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Double  Decays, DUSEL, and the Standard Model

Double  Decays, DUSEL, and the Standard Model. Wolfgang Bauer Michigan State University. Elementary Fermions. Mass Hierarchy. Largest Suppressed Highly Suppressed. Beta Decays. Composites: Mesons. Strong. Electromagnetic. Weak. Composites: Isotopes. - 2. - 1. N. + 1. + 2.

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Double  Decays, DUSEL, and the Standard Model

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  1. Double  Decays, DUSEL,and the Standard Model Wolfgang Bauer Michigan State University W. Bauer

  2. Elementary Fermions W. Bauer

  3. Mass Hierarchy W. Bauer

  4. Largest Suppressed Highly Suppressed Beta Decays W. Bauer

  5. Composites: Mesons Strong Electromagnetic Weak W. Bauer

  6. Composites: Isotopes W. Bauer

  7. -2 -1 N +1 +2 Z+2 Z+1 Z Z-1 Z-2 Favorite Decay Channels W. Bauer

  8. -2 -1 N +1 +2 Z+2 Z+1 Z Z-1 Z-2 Favorite Decay Channels W. Bauer

  9. -2 -1 N +1 +2 Z+2 Z+1 Z Z-1 Z-2 Favorite Decay Channels W. Bauer

  10. -2 -1 N +1 +2 Z+2 Z+1 Z Z-1 Z-2 Favorite Decay Channels W. Bauer

  11. -2 -1 N +1 +2 Z+2 Z+1 Z Z-1 Z-2 Favorite Decay Channels W. Bauer

  12. -2 -1 N +1 +2 Z+2 Z+1 Z Z-1 Z-2 Favorite Decay Channels W. Bauer

  13. Favorite Decay Channels W. Bauer

  14. W. Bauer

  15. W. Bauer

  16. Already counted in atomic mass that contains Z+1 electrons W. Bauer

  17. + decay:positron emission W. Bauer

  18. + decay:electron capture W. Bauer

  19. -2 -1 N +1 +2 Z+2 Observed double beta decays Z+1 Z Z-1 Z-2 Favorite Decay Channels W. Bauer

  20. Z N W. Bauer

  21. W. Bauer

  22. Double Beta Decay Isotopes • Only 12 known isotopes exhibit this decay • 48Ca, 76Ge, 82Se, 96Zr, 100Mo, 116Cd, 128Te, 130Te, 134Xe, 136Xe, 150Nd, and 160Gd • Typical lifetimes ~ 1019 years (billion times the lifetime of universe) • First observed in 1986 by Michael Moe et al. for 82Se W. Bauer

  23. Life Times and Q-Values W. Bauer

  24. -2 -1 N +1 +2 Z+2 Z+1 Z Z-1 Z-2 W. Bauer

  25. Double + Candidate 78Kr • Mass(78Kr) = 77.9203 GeVMass(78Se) = 77.9173 GeVMass difference = 2.85 MeV • 2 EC, e+EC (threshold 1.022 MeV), and e+e+ (threshold 2.044 MeV) channels are all open (in principle!) W. Bauer

  26. Double + Candidate 78Kr • Typical predicted half-life*  ~ 1022 years • Need N ~ 1025 atoms of 78Kr • Natural abundance of 78Kr = 0.35% • Need N ~ 3•1028 atoms of natKr • Need 0.168 kg*(3•1028)/(6•1023) =90 tons = 40,000 liters of natKr • Cost: ~$200,000 * A.Staudt, K.Muto and H.V.Klapdor-Kleingrothaus, “Nuclear matrix elements for double positron emission”, Phys. Lett. B268 (1991) 312 W. Bauer

  27. Detection • Gamma ray detectors for 511 keV Photons and/or photons from K-shell ionization cascades • Detection of single atom of Selenium a la Ray Davis • Detection of positron paths in TPC (perhaps liquid Kr, or perhaps even better high pressure gas Kr (0.1g/cm3) W. Bauer

  28. Liquid Argon TPC • One example forLANNDD (Liquid Argon Neutrino and NucleonDecay Detector) • Smallest shown:V = 125 m3 • Design can be taken over with slight modifications D.B. Cline and F. Sergiampietri, “A Concept for a Scalable 2 kTon Liquid Argon TPC Detector for Astroparticle Physics”, http://arxiv.org/abs/astro-ph/0509410 W. Bauer

  29. Previous Experiment •  > 0.9•1020 years • J.M. Gavriljuk et al., Phys. Atom. Nuclei 61, 1287 (1998) W. Bauer

  30. From:DUSEL_121306.pdf Neutrino-less Double  decay • Only possible if neutrino is its own anti-particle • Violation of Standard Model W. Bauer

  31. Current lower half-life limits Compiled by Steven Elliott, LANL, 2006) W. Bauer

  32. Could  be detected? • Monte Carlo: 5 body vs. 3 body phase space withconstant or Fermi cross sections • Importance sampling with N-body event generator GENBOD (F. James, CERN library) • Lorentz-invariant Fermi phase space • Respects all conservation laws (energy, momentum) and uses proper reaction Q-value W. Bauer

  33. Monte Carlo Events NeutrinoPositron Recoil Nucleus 3d momentum space event displays in cm-system W. Bauer

  34. Positron Energy distributions • Monte Carlo: 5 body vs. 3 bodyphase space withconstant or Fermicross sections • Here: 106 events • More realistic:101-102 events,p/p ~ 0.1 W. Bauer

  35. Coincidence Counts • In 0 case thedaughter nucleusreceives almostvanishing recoilenergy • Clear signal • (Note: not true forrecoil momentumof daughter nucleus) W. Bauer

  36. Where to put this ++ experiment? W. Bauer

  37. Background: 2 simult. + decays • Very rare • But we are dealinga very rare signal! W. Bauer

  38. UndergroundLabs W. Bauer

  39. W. Bauer

  40. DUSEL • Nov.07@NAS: Homestake/Sanford/DUSEL W. Bauer

  41. q q q q q q q q q q q q q q W W g g W W Z q Z q q q W g q q q g q q q q W q g q g q q g W q g Z q Z q Inflation q g q g Z g q g g q g g CMB W. Bauer

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