Neutrino Mass and Mixing David Sinclair Carleton University PIC2004

Outline History of neutrino mass and mixing History of neutrino mass and mixing Recent results and current status Recent results and current status Future Prospects Future Prospects

History Original proposal by Pauli, Fermi Original proposal by Pauli, Fermi –Neutrino mass must be small –Only 1 neutrino proposed so no mixing

Mass Measurements Electron Energy M =0 M >0  Decay

Neutrino Mass from Tritium Decay

Neutrino Mixing Pontecorvo suggested (late 50’s) that neutrinos would oscillate by analogy with K 0 Pontecorvo suggested (late 50’s) that neutrinos would oscillate by analogy with K 0 When Davis showed deficit of solar neutrinos, oscillation again raised as a possible solution When Davis showed deficit of solar neutrinos, oscillation again raised as a possible solution This solution not popular until MSW This solution not popular until MSW

Neutrino Vacuum Oscillation

MSW Effect Electron Density  e Mass

Implications of neutrino oscillations e     are not mass eigenstates e     are not mass eigenstates Mass states are     and  Mass states are     and  Lepton number not conserved Lepton number not conserved

Theoretical Biases Mixings would be small (comparable to Cabibbo mixing) Mixings would be small (comparable to Cabibbo mixing) SeeSaw model suggests SeeSaw model suggests

If neutrinos have mass: For three neutrinos: SolarAtmospheric Using the oscillation framework: CP Violating PhaseReactor...Majorana Phases Maki-Nakagawa-Sakata-Pontecorvo matrix (Double  Decay) Full neutrino mixing matrix

Recent Results Neutrino mass from cosmology Neutrino mass from cosmology WMAP, 2DF m 1 +m 2 +m 3 < 1 eV

Evidence for Neutrino Oscillation - Atmospheric

Definitive Data from SK

Evidence for Oscillations Solar Chlorine experiment sees ¼ SSM flux Chlorine experiment sees ¼ SSM flux Gallium experiments see ½ SSM flux Gallium experiments see ½ SSM flux Kamiokande sees ½ SSM flux Kamiokande sees ½ SSM flux

Definitive data - SNO Heavy water Cerenkov detector Heavy water Cerenkov detector Measure e flux with CC reaction Measure e flux with CC reaction Measure total flux with NC reaction Measure total flux with NC reaction CC NC

SNO SNO 1000 Tonnes of D 2 O 1000 Tonnes of D 2 O 12 M Acrylic vessel 12 M Acrylic vessel 10,000 phototubes 10,000 phototubes 8000 Tonnes of pure light water 8000 Tonnes of pure light water 2000 m deep in Mine 2000 m deep in Mine World’s largest deep cavern World’s largest deep cavern All materials very pure All materials very pure

3 Phases of SNO 1) Run with pure Heavy Water 1) Run with pure Heavy Water 2) Add 0.2% NaCl to enhance NC detection 2) Add 0.2% NaCl to enhance NC detection 3) Remove NaCl, add Neutral Current Detectors (NCDs) 3) Remove NaCl, add Neutral Current Detectors (NCDs) Each phase is approx. 2 years Each phase is approx. 2 years

Salt – Pure D 2 O Constrained Constrained Not Constrained Pure D 2 O Salt

Neutrino parameters from Solar experiments ( e )

Evidence for Oscillation Reactor Neutrinos Short distance searches (CHOOZ, Palo Verde etc) have been negative Short distance searches (CHOOZ, Palo Verde etc) have been negative Kamland provides definitive demonstration Kamland provides definitive demonstration

Where are we

Neutrino-less double beta decay Nice data on 2 neutrino decay from NEMO Nice data on 2 neutrino decay from NEMO Nice cryogenic techniques Nice cryogenic techniques Tantalizing results from Germanium Tantalizing results from Germanium

Mass of Neutrinos Normal Inverted

Double-beta effective mass constrained by oscillation data

NEMO Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

100 Mo kg Q  = 3034 keV  decay isotopes in NEMO-3 detector 82 Se kg Q  = 2995 keV 116 Cd 405 g Q  = 2805 keV 96 Zr 9.4 g Q  = 3350 keV 150 Nd 37.0 g Q  = 3367 keV Cu 621 g 48 Ca 7.0 g Q  = 4272 keV nat Te 491 g 130 Te 454 g Q  = 2529 keV  measurement External bkg measurement  search Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004 (All the enriched isotopes produced in Russia)

Background subtracted 82 Se T 1/2 = 10.3  0.2 (stat)  1.0 (syst)  y 116 Cd if SSD T 1/2 = 2.8  0.1 (stat)  0.3 (syst)  y if HSD T 1/2 = 3.05  0.1 (stat)  0.3 (syst)  y 150 Nd T 1/2 = 9.7  0.7 (stat)  1.0 (syst)  y 96 Zr T 1/2 = 2.0  0.3 (stat)  0.2 (syst)  y 82 Se 116 Cd 150 Nd 2  2 preliminary results for other nuclei 96 Zr Data  simulation Data  simulation Data  simulation Data  simulation NEMO g days 2385 events S/B = 3.3 NEMO g days 72 events S/B = g days 449 events S/B = g days 1371 events S/B = 7.5 E 1 +E 2 (keV) E 1 +E 2 (MeV) Xavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris June 2004

Experimental approach - CUORE Source = detector (calorimetric) Incident particle absorber crystal e-e- e-e- Thermal detectors heat bath Thermal sensor

Resolution of the 5x5x5 cm 3 (~ 760 g ) crystals : 0.8 keV 46 keV 1.4 keV MeV 2.1 keV MeV 2.6 keV MeV 3.2 keV MeV (the best  spectrometer ever realized) Energy [keV] Counts 210 Po  line

The Future Determine  13 Determine  13 –New Reactor experiments –Long baseline Are masses Majorana or Dirac Are masses Majorana or Dirac –Double beta decay Is CP violated Is CP violated –Superbeams Sterile neutrinos? Sterile neutrinos? –Miniboone

The Future Looks Very Exciting Many new experiments taking data or about to start Many new experiments taking data or about to start Precision measurements of MNSP matrix Precision measurements of MNSP matrix Look for CP violation Look for CP violation Neutrino astrophysics Neutrino astrophysics