Implications of solar 7Be-neutrino result
f = measured / expected (solar model, MSW)
Before Borexino fBe =
After Borexino fBe =
New constraints on pp- and CNO-fluxes from BOREXINO and all other solar neutrino experiments =>
L. Oberauer, TUM

15. CNO contribution to solar energy generation
Without solar luminosity constraint
With solar luminosity constraint
CNO contribution to solar energy generation
< 5.4 % (90 % cl)
L. Oberauer, TUM

16. Correlation between constraints on pp- and CNO- fluxes
Borexino result and solar luminosity constraint
fCNO < 4.8 (90 %cl)
L. Oberauer, TUM

17. Survival probability at Earth for solar ne as function of their energy
Measurements and expectations (MSW effect)
Borexino
L. Oberauer, TUM

18. Prospects of BOREXINO Improvement of systematical uncertainties
7Be flux measurement at < 5 % total uncertainty
8B flux measurement with increased statistics
Measurement of pep and CNO-neutrinos (if 11C event rejection and purity allows…)
ne measurement by ne p -> e+ n
=> Geo neutrinos & reactor neutrinos
Supernova neutrinos (~100 events) for a galactic SN type II , limits on magnetic moment…
L. Oberauer, TUM

19. New Analysis of SNO phases I and II
Threshold at 3.5 MeV (nucl-ex: )
L. Oberauer, TUM

20. Two flavor neutrino oscillation hypothesis analysis
Global fit including:
Solar neutrino experimental results (SNO, Cl, Gallex/GNO, Sage, Borexino, SK I & II)
KamLAND reactor neutrino data
(SNO collaboration:
nucl-ex: )
L. Oberauer, TUM

21. Three flavor neutrino oscillation analysis
nucl-ex:
L. Oberauer, TUM

22. Three flavor neutrino oscillation analysis
Current best parameter values from solar neutrino experiments and KamLAND
Q12 = ( – 0.84) degrees
Dm212 = ( – 0.21) x 10-5 eV2
Three flavor neutrino oscillation analysis
sin2Q13 = ( ) x 10-2
Limit on Q13: sin2Q13 < (95% cl)
nucl-ex:
L. Oberauer, TUM

23. Prospects of low energy neutrino astronomy in Europe
3 large detector types are proposed
0.4 Mt Water Cherenkov (Memphis)
100 kt Liquid Argon (Glacier)
50 kt Liquid Scintillator (LENA)
LAGUNA (Large Apparatus for Grand Unification and Neutrino Astrophysics): European funded FP7 design study for a future underground facility in Europe (report to be completed in 2010)
L. Oberauer, TUM

24. LAGUNA Consortium
- Italy

25. Low Energy Neutrino Astronomy – LENA
L. Oberauer1, F. v. Feilitzsch1, M. Göger-Neff1, Y. Bezrukov10, A. Sherpukov9, C. Hagner2, J. Jochum3, T. Lachenmaier1,4, T. Lewke1, M. Lindner5, E. Kokko12, K. Loo12, J. Maalampi12 ,T. Marrodán Undagoitia7, G. Nujiten11,Q. Meindl1, R. Möllenberg1, J. Peltoniemi1,4, W. Potzel1, T. Risikko12, K. Rummukainen13, A. Stahl8, M. Tippmann1, C. Traunsteiner1, W. Trzaska6, J. Winter1, M. Wurm1
1 Technische Universität München, Physikdepartment E15, James-Franck-Str. 1, Garching
2 Universität Hamburg, Institut für Experimentalphysik, Luruper Chaussee 149, Hamburg
3 Universität Tübingen, Physikalisches Institut, Auf der Morgenstelle 14, Tübingen
4 The Cluster of Excellence for Fundamental Physics, „Origin and Structure of the Universe“, Boltzmannstr. 2, Garching (Germany)
5 Max-Planck-Institut für Kernphysik, Am Saupferchweg 1, Heidelberg (Germany)
6 University of Jyväskylä, Department of Physics, P.O. Box 35 (YFL), FI Jyväskylä (Finland) 7 Universität Zürich, Physik-Insitut, Winterthurstr. 189, 8057 Zürich (Switzerland)
8 RWTH Aachen, III. Physikalisches Institut, Physikzentrum, Aachen (Germany)
9Moscow State University (Russia)
10Institute for Nuclear Research, Moscow, Russia
11Rockplan, Helsinki (Finland)
12University Oulu, Oulu (Finland)
13University of Helsinki (Finland)
+ collaboration with APC, CNRS, Paris (France) for common development MEMPHIS/LENA

