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Neutrinoless Double-Beta Decay and Double-Electron capture

HEP2012, Valparaiso, January 3-9, 2012. Neutrinoless Double-Beta Decay and Double-Electron capture. Fedor Šimkovic JINR Dubna and Comenius University Bratislava). OUTLINE. Introduction 0 nbb -decay (present status) - effective Majorana neutrino mass - nuclear matrix elements

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Neutrinoless Double-Beta Decay and Double-Electron capture

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  1. HEP2012, Valparaiso, January 3-9, 2012 Neutrinoless Double-Beta Decay and Double-Electron capture Fedor Šimkovic JINR Dubna and Comenius University Bratislava) Fedor Simkovic

  2. OUTLINE • Introduction • 0nbb-decay (present status) • - effective Majorana neutrino mass • - nuclear matrix elements • - distinguishing the 0nbb-decay mechanisms • Resonant 0nee-decay • Conclusion Fedor Simkovic

  3. AmandFaessler, Vadim Rodin, Herbert Muether(University of Tuebingen) Sergey Kovalenko (University of Valparaiso) Mikhail Krivoruchenko(ITEP Moscow) Petr Vogel (Caltech, Pasadena) Walter Potzel(TU Muenchen) Dieter Frekers(University of Muenster) John Vergados(University of Ioannina) SergueyPetcov(SISSA Trieste) E. Lisi, G. Fogli, A. Rotunno(University of Bari) … Fedor Simkovic

  4. Sources of neutrinos The Sun is the most intense detected source with a flux on Earth of 6 1010n/cm2s Flux on Earth of neutrinos from different sources as a function of energy Fedor Simkovic D. Vignaud and M. Spiro, Nucl. Phys.A 654 (1999) 350

  5. Like most people, physicists enjoy a good mystery. When you start investigating a mystery you rarely know where it is going Fundamental properties of neutrinos After 55 years we know • 3 families of light (V-A) neutrinos: ne, nm, nt • n are massive: we know mass squared differences • relation between flavor states and mass states • (neutrino mixing) only partially known Claim for evidence of the 0nbb-decay H.V. Klapdor-Kleingrothaus et al.,NIM A 522, 371 (2004); PLB 586, 198 (2004) • Absolute n mass scale from the 0nbb-decay. (cosmology, 3H, 187Rh ?) • n’s are their own antiparticles – Majorana. No answer yet • Is there a CP violation in n sector? (leptogenesis) • Are neutrinos stable? • What is the magnetic moment of n? • Sterile neutrinos? • Statistical properties ofn? Fermionic or partly bosonic? Fedor Simkovic

  6. Standard Model Lepton Universality Lepton Family Number Violation NEW PHYSICS massive neutrinos, SUSY... Total Lepton Number Violation Fedor Simkovic

  7. Compelling evidence about new physics beyond the SM. Reactor neutrinos Solar neutrinos 1968 1957 Atmospheric neutrinos Accelerator neutrinos Fedor Simkovic

  8. Mass matrix of light neutrinos Flavor eigenstates Large off diagonal elements ! Mass eigenstates 0nbb-decay Majorana condition Effective mass of Majorana neutrinos Fedor Simkovic

  9. Neutrinoless Double-Beta Decay (A,Z)  (A,Z+2) + e- + e- Fedor Simkovic

  10. The double beta decay process can be observed due to nuclear pairing interaction that favors energetically the even-even nuclei over the odd-odd nuclei The NMEs for 0nbb-decay must be evaluated using tools of nuclear theory Fedor Simkovic

  11. The answer to the question whether neutrinos are their own antiparticles is of central importance, not only to our understanding of neutrinos, but also to our understanding of the origin of mass. Absolute n mass scale Normal or inverted Hierarchy of n masses CP-violating phases An accurate knowledge of the nuclear matrix elements, which is not available at present, is however a pre-requisite for exploring neutrino properties. Fedor Simkovic

  12. Perspectives of the 0nbb-decay search sin2q13 < 5 10-2 Normal hierarchy Inverted hierarchy Fedor Simkovic

  13. Quark-Lepton Complemenarity H. Minakata, A.S. Phys. Rev. D70: 073009 (2004) QLC- relations: ql12 + qq12 ~ p/4 q12 + qC = 46.5o +/- 1.3o ql23 + qq23 ~ p/4 q23 + Vcb=43.9o + 5.1 -3.6o • Qualitatively correlation: • 2-3 leptonic mixing is close to maximalbecause 2-3quark mixing is small • 1-2leptonic mixing deviates from maximal substantially because • 1-2quark mixing is relatively large Fedor Simkovic

