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Neutrinos – Ghost Particles of the Universe

Neutrinos – Ghost Particles of the Universe. Neutrinos Ghost Particles of the Universe. Georg G. Raffelt Max-Planck-Institut f ür Physik, München, Germany. Periodic System of Elementary Particles. Quarks. Leptons. Charge + 2/3 . Charge - 1/3 . Charge - 1 .

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Neutrinos – Ghost Particles of the Universe

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  1. Neutrinos – Ghost Particles of the Universe Neutrinos Ghost Particles of the Universe Georg G. Raffelt Max-Planck-Institut für Physik, München, Germany

  2. Periodic System of Elementary Particles Quarks Leptons Charge +2/3 Charge -1/3 Charge -1 Charge 0 d e ne Up u Electron 1stFamily Down e-Neutrino d e ne u Up Electron Down e-Neutrino s m nm 2ndFamily Strange Charm Muon m-Neutrino c b t nt 3rd Family Bottom Top Neutron t Tau t-Neutrino Strong Interaction (8 Gluons) Electromagnetic Interaction (Photon) Proton Weak Interaction (W and Z Bosons) Gravitation (Gravitons?)

  3. Where do Neutrinos Appear in Nature?   Sun Nuclear Reactors Supernovae (Stellar Collapse) SN 1987A   Particle Accelerators Earth Atmosphere (Cosmic Rays) Astrophysical Accelerators Soon ?  Cosmic Big Bang (Today 330 n/cm3) Indirect Evidence Earth Crust (Natural Radioactivity) 

  4. Pauli’s Explanation of the Beta Decay Spectrum (1930) Niels Bohr: Energy not conservedin the quantum domain? Wolfgang Pauli (1900–1958) Nobel Prize 1945 “Neutrino” (E. Fermi) “Neutron” (1930) “Neutron” (1930)

  5. Neutrinos from the Sun Helium Reaction- chains Energy 26.7 MeV Solar radiation: 98 % light 2 % neutrinos At Earth 66 billion neutrinos/cm2 sec Hans Bethe (1906-2005, Nobel prize 1967) Thermonuclear reaction chains (1938)

  6. Sun Glasses for Neutrinos? 8.3 light minutes Several light years of lead needed to shield solar neutrinos Bethe & Peierls 1934: … this evidently means that one will never be able to observe a neutrino.

  7. First Detection (1954 – 1956) Clyde Cowan (1919 – 1974) Fred Reines (1918 – 1998) Nobel prize 1995 Detector prototype Anti-Electron Neutrinos from Hanford Nuclear Reactor 3 Gammas in coincidence g n Cd g p g

  8. First Measurement of Solar Neutrinos Inverse beta decay of chlorine 600 tons of Perchloroethylene Homestake solar neutrino observatory (1967–2002)

  9. Cherenkov Effect Light Electron or Muon (Charged Particle) Neutrino Light Cherenkov Ring Elastic scattering or CC reaction Water

  10. Super-Kamiokande Neutrino Detector (Since 1996) 42 m 39.3 m

  11. Super-Kamiokande: Sun in the Light of Neutrinos

  12. Neutrino Flavor Oscillations Two-flavor mixing Each mass eigenstate propagates as with Phase difference implies flavor oscillations Probability Bruno Pontecorvo (1913–1993) Invented nu oscillations z Oscillation Length

  13. KamLAND Long-Baseline Reactor-Neutrino Experiment • Japanese Nuclear Reactors • 80 GW (20% world capacity) • Average distance 180 km • Flux 6 105cm-2s-1 • Without oscillations • 2 captures per day

  14. Oscillation of Reactor Neutrinos at KamLAND (Japan) Oscillation pattern for anti-electron neutrinos from Japanese power reactors as a function of L/E KamLAND Scintillator detector (1000 t)

  15. Atmospheric Neutrino Anomaly Zenith-angle distribution of atmospheric neutrinos in Super-Kamiokande [hep-ex/0210019] Half of the muon neutrinos from below are missing

  16. Long-Baseline Experiment K2K K2K Experiment (KEK to Kamiokande) has confirmed neutrino oscillations, to be followed by T2K (2010)

