Presentation on theme: "Steve Elliott, UK Forum 2003 Outline Neutrino Mass and General Experimental Issues The Matrix Elements The New Proposals Future Zero-Neutrino Double Beta."— Presentation transcript:
Steve Elliott, UK Forum 2003 Outline Neutrino Mass and General Experimental Issues The Matrix Elements The New Proposals Future Zero-Neutrino Double Beta Decay Experiments
Steve Elliott, UK Forum 2003 Neutrino Mass: What do we want to know? Mass Absolute Mass Scale Relative Mass Scale Dirac or Majorana e Mixing
Steve Elliott, UK Forum Complementary Experimental Techniques Need all three types of experiments to fully understand the nature of the.
Steve Elliott, UK Forum 2003 Neutrino Masses Direct mass and experiments set absolute mass scale. < 2.2 eV The results of oscillation experiments set the relative mass scale. Sets m scale > 50 meV addresses Dirac/Majorana nature of.
Steve Elliott, UK Forum 2003 Example Decay Scheme In many even-even nuclei, decay is energetically forbidden. This leaves as the allowed decay mode. Endpoint Energy
Steve Elliott, UK Forum 2003 (2 ) vs. (0 ) (2 ): Allowed and observed 2 nd order weak process. (0 ): requires massive Majorana neutrinos even in presence of alternative mechanisms.
Steve Elliott, UK Forum 2003 Energy Spectrum for the 2 e - Endpoint Energy
Steve Elliott, UK Forum 2003 Decay Rates G are calculable phase space factors. G 0 ~ Q 5 |M| are nuclear physics matrix elements. Hard to calculate. m is where the interesting physics lies.
Steve Elliott, UK Forum 2003 What about mixing, m & (0 )? Compare to decay result: real emission virtual exchange ±1, CP cons. No mixing:
Steve Elliott, UK Forum 2003 Neutrino Mixing From KamLAND, solar and atmospheric
Steve Elliott, UK Forum 2003 Min. as a vector sum is the modulus of the resultant vector in the complex plane. (In this example, has a min. It cannot be 0.) min Figure from: PR D63,
Steve Elliott, UK Forum 2003 More General: 3 (Inverted Heir.) 30 meV or few x yr m smallest Plot Thanks to Petr Vogel
Steve Elliott, UK Forum 2003 More General: (Normal Heir.) 30 meV or few x yr Plot Thanks to Petr Vogel
Steve Elliott, UK Forum 2003 Physics Reach Normal HierarchyInverted HierarchyDegenerate m 1 ~ 0 meV~55 meV= M > about 100 meV m 2 ~ 7 meV~55 meVM m 3 ~ 55 meV~0 meVM ~ 5 meV28 or 55 meVM/2 or M Solar + KamLAND + Atmospheric (U e3 ~ 0)
Steve Elliott, UK Forum 2003 An exciting time for ! in the range of meV is very interesting. For the next experiments: For at least one neutrino:
Steve Elliott, UK Forum 2003 History ~2015 |M| Reference Eur. Lett. 13, 31 (1990)
Steve Elliott, UK Forum 2003 An Ideal Experiment Maximize Rate/Minimize Background Large Mass (~ 1 ton) Good source radiopurity Demonstrated technology Natural isotope Small volume, source = detector Good energy resolution Ease of operation Large Q value, fast (0 ) Slow (2 ) rate Identify daughter Event reconstruction Nuclear theory
Steve Elliott, UK Forum 2003 Classes of Background (2 ) tail Need good energy resolution. Natural U, Th in source and shielding Pure materials, identify daughter, pulse shape, timing, position. Cosmic ray activation Store and prepare materials underground.
Steve Elliott, UK Forum 2003 (2 ) as a Background. Sum Energy Cut Only next generation experimental goal
Steve Elliott, UK Forum 2003 Natural Activity The Problem: (U, Th) ~ years Target: ( (0 ) ~ years Detector Shielding Cryostat, or other experimental support Front End Electronics etc.
Steve Elliott, UK Forum 2003 Cosmic Ray Induced Activity Material dependent. Need for depth to avoid activation. Need for storage to allow activation to decay.
Steve Elliott, UK Forum 2003 Evidence of 68 Ge From: NIM A292 (1990) Experimental data from two 1.05 kg natural detectors Integral of this spectrum equals integral of this peak. This peak decays with the right half life. ROI
Steve Elliott, UK Forum 2003 Depth Requirement Remove Surface Activation 100 mwe, low E neutrons from rock Muons ~30% of events in ROI vetoed at 2500 mwe Muon-induced secondary activation Still observed at low E at 2000 mwe. For MOON-like nat Mo expt., ~ Mo(n,2n) 91 Mo per year directly induced OK at 4700 mwe (e.g. SAGE) Unknown components Deeper is better!
Steve Elliott, UK Forum 2003 Matrix Elements There are many calculations. Most authors quote mass limits derived from all or at least representatives of the whole range. How do we interpret the uncertainty associated with the mass due to the nuclear physics?
