The Search for Neutrinoless Double Beta DecayTashi Parsons-MossBNL NCSS 2006

Decay and Weak Interaction(A, Z) (A, Z + 1) + - + e(1)(A, Z) (A, Z - 1) + + + e (2)(A, Z) + e- (A, Z - 1) + e(3)

Neutrinose , , 1930 postulated by Pauli1956 detected by Cowen et al. Oscillations and Mass

Double Beta Decay(A, Z) (A, Z + 2) + 2e- + 2(48Ca, 76Ge, 82Se, 96Zr, 100Mo, 116Cd, 128Te, 130Te, 150Nd, 238U) (A, Z) (A, Z + 2) + 2e- (A, Z) (A, Z + 2) + 2e- + 0(+0)

Possible Mechanisms of 0 decay SUSY particlesLeptoquarks Right-Handed weak interaction Light of Heavy Majorana Neutrinos

0 Decay and Neutrino Mass3 Ranges of Mass sensitivity:Quasi-Degenerate ~100-500 meVAtmospheric neutrino oscillation results ~20-55 meVSolar neutrino oscillation results ~2-5 meV

Whats the big deal? = ?Absolute mass scale for neutrinosLeptogenesisWeak ForceGrand Unified Theories

ChallengesDetermining the dominant mechanismUncertainties in nuclear matrix elementsLimited resources, expenseBackground, background, Background!!!2 peakCosmic radiationIntrinsic backgroundShielding and cryostat material

Recent 0 results

Recent claim of 0 detection

Heidelberg-Moscow71.7 Kg-y dataControversial ResultsIncreased interest in quasi-degenerate 76Ge experiments

0 Proposals

GENIUS (Germanium Nitrogen Underground Setup)Assumes limiting background on HM from external sourcesArray of 2.5 Kg p-type 86% enriched Ge crystals naked in LN2

MajoranaAssumes 68Ge within Ge detectors was limiting background in IGEX210 86% enriched, segmented n-type Ge crystals in ultra-pure electroformed Cu cryostats

Majorana

MOON (Mo Observatory of Neutrinos)Uses unique nuclear structure of 100Mo to combine 0 search and solar neutrino experimentModules of plastic fiber scintillators with thin layers Mo

MOON

AcknowledgementsI would like to thank Richard Ferrieri and all of the TAs, professors, students and supporters of the BNL Nuclear and Radiochemistry Summer School