Neutrino Physics Caren Hagner Universität Hamburg Caren Hagner Universität Hamburg Part 3:...

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Transcript of Neutrino Physics Caren Hagner Universität Hamburg Caren Hagner Universität Hamburg Part 3:...

  • Neutrino PhysicsCaren HagnerUniversitt HamburgPart 3: Absolute neutrino mass Introduction beta decay double beta decay

  • Evidence for Neutrino Oscillations:Neutrino oscillations were observed in 2 regions:

    Solar neutrinos and reactor neutrinos ve v, with m2 810-5 eV2, large mixing Atmospheric neutrinos and accelerator neutrinos v v,(s) mit m2 210-3 eV2, maximal mixing LSND? Anti-v Anti-ve with m2 1 eV2 (Tested by MiniBooNE)(3)

  • Nature of Neutrino Mass INeutrino fields v(x) with mass m are described by the Dirac equation:From Goldhaber experiment one knows that vL is realized. With m=0 there is no need to have vR. Therefore there were no vR in the Standard Model.

  • Dirac mass termDirac Mass TermThe neutrino mass term in L could have exactly the same form as the mass term of the quarks and charged leptons:Must add vR (right handed SU(2) singlets) to standard model!Problem: When the mechanism is the same, why are the masses so small?mt = 174.3 5.1 GeV; mb = (4.0-4.5) GeV; m = 1776.99 0.29 MeV; m3 < 2eV Lepton number is conserved!Footnote: A Lorentz invariant mass term must link a chirally left-handed field with a chirally right handed field

  • Majorana ParticlesBecause neutrinos carry no electric charge (and no color charge), there is the possibility: particle anti-particle Majorana particleBut what about experiments?There are two different states per flavor but the difference could be due to left-handed and right-handed states!

  • Majorana Mass TermNote thatis a left-handed fieldandis a right-handed fieldFootnote: A Lorentz invariant mass term must link a chirally left-handed field with a chirally right handed fieldLets tryok!works too!Lepton number violation!

  • Eigenstates of the interaction: vL and vRMass eigenstates: 1 (mass mL), 2 (mass mR)

  • Dirac-Majorana Mass Termmass matrix Mmass term for each flavor:In order to obtain the mass eigenstates one must diagonalize M:find unitary U with

  • What if1. mL = mR = 0: pure Dirac case = 45, m1=m2=mD. 2 degenerate Majorana states can be combined to form 1 Dirac state.2. mD = 0: pure Majorana case = 0, m1=mL m2=mRper neutrino flavor: one very light Majorana neutrino v1L = vL one very heavy Majorana neutrino v2L = (vR)cmD of the order of lepton masses, mR reflects scale of new physics explains small neutrino masses!

  • Lower Limit of Neutrino MassSuper-K (atmospheric neutrinos): m2atm = 2.5 10-3 eV2 m(i) 0.05 eVThis sets the energy scale for mass search!

  • Which mass hierarchy?v3v1v2msolarmatmnormal hierarchy 0.05 eV Lightest neutrino mass not known m2atm < 0 or >0 ??0

  • Neutrino Mass Measurements Strategies?

  • -decayuddudunpW-e-q = 2/3 - 1/3 -1/3 = 0q = 2/3 + 2/3 -1/3 = 1

  • Tritium -Decay: Mainz/TroitskE0 = 18.6 keVdN/dE = K F(E,Z) p Etot (E0-Ee) [ (E0-Ee)2 mn2 ]1/2

  • Problem: All experiments measured negative m2!Only recently solved by electrostatic spectrometers with MAC-E filter

  • principle of an electrostatic filter withmagnetic adiabatic collimation (MAC-E)adiabatic magnetic guiding of bs along field lines in stray B-field of s.c. solenoids:Bmax = 6 TBmin = 310-4 T

    energy analysis bystatic retarding E-fieldwith varying strength:

    high pass filter withintegral b transmissionfor E>qU

  • results from the MAINZ experiment

  • KATRIN~70 m beamline, 40 s.c. solenoidsThe KArlsruhe TRItium Neutrino Experiment

  • KATRIN Main Spectrometer stainless steel vessel (=10m & l=22m) on HV potential minimisation of bg UHV: p 10-11 mbar massless inner electrode systemUHV requirements:outgassing < 10-13 mbar l/sinner surface ~ 800m2volume to pump ~ 1500m3Commissioning 2008

  • 187Re b-decay: m-calorimetersMIBETA experiment(Milano, Como, Trento)array of 10 AgReO4 crystals