  14. θ13 ≠ 0 : How Big or How Small? Convincing flavor theory has been lacking—it is at present impossible to predict fermion masses, flavor mixing angles and CP phases fundamental level the flavor problem Bi-maximal mixing As dominant structure? Zero order? Ubm = U23mU12m θ13 has a role! T2K: 0.03 < sin2 2q13< 0.34 (June 2011) DOOBLE CHOOZ: sin2 2q13 =0.085±0.051 (9.11.2011) Fedor Simkovic

  15. T2K: 0.03(0.04) < sin2 2q13< 0.28(0.34) for NH(IH) Si=1,2,3=0.28 eV 0.084 eV Fedor Simkovic

  16. DOOBLE CHOOZ: sin2 2q13 =0.085±0.051 (9.11.2011) Fedor Simkovic

  17. Assumption MR» mD See-Saw mechanism n N Left-right symmetric models SO(10) Probability of Neutrino Oscillations As N increases, the formalism gets rapidly more complicated! NDmij2 qij CP -------------------------------------- 2 1 1 0 3 2 3 1 6 5 1510 large small Fedor Simkovic small large

  18. Reactor neutrinos anomaly (January 2011) • Double Chooz re-evaluated reactor antineutrino flux (PRD 83, 073006 (2011)) • previous procedure used a phenomenological model based 30 effective beta • branches • new analysis used detailed knowledge of the decays of 10,000 + fission products New calculations results in flux increase of 3.5% in reactor antineutrinos sin2(2qnew) ~ 0.14 Dmnew2 > 1.5 eV2

  19. Reactor neutrinos anomaly and 0nbb-decay Fedor Simkovic

  20. If (or when) the 0nbb decay is observed two theoretical problems must be resolved S.R. Elliott, P. Vogel, Ann.Rev.Nucl.Part.Sci. 52, 115 (2002) • What is the mechanism of the decay, i.e., • what kind of virtual particle is exchanged • between the affected nucleons (quarks). • How to relate the observed decay rate to • the fundamental parameters, i.e., • what is the value of the corresponding • nuclear matrix elements. Fedor Simkovic

  21. The 0nbb-decay NME In double beta decay two neutrons bound in the ground state of an initial even-even nucleus are simultaneously transformed into two protons that are bound in the ground state or excited (0+, 2+) states of the final nucleus It is necessary to evaluate, with a sufficient accuracy, wave functions of both nuclei, and evaluate the matrix element of the 0nbb-decay operator connecting them This can not be done exactly, some approximation and/or truncation is always needed. Moreover, there is no other analogues observable that can be used to judge directly the quality of the result. Fedor Simkovic

  22. 0f1p N=4 0d1s N=2 1p N=1 0s N=0 Many-body Hamiltonian • Start with the many-body Hamiltonian • Introduce a mean-field U to yield basis • The mean field determines the shell structure • In effect, nuclear-structure calculations rely on perturbation theory Residual interaction The success of any nuclear structure calculation depends on the choice of the mean-field basis and the residual interaction! Fedor Simkovic

  23. The 0nbb-decay NMEs from literature - 2004 (mostly QRPA-like) Uncertainties in 0nbb-decay NME? This suggest an uncertainty of NME as much as factor 5 !!! Is it really so bad?! Bahcall, Murayama, Pena-Garay, Phys. Rev. D 70, 033012 (2004) Fedor Simkovic

  24. Large Scale Shell Model: Caurier, Menendez, Nowacki, Poves, PRL 100, 052503 (2008). Nuclear structure approaches (Renormalized) QRPA: Šimkovic, Faessler, Müther, Rodin, Stauf, PRC 79, 055501 (2009). Projected Hartree-Fock-Bogoliubov: Rath, Chandra, et al. PRC 82, 064310 (2010). Interacting Boson Model: Barea, Iachello, PRC 79, 044301 (2009). Energy Dendity Functional appr.: Rodrígez, Martínez-Pinedo, arXiv:1008.5260 [nucl-th]. gA=1.25, Jastrow s.r.c., r0=1.20 fm The 0nbb-decay NMEs (Status:2012) Differences: i) mean field; ii) residual interaction; iii) size of the model space iv) many-body approximation

