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ACFI-FRIB M. Horoi CMU
Double-beta decay and BSM physics: shell model nuclear matrix elements for
competing mechanisms
Mihai Horoi Department of Physics, Central Michigan University, Mount Pleasant, Michigan 48859, USA
Support from NSF grant PHY-1404442 and DOE/SciDAC grants DE-SC0008529/SC0008641 is acknowledged
Overview• Neutrino physics within and beyond the
Standard Model (BSM)• DBD mechanisms: light Majorana neutrino
exchange, right-handed currents, heavy neutrinos, SUSY R-parity violation,…
• 48Ca: 2v and 0v shell-model matrix elements– Beyond closure approximation
• 76Ge, 82Se, 130Te, and 136Xe results
ACFI-FRIB M. Horoi CMU
Classical Double Beta Decay Problem
ACFI-FRIB M. Horoi CMU
Adapted from Avignone, Elliot, Engel, Rev. Mod. Phys. 80, 481 (2008) -> RMP08
A.S. Barabash, PRC 81 (2010)
2-neutrino double beta decay
neutrinoless double beta decay
Neutrino Masses
ACFI-FRIB M. Horoi CMU
- Tritium decay:
- Cosmology: CMB power spectrum, BAO, etc,
Two neutrino mass hierarchies
arXiv:0710.4947v3
The origin of Majorana neutrino masses
ACFI-FRIB M. Horoi CMU
Type I see-saw
- SU2eimi term dominates in
most cases
- TeV collider Majorana tests not relevant
arXiv:0710.4947v3
The origin of Majorana neutrino masses
ACFI-FRIB M. Horoi CMU
See-saw mechanisms
Left-Right Symmetric model
WR search at CMS arXiv:1407.3683
Contributions to 0vbb decay: no neutrinos
ACFI-FRIB M. Horoi CMU
See-saw type III
GUT/SUSY R-parity violation
Squark exchangeGluino exchange
Hadronization /w R-parity v.
The Black Box Theorem
ACFI-FRIB M. Horoi CMU
J. Schechter and J.W.F Valle, PRD 25, 2951 (1982)
E. Takasugi, PLB 149, 372 (1984)
J.F. Nieves, PLB 145, 375 (1984)
M. Hirsch, S. Kovalenko, I. Schmidt, PLB 646, 106 (2006)
0nbb observed
at some level
(i) Neutrinos are Majorana fermions.
(ii) Lepton number conservation is violated by 2 units
Regardless of the dominant 0nbb mechanism!
M. Horoi CMU
Is there a more general description?
ACFI-FRIB
Long-range terms: (a) - (c ) Short-range terms: (d)
M. Horoi CMU
Summary of 0vDBD mechanisms
• The mass mechanism (a.k.a. light-neutrino exchange) is likely, and the simplest BSM scenario.
• Low mass sterile neutrino would complicate analysis• Right-handed heavy-neutrino exchange is possible, and
requires knowledge of half-lives for more isotopes.• h- and l- mechanisms are possible, but could be ruled
in/out by energy and angular distributions.• Left-right symmetric model may be also (un)validated
at LHC/colliders.• SUSY/R-parity, KK, GUT, etc, scenarios need to be
checked, but validated by other means. ACFI-FRIB
ACFI-FRIB M. Horoi CMU
2v Double Beta Decay (DBD) of 48Ca
Ikeda satisfied in pf !
The choice of valence space is important!
Horoi, Stoica, Brown,
PRC 75, 034303 (2007)
ISR 48Ca 48Ti
pf 24.0 12.0
f7 p3 10.3 5.2
Closure Approximation and Beyond in Shell Model
ACFI-FRIB M. Horoi CMU
Challenge: there are about 100,000 Jk states in the sum for 48Ca
Much more intermediate states for heavier nuclei, such as 76Ge!!!
No-closure may need states out of the model space (not considered).
