FROM NUCLEAR PHYSICS TO PHYSICS BEYOND THE STANDARD MODEL: FIRST EVIDENCE FOR LEPTON NUMBER VIOLATION AND THE MAJORANA CHARACTER OF NEUTRINOS

2004 ◽  
Vol 13 (10) ◽  
pp. 2107-2126 ◽  
Author(s):  
H. V. KLAPDOR-KLEINGROTHAUS
Keyword(s):  
Beyond Standard Model ◽  
Standard Model ◽  
Beta Decay ◽  
Neutrino Mass ◽  
Half Life ◽  
Nuclear Physics ◽  
High Energy ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Boson Mass

Nuclear double beta decay provides an extraordinarily broad potential to search for beyond-standard-model physics. The occurrence of the neutrinoless decay(0νββ) mode has fundamental consequences: first, the total lepton number is not conserved, and second, the neutrino is a Majorana particle. Furthermore, the measured effective mass provides an absolute scale of the neutrino mass spectrum. In addition, double beta experiments yield sharp restrictions for other beyond-standard-model physics. These include SUSY models (R-parity breaking and conserving), leptoquarks (leptoquark-Higgs coupling), compositeness, left-right symmetric models (right-handed W boson mass), test of special relativity and of the equivalence principle in the neutrino sector and others. First evidence for neutrinoless double beta decay was reported by the HEIDELBERG–MOSCOW experiment in 2001. The HEIDELBERG–MOSCOW experiment is by far the most sensitive0νββ experiment since more than 10 years. It is operating 11 kg of enriched 76Ge in the GRAN SASSO Underground Laboratory. The analysis of the data taken from 2 August 1990–20 May 2003 is presented here. The collected statistics is 71.7 kg y. The background achieved in the energy region of the Q value for double beta decay is 0.11 events/kg y keV. The two-neutrino accompanied half-life is determined on the basis of more than 100,000 events to be [Formula: see text] years. The confidence level for the neutrinoless signal has been improved to a 4.2σ level. The half-life is [Formula: see text] years. The effective neutrino mass deduced is (0.2–0.6) eV (99.73% C.L.), with the consequence that neutrinos have degenerate masses. The sharp boundaries for other beyond SM physics, mentioned above, are comfortably competitive to the corresponding results from high-energy accelerators like TEVATRON, HERA, etc.

STATUS AND PERSPECTIVES OF DOUBLE BETA DECAY — WINDOW TO NEW PHYSICS BEYOND THE STANDARD MODEL OF PARTICLE PHYSICS

1998 ◽  
Vol 13 (23) ◽  
pp. 3953-3992 ◽  
Author(s):  
H. V. KLAPDOR-KLEINGROTHAUS
Keyword(s):  
Standard Model ◽  
Beta Decay ◽  
Neutrino Oscillation ◽  
Atmospheric Neutrino ◽  
Large Angle ◽  
High Energy ◽  
New Physics ◽  
Double Beta Decay ◽  
Boson Mass ◽  
Electron Mass

Nuclear double beta decay provides an extraordinarily broad potential to search for beyond Standard Model physics, probing already now the TeV scale, on which new physics should manifest itself. These possibilities are reviewed here. First, the results of present generation experiments are presented. The most sensitive one of them — the Heidelberg–Moscow experiment in the Gran Sasso — probes the electron mass now in the sub eV region and will reach a limit of ~ 0.1 eV in a few years. Basing to a large extent on the theoretical work of the Heidelberg Double Beta Group in the last two years, results are obtained also for SUSY models (R-parity breaking, sneutrino mass), leptoquarks (leptoquark–Higgs coupling), compositeness, right-handed W boson mass and others. These results are comfortably competitive to corresponding results from high-energy accelerators like TEVATRON, HERA, etc. Second, future perspectives of ββ research are discussed. A new Heidelberg experimental proposal (GENIUS) is presented which would allow one to increase the sensitivity for Majorana neutrino masses from the present level of at best 0.1 eV down to 0.01 or even 0.001 eV. Its physical potential would be a breakthrough into the multi-TeV range for many beyond standard models. Its sensitivity for neutrino oscillation parameters would be higher than that for all present terrestrial neutrino oscillation experiments and of those planned for the future. It could probe directly the atmospheric neutrino problem and even the large angle solution of the solar neutrino problem. It would further, already in a first step, using only 100 kg of natural Ge detectors, cover almost the full MSSM parameter space for prediction of neutralinos as cold dark matter, making the experiment competitive to LHC in the search for supersymmetry.

