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Neutrinos as Probes: Solar-, Geo-, Supernova neutrinos; Laguna

Neutrinos as Probes: Solar-, Geo-, Supernova neutrinos; Laguna. MPIK Heidelberg, November 2009 Lothar Oberauer, Physikdepartment E15, TU München. Solar Neutrinos. Borexino results SNO results What do we know now about solar neutrino branches ?

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Neutrinos as Probes: Solar-, Geo-, Supernova neutrinos; Laguna

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  1. Neutrinos as Probes: Solar-, Geo-, Supernova neutrinos; Laguna MPIK Heidelberg, November 2009 Lothar Oberauer, Physikdepartment E15, TU München

  2. Solar Neutrinos • Borexino results • SNO results • What do we know now about solar neutrino branches ? • What can we learn about neutrino oscillation parameter ?

  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. Neutrino Energy in MeV Solar Neutrinos L. Oberauer, TUM

  6. BOREXINO Neutrino electron scattering n e ->n e Liquid scintillator technology (~300t): Low energy threshold (~60 keV) Good energy resolution (~ 5% @ 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 (since winter 2008/09) Study of response function (e.g. gamma quenching, kb – parameter…) 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. 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:09102984)

  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:09102984)

  21. Three flavor neutrino oscillation analysis nucl-ex:09102984

  22. Current best parameter values from solar neutrino experiments and KamLAND • Q12 = (34.06 + 1.16 – 0.84) degrees • Dm212 = (7.59 + 0.20 – 0.21) eV2 Three flavor neutrino oscillation analysis • sin2Q13= (2.00 + 2.09 - 1.63) x 10-2 • Limit on Q13: sin2Q13< 0.057 (95% cl) nucl-ex:09102984

  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: design study for a future underground facility in Europe (report completed in 2010)

  24. Physics Goals • Proton Decay • Long baseline neutrino oscillations • Diffuse Supernova Neutrino Background • Galactic Supernova Burst • Solar Neutrinos • Geo neutrinos • Reactor neutrinos • Atmospheric neutrinos • Dark Matter indirect search T. Lachenmaier my talk today

  25. Search for theDiffuse Supernova Neutrino Backgroundin LENA Phys.Rev.D 75 (2007) 023007 M. Wurm, F. v. Feilitzsch, M. Göger-Neff,T. Marrodán Undagoitia, L. Oberauer, W. Potzel, J. Winter Technische Universität Münchenmwurm@ph.tum.de http://www.e15.physik.tu-muenchen.de/research/lena.html

  26. DSNB Detection via inverse beta decay • Free protons as target Delayed signal (~200 ms) • Threshold 1.8 MeV • En ~ Ee - Q (n spectroscopy) • suppress background via delayed coincidence method • n + p -> D + g(2.2 MeV) • position reconstruction => fiducial volume (suppress external background) Prompt signal

  27. OutlineDSNB BackgroundEvent Rates Spectroscopy TU München LENA at Pyhäsalmi(Finland) DSN event rate in 10yrsinside the energy window from 9.7 to 25 MeV dependent on SN model and on Supernova rate as function of redshift z Number of events 20 – 200 (10 years) ~25% of events are due to v’s originating from SN @ z>1

  28. Diffuse Supernova Neutrino Background Detection • Excellent background rejection • 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)

  29. Galactic Supernova neutrino burst in LENA

  30. Separation of SN models ? • Yes! Possible independent from oscillation model due to neutral current reactions in LENA TBP KRJ LL 12-C: 700 950 2100 Nu-p: 1500 2150 5700 for 8 solar mass progenitor and 10 kpc distance

  31. Supernova neutrinos with LENA • 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

  32. Solar Neutrino Detection in LENA

  33. Solar Neutrinos and LENA n + e -> n + e and 13C + ne-> 13N + e

  34. Solar Neutrinos and LENA • High statistics in 7-Be • Search for time fluctuations • CNO and pep n • 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 -> netransitions

  35. LENA and neutrinos from the Earth

  36. Signal & Backgrounds in LENA • ~ 1500 per year signal • ~ 240 per year in [1.8 MeV – 3.2 MeV] from reactor neutrinos • < 30 per year due to 210Po alpha -n reaction on 13C (Borexino purity assumed) • ~ 1 per year due to cosmogenic background (9Li - beta-neutron cascade) Can be statistically subtracted K. Hochmuth et al., Astropart.Phys. 27 (2007) 21-29

  37. LENA and Geo-neutrinos • LENAis 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

  38. 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

  39. 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

  40. One Option: + Tank Construction: 8 years

  41. 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 L. Oberauer, TUM

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