Minimal model spaces
82Se : 10M states
130Te : 22M states
76Ge : 150M states
M. Horoi CMU
New Approach to calculate NME: New Tests of Nuclear Structure
ACFI-FRIB
Brown, Horoi, Senkov
arXiv:1409.7364,
ACFI-FRIB M. Horoi CMU
136Xe bb Experimental ResultsPublication Experiment T2n
1/2 T0n1/2(lim) T0n
1/2(Sens)
PRL 110, 062502 KamLAND-Zen > 1.9x1025 y 1.1x1025 y
PRC 89, 015502 EXO-200 (2.11 0.04 0.21)x1021 y
Nature 510, 229 EXO-200 >1.1x1025 y 1.9x1025 y
PRC 85, 045504 KamLAND-Zen (2.38 0.02 0.14)x1021 y
EXO-200
arXiv:1402.6956, Nature 510, 229
ACFI-FRIB M. Horoi CMU
136Xe 2nbb Results
0g7/2 1d5/2 1d3/2 2s5/2 0h11/2 model space
0h11/2
2s5/2
1d3/2
1d5/2
0g7/2
0h9/2
0g9/2
0h11/2
2s5/2
1d3/2
1d5/2
0g7/2
0h9/2
0g9/2
0h11/2
2s5/2
1d3/2
1d5/2
0g7/2
0h9/2
0g9/2
0g9/2 0g7/21d5/2 1d3/2 2s5/2 0h11/2 0h9/2
New effective interaction,
0h11/2
2s5/2
1d3/2
1d5/2
0g7/2
0h9/2
0g9/2
np - nh
n (0+) n (1+) M(2v)
0 0 0.062
0 1 0.091
1 1 0.037
1 2 0.020
M. Horoi CMU
IBA-2 J. Barea, J. Kotila, and F. Iachello, Phys. Rev. C 87, 014315 (2013).
QRPA-En M. T. Mustonen and J. Engel, Phys. Rev. C 87, 064302 (2013).
QRPA-Jy J. Suhonen, O. Civitarese, Phys. NPA 847 207–232 (2010).
QRPA-Tu A. Faessler, M. Gonzalez, S. Kovalenko, and F. Simkovic, arXiv:1408.6077
ISM-Men J. Menéndez, A. Poves, E. Caurier, F. Nowacki, NPA 818 139–151 (2009).SM M. Horoi et. al. PRC 88, 064312 (2013), PRC 89, 045502 (2014), PRC 90, PRC 89, 054304 (2014), in preparation, PRL 110, 222502 (2013).
ACFI-FRIB
M. Horoi CMU
IBA-2 J. Barea, J. Kotila, and F. Iachello, Phys. Rev. C 87, 014315 (2013).
QRPA-Tu A. Faessler, M. Gonzalez, S. Kovalenko, and F. Simkovic, arXiv:1408.6077
SM M. Horoi et. al. PRC 88, 064312 (2013), PRC 90, PRC 89, 054304 (2014), in preparation, PRL 110, 222502 (2013).
ACFI-FRIB
Take-Away Points
ACFI-FRIB M. Horoi CMU
Black box theorem (all flavors + oscillations)
Observation of 0 nbb will signal New Physics Beyond the Standard Model.
0nbb observed
at some level
(i) Neutrinos are Majorana fermions.
(ii) Lepton number conservation is violated by 2 units
Regardless of the dominant 0nbb mechanism!
ACFI-FRIB M. Horoi CMU
Take-Away Points
The analysis and guidance of the experimental efforts need accurate Nuclear Matrix Elements.
ACFI-FRIB M. Horoi CMU
Take-Away Points
Extracting information about Majorana CP-violation phases may require the mass hierarchy from LBNE, cosmology, etc, but also accurate Nuclear Matrix Elements.
ACFI-FRIB M. Horoi CMU
Take-Away PointsAlternative mechanisms to 0nbb need to be carefully tested: many isotopes, energy and angular correlations.
These analyses also require accurate Nuclear Matrix Elements.
SuperNEMO; 82Se
ACFI-FRIB M. Horoi CMU
76Ge
Take-Away PointsAccurate shell model NME for different decay mechanisms were recently calculated.
The method provides optimal closure energies for the mass mechanism.
Decomposition of the matrix elements can be used for selective quenching of classes of states, and for testing nuclear structure.
M. Horoi CMU
Collaborators:
• Alex Brown, NSCL@MSU• Roman Senkov, CMU and CUNY• Andrei Neacsu, CMU• Jonathan Engel, UNC• Jason Holt, TRIUMF
ACFI-FRIB
ACFI-FRIB M. Horoi CMU
Summary and Outlook
• Observation of neutrinoless double beta decay would signal physics beyond the Standard Model: massive Majorana neutrinos, right-handed currents, SUSY LNV, etc
• 48Ca and 136Xe cases suggest that 2 double-beta decay can be described reasonably within the shell model with standard quenching, provided that all spin-orbit partners are included.