scholarly journals Neutrinoless Double-Beta Decay: Status and Prospects

2019 ◽  
Vol 69 (1) ◽  
pp. 219-251 ◽  
Author(s):  
Michelle J. Dolinski ◽  
Alan W.P. Poon ◽  
Werner Rodejohann
Keyword(s):  
Beta Decay ◽  
Half Life ◽  
Particle Physics ◽  
Nuclear Physics ◽  
Large Scale ◽  
Neutrinoless Double Beta Decay ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Beyond The Standard Model ◽  
The Standard Model

Neutrinoless double-beta decay is a forbidden, lepton-number-violating nuclear transition whose observation would have fundamental implications for neutrino physics, theories beyond the Standard Model, and cosmology. In this review, we summarize the theoretical progress to understand this process, the expectations and implications under various particle physics models, and the nuclear physics challenges that affect the precise predictions of the decay half-life. We also provide a synopsis of the current and future large-scale experiments that aim to discover this process in physically well-motivated half-life ranges.

scholarly journals Searching for Neutrinoless Double-Beta Decay of130Te with CUORE

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
D. R. Artusa ◽  
F. T. Avignone ◽  
O. Azzolini ◽  
M. Balata ◽  
T. I. Banks ◽  
...  
Keyword(s):  
Beta Decay ◽  
Energy Resolution ◽  
Confidence Level ◽  
Half Life ◽  
Average Energy ◽  
Neutrinoless Double Beta Decay ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Current Status ◽  
Upper Limit

Neutrinoless double-beta (0νββ) decay is a hypothesized lepton-number-violating process that offers the only known means of asserting the possible Majorana nature of neutrino mass. The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for 0νββdecay of130Te using an array of 988 TeO2crystal bolometers operated at 10 mK. The detector will contain 206 kg of130Te and have an average energy resolution of 5 keV; the projected 0νββdecay half-life sensitivity after five years of livetime is 1.6 × 1026 y at 1σ(9.5 × 1025 y at the 90% confidence level), which corresponds to an upper limit on the effective Majorana mass in the range 40–100 meV (50–130 meV). In this paper, we review the experimental techniques used in CUORE as well as its current status and anticipated physics reach.

scholarly journals SEESAW AT LHC THROUGH LEFT–RIGHT SYMMETRY

2011 ◽  
Vol 26 (09) ◽  
pp. 1469-1491 ◽  
Author(s):  
GORAN SENJANOVIĆ
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Neutrinoless Double Beta Decay ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Seesaw Mechanism ◽  
Lepton Number Violation ◽  
Number Violation ◽  
The Right ◽  
The Masses

I argue that LHC may shed light on the nature of neutrino mass through the probe of the seesaw mechanism. The smoking gun signature is lepton number violation through the production of same sign lepton pairs, a collider analogy of the neutrinoless double beta decay. I discuss this in the context of left–right symmetric theories, which led originally to neutrino mass and the seesaw mechanism. A WR gauge boson with a mass in a few TeV region could easily dominate neutrinoless double beta decay, and its discovery at LHC would have spectacular signatures of parity restoration and lepton number violation. Moreover, LHC can measure the masses of the right-handed neutrinos and the right-handed leptonic mixing matrix, which could in turn be used to predict the rates for neutrinoless double decay and lepton flavor violating violating processes. The LR scale at the LHC energies offers great hope of observing these low energy processes in the present and upcoming experiments.

scholarly journals Shell Model Studies of Competing Mechanisms to the Neutrinoless Double-Beta Decay in 124Sn, 130Te, and 136Xe

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Andrei Neacsu ◽  
Mihai Horoi
Keyword(s):  
Beyond Standard Model ◽  
Standard Model ◽  
Shell Model ◽  
Beta Decay ◽  
Neutrinoless Double Beta Decay ◽  
Mass Scale ◽  
Double Beta Decay ◽  
Majorana Fermion ◽  
Mass Hierarchy ◽  
Model Studies

Neutrinoless double-beta decay is a predicted beyond Standard Model process that could clarify some of the not yet known neutrino properties, such as the mass scale, the mass hierarchy, and its nature as a Dirac or Majorana fermion. Should this transition be observed, there are still challenges in understanding the underlying contributing mechanisms. We perform a detailed shell model investigation of several beyond Standard Model mechanisms that consider the existence of right-handed currents. Our analysis presents different venues that can be used to identify the dominant mechanisms for nuclei of experimental interest in the mass A~130 region (124Sn, 130Te, and 136Xe). It requires accurate knowledge of nine nuclear matrix elements that we calculate in addition to the associated energy-dependent phase space factors.

