nuclear matrix elements


Since then, more than 1000 papers have been published on the subject by numerous workers around the world. This is the first book devoted to reviewing the major developments in this growing field. Graduate students and researchers in these fields will find this book a reliable advanced text and source of reference. In the case of the 0νβ+β+ decay, the 1+ multipole plays a dominant role both for the bare Woods-Saxon basis and for the adjusted basis. The operators in terms of which one can describe the entire theory are of five types. NUMEN proposes an innovative technique to access the nuclear matrix elements entering the expression of the lifetime of the double beta decay by cross section measurements of heavy-ion induced Double Charge Exchange (DCE . The matrix elements are computed in the adjusted Woods-Saxon basis (“Adj.”) with the parameter value gpp(T=0)=0.7. Provided the matrix elements can be accurately calculated, analysis of mea-sured lifetimes in several isotopes or to several states in the same istotope can tell you whether long or short range is responsible. After the discovery of neutrino oscillations [2–4], this process has become even the more of vital interest because its discovery could potentially provide us with information on the yet-unknown absolute mass scale of neutrinos. Nuclear matrix elements for 0νβ+β+ decay of 106Cd corresponding to gA(0)=gAeff=1.0 in the single-particle bases used in [14], corresponding to the “Adj.” basis of the present study. Salvat F, Fernández-Varea J, Williamson W Jr. Note that the unit and scale of the matrix element comes from our definition of the average OMC matrix element (20). University of Jyväskylä, Jyväskylä, Finland (2020). In [13], we extended these studies to 0νβ−β− decays of medium-heavy and heavy nuclei by computing the average matrix elements corresponding to the OMC transitions to the intermediate nuclei of 0νβ−β− decays up to some 50 MeV using the pnQRPA formalism. In this work we choose the slightly quenched values of gA(0)=gAeff=1.0 and gP(0) = 7.0 and keep the CVC value gV(0) = 1.0 for all the studied cases. Observables in muon capture on 23Na and the effective weak couplings ga and gp. HEAVY MAJORANA NEUTRINOS IN e − e . arXiv:1810.13042 [physics.comp-ph]. Bohr A, Mottelson BR. Holinde K. Two-nucleon forces and nuclear matter. Muon capture reaction on 100Mo to study the nuclear response for double-β decay and neutrinos of astrophysics origin. The factor G2ν is a leptonic phase-space factor (in units of inverse years) defined in [15, 16]. 9 In order to make the comparison between the two processes meaningful, we need to adjust the excitation energies in 106Ag (being the intermediate nucleus of 0νβ+β+ decay and the final nucleus of OMC) in a consistent manner. This is the first time when such calculations are being done on the positron-decay side of the nuclear chart. The scale values of the y axes have been omitted, since they are not relevant for the current analysis. |, 5. Phys Rev C. (2009) 79:055501. doi: 10.1103/PhysRevC.79.055501, 21. Figures 7, 8 show similar behavior for both the multipoles Jπ = 1+ and 2+: decreasing the value of gpp(T=0) from 0.8 to 0.6 shifts the spectrum to lower energies for both the 0νβ+β+ decay and OMC. V ud | 2 + | V us | 2 + | V ub | 2)*+,-. 2. They are considered nucleosynthesis sites of the rapid neutron-capture process (r-process), which is responsible for creating approximately half of all heavy elements beyond Fe and is the only source of elements . Hence, in this section we study the effect of gpp on both the 0νβ+β+-decay and OMC matrix elements of 106Cd in detail. Phys Rev C. (2017) 96:034308. doi: 10.1103/PhysRevC.96.034308, 36. Best values and reasonable ranges for hadronic matrix elements of QCD theta term and dimension six CP-violating operators. Phys Rev C. (2020) 102:034301. doi: 10.1103/PhysRevC.102.034301, 40. Next we study the effect of the different bound-muon wave functions on the multipole decomposition of the average OMC matrix elements in the cases of the multipoles Jπ = 1+, 2+, which are among the leading ones for both the 0νβ+β+ decay and the OMC. Theoretical results on the double positron decay of 106Cd. Hashim IH, Ejiri H. New research project with muon beams for neutrino nuclear responses and nuclear isotopes production. Form factors in β decay and μ capture. Provided the matrix elements can be accurately calculated, analysis of mea-sured lifetimes in several isotopes or to several states in the same istotope can tell you whether long or short range is responsible. Equation (14) can then be solved by means of the package RADIAL [25] by using a piecewise-exact power-series expansion of the radial functions, which then are summed up to a prescribed accuracy. In this section we investigate the multipole decompositions of the 0νβ+β+-decay and OMC matrix elements. Front Phys. (2017) 5:55. doi: 10.3389/fphy.2017.00055, 31. Tables 7 and 13 provide a summary of "best" values and "reasonable ranges" for the hadronic and nuclear matrix element computations. We analyze the summed absolute values of the matrix elements in the same way as we did in Figures 7, 8. The isovector parameter gpp(T=1) is adjusted such that the Fermi part of the corresponding two-neutrino double beta (2νβ+β+) NME vanishes, leading to partial isospin-symmetry restoration. At present, there are three running experiments searching for the β+β+ decay of 106Cd, namely COBRA [5, 6], TGV-2 [7], and 106CdWO4 crystal scintillator [8]. nuclear matrix elements that enter. Nuclear finite size effects are included by using exact electron radial wave functions. The program is written for the IBM 7090 digital computer in the compiler language known as MAD (Michigan Algorithmic Decoder). (auth). Ejiri H, Suhonen J, Zuber K. Neutrino-nuclear responses for astro-neutrinos, single beta decays and double beta decays. The Gamow-Teller NME involved in Equation (1) can be written as. (A) Basis: “Adj.”