1 / 31

Neutrinos from the sun, earth and SN’s: a brief excursion

Neutrinos from the sun, earth and SN’s: a brief excursion. Aldo Ianni @ IFAE 2006 Pavia April 19 th. Outline. Solar neutrinos: established facts Solar neutrinos: the future Neutrinos from the Earth: present & future Neutrinos from SN. Solar neutrinos. Pure n e beam Low energy

teigra
Download Presentation

Neutrinos from the sun, earth and SN’s: a brief excursion

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Neutrinos from the sun, earth and SN’s: a brief excursion Aldo Ianni @ IFAE 2006 Pavia April 19th

  2. Outline • Solar neutrinos: established facts • Solar neutrinos: the future • Neutrinos from the Earth: present & future • Neutrinos from SN

  3. Solar neutrinos • Pure ne beam • Low energy • Long baseline (1013 cm) • Moving through high density matter (at sun’s core ~150 g/cm3)

  4. Solar neutrinos: observations * Super-Kamiokande recovers full detector performances this year ** SNO is planned to be shut down end of this year

  5. Phenomenology of solar neutrino observations • Observations explained by neutrino oscillations + matter effects (MSW) • MSW leads to energy spectrum distortion and regeneration in the earth (day-night effect) • After SNO with NC the space of parameters gets reduced a lot • After KamLAND (assuming CPT) one dominant solution is tackled, namely the LMA

  6. The great turn with SNO (>2001)

  7. Established dominant solution Taken from V. Barger et al hep-ph/0501247 Taken from G.L.Fogli et al hep-ph/0506083

  8. Established facts • 0.01% of solar neutrinos measured in real time • Data explained by the MSW LMA • MWS defines mass hierarchy (m2 > m1) • SNO CC/NC sets tan2q12<1 • MSW predicts up-turn of survival probability (spectral distortion) and regeneration • MSW predicted effects not yet observed in SNO and SK due to high systematrics and still poor statistics

  9. SNO data

  10. A look at the future for Solar neutrinos • Measure in real time 99.99% of spectrum below 5 MeV : low energy detectors • Measure spectral distortion and regeneration : low energy and/or Mton water Cherenkov • Compare photon to neutrino luminosity : low energy solar neutrinos pp, pep, Be • Test new physics with sub-dominant effects : e.m. properties, mass varying neutrinos, non-standard interactions, light sterile neutrino

  11. Borexino @ Gran Sasso A pioneering experiment to search for sub-MeV 7Be solar neutrinos • Target medium : 100tons of high radiopurity organic liquid scintillator • Detection channel: neutrino-electron elastic scattering (about 30cpd expected) • Signature : seasonal variation + Compton-like threshold due to monoenergetic 7Be neutrinos • Challenge : reduce background sources (238U, 232Th, 40K, 222Rn, 85Kr, 39Ar, 210Pb, 210Po) to get S/N>1 • Lower detection energy : 250 keV limited to intrinsic 14C contamination • Experimental strategies to reduce background : established by a 4-ton scale prototype

  12. pep neutrinos with Borexino • Basic idea : reduce 11C cosmogenic background • Method: tagging 11C by tackling the produced (95%) neutrons in spallation interactions Taken from C. Galbiati et al PRC 71, 055805 (2005) Remark: a pep measurement gives the same information of a pp one

  13. Spherical cut aroundneutron Capture to reject 11C event Cylindrical cut Around muon-track Reduction of background forpep neutrinos Muon track Neutron production

  14. 11C tagged with the Borexino prototype 11C decays b+ with Qb~1MeV and t~30min Measured production rate ~0.14 events/day/ton at Gran Sasso depth Taken from Borexino coll. hep-ex/0601035

  15. Predictions to falsify with Borexino Bahcall et al, JHEP 8 (2004) 016, hep-ph/04060294 2 monoenergetic beams to test solar physics and neutrino physics

  16. pep new goal for KamLAND-II Taken from Nakajima, La Thuile

  17. pep for SNO+ • Main physics goal for 1kton organic liquid scintillator after SNO • At SNOlab 11C is reduced by a factor of about 10 with respect to Gran Sasso and 70 to Kamioka

