Search results for "double beta decay"
showing 10 items of 317 documents
Nuclear matrix elements for Majoron emitting double-$\beta$ decay
2021
A complete calculation of the nuclear matrix elements (NMEs) for Majoron emitting neutrinoless double beta decay within the framework of IBM-2 for spectral indices $n=1,3,7$ is presented. By combining the results of this calculation with previously calculated phase-space factors (PSFs) we give predictions for expected half-lives. By comparing with experimental limits on the half-lives we set limits on the coupling constants $\ensuremath{\langle}{g}_{ee}^{M}\ensuremath{\rangle}$ of all proposed Majoron-emitting models.
Electroluminescence TPCs at the thermal diffusion limit
2019
Artículo escrito por un elevado número de autores, solo se referencian el que aparece en primer lugar, el nombre del grupo de colaboración, si le hubiere, y los autores pertenecientes a la UAM
Near-intrinsic energy resolution for 30-662 keV gamma rays in a high pressure xenon electroluminescent TPC
2013
We present the design, data and results from the NEXT prototype for Double Beta and Dark Matter (NEXT-DBDM) detector, a high-pressure gaseous natural xenon electroluminescent time projection chamber (TPC) that was built at the Lawrence Berkeley National Laboratory. It is a prototype of the planned NEXT-100 Xe-136 neutrino-less double beta decay (0 nu beta beta) experiment with the main objectives of demonstrating near-intrinsic energy resolution at energies up to 662 keV and of optimizing the NEXT-100 detector design and operating parameters. Energy resolutions of similar to 1% FWHM for 662 keV gamma rays were obtained at 10 and 15 atm and similar to 5% FWHM for 30 keV fluorescence xenon X-…
New antineutrino energy spectra predictions from the summation of beta decay branches of the fission products
2012
In this paper, we study the impact of the inclusion of the recently measured beta decay properties of the $^{102;104;105;106;107}$Tc, $^{105}$Mo, and $^{101}$Nb nuclei in an updated calculation of the antineutrino energy spectra of the four fissible isotopes $^{235, 238}$U, and $^{239,241}$Pu. These actinides are the main contributors to the fission processes in Pressurized Water Reactors. The beta feeding probabilities of the above-mentioned Tc, Mo and Nb isotopes have been found to play a major role in the $\gamma$ component of the decay heat of $^{239}$Pu, solving a large part of the $\gamma$ discrepancy in the 4 to 3000\,s range. They have been measured using the Total Absorption Techni…
Stimulated transitions in resonant atom Majorana mixing
2018
Massive neutrinos demand to ask whether they are Dirac or Majorana particles. Majorana neutrinos are an irrefutable proof of physics beyond the Standard Model. Neutrinoless double electron capture is not a process but a virtual $\Delta L = 2$ mixing between a parent $^AZ$ atom and a daughter $^A(Z-2)$ excited atom with two electron holes. As a mixing between two neutral atoms and the observable signal in terms of emitted two-hole X-rays, the strategy, experimental signature and background are different from neutrinoless double beta decay. The mixing is resonantly enhanced for almost degeneracy and, under these conditions, there is no irreducible background from the standard two-neutrino cha…
Generalized mu-tau reflection symmetry and leptonic CP violation
2016
14 pages.- 9 figures
Neutrino oscillations and flavor theories
2020
I discuss neutrino mixing ansatze, such as the generalized Tri-bimaximal and bi-large mixing patterns, and their utility in describing the oscillation data. Unitarity tests and probes of the absolute neutrino mass scale are briefly discussed. A short overview of neutrino mass generation is given. I discuss an orbifold approach to the flavor problem and the resulting implications, e.g. the golden quark-lepton mass relation, neutrinoless double beta decay and neutrino oscillation predictions.
Quenching of gA and its impact in double beta decay
2015
The theory of double beta decay is briefly reviewed. The most recent (2015) results for 0νβ −β − nuclear matrix elements in the interacting boson model (IBM-2) with light and heavy neutrino exchange are given for all nuclei of interest from 48Ca to 238U. The question of quenching of the axial vector coupling constant gA in nuclei is discussed. Possible additional scenarios, such as Majoron emission, and mechanisms, such as sterile neutrino exchanges, are also discussed. nonPeerReviewed
Recent results on heavy-ion induced reactions of interest for neutrinoless double beta decay at INFN-LNS
2019
Abstract The NUMEN project aims at accessing experimentally driven information on Nuclear Matrix Elements (NME) involved in the half-life of the neutrinoless double beta decay (0νββ). In this view measurements of Heavy Ion (HI) induced Double Charge Exchange (DCE) reaction cross sections are performed with high-accuracy. In particular, the (18O,18Ne) and (20Ne,20O) reactions are used as tools for β+β+ and β-β- decays, respectively. In the experiments, performed at INFN - Laboratory Nazionali del Sud (LNS) in Catania, the beams are accelerated by the Superconducting Cyclotron (CS) and the reaction ejectiles are detected the MAGNEX magnetic spectrometer. The measured cross sections are challe…
Recent results on Heavy-Ion induced reactions of interest for 0νββ decay
2019
An updated overview of recent results on Heavy-Ion induced reactions of interest for neutrinoless double beta decay is reported in the framework of the NUMEN project. The NUMEN idea is to study heavy-ion induced Double Charge Exchange (DCE) reactions with the aim to get information on the nuclear matrix elements for neutrinoless double beta (0νββ) decay. Moreover, to infer the neutrino average masses from the possible measurement of the half- life of 0νββ decay, the knowledge of the nuclear matrix elements is a crucial aspect. Uma visão geral atualizada dos resultados recentes sobre reações induzidas por íons pesados de interesse para o decaimento beta duplo sem neutrinos é relatada na es…