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Proposal to join NEMO-3  decay experiment

Proposal to join NEMO-3  decay experiment. P. Adamson, R. Saakyan, J. Thomas UCL 27 January 2003. Outline. Motivation bb decay basics Short term future for bb experiments NEMO-III detector Future bb experiments Possible UK involvement in NEMO-III Costs. Motivation.

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Proposal to join NEMO-3  decay experiment

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  1. Proposal to join NEMO-3  decay experiment P. Adamson, R. Saakyan, J. Thomas UCL 27 January 2003

  2. Outline • Motivation • bb decay basics • Short term future for bb experiments • NEMO-III detector • Future bb experiments • Possible UK involvement in NEMO-III • Costs

  3. Motivation Neutrino oscillations 510-5 eV2 2.510-3 eV2 2.510-3 eV2 510-5 eV2 mscale = 0.01 eV mscale = 0.05 eV

  4. Motivation neutrino oscillations can not measure: • Nature of neutrino mass • = nbar (Majorana) OR nnbar (Dirac) • Absolute mass scale bb decay Direct kinematic searches (3H bdecay)

  5. UK Involvement. Current Picture

  6. bb decay basics T0.5~ 1020 yr T0.5 > 1025 yr Find isotopes where (A,Z)(A,Z+2) is energetically allowed, but forbidden in steps (A,Z)(A,Z+1)(A,Z+2)

  7. bb decay basics • Average Majorana mass: • mna depends on sum over Uab2*mb • If large, could be dominated by Ue32m3 (depends on hierarchy) Majorana CP phases Mixing matrix

  8. (A,Z) (A,Z+2) + e- + e- + nbar + nbar 2n (A,Z) (A,Z+2) + e- + e- 0n (A,Z) (A,Z+2) + e- + e- + C0 0nC(Majoran) Qbb Phase space Nuclear matrix element (0.35 – 1 eV) 48Ca, 76Ge, 100Mo, 150Nd, 136Xe, 116Cd, 96Zr, 82Se, 130Te Tkin(e-+e-) Due to uncertainties in M0n we have to study as many isotopes as possible!

  9. A look at short term future bb decay experiments Future bb projects: CUORE, Majorana, EXO, etc to have  0.05 eV sensitivity (~ 2008 – 2010) 3H expts sensitivity in ~ 2008 mscale ~ 0.01 – 0.05 eV from oscillation expts

  10. Short-term future: now - 2007 Heidelberg-Moscow Experiment “Evidence” strongly criticized by bbcommunity Not background free region <mn> = 0.4 eV NEMO-3 CUORICINO by 2007 0.1 – 0.7 eV 130Te (34%) natural abundance, good bolometric properties

  11. NEMO-3 Collaboration 50 physicists and engineers  12 Laboratories/Universities  5 Countries

  12. 250ps Dt timing from plasma propagation in tracker, Dz = 1cm Dx, Dy = 100mm,

  13. Data taking 2e events

  14. Data taking Background events 208Th <.02mBq/kg 214Bi < .3mBq/kg These have HE electron, but not same topology,or timing Excited states O() less common, used to measure NME

  15. Somewhat involved analysis •  detection (105 2n events/y !!! for 100Mo) • BG rejection techniques • Source contamination measurements (for future developments) • Running since June’02 but only 200 hrs 100Mo carefully analysed October visit summary: Significant shortage in manpower for data analysis. We are welcome to start right away

  16. Possible UK involvement in data analysis • Isotopes “distributed” between institutions • We are suggested to take up analysis of 82Se (NEMO3 upgrade isotope)

  17. NEMO-3 0nbb sensitivity5 years E = 2.8 – 3.2 MeV 100Mo 7 kg Qbb =3.034 MeV External BG: 0 Internal BG: radioactivity < 0.04 event/y/kg 2nbb = 0.11 event/y/kg  T1/2 > 5 × 1024 yr  <m> < 0.2 – 0.7 eV 82Se 1 kg Qbb =2.995 MeV External BG: 0 Internal BG: radioactivity < 0.01 event/y/kg 2nbb = 0.01 event/y/kg  T1/2 > 1 × 1024 yr  <m> < 0.6 – 1.2 eV

  18. Possible UK involvementUpgrade of NEMO-3 • 12 kg 82Se • Why 82Se? And theory says there is NO scaling • Improve S/B by ~10 • Sensitivity <mn>~0.14 eV in 5 yr

  19. SuperNEMO ~ 100 kg 82Se (or other) • Sensitivity <mn> ~ 0.05 eV in 5 yr • Feasible if: • BG only from 2n (NEMO3) • b) DE/E = 10-11% at 1 MeV • (R&D needed) 4 supermodules, planar geometry

  20. Future bb projects comparison“Conservative” approach * 5 different latest NME calculations

  21. SuperNEMO – UK involvementScintillator R&D Improving DE/E from 9% to 6% (at 3 MeV) will reduce BG by a factor of ~ 10 • Increase light output • Scintillator studies • Light collection • PMT-scintillator optical coupling • PMT studies matches our experience (MINOS)

  22. Responsibilities2003-2004 • MC of 2e and BG events from 82Se (Saakyan, New PostDoc) • Off-line DA for 82Se, cross-check with other isotopes (Adamson, NewPostDoc, Saakyan, Thomas) • Laser LI calibration/monitoring (Adamson, Thomas) • Scintillator R&D for SuperNEMO (Saakyan, Thomas, NewPostDoc, Technician) • DAQ/electronics for R&D setup (Adamson, NewPostDoc, Software Engineer) • DA from R&D setup (Adamson, NewPostDoc, Saakyan, Thomas)

  23. Costs

  24. Concluding Remarks • 0nbb is the only practical approach for Majorana ‘s • Participation in NEMO-3 is a good opportunity to understand feasibility of this technique… • …and to put UK in the DBD arena • NEMO-3 will confirm or rule out H-M result (0.1-0.2eV depending on Se availability) • Next generation DBD experiments to probe ~ 0.05 eV scale • NEMO technology orthogonal to other competitors

  25. Concluding Remarks II • Window of opportunity with MINOS for authors (beam due end of 04) • Possibility to analyse data this week! • Results will be competitive (many isotopes, orthogonal approach) • This proposal does not commit us to Super-NEMO

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