  25. Half-life T1/2 for mbb= 50 meV Fedor Simkovic

  26. 0nbb-decay and 2nbb-decay NMEs F.Š., R. Hodák, A. Faessler, P. Vogel, PRC 83, 015502 (2011) Fedor Simkovic

  27. 2nbb-decay: (A,Z)  (A,Z+2)+e-+e-+ne+ ne - - Why the spread of the 2nbbNMEs is large and of the 0nbbNMEs is small? Are both type of NMEs related? Differencies among 2nbb-decay NMEs: up tofactor 10 Fedor Simkovic

  28. The cross sections of (t,3He) and (d,2He) reactions give B(GT±) for b+ and b-, product of the amplitudes (B(GT)1/2) entering the numerator of M2nGT Closure 2nbb-decay NME SSD hypothesis Fedor Simkovic Grewe, …Frekers at al, PRC 78, 044301 (2008)

  29. Going to relative coordinates: A connection between closure 2nbb and 0nbb GT NMEs F.Š., R. Hodák, A. Faessler, P. Vogel, PRC 83, 015502 (2011) r- relative distance of two nucleons Neutrino potential Fedor Simkovic Neutrino potential prefer short distances

  30. Closure 2nbb GT NME The only non-zero contribution from Jp=1+ = Fedor Simkovic

  31. M0nGTdepends weakly on gA/gpp and QRPA approach unlike M2nGT Nucleon Nuclear physics Nucleon Nuclear physics 76Ge 76Ge Different QRPA-like approches Fedor Simkovic Dependence on axial-vector coupling

  32. Co-existence of few mechanisms of the 0nbb-decay It may happen that in year 201? (or 2???) the 0nbb-decay will be detected for 2-3 or more isotopes … F.Š., J.D. Vergados,A. Faessler, PRD 82, 113015 (2010) A. Faessler, G. Fogli, E. Lisi, A. Rotunno, F. Š., Phys. Rev. D 83, 113015 (2011) A. Faessler, A. Meroni, S.T. Petcov, F. Š., J.D. Vergados, Phys. Rev. D 83, 113003 (2011) Fedor Simkovic

  33. Dominance of light nmass mechanism of the 0nbb-decay H.V. Klapdor, I. Krivosheina, Mod. Phys. Lett. A 21, 1547 (2006) Fedor Simkovic Faessler, Fogli, Lisi, Rodin, Rotunno, F.Š., PRD 79, 053001 (2009)

  34. Probing the see-saw mechanism There exist heavy Majorana neutral leptons Ni (singlet of SU(2)xU(1) group) Effective interaction for processes with virtual Niat electroweak scale n N After spontaneous violation of the electroweak symmetry the left-handed Majorana mass term is generated Neutrino mixing Inverted hierarchy Fedor Simkovic

  35. Probe of the see-saw mechanism Inverted hierarchy Fedor Simkovic Bilenky, Faessler, Potzel, F.Š, Eur. Phys. J. C 71 (2011) 1754

  36. gluino/neutralino exchange R-parity breaking SUSY mechanism of the 0nbb-decay d+d → u + u + e- + e- exchange of squarks, neutralinos and gluinos (l’111)2 mechanism Fedor Simkovic

  37. Squark mixing SUSY mechanism Mixing between scalarsuperpartners of the left- and right-handed fermions A. Faessler, Th. Gutsche, S. Kovalenko, F.Š., PRD 77, 113012 (2008) M. Hirsch, H.V. Klapdor-Kleingrothaus, S. Kovalenko PLB 372 (1996) 181 L R Fedor Simkovic

  38. Co-existence of 2, 3 or more interferring mechanisms of 0nbb-decay It is well-known that there exist many mechanisms that may contribute to the 0nbb. Let consider 3 mechanisms: i) light n-mass mechanism, ii) heavy n-mass mechanism, iii) R-parity breaking SUSY mechanism with gluino exchange and CP conservation Klapdor-Kleingrothaus, Krivosheina, Mod. Phys. A 21, 1547 (2009) Claim of evidence: ξTe< 1.2 ξMo< 2.6 We introduce ξ=0,non-observation(T2→∞) ξ=1, solution for single active mech. is reproduced Fedor Simkovic