. This basis, in turn, is denoted by “Adj.”. The decompositions correspond to the parameter value gpp(T=0)=0.7. In this article we denote also this mode by the generic symbol 0νβ+β+. These transcriptional effects are mainly at promoter and enhancer elements. Quantum Mechanics of One- and Two-Electron Atoms. The nuclear matrix elements associated with the light Majorana neutrino mass mechanism of the neutrinoless double beta decay of 48Ca, 76Ge, 82Se, 96Zr, 100Mo, 116Cd, 128Te, 130Te, 136Xe, and 150Nd . It is evident from the plots that the value of M(0ν) is sensitive to the value of gpp(T=0): increasing gpp(T=0) decreases the value of the matrix element. The editor and reviewers' affiliations are the latest provided on their Loop research profiles and may not reflect their situation at the time of review. It was found that there was a clear correlation between the energy-distributed OMC rates to 1+ states and the energy-based decomposition of the NMEs for the 2νβ−β− decays of the sd-shell nuclei 36Ar, 46Ca, and 48Ca. However, note that we use different notation for the coupling constants. Phys Rev C. (2018) 98:024608. doi: 10.1103/PhysRevC.98.024608, 41. In any case, the neutrinoless double beta decay would immediately provide striking new-physics vistas beyond the standard model, since it not only violates lepton-number conservation, but also requires the neutrino to be of Majorana character. Double-Beta Decay Experiment. The ratio of P,T-violating to P-violating matrix elements is found to remain approximately constant across the nuclear mass table, thus . Phys Rev C. (2013) 87:045501. doi: 10.1103/PhysRevC.87.045501, 38. We also take into account the overlap of these two sets in the definition of the matrix element. These matrix elements correspond the adjusted Woods-Saxon basis and gpp(T=0)=0.7. Zinatulina D, Brudanin V, Egorov V, Petitjean C, Shirchenko M, Suhonen J, et al. In principle, the expression in Equation (2) could also contain a Fermi NME. For the isovector part gpp(T=1), we adopt the value that was adjusted so that the Fermi part of the 2νβ+β+-decay NME vanishes, as explained in section 5. (A) Basis: “Adj.”. Nuclear matrix elements and the connection to fundamental physics There is a version of double-beta decay (2 νββ decay, in which the emitted electrons are accompanied by two antineutrinos) that is violates none of the rules of the standard model. As mentioned in section 5, the particle-particle strength parameter gpp strongly affects the ββ-decay rates. "A theoretical analysis of the best presently known set of experimental data on the 2.41 Mev first-forbidden ß-transition in As76 is performed. Outline pIntroduction pGenerator coordinate method pApplication to SO(8) model, 76Ge double-beta decay pFuture plans pSummary. We assume that the 0νββ decay is dominated by the light-Majorana-neutrino-exchange mechanism, and exploit the formalism presented in [17]. Phase-space factors [16], half-lives [8], and the resulting experimental NMEs of different decay modes of 106Cd. Ordinary muon capture (OMC) on nuclei is a weak-interaction nuclear process, in which a negative muon μ− is captured by a nucleus (A, Z) resulting in an atomic-number reduction by one and emission of a muon neutrino. Here we extend those studies, for the ground-state-to-ground-state transition, by making a comparative analysis of the 0νβ+β+-decay and OMC NMEs of 106Cd in the pnQRPA formalism with large no-core single-particle bases, in a manner pursued in [13]. Physical issues of neutrino 2. Comput Phys Commun. The OMC rate from a Ji initial state to a Jf final state can be written as, and the Q-value of the OMC process can be computed from, where W0 = Mf −Mi+me+EX [21]. Multipole decomposition of the total 0νβ+β+-decay matrix element in different single-particle bases. Jokiniemi L, Suhonen J. The effect of the particle-particle interaction parameter gpp of pnQRPA on the NMEs is discussed. The observed values of the NMEs M exp ± (SD 2) are compared with the values of the single-quasiparticle NMEs M qp ± (SD 2) without . The existence of neutron star mergers has been supported since the discovery of the binary pulsar and the observation of its orbital energy loss, consistent with General Relativity. As a starting point, the single-particle energies were generated by a spherical Coulomb-corrected Woods-Saxon (WS) potential with the parametrization of [33]. 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. (A) Basis: “Adj.”. Rev Mod Phys. We have previously shown that in Saccharomyces cerevisiae, autonomously replicating sequence elements bind the nuclear scaffold. We plot the summed absolute values of the 0νβ+β+-decay NMEs and the average OMC matrix elements for Jπ = 0+, 1+, 2+, 3+, 4+, 1−, 2−, 3−, and 4− in Figure 11. In the 0νβ−β− mode the final nucleus is (A, Z + 2), and two electrons are emitted.
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