  17. Current Long-Baseline Experiments FermiLab–Soudan (MINOS) CERN – Gran Sasso

  18. Three-Flavor Neutrino Parameters e e m m t t e e m m t t m m t t Three mixing angles ,, (Euler angles for 3D rotation), , a CP-violating “Dirac phase” , and two “Majorana phases” and v Relevant for 0n2b decay Reactor Solar/KamLAND Atmospheric/LBL-Beams v Normal Inverted • Tasks and Open Questions • Precision for q12 andq23 • How large is q13? • CP-violating phase d? • Mass ordering? • (normal vs inverted) • Absolute masses? • (hierarchical vs degenerate) • Dirac or Majorana? 72–80 meV2 2 3 Sun Atmosphere 1 Atmosphere 2180–2640 meV2 2 Sun 1 3

  19. Antineutrino Oscillations Different from Neutrinos? Dirac phase causes different 3-flavor oscillations for neutrinos and antineutrinos same as Distance [1000 km] for E = 1 GeV

  20. Neutrino Carabiner Now also in color Named for a subatomic particle with almost zero mass, … n Greek “nu”

  21. “Weighing” Neutrinos with KATRIN • Sensitive to common mass scale m • for all flavors because of small mass • differences from oscillations • Best limit from Mainz und Troitsk • m < 2.2 eV (95% CL) • KATRIN can reach 0.2 eV • Under construction • Data taking foreseen to begin in 2012 http://www-ik.fzk.de/katrin/

  22. “KATRIN Coming” (25 Nov 2006)

  23. Pie Chart of Dark Universe Dark Energy 73% (Cosmological Constant) Neutrinos 0.1-2% Ordinary Matter 4% (of this only about 10% luminous) Dark Matter 23%

  24. Cosmological Limit on Neutrino Masses Cosmic neutrino “sea”112 cm-3neutrinos + anti-neutrinos per flavor For all stable flavors JETP Lett. 4 (1966) 120

  25. Weakly Interacting Particles as Dark Matter • Almost 40 years ago, • beginnings of the idea of • weakly interacting particles • (neutrinos) as dark matter • Massive neutrinos are no • longer a good candidate • (hot dark matter) • However, the idea of • weakly interacting massive • particles (WIMPs) as • dark matter is now standard

  26. What is wrong with neutrino dark matter? Galactic Phase Space (“Tremaine-Gunn-Limit”) Maximum mass density of a degenerate Fermi gas Spiral galaxies mn>20–40 eV Dwarf galaxies mn> 100–200 eV Neutrino Free Streaming (Collisionless Phase Mixing) • AtT<1MeVneutrinoscatteringinearlyuniverse is ineffective • Stream freely until non-relativistic • Wash out density contrasts on small scales • Neutrinos are “Hot Dark Matter” • Ruled out by structure formation Neutrinos Neutrinos Over-density

  27. Structure Formation with Hot Dark Matter Standard LCDM Model Neutrinos with Smn = 6.9 eV Structure fromation simulated with Gadget code Cube size 256 Mpc at zero redshift Troels Haugbølle, http://users-phys.au.dk/haugboel

  28. Power Spectrum of Cosmic Density Fluctuations Tegmark, TAUP 2003

  29. Power Spectrum of CMB Temperature Fluctuations Sky map of CMBR temperature fluctuations Multipole expansion Acoustic Peaks Angular power spectrum

  30. Latest Angular Power Spectrum (WMAP 7 years) Ratio 1st/3rd peak fixes zeq Komatsu et al. (WMAP Collaboration), arXiv:1001.4538

  31. Radiation Content at CMB Decoupling WMAP alone + Large-scale structure (LSS) and H0 Komatsu et al. (WMAP Collaboration), arXiv:1001.4538 • Existence of cosmic neutrino sea clearly confirmed by precision cosmology • All analyses find mild indication for excess radiation • Planck data will fix Neff to ±0.26 (68% CL) or better

  32. Weak Lensing - A Powerful Probe for the Future Distortion of background images by foreground matter Unlensed Lensed

  33. Mass-Energy-Inventory of the Universe W 10-3 10-2 10-1 1 Assuming h = 0.72 Luminous Baryons Total Dark Matter L 1 10 eV 10-2 10-1 Super-K Neutrinos Tritium (Mainz/Troitsk) Future Tritium (KATRIN) CMB & LSS Weak lensing tomography

  34. Are Neutrinos their own Antiparticles? Matter Anti-Matter Much less anti-matter in the universe: Baryon asymmetry of the Universe (BAU) „Majorana Neutrinos” are their own antiparticles Quarks Anti-Leptons Anti-Quarks Leptons Charge 0 +1 -2/3 +1/3 -1/3 +2/3 -1 0 1stFamily e d u 0 0 2ndFamily s c 3rd Family b t Strong Int’n Strong Int’n Electromagnetic Int’n Electromagnetic Int’n Weak Interaction Gravitation