  18. Searching for pp solar neutrinos • Goal : no 14C or a strong tagging • Solution-I : liquid Ne(CLEAN) or Xe(XMASS), detection channel = ES • Solution-II : loaded 115In liquid scintillator (LENS) • Solution-III : 100Mo sheets + plastic scintillator • Time scale : due to experimental difficulties >2010

  19. Conclusions on solar neutrinos • Wonderful effort made by researchers (both on experiments and theory) to collect and explain data • Unique opportunity with low energy solar neutrinos both in astrophysics and neutrino physics • A great challenge for experiments • pep neutrinos measurable • Not too much to add to oscillation parameters

  20. Neutrinos from the earth: geoneutrinos • Goals: • determine distribution of U, Th and K in earth interior • measure total heat due to radioactivity [earth gives 30-44 TW] • determine hot spots (geo-reactor etc) if any

  21. Detection of geoneutrinos Above 1.8MeV (only U,Th): inverse-beta decay (strong tagging) Below 1.8MeV (K as well): elastic scattering (weak tagging)

  22. The earth looked through geoneutrinos Geoneutrino flux (Fiorentini et al) Middle oceanic crust KamLAND SNO+ Lena 30kt Borexino

  23. Present observations @ KamLAND • Energy window: 0.9<E<2.6 MeV • Observed : 152 events • Background : 127 ± 13 events • Geoneutrino signal : 25+19-18 events • Main sources of background : reactors and 13C(a,n)16O with a’s from 210Po

  24. Geoneutrinos @ Gran Sasso Borexino 300t target mass : S/N~1

  25. LENA in Finland • Proposeda 30kt multi-puspose liquid scintillator based on PXE • PXE tested with the Borexino prototype • High statistics and angular resolution (26°) may allow 40K neutrino measurement looking toward the earth’s nucleus (if any hidden K in there!)

  26. Conclusions on geoneutrinos • U and Th geoneutrinos to get information on radiogenic heat on earth and test earth formation mechanism • U and Th geoneutrinos easy to detect far away from reactors and with a low background liquid scintillator • More detectors in different locations to reduce uncertainties • First (2s) evidence of geoneutrinos from KamLAND • Hope : detect K neutrinos somehow. See M. Chen talk at Neutrino Geophysics, Honolulu, Hawaii December 15, 2005

  27. SN neutrinos

  28. Detection of SN neutrinos [1] • SN neutrinos are affected by oscillations: • In the standard figure each flavor has a peculiar mean energy and temperature (Te~3.5MeV, Tanti-e~5MeV, Tx~8MeV with <E>~3.15T) • Uncertainty of standard figure ~50% • SN in galaxy: 40±10 yr/SN. Long-term stability of detectors required • in order to measure the temperature and energy of x’s and their antiparticles one needs a spectral signature ne nanti-e nx

  29. Detection of SN neutrinos [2] • SuperKamiokande will play a crucial role with ~8000 events for inverse-beta decay and ~700 for NC on 16O @10kpc • SuperKamiokande will see ~300 events of antineutrino @50kpc in the LMC • SNO has a unique channel e +dppe- for studying the neutronization phase but it will be shut down in 2007 • NC with neutrino-proton elastic scattering to measure x’s and their antiparticles with a spectral signature in low threshold liquid scintillators (Borexino, KamLAND) • Italy has a great opportunity with LVD, T600 and Borexino at the same location

  30. Detection of SN neutrinos [3]

  31. Conclusions on SN neutrinos • A future galactic SN will yield 100-1000 events in the existing detectors for the well tagged channel of inverse-beta decay (electron-antineutrino spectral signature) • Neutrino-proton elastic scattering will allow to measure the energy and temperature of mu and tau (anti)neutrinos • Collection of nice data for the cooling phase, not as well for the neutronization phase after SNO shut-down • Future proposed LENA to see modulation of spectra due to matter effect in the earth

More Related