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Recent developments in Double Beta Decay Fedor Š imkovic Comenius University, Bratislava

NOW 2006 Conca Specchiulla, September 9-16, 2006. Recent developments in Double Beta Decay Fedor Š imkovic Comenius University, Bratislava. OUTLINE. Introduction NO, n -masses, m n From NO to 0 nbb -decay CP-phases, q 13 , sterile n Bosonic n and 2 nbb -decay Conclusions.

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Recent developments in Double Beta Decay Fedor Š imkovic Comenius University, Bratislava

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  1. NOW 2006 Conca Specchiulla, September 9-16, 2006 Recent developments in Double Beta Decay Fedor Šimkovic Comenius University, Bratislava Fedor Simkovic

  2. OUTLINE • Introduction • NO, n-masses, mn • From NO to 0nbb-decay • CP-phases, q13, sterile n • Bosonic n and 2nbb-decay • Conclusions Fedor Simkovic

  3. Standard Model Lepton Universality NEW PHYSICS massive neutrinos, SUSY... Lepton Family Number Violation Total Lepton Number Violation !!! Perspectives are opened !!! Fedor Simkovic

  4. Neutrino oscillations  Massive neutrinos Reactor neutrinos Solar neutrinos 1968 Atmospheric neutrinos Accelerator neutrinos 1957 Fedor Simkovic

  5. Mixing of 3 light Neutrinos Pontecorvo -Maki-Nakagawa-Sakata matrix Flavor eigenstates Mass eigenstates mbb= SUeiUei mi ??? q13, CP- phases, hierarchy, absolute mass scale ??? Mass matrix Fedor Simkovic

  6. n-masses in flavor basis: Inverted hierarchy em et ee mm mt tt Fedor Simkovic Gozdz,Kaminski, F.Š, Faessler, Acta Phys. Pol. 37 (2006) 2203

  7. n-masses in flavor basis: Normal hierarchy em et ee mt mm tt Fedor Simkovic Gozdz,Kaminski, F.Š, Faessler, Acta Phys. Pol. 37 (2006) 2203

  8. n Majorana transitional magnetic moment n-oscillations  n magnetic moment n-e scattering g → nn Fedor Simkovic

  9. Transitional magnetic moment of Majorana n R-parity violation SUSY, masses generated via lepton-slepton loops m0=m1/2=150 GeV, A0=100 GeV tan b=19 Inverted hierarchy Normal hierarchy Fedor Simkovic Gozdz,Kaminski, F.Š, Faessler, hep-ph/0606077, to be published in PRD

  10. n-oscillations  0nbb-decay Fedor Simkovic

  11. Double Beta Decay Observed for 10 isotopes: 48Ca, 76Ge, 82Se, 96Zr,100Mo. 116Cd. 128Te, 130Te, 150Nd, 238U, T1/2 ≈1018-1024 years SMforbidden ,not observed yet: T1/2 ( 76Ge)>1025 years Fedor Simkovic

  12. Bilenky,Faessler, Gutsche, F.Š., PRD 72, 053015 (2005) Inverted hierarchy Normal hierarchy Fedor Simkovic 1027-1028years Goals for 0nbb-experiments 1029-1030years

  13. q13 and the cancellation Fedor Simkovic Bilenky,Faessler, Gutsche, F.Š., PRD 72, 053015 (2005)

  14. Perspectives of the 0nbb-search Fedor Simkovic

  15. 0nbb-decay NME Fedor Simkovic

  16. NME-Nuclear structure approaches H Y = E Y We can not solve the full problem in the complete Systematical study of the 0nbb-decay NME Projected mean field (Vampir) ●Tomoda, Faessler, Schmid, Grummer, PLB 157, 4 (1985) Shell model:●Haxton, Stephensson,Prog. Part. Nucl. Phys. 12, 409(1984) ●Caurier, Nowacki, Poves, Retamosa, PRL 77, 1954 (1996) QRPA, RQRPA: About 10 papers 1987→ 2006 Other approaches: Shell Model Monte Carlo (1996), Operator Expansion Method (1988-1994)... Fedor Simkovic

  17. QRPA 2nbb-decay NME H=H0 + gphHph + gpp Hpp 21 lev. 12 lev. Collapse of the QRPA 21 l.m.s. 12 l.m.c Fedor Simkovic

  18. Neutrinoless Double Beta Decay Nuclear Matrix Elements Light Majorana Neutrino Exchange Mechanism Recommended 0nbb-decay NME (April 2005) V.Rodin, A. Faessler, F. Š., P. Vogel, NPA 766 (2006) 107 Fedor Simkovic