• Higher order effects for 0 NME included: range 1.0 – 1.4
• Reliable 0bb nuclear matrix elements could be used to identify the dominant mechanism if energy/angular correlations and data for several isotopes become available.
• The effects of the quenching and the missing spin-orbit partners are important (see the 136Xe case), and they need to be further investigated for 76Ge, 82Se and 130Te.
M. Horoi CMU
Effective Field Theory for BSM
ACFI-FRIB
V. Cirigliano talk at LPR Town Meeting, Chicago, Sep 28-29, 2014
ACFI-FRIB M. Horoi CMU
Comparisons of M0n 0nbb Results
From T. Rodriguez, G. Martinez-Pinedo,
Phys. Rev. Lett. 105, 252503 (2010)
Present Shell Model results:
Phys. Rev. Lett. 110, 222502 (2013)
PRC 89, 045502 & 88, 064312 (2013)
PRC 89, 054304 (2014), submitted
(MS)
M. Horoi CMU
Shell Model GT Quenching
core polarization: Phys.Rep. 261, 125 (1995)
ACFI-FRIB
empty
valence
frozen core
J. Menendez, D. Gazit and A. Schwenk, arXiV:1103.3622, PRL 107
The effect of larger model spaces for 48Ca
ACFI-FRIB M. Horoi CMU
M(0v) SDPFU SDPFMUP
0 0.941 0.623
0+2 1.182 (26%) 1.004 (61%)
SDPFU: PRC 79, 014310 (2009)
SDPFMUP: PRC 86, 051301(R) (2012)
arXiv:1308.3815, PRC 89, 045502 (2014)
M(0v)
0 / GXPF1A 0.733
0 +2nd ord./GXPF1A 1.301 (77%)
PRC 87, 064315 (2013)
The Black Box Theorem
ACFI-FRIB M. Horoi CMU
J. Schechter and J.W.F Valle, PRD 25, 2951 (1982)
E. Takasugi, PLB 149, 372 (1984)
J.F. Nieves, PLB 145, 375 (1984)
However:
M. Duerr et al, JHEP 06 (2011) 91
M. Hirsch, S. Kovalenko, I. Schmidt, PLB 646, 106 (2006)
0nbb observed
at some level
(i) Neutrinos are Majorana fermions.
(ii) Lepton number conservation is violated by 2 units
Regardless of the dominant 0nbb mechanism!
Some mechanisms tested at LHC
ACFI-FRIB M. Horoi CMU
PRD 86, 055006 (2012)
arXiv:1307.4849
Left-right symmetric model
Some mechanisms tested at LHC
ACFI-FRIB M. Horoi CMU
Recent CMS results a 2.8s effect arXiv:1407.3683
Broken D-parity left-right symmetric model: arXiv:1409.2820
Consequences of Majorana Neutrinos
ACFI-FRIB M. Horoi CMU
- Leptogenesis (DL=2) => (SM sphalerons) => Baryogenesis
- Exotic (DL=2) decays:
- Larger magnetic moments => Larger decay rates of heavy neutrino
- Different neutrino contribution to Supernovae explosion mechanism => different signals measured on Earth detectors
Fermion masses in and beyond the Standard Model
ACFI-FRIB M. Horoi CMU
Standard Model neutrino (m=0)
Beyond Standard Model Dirac neutrino (m>0)
Beyond Standard Model Majorana neutrino (m>0)
Standard Model Dirac fermions (m>0)
Standard Model photon (m=0)
Matrix Elements: Light Neutrinos
ACFI-FRIB M. Horoi CMU
PRD 83, 113003 (2011)
PRL 109, 042501 (2012)
NPA 818, 139 (2009)
Present Interacting Shell-Model
Matrix Elements: Heavy Neutrinos
ACFI-FRIB M. Horoi CMU
PRL 109, 042501 (2012)
PRD 83, 113003 (2011)
Present Interacting Shell-Model
Fermions masses in the Standard Model
ACFI-FRIB M. Horoi CMU
Standard Model neutrino (m=0)
Extended Standard Model Dirac neutrino (m>0)
Beyond Standard Model Majorana neutrino (m>0)
Standard Model Dirac fermions (m>0)
Standard Model photon (m=0)
Beyond Closure in Shell Model
ACFI-FRIB M. Horoi CMU
- About 300 intermediate states for each spin are (more than) enough
- GT dominates, and exhibits the largest change
- A 8-12% increase from closure was found
Challenge: there are about 100,000 Jk states in the sum for 48Ca !!!
Senkov & Horoi, PRC 88, 064312 (2013)
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