    M.Sisti et al, NIM A520(2004)125A.Nucciotti et al, NIM A520(2004)148C. Arnaboldi et al, PRL 91, 16802 (2003)E0 = 2.46 keVTop ~ 70-100mK

  • free fit parameters: b endpoint energy mn2 b spectrum normal. pile-up amplitude background level187Re b decay m-calorimeters Kurie plot of 6.2 106 187Re b decay events above 700 eV mn2 = -112 207 90 eV2

    mn < 15 eV (90%CL) (2 eV in 2007?)dN/dE = K F(E,Z) p Etot (E0-Ee) [ (E0-Ee)2 mn2 ]1/2

  • Double-beta decayLepton number violationL = 2

  • Neutrinoless Double Beta Decayonly for Majorana-neutrino and mV > 0!

  • Neutrinoless Double Beta Decay

  • Dirac CP-PhaseMajorana CP-PhasesComplex phases in the mixing matrix

  • in eVMasse des leichtesten Neutrinos in eVnormale Hierarchieinvertierte Hierarchie

  • 0v Doppel-Beta Experimente: Ergebnisse

  • Jedoch: ein Teil der HdM Kollaboration verffentlicht Evidenz fr 0v Doppel-Beta Zerfall!(Q = 2039 keV fr 76Ge Doppel-Beta Zerfall)?

  • Zukunft: Heidelberg Ge Initiative (MPIK Heidelberg)Phase I: 20kg angereichertes (86%) 76Ge, vgl. HDM Phase II: 100 kgJahre, 0.1 0.3 eV Phase III: O(1t) angereichertes 76Ge, 10meV

  • CUORICINO11 modules, 4 detector each,crystal dimension 5x5x5 cm3crystal mass 790 g4 x 11 x 0.79 = 34.76 kg of TeO22 modules, 9 detector each,crystal dimension 3x3x6 cm3crystal mass 330 g9 x 2 x 0.33 = 5.94 kg of TeO22v Doppelbeta mit 130Te (Q=2529 keV) 18 crystals 3x3x6 cm3 + 44 crystals 5x5x5 cm3 40.7 kg of TeO2Start in 2003 Suche nach 0v Doppelbeta: T 1/2 0v (130Te) > 7.5 x 1023 y < 0.3 - 1. 6 eV

  • IL PROGETTO CUOREarray of 988 bolometersgrouped in 19 colums with 13 flours of 4 crystals750 kg TeO2 => 600 kg Te = 203 kg 130Te

  • Source: 10 kg of isotopes cylindrical, S = 20 m2, e ~ 60 mg/cm2

    Tracking detector: drift wire chamber operating in Geiger mode (6180 cells)Gas: He + 4% ethyl alcohol + 1% Ar + 0.1% H2O Calorimeter: 1940 plastic scintillators coupled to low radioactivity PMTs The NEMO3 detector Frjus Underground Laboratory : 4800 m.w.e.

  • 100Mo foil100Mo foilTransverse viewLongitudinal viewRun Number: 2040Event Number: 9732Date: 2003-03-20Geiger plasmalongitudinalpropagationScintillator + PMTbb events selection in NEMO-3 Typical bb2n event observed from 100Mo

  • 100Mo 6.914 kg Qbb = 3034 keVbb decay isotopes in NEMO-3 detector82Se 0.932 kg Qbb = 2995 keV116Cd 405 g Qbb = 2805 keV96Zr 9.4 g Qbb = 3350 keV150Nd 37.0 g Qbb = 3367 keV Cu 621 g48Ca 7.0 g Qbb = 4272 keVnatTe 491 g130Te 454 g Qbb = 2529 keVExternal bkg measurement(All the enriched isotopes produced in Russia)

  • 100Mo bb0n likelihood analysisEc1+Ec2 (keV)100Mo 6914 g216.4 days4.10 kg.yXavier Sarazin for the NEMO-3 Collaboration Neutrino 2004 Paris 14-19 June 2004ee < 0.7 1.2 eV

  • Double Beta Decay: Futureto t13

  • End part 3

    Super-erlaubt, E0 = 18.6 keV, T1/2 = 12.3a

    Mischen mit 3.folie doppelbetaBeide Verfahren liefern komplemaentaere InfoEine Majorana Phase kann bestimmt werdenDa im solaren Bereich keine max. Mischung -> keine vollstaendige Ausloeschung moeglich!12 Vorschlaege Neutrinomasenbereich: einige 10 meV Oszillationsexperiment