Steve Elliott, UK Forum 2003 Uncertainties Imagine signal at 7x10 26 years 500 kg for 10 years ~50% unc. for 1/2 (with BG) ~20% without BG |M| Range: meV Statistics (with BG): ±25 meV
Steve Elliott, UK Forum 2003 Consider a 100 meV result. Matrix Element contribution to uncertainty. Need improvement in the Theory. Would this exclude the inverted hierarchy with small m smallest ? Statistical contribution to uncertainty.
Steve Elliott, UK Forum 2003 Found Peaks PR D45, 2548 (1992) A 2527-keV Ge-det. peak that was an electronic artifact. A ~2528-keV Te-det. peak that was a 2 Statisticalflucuation. NP B35 (Proc. Supp.), 366 (1994). Need more than one experiment
Steve Elliott, UK Forum 2003 A Great Number of Proposed Experiments COBRATe kg CdTe semiconductors DCBANd kg Nd layers between tracking chambers NEMOMo-100, Various 10 kg of isotopes (7 kg of Mo) CAMEOCd-1141 t CdWO 4 crystals CANDLESCa-48Several tons CaF 2 crystals in liquid scint. CUORETe kg TeO 2 bolometers EXOXe-1361 ton Xe TPC (gas or liquid) GEMGe-761 ton Ge diodes in liquid nitrogen GENIUSGe-761 ton Ge diodes in liquid nitrogen GSOGd-1602 t Gd 2 SiO 5 :Ce crystal scint. in liquid scint. MajoranaGe kg Ge diodes MOONMo-100Mo sheets between plastic scint., or liq. scint. XeXe t of Xe in liq. Scint. XMASSXe t of liquid Xe
Steve Elliott, UK Forum 2003 Potential Large-Mass (~1 ton) Future Experiments Experiments in Europe CUORE, GENIUS NUSEL Candidates EXO*, MAJORANA, MOON Smaller Mass and Development Experiments Cobra*, DCBA, NEMO*, CAMEO, CANDLES, GSO…
Steve Elliott, UK Forum 2003 H.Ejiri, Y. Itahashi, N. Kudomi, M. Nomachi, T. Shima RCNP, Osaka Univ. Japan R. Hazama, K. Matsuoka, Y. Sugaya, S. Yoshida Phys. Dept. Osaka Univ. Japan K. Fushimi, K. Ichihara, Y. Shichijo University of Tokushima, Japan P.J. Doe, V. Gehman, R.G.H. Robertson, O. E. Vilches, J.F. Wilkerson, D.I. Will CENPA, Univ. Washington Seattle, USA S.R. Elliott, LANL, USA J. Engel Univ. North Carolina, USA A. Para, FNAL, USA M. Greenfield, International Christian Univ., USA M. Finger Phys. Dept., Charles Univ., Prague, Czech Republic A. Gorin, I.Manouilov, A. Rjazantsev Inst. High Energy Physics, Protvino, Russia K. Kuroda, P. Kavitov, V. Vatulin, VNIIEF, Sarov, Russia V. Kekelidze, V. Kutsalo, G. Shirkov, A. Sisakian, A. Titov, V. Voronov, JINR, Dubna, Russia In Association with: The Majorana Collaboration C. Aalseth, F. Avignone, S.R. Elliott, H. Miley…... The MOON Collaboration:
Steve Elliott, UK Forum Mo 100 Tc 100 Ru MOON is 4 experiments… CC Solar H. Ejiri et al. PRL 85 (2000) x y 6.1 x y 16 s Hamish RobertsonAPS, April 5, 2003 ?
Steve Elliott, UK Forum 2003 Signal Rates per year per ton of 100 Mo 0 (ground state) 20 ( / 50 meV) 2 2 (ground state) 3.6 x (0 + 1 state).03 ( / 50 meV) 2 2 (0 + 1 state) 0 (0 + 2 state) 6.9 x ( / 50 meV) 2 pp120 7 Be40 pep2.5 8B8B N O6.1 SSM rates * *QRPA: J. Souhonen, NP A700, 649 (2002). 76 Ge : 3.8 ( / 50 meV) 2 * *
Steve Elliott, UK Forum 2003 MOON Overview 3.3 tons 100 Mo, 34 tons Mo Doesnt require enriched material (but would probably want it). Scintillator/source sandwich Position and single E data play big role in (2 ) and U, Th rejection. Or possibly bolometer 14% efficiency ELEGANTS is precursor.