26. LENA Physics Goals Proton Decay Diffuse Supernova Neutrino Background
Galactic Supernova Burst
Long baseline neutrino oscillations
Solar Neutrinos
Geo neutrinos
Reactor neutrinos
Atmospheric neutrinos
Dark Matter indirect search
L. Oberauer, TUM

27. ~ 50 kt Liquid Scintillator
L. Oberauer, TUM

28. LENA and proton decay High sensitivity to p -> K n
(eff. ~ 68% instead 6% in SK
t ~ 5 x 1034 y)
Sensitive to a variety of decay channels
“invisible” modes, e.g. n -> n n n
For e.g. p -> e+ p0 we expect ~ 1033 y
(work in progress)
T. Marrodan et al., Phys. Rev. D72, (2005)
L. Oberauer, TUM

29. LENA and the Diffuse Supernova Background
Excellent background rejection (nep->e+n)
Energy window 10 to 30 MeV.
High efficiency (100% with 50 kt target)
High discovery potential in LENA
~2 to 20 events per year are expected (model dependent)
M. Wurm et al., Phys.Rev.D 75 (2007)
L. Oberauer, TUM

30. LENA and a Galactic Supernova Burst
Antielectron n spectrum with high precision
Electron n flux with ~ 10 % precision
Total flux via neutral current reactions
Separation of SN models
Spectroscopy of all n flavors
Time evolution of neutrino burst
Details of SN gravitational collapse
Chance to separate low/high Q13 and mass hierarchy (normal/inverted)
Coincidence with gravitational wave detectors
L. Oberauer, TUM

31. LENA and long baseline neutrino oscillations
Separation between e- and m-like events
Pulse shape discrimination (risetime, width)
Track reconstruction
Muon decay m -> e n n
Work in progress
electrons (1.2 GeV) muons (1.2 GeV)
L. Oberauer, TUM

32. Study CERN – LENA at Pyhäsalmi (Finland)
CERN - Pyhäsalmi 2288 km
5 years nu + 5 years anti-nu
GeV
Wide band beam 1 – 6 GeV
1.5 MW power
Sensitivity on theta_13, CP-parameter, mass hierarchy
J. Peltoniemi, Simulations of neutrino oscillations for a wide band beam from CERN to LENA, arXiv: v1 [hep-ex]
L. Oberauer, TUM

33. CP – violating parameter
Detection signifigance (chi)
CP – violating parameter
preliminary
> 3 sigma
Log (osc. Amplitude)
L. Oberauer, TUM

34. preliminary
L. Oberauer, TUM

35. LENA and Solar Neutrinos
High statistics in 7-Be (~ 5400 events per day)
Search for small time fluctuations
CNO and pep n (~ 360 events per day)
Very sensitive test of MSW effect
CC and NC measurements of 8-B
Search for spectrum deformation
Search for non-standard n interactions
Search for solar ne -> ne transitions
L. Oberauer, TUM

36. LENA and Geo-neutrinos
LENA is the only detector within Laguna able to determine the geo neutrino flux
In LENA we expect between 300 to 3000 events per year (“best bet” ~ 1500 / year)
Good signal / background ratio
most significant contribution can be subtracted statistically
Separation of geological models
L. Oberauer, TUM

37. LENA and Reactor neutrinos
At Frejus ~ 17,000 events per year
High precision on solar oscillation parameter:
Dm212 ~ 1%
Q12 ~ 10%
S.T. Petcov, T. Schwetz, Phys. Lett. B 642, (2006), 487
J. Kopp et al., JHEP 01 (2007), 053
L. Oberauer, TUM

38. Pre-feasibility study for LENA at Pyhäsalmi (TUM and company Rockplan, Finland)
Depth at 1400 m – 1500 m possible !
Geological study completed
Vertical detector position
Logistics (Vent, Electricity, etc.) considered
Construction time of cavern ~ 4 years
1st costs estimate for the whole project
Tank construction plan (accomplished April 2010)
L. Oberauer, TUM

39. favoured option:
+ Tank Construction: 8 years
L. Oberauer, TUM

40. Conclusions Solar neutrino experiments very successful
Strong impact on neutrino oscillation parameter
Precise determination of solar nuclear fusion processes
Missing CNO-neutrinos -> determination of solar inner metallicity
Geo neutrinos (stay tuned !)
Prospects (Large detectors like LENA) in this field & proton decay and long baseline experiments
LAGUNA design study accomplished in 2010
L. Oberauer, TUM