scholarly journals A Froggatt–Nielsen flavor model for neutrino physics

2019 ◽  
Vol 34 (19) ◽  
pp. 1950102 ◽  
Author(s):  
Micheal S. Berger ◽  
Maria Dawid
Keyword(s):  
Neutrino Physics ◽  
Beta Decay ◽  
Neutrino Mass ◽  
Mass Matrix ◽  
Neutrinoless Double Beta Decay ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Low Energy ◽  
Lepton Number Violation ◽  
Flavor Violation

Superheavy neutrinos can, via the seesaw model, provide a mechanism for lepton number violation. If they are combined with flavor violation as characterized by the Froggatt–Nielsen mechanism, then the phenomenology for the neutrinos in oscillation experiments, neutrinoless double beta decay, and other experiments can be described by a relatively few number of parameters. We describe the low-energy neutrino mass matrix and show that the results are consistent with currently available data.

scholarly journals The Standard Model of Particle Physics with Diracian Neutrino Sector

Symmetry ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 994 ◽  
Author(s):  
Theodorus Maria Nieuwenhuizen
Keyword(s):  
Standard Model ◽  
Particle Physics ◽  
Mass Matrix ◽  
High Energy ◽  
Solar Neutrinos ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Sterile Neutrinos ◽  
Neutrino Sector ◽  
The Standard Model

The minimally extended standard model of particle physics contains three right handed or sterile neutrinos, coupled to the active ones by a Dirac mass matrix and mutually by a Majorana mass matrix. In the pseudo-Dirac case, the Majorana terms are small and maximal mixing of active and sterile states occurs, which is generally excluded for solar neutrinos. In a “Diracian” limit, the physical masses become pairwise degenerate and the neutrinos attain a Dirac signature. Members of a pair do not oscillate mutually so that their mixing can be undone, and the standard neutrino model follows as a limit. While two Majorana phases become physical Dirac phases and three extra mass parameters occur, a better description of data is offered. Oscillation problems are worked out in vacuum and in matter. With lepton number –1 assigned to the sterile neutrinos, the model still violates lepton number conservation and allows very feeble neutrinoless double beta decay. It supports a sterile neutrino interpretation of Earth-traversing ultra high energy events detected by ANITA.

scholarly journals What Is Matter According to Particle Physics, and Why Try to Observe Its Creation in a Lab?

Universe ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 61
Author(s):  
Francesco Vissani
Keyword(s):  
Standard Model ◽  
Conservation Laws ◽  
Beta Decay ◽  
Particle Physics ◽  
Neutrinoless Double Beta Decay ◽  
Lepton Number ◽  
Double Beta Decay ◽  
Nuclear Process ◽  
The Standard Model ◽  
Technical Considerations

The standard model of elementary interactions has long qualified as a theory of matter, in which the postulated conservation laws (one baryonic and three leptonic) acquire theoretical meaning. However, recent observations of lepton number violations—neutrino oscillations—demonstrate its incompleteness. We discuss why these considerations suggest the correctness of Ettore Majorana’s ideas on the nature of neutrino mass and add further interest to the search for an ultra-rare nuclear process in which two particles of matter (electrons) are created, commonly called neutrinoless double beta decay. The approach of the discussion is mainly historical, and its character is introductory. Some technical considerations, which highlight the usefulness of Majorana’s representation of gamma matrices, are presented in the appendix.

Remark on Majorana CP phases in neutrino mixing and leptogenesis

2014 ◽  
Vol 29 (16) ◽  
pp. 1450087
Author(s):  
Teruyuki Kitabayashi ◽  
Naoto Koizumi
Keyword(s):  
Beta Decay ◽  
Neutrino Mass ◽  
Half Life ◽  
Neutrinoless Double Beta Decay ◽  
Majorana Neutrino ◽  
Double Beta Decay ◽  
Neutrino Mixing ◽  
Seesaw Model ◽  
Mixing Matrix ◽  
Majorana Neutrino Mass

We estimate Majorana CP phases for a simple flavor neutrino mixing matrix which has been reported by Qu and Ma. Sizes of Majorana CP phases are evaluated in the study of the neutrinoless double beta decay and a particular leptogenesis scenario. We find the dependence of the physically relevant Majorana CP phase on the mass of lightest right-handed neutrino in the minimal seesaw model and the effective Majorana neutrino mass which is related with the half-life of the neutrinoless double beta decay.

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