Steve Elliott, UK Forum 2003 Scintillator Mo Foil Sandwich Mo loaded liquid scintillator Cryogenic calorimeter One possible configuration scintillator Mo foil Readout fibers 1 module: Mo foil, 6m x 6m x 0.05 gm/cm Scintillator 6m x 6m x 0.25cm 222 wavelength shifting fibers Super module (detector) 1950 Modules 6m x 6m x 5m 34 t n Mo (3 t 100 Mo) 13600, 16-anode PMT readout Detection Techniques under Consideration:
Steve Elliott, UK Forum 2003 MOON Prototype
Steve Elliott, UK Forum 2003 Cryogenic Underground Observatory for Rare Events - CUORE Berkeley Firenze Gran Sasso Insubria (COMO) Leiden Milano Neuchatel U. of South Carolina Zaragoza Spokesperson Ettore Fiorini Milano
Steve Elliott, UK Forum 2003 CUORE Overview 0.21 ton, 34% natural abundance 130 Te TeO 2 bolometers, 750 g crystals Doesnt require enriched material x5x5 cm 3 crystals 25 towers of 10 layers of 4 crystals Gran Sasso Laboratory CUORICINO is an approved prototype (1 tower). CUORICINO began operation in Feb. 2003
Steve Elliott, UK Forum 2003 CUORE Detector Detector Damping Suspension Dilution Unit Thermal Shields
Steve Elliott, UK Forum 2003 CUORICINO IS OPERATING FIRST PULSE. Data runs began In Feb. 2003
Steve Elliott, UK Forum 2003 Enriched Xenon Observatory - EXO U. of Alabama Caltech IBM Almaden ITEP Moscow U. of Neuchatel INFN Padova SLAC Stanford U. U. of Torino U. of Trieste WIPP Carlsbad Spokesperson Giorgio Gratta Stanford
Steve Elliott, UK Forum 2003 EXO Overview (latter talk) 10 ton, ~70% enriched 136 Xe 70% effic., ~10 atm gas TPC or LXe chamber Optical identification of Ba ion. Drift ion in gas to laser path or extract on cold probe to trap. TPC performance similar to that at Gottard. 100-kg enr Xe prototype (no Ba ID) Isotope in hand
Steve Elliott, UK Forum 2003 The Majorana Project Duke U. North Carolina State U. TUNL Argonne Nat. Lab. JINR, Dubna ITEP, Moscow New Mexico State U. Pacific Northwest Nat. Lab. U. of Washington LANL LLNL U. of South Carolina Brown Univ. of Chicago RCNP, Osaka Univ. Univ. of Tenn. Co-Spokespersons Frank Avignone Harry Miley
Steve Elliott, UK Forum 2003 Majorana Overview 0.5 ton of 86% enriched 76 Ge Segmented detectors using pulse shape discrimination to improve background rejection. Prototype ready to go this fall/winter. (14 crystals, 1 enriched) 100% efficient Can do excited state decay. IGEX is precursor
Steve Elliott, UK Forum 2003 Majorana Layout
Steve Elliott, UK Forum 2003 A Ge + fast n -> 68 Ge + X 68 Ge is the dominate background. For 500-kg enriched detector, initially expect ~ Ge decays/day. 1\2 = 288 d The naturally occurring 40 K in the human body decays at a rate of decays/second. 68 Ge 68 Ga 2.9 MeV 68 Zn 288d
Steve Elliott, UK Forum 2003 Why Segmentation and Pulse Shape Analysis? is pointlike. + or Compton scattered rays deposit energy in multiple locations. Segmentation and PSD help reduce these Backgrounds.
Steve Elliott, UK Forum 2003 Recent Crystal Packaging Test (MEGA)
Steve Elliott, UK Forum 2003 GErmanium NItrogen Underground Setup - GENIUS MPI, Heidelberg Kurchatov Inst., Moscow Inst. Of Radiophysical Research, Nishnij Novgorod Braunschweig und Technische Universität, Braunschweig U. of L'Aquila, Italy Int. Center for Theor. Physics, Trieste JINR, Dubna Northeastern U., Boston U. of Maryland, USA University of Valencia, Spain Texas A & M U. Spokesperson Hans Klapdor-Kleingrothaus MPI GENIUS
Steve Elliott, UK Forum 2003 GENIUS Overview 1 ton, ~86% enriched 76 Ge Naked Ge crystals in LN Very little material near Ge. 1.4x10 6 liters LN 40 kg test facility is approved. 100% efficient Heid.-Moscow experiment is precursor GENIUS
Steve Elliott, UK Forum 2003 GENIUS Layout GENIUS Data Acquisition Clean Room Liquid Nitrogen Insulation Steel Vessel 12 m Setup for operation of three 'naked Germanium detectors in liquid nitrogen.
Steve Elliott, UK Forum 2003 A Recent Claim for (0 ) Mod. Phys. Lett. A16, 2409 (2001)
Steve Elliott, UK Forum 2003 The Controversy. Locations of claimed peaks If one had to summarize the controversy in a short statement: Consider two extreme background models: 1. Entirely flat in keV region. 2. Many peaks in larger region, only peak in small region. These 2 extremes give very different significances for peak at 2039 keV. KDHK chose Model 2 but did not consider a systematic uncertainty associated with that choice. Mod. Phys. Lett. A16, 2409 (2001)
Steve Elliott, UK Forum 2003 Summary of Proposals The limits depend on background assumptions and matrix elements which vary from proposal to proposal.
Steve Elliott, UK Forum 2003 Conclusions Research and Development are needed for all the future proposed detectors. UG Lab space will be needed for some of that R&D. The next generation experiments have a good possibility of reaching an interesting region.
Steve Elliott, UK Forum 2003 Pulse Shape Discrimination