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Neutrino Mass and Mixing. David Sinclair Carleton University PIC2004. Outline . History of neutrino mass and mixing Recent results and current status Future Prospects. History. Original proposal by Pauli, Fermi Neutrino mass must be small Only 1 neutrino proposed so no mixing.
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Neutrino Mass and Mixing David Sinclair Carleton University PIC2004
Outline • History of neutrino mass and mixing • Recent results and current status • Future Prospects
History • Original proposal by Pauli, Fermi • Neutrino mass must be small • Only 1 neutrino proposed so no mixing
Mass Measurements b Decay Mn=0 Mn>0 Electron Energy
Neutrino Mixing • Pontecorvo suggested (late 50’s) that neutrinos would oscillate by analogy with K0 • When Davis showed deficit of solar neutrinos, oscillation again raised as a possible solution • This solution not popular until MSW
MSW Effect ne Mass nm Electron Density
Implications of neutrino oscillations • ne, nm, nt are not mass eigenstates • Mass states are n1, n2, and n3 • Lepton number not conserved
Theoretical Biases • Mixings would be small (comparable to Cabibbo mixing) • SeeSaw model suggests
If neutrinos have mass: Using the oscillation framework: For three neutrinos: Maki-Nakagawa-Sakata-Pontecorvo matrix (Double b Decay) Solar Atmospheric CP Violating Phase Reactor... Majorana Phases Full neutrino mixing matrix
Recent Results • Neutrino mass from cosmology WMAP, 2DF m1+m2+m3< 1 eV
Evidence for OscillationsSolar • Chlorine experiment sees ¼ SSM flux • Gallium experiments see ½ SSM flux • Kamiokande sees ½ SSM flux
Definitive data - SNO • Heavy water Cerenkov detector • Measure ne flux with CC reaction • Measure total n flux with NC reaction CC NC
SNO • 1000 Tonnes of D2O • 12 M Acrylic vessel • 10,000 phototubes • 8000 Tonnes of pure light water • 2000 m deep in Mine • World’s largest deep cavern • All materials very pure
3 Phases of SNO • 1) Run with pure Heavy Water • 2) Add 0.2% NaCl to enhance NC detection • 3) Remove NaCl, add Neutral Current Detectors (NCDs) • Each phase is approx. 2 years
Salt – Pure D2O • Constrained Not Constrained Pure D2O Salt
Evidence for OscillationReactor Neutrinos • Short distance searches (CHOOZ, Palo Verde etc) have been negative • Kamland provides definitive demonstration
Neutrino-less double beta decay • Nice data on 2 neutrino decay from NEMO • Nice cryogenic techniques • Tantalizing results from Germanium
Mass of Neutrinos Inverted Normal
NEMO Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris 14-19 June 2004
bb2n measurement bb0n search bb decay isotopes in NEMO-3 detector 116Cd405 g Qbb = 2805 keV 96Zr 9.4 g Qbb = 3350 keV 150Nd 37.0 g Qbb = 3367 keV 48Ca 7.0 g Qbb = 4272 keV 130Te454 g Qbb = 2529 keV External bkg measurement natTe491 g 100Mo6.914 kg Qbb = 3034 keV 82Se0.932 kg Qbb = 2995 keV Cu621 g (All the enriched isotopes produced in Russia) Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris 14-19 June 2004
Data Data Data 22 preliminary results for other nuclei NEMO-3 932 g 241.5 days 2385 events S/B = 3.3 Background subtracted 82Se 82Se T1/2 = 10.3 ± 0.2 (stat) ± 1.0 (syst) 1019 y 116Cd if SSD T1/2 = 2.8 ± 0.1 (stat) ± 0.3 (syst) 1019 y if HSD T1/2 = 3.05 ± 0.1 (stat) ± 0.3 (syst) 1019 y 150Nd T1/2 = 9.7 ± 0.7 (stat) ± 1.0 (syst) 1018 y 96Zr T1/2 = 2.0 ± 0.3 (stat) ± 0.2 (syst) 1019 y • Data bb2n simulation E1+E2 (keV) NEMO-3 NEMO-3 NEMO-3 37 g 168.4 days 449 events S/B = 2.8 405 g 168.4 days 1371 events S/B = 7.5 5.3 g 168.4 days 72 events S/B = 0.9 96Zr 150Nd 116Cd bb2n simulation bb2n simulation bb2n simulation E1+E2 (MeV) E1+E2 (MeV) E1+E2 (MeV) Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris 14-19 June 2004
heat bath Thermal sensor e- absorber crystal e- Incident particle Experimental approach - CUORE Thermal detectors Source = detector (calorimetric)
210Po a line Counts Energy [keV] Resolution of the 5x5x5 cm3 (~ 760 g ) crystals : 0.8 keV FWHM @ 46 keV 1.4 keV FWHM @ 0.351 MeV 2.1 keV FWHM @ 0.911 MeV 2.6 keV FWHM @ 2.615 MeV 3.2 keV FWHM @ 5.407 MeV (the best a spectrometer ever realized)
The Future • Determine q13 • New Reactor experiments • Long baseline • Are masses Majorana or Dirac • Double beta decay • Is CP violated • Superbeams • Sterile neutrinos? • Miniboone
The Future Looks Very Exciting • Many new experiments taking data or about to start • Precision measurements of MNSP matrix • Look for CP violation • Neutrino astrophysics