XXIV WWND South Padre, TX, April 08 W. Bauer Slide 1 Double  Decays, DUSEL, and the Standard Model Wolfgang Bauer Michigan State University

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 2 Generation123 Charge -1/3 quark Charge +2/3 quark Lepton Neutrino Elementary Fermions

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 3 Mass Hierarchy

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 4 Beta Decays Largest Suppressed Highly Suppressed

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 5 Composites: Mesons Strong Electromagnetic Weak

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 6 Composites: Isotopes

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 7 Favorite Decay Channels N Z Z-1 Z-2 Z+1Z Z+2Z+2

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 8 Favorite Decay Channels N Z Z-1 Z-2 Z+1Z Z+2Z+2

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 9 Favorite Decay Channels N Z Z-1 Z-2 Z+1Z Z+2Z+2

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 10 Favorite Decay Channels N Z Z-1 Z-2 Z+1Z Z+2Z+2

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 11 Favorite Decay Channels N Z Z-1 Z-2 Z+1Z Z+2Z+2

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 12 Favorite Decay Channels N Z Z-1 Z-2 Z+1Z Z+2Z+2

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 13 Favorite Decay Channels

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 14

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 15

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 16 Already counted in atomic mass that contains Z+1 electrons

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 17  + decay: positron emission

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 18  + decay: electron capture

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 19 Favorite Decay Channels Observed double beta decays N Z Z-1 Z-2 Z+1Z Z+2Z+2

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 20 N Z

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 21

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 22 Double Beta Decay Isotopes Only 12 known isotopes exhibit this decay 48 Ca, 76 Ge, 82 Se, 96 Zr, 100 Mo, 116 Cd, 128 Te, 130 Te, 134 Xe, 136 Xe, 150 Nd, and 160 Gd Typical lifetimes ~ years (billion times the lifetime of universe) First observed in 1986 by Michael Moe et al. for 82 Se

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 23 Life Times and Q-Values

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 24 N Z Z-1 Z-2 Z+1Z Z+2Z+2

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 25 Double  + Candidate 78 Kr Mass( 78 Kr) = GeV Mass( 78 Se) = GeV Mass difference = 2.85 MeV 2 EC, e + EC (threshold MeV), and e + e + (threshold MeV) channels are all open (in principle!)

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 26 Double  + Candidate 78 Kr Typical predicted half-life*  ~ years Need N ~ atoms of 78 Kr Natural abundance of 78 Kr = 0.35% Need N ~ atoms of nat Kr Need kg*( )/( ) = 90 tons = 40,000 liters of nat Kr Cost: ~$200,000 * A.Staudt, K.Muto and H.V.Klapdor-Kleingrothaus, “ Nuclear matrix elements for double positron emission ”, Phys. Lett. B268 (1991) 312

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 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/cm 3 )

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 28 Liquid Argon TPC One example for LANNDD (Liquid Argon Neutrino and Nucleon Decay Detector) Smallest shown: V = 125 m 3 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 ”,

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 29 Previous Experiment  > years J.M. Gavriljuk et al., Phys. Atom. Nuclei 61, 1287 (1998)

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 30 Neutrino-less Double  decay Only possible if neutrino is its own anti-particle Violation of Standard Model From: DUSEL_ pdf

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 31 Current lower half-life limits Compiled by Steven Elliott, LANL, 2006)

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 32 Could  be detected? Monte Carlo: 5 body vs. 3 body phase space with constant 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

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 33 Monte Carlo Events Neutrino Positron Recoil Nucleus 3d momentum space event displays in cm-system

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 34 Positron Energy distributions Monte Carlo: 5 body vs. 3 body phase space with constant or Fermi cross sections Here: 10 6 events More realistic: events,  p/p ~ 0.1

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 35 Coincidence Counts In 0 case the daughter nucleus receives almost vanishing recoil energy Clear signal (Note: not true for recoil momentum of daughter nucleus)

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 36 Where to put this  ++ experiment?

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 37 Background: 2 simult.  + decays Very rare But we are dealing a very rare signal!

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 38 Underground Labs

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 39

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 40 DUSEL Homestake/Sanford/DUSEL

XXIV WWND South Padre, TX, April 08 W. Bauer Slide 41 CMB Inflation W Z q q q q q q q q q q q q q q q q q g gg g g g g g g q q q q q q q g q q q q q q q g g g q q q qq g g W W W WW W Z Z Z Z