  19. Shell Model • Define a valence space • Derive an effective interactionH Y = E Y→ HeffYeff = E Yeff • Build and diagonalize Hamiltonian matrix (1011) • Transition operator < Yeff| Oeff | Yeff> • Some phenomenological input needed energy of states, systematics of B(E2) and GT transitions (quenching f.) 48Ca → 48Ti 76Ge → 76Se 76Se42 in the valence 6 protons and 14 neutrons Small calculations Fedor Simkovic

  20. Comparison of M0nof Rodin et al. (RQRPA) and Nowacki et al. (SM, private comm., preliminary 2004, 2006) 0nbb-decay Nucleus RQRPA SM SM (2005) (2004) (2006) 76Ge 2.3-2.4 1.6 1.8 82Se1.9-2.1 1.7 1.7 96Zr 0.3-0.4 0.4 100Mo 1.1-1.2 0.3 116Cd 1.2-1.4 1.9 130Te 1.3 2.0 (1.0) 1.7 136Xe 0.6-1.0 1.6 (0.6) 1.4 Except for 100Mo the agreement between these very different calculations is reasonably good. Note that the SM calculations include the reduction caused by the s.r.c. and induced currents(30%). SM results 2nbb-decay Isotope T1/2(th.)[y] T1/2(exp.)[y] 48Ca3.7 10194.2 1019 76Ge 1.2 1021 1.4 1021 82Se 3.4 1019 9.0 1019 130Te 4. 1020 6.1 1020 136Xe 6. 1020 8.1 1020 Strasbourg group, Nowacki, IDEA meeting, Heidelberg, 2004 Fedor Simkovic

  21. Nuclear deformation Exp. I (nuclear reorientation method) Exp.II (based on measured E2 trans.) Theor. I (Rel. mean field theory) Theor. II (Microsc.-Macrosc. Model of Moeller and Nix) Till now, in the QRPA-like calculations of the 0nbb-decay NME spherical symmetry was assumed The effect of deformation on NME has to be considered Fedor Simkovic

  22. New Suppression Mechanism of the DBD NME The suppression of the NME depends on relative deformation of initial and final nuclei F.Š., Pacearescu, Faessler. NPA 733 (2004) 321 Systematic study of the deformation effect on the 2nbb-decay NME within deformed QRPA Alvarez,Sarriguren, Moya,Pacearescu, Faessler, F.Š., Phys. Rev. C 70 (2004) 321 Fedor Simkovic

  23. Sterile neutrino in 0nbb-decay Fedor Simkovic

  24. Sterile neutrino in 0nbb-decay Beneš, Faesler, F.Š., Kovalenko, PRD 71 (2005) 077901 Fedor Simkovic

  25. Bosonic n in the 0nbb-decay Fedor Simkovic

  26. Since n´s have spin one half they are believed to obey Fermi statistics Bosonic n introduced: Ignatiev, Kuzmin,Yad. Fiz 46 (1987) 786 Bosonic n in 2nbb-decay: Dolgov, Smirnov, PLB 621 (2005) 1 Motivations: Dark matter, BBN, supernova n For electrons and nucleons, a possible violation of statistics is strongly restricted by experiments. A consistent quantum field theory with of half-integer spin particles with any other statistics than the Fermi one is missing Fedor Simkovic

  27. 2nbb-decay:fermionic (f)or bosonic (b) n Sign difference!!! Lepton energies!!! Fedor Simkovic

  28. 2nbb-decay of 100Mo 0+g.s.→ 0+g.s Barabash, Dolgov, Dvornický, F.Š., Smirnov, in preparation bosonic fermionic Fedor Simkovic

  29. Mixed statistics Definition: Commutators: Amplitude: Decay rate: Fedor Simkovic

  30. Barabash, Dolgov, Dvornický, F.Š., Smirnov, in preparation SSD free of log ft values Large admixture of bosonic n excluded: b2 < 0.75 Fedor Simkovic

  31. Sensitive to a small admixture of bosonic n Barabash, Dolgov, Dvornický, F.Š., Smirnov, in preparation SSD free of log ft values HSD nuclei even more sensitive to admixture of bosonicn but calculation of M.E. needed Fedor Simkovic

  32. Outlook (NME) There will be a progress Moore’s law of 0nbb-decay Elliott, Vogel, Ann.Rev.Nucl.Part.Sci. 52 (2002)115 Shell model: increased computer power, larger m.s., better effective interactios, new groups (T. Otsuka – Tokyo U.) MCSM: unsolved problems? H. Nakada (NNR05), Alhassid, Bertsch, Liu, Fang Projected mena field: New calculations are planed, Petrovici, Schmid QRPA: further progress expected→ effects of deformation,overlap factor What is the dominant mechanism of the 0nbb-decay? Inverted hierarchy NME + PPP There is still some time Fedor Simkovic

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