  35. Solar Neutrinos vs. Reactor Antineutrinos Neutron Fissionable nucleus Energy 26.7 MeV Nucleus splitting Ray Davis radiochemical detector (1967–1992) Fission products w/ neutron excess unstable nuclei effectively decay by Amounts to neutino capture by neutron Detection by inverse decay Does not work for reactor flux! Reines and Cowan 1954–1956

  36. Role of Neutrino Helicity (Handedness) Basic production process in reactors Anti-neutrinos always right-handed helicity Basic production process in the Sun Neutrinos always left-handed helicity Majorana neutrinos: Helicity flip anti-neutrino property depends on Lorentz frame Cowan & Reines detector in fast-moving rocket, overtakes small-mass solar

  37. Neutrinoless bb Decay Some nuclei decay only by the bb mode, e.g. Ge-76 76As 2- 76Ge 0+ 76Se 2+ 0+ Standard 2n mode 0n mode, enabled by Majorana mass Half life 1021 yr Measured quantity Best limit from 76Ge

  38. GERDA Germanium Double Beta Experiment Bare enriched Ge-76 array in liquid Ar, located in Gran Sasso Phase I (being commissioned) 18 kg (HdM/IGEX) + 15 kg natural Ge Test claim of Klapdor-Kleingrothaus Phase II, O(100 kg years) Add 20 kg enriched new detectors Degenerate masses: 75–130 meV Phase III, O(1000 kg years) with Majorana collaboration? 1-ton scale Inverted hierarchy: 24–41 meV Several other large projects worldwide

  39. See-Saw Model for Neutrino Masses QCD scale Planck mass Cosmological constant Electroweak scale GUT scale eV Mass matrix for one family of ordinary and heavy r.h. neutrinos Diagonalization One light and one heavy Majorana neutrino

  40. Leptogenesis by Majorana Neutrino Decays Lepton N Heavy sterile neutrino N + N Higgs CP-violating decays of heavy sterile neutrinos by interference of tree-level with one-loop diagram

  41. Baryogenesis by Leptogenesis? Dark Energy 73% (Cosmological Constant) Neutrinos 0.1-2% Ordinary Matter 4% (of this only about 10% luminous) Dark Matter 23%

  42. Applied Neutrino Physics

  43. Reactor Monitoring

  44. Neutrino Monitoring of Nuclear Reactors San Onofre Nuclear Reactor (California) Neutrino measurements with SONGS1 detector (1m3Scintillator) • 3.4GWthermal power • Produces • 3800 neutrino reactions/day • in 1 m3liquid scintillator • Relatively small detectors can measure nuclear • activity without intrusion • Of interest for monitoring by • International Atomic Energy Agency (IAEA)

  45. Geo Neutrinos: What is it all about? • We know surprisingly little about • the Earth’s interior • Deepest drill hole 12 km • Samples of crust for chemical • analysis available (e.g. vulcanoes) • Reconstructed density profile • from seismic measurements • Heat flux from measured • temperature gradient 30-44 TW • (Expectation from canonical BSE • model 19 TW from crust and • mantle, nothing from core) • Neutrinos escape unscathed • Carry information about chemical composition, radioactive energy • production or even a hypothetical reactor in the Earth’s core

  46. Geo Neutrinos Expected Geoneutrino Flux KamLAND Scintillator-Detector (1000 t) Reactor Background

  47. Latest KamLAND Measurements of Geo Neutrinos K. Inoue at Neutrino 2010

  48. AAP 2011 Vienna http://aap2011.in2p3.fr/

  49. Sanduleak -69 202 Sanduleak -69 202 Supernova 1987A 23 February 1987 Tarantula Nebula Large Magellanic Cloud Distance 50 kpc (160.000 light years)

  50. Neutrino Signal of Supernova 1987A Kamiokande-II (Japan) Water Cherenkov detector 2140 tons Clock uncertainty 1 min Irvine-Michigan-Brookhaven (US) Water Cherenkov detector 6800 tons Clock uncertainty 50 ms Baksan Scintillator Telescope (Soviet Union), 200 tons Random event cluster 0.7/day Clock uncertainty +2/-54 s Within clock uncertainties, all signals are contemporaneous

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