  39. 4 sets of two linear eq. 2 different solutions CP-conservation assumed F.Š., J.D. Vergados,A. Faessler, PRD 82, 113015 (2010) 2 active mechanisms of the 0nbb-decay: Light and heavy n-mass mechanism ● Non-observation of the 0nbb-decay for some isotopes might be in agreement with non- zero mbb Non-observation for 130Te ● Single solution for light n-mass mech. Fedor Simkovic

  40. Two non-interfering mechanisms of the 0nbb-decay (light LH and heavy RH neutrino exchange) Half-life: Set of equations: Solutions: Fedor Simkovic • Faessler, A. Meroni, S.T. Petcov, F. Š., J.D. Vergados, • Phys. Rev. D 83, 113003 (2011)

  41. Two non-interfering mechanisms of the 0nbb-decay (light LH and heavy RH neutrino exchange) The positivity condition: Very narrow ranges! Fedor Simkovic

  42. Neutrinoless Double-Electron Capture F.Š., M. Krivoruchenko, Phys.Part.Nucl.Lett. 6 (2009) 485 M. Krivoruchenko, F.Š., D. Frekers,A. Faessler, Nucl. Phys. A 859, 140171 (2011) F.Š., Krivoruchenko, Faessler, PPNP 66, 446 (2011) Eliseev, et al., F.Š, M. Krivoruchenko, PRL 106, 052504 (2011) Fedor Simkovic

  43. Neutrinoless double electron capture (resonance transitions) (A,Z)→(A,Z-2)*HH’ J. Bernabeu, A. DeRujula, C. Jarlskog, Nucl. Phys. B 223, 15 (1983) Atom mixing amplitude DM Decay rate Pertubation theory Sujkowski, Wycech, PRC 70, 052501 (2004) Fedor Simkovic

  44. Oscillations of atoms Oscillation ofatoms (lepton number violation) F.Š., M. Krivoruchenko, Phys.Part.Nucl.Lett. 6 (2009) 485 In analogy with oscillations of n-anti{n} (baryon number violation) Fedor Simkovic

  45. oscillations between two STABLE atoms • = 0 & W = (Mi - Mf)/2. Transitionprobability: 1/2 The exposure time of atoms in double-beta decay experiments (months and years) is greater than 1/W by many orders of magnitude. Typically V = 10-30 MeV , and so with no chances to observe the effect.

  46. oscillations & resonant transitions between ground-state and excited atoms To the lowest order in V: where i = (A,Z) f = (A,Z - 2)** Unitarylimit: MA,Z = m**A,Z-2 Breit-Wigner factor

  47. LIKELY RESONANT 0nee TRANSITIONS Decay width of the parent atom: Calculations: 1. Mass difference  Coulomb energy of electron holes. 2. Decay width G widths of the excited electron shells, Auger & radiative transitions. 3. V  LT violating potential, electron w.f. & NME. M. Krivoruchenko, F.Š., D. Frekers,A. Faessler, Nucl. Phys. A 859, 140171 (2011) The process of the 0νεε has been revisited. New 0νεε transitions with parity violation to ground and excited states of final atom/nucleus were found. Selection rules for the 0νεε transitions were established. The explicit form of corresponding NMEs was derived. Assuming an effective Majorana neutrino mass of 1 eV, some half-lives has been predicted to be as low as 1022 years in the unitary limit.

  48. Decay widths of two-electron holes • Decays are dominated by • radiative transitions with the emission of X-rays, • the emission of Auger electrons. • X-rays are dominant in the decays of atoms with Z > 35. • The width of a two-hole state ab is represented by • are taken from: J. L. Campbell and T. Papp, • At. Data and Nuclear Data Tables, 77 (2001) 1. nuclear de-excitation electron shell

  49. Improved Q-value measurements Klaus Blaum (MPI Heidelberg) 152Gd152Sm (Eliseev, et al., F.Š, M. Krivoruchenko, PRL 106, 052504 (2011)) (F.Š., Krivoruchenko, Faessler, PPNP 66, 446 (2011) Remeasured Q-value:112Sn, 74Se, 136Ce, 96Ru, 152Gd, 162Er, 168Yb, 106Cd, 156Dy need to be remeasured: 124Xe, 130Ba, 180W, 184Os, 190Pt Fedor Simkovic

  50. 0nee experiment in Bratislava 74Se Muenster and Bratislava groups T1/2 > 4.3 1019 years Frekers, Puppe, Thies, Povinec, F.Š., Staníček, Sýkora, NPA 860, 1 (2011) Fedor Simkovic

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