Search results for " Beta Decay"
showing 10 items of 323 documents
Nuclear matrix elements and the neutrinoless double beta decay
2005
Systematics of the nuclear matrix elements related to the neutrinoless double beta ( 0 ν β β ) decay are discussed. The calculation of the related nuclear matrix elements in the framework of the proton-neutron quasiparticle random-phase approximation (pnQRPA) is analyzed. In particular, the extraction of a proper value of the proton-neutron particle-particle interaction parameter in this theory is addressed. The relevance of different multipoles in the multipole decomposition of the 0 ν β β matrix element is also discussed.
Description of the two-neutrino ββ decay of100Mo by pnMAVA
2009
The microscopic anharmonic vibrator approach (MAVA) is a scheme where the one- and two-phonon states of an even–even nucleus are treated consistently by using a realistic microscopic nuclear Hamiltonian. This model has recently been extended to describe odd–odd nuclei by adding proton–neutron phonons in a scheme called the proton–neutron MAVA (pnMAVA). In this paper, we apply pnMAVA to compute the nuclear matrix elements corresponding to the two-neutrino double beta (2νββ) decay of 100Mo to the ground state and the first excited 0+ state of 100Ru in a realistic single-particle space. We also compute the GT− and GT+ Gamow–Teller strength functions and compare them with the plain pnQRPA (prot…
Perturbative analysis of the 2νββ decays of 100Mo and 116Cd
2003
We have performed a theoretical analysis of the ground-state-to-ground-state transitions in 100Mo and 116Cd, based on the quasiparticle random-phase approximation and on a straightforward perturbative scheme. The results show that the single-state dominance found in the realistic calculations of the nuclear matrix elements, which is consistent with data, can be viewed as a result of the interference between few two-quasiparticle configurations.
Estimation of bounds for left-right mixing from nuclear double beta decay processes
1993
Abstract Nuclear matrix elements, extracted from a systematic calculation of neutrinoless double beta decay rates for 0 + g.s →o + g.s transitions in 76 Ge, 82 Se, 128 Te, 130 Te and 136 Xe, have been used to compute bounds on the left-right mixing angle ζ of the weak currents. The parameters of the nuclear model have been fixed by calculating the corresponding two-neutrino double beta decay half lives. The present analysis favours a mixing of the order of |tanξ| −3 which is to be compared with those obtained in muon decay (|tan ξ | ⩽ 0.035) and in supernova (|tan ξ | ⩽ 10 −5 ) analysis. It shows that nuclear structure calculations yield estimates on ξ which complement the existing data.
Neutrinoless double beta-decay in the su(4) symmetry scheme
1991
TheSU(4) symmetry scheme, used in a previous paper for the study of the 2v double β decay, is applied to the study of the 0v double β decay. Differences and similarities between the 2 processes are emphasized. The sensitivity to short-range correlations is discussed.
β-delayed neutron emission measurements around the third r-process abundance peak
2013
This contribution summarizes an experiment performed at GSI (Germany) in the neutron-rich region beyond N=126. The aim of this measurement is to provide the nuclear physics input of relevance for r-process model calculations, aiming at a better understanding of the third r-process abundance peak. Many exotic nuclei were measured around 211Hg and 215Tl. Final ion identification diagrams are given in this contribution. For most of them, we expect to derive halflives and and β-delayed neutron emission probabilities. The detectors used in this experiment were the Silicon IMplantation and Beta Absorber (SIMBA) detector, based on an array of highly segmented silicon detectors, and the BEta deLayE…
1p3/2Proton-Hole State inSn132and the Shell Structure AlongN=82
2014
5 pags. ; 3 figs. ; PACS numbers: 23.40.-s, 21.10.Pc, 27.60.+j, 21.60.Cs ; Taprogge, J., et al.
β-decay of [sup 23]Al and nova nucleosynthesis
2010
We have studied the β‐decay of 23Al with a novel detector setup at the focal plane of the MARS separator at the Texas A&M University to resolve existing controversies about the proton intensities of the IAS in 23Mg and to determine the absolute proton branching ratios by combining our results to the latest γ‐decay data. Experimental technique, results and the relevance for nova nucleosynthesis are discussed.
AccurateQValue for theSn112Double-βDecay and its Implication for the Search of the Neutrino Mass
2009
The $Q$ value of the $^{112}\mathrm{Sn}$ double-beta decay was determined by using a Penning trap mass spectrometer. The new atomic-mass difference between $^{112}\mathrm{Sn}$ and $^{112}\mathrm{Cd}$ of 1919.82(16) keV is 25 times more precise than the previous value of 1919(4) keV. This result removes the possibility of enhanced resonance capture of the neutrinoless double-EC decay to the excited ${0}^{+}$ state at 1871.00(19) keV in $^{112}\mathrm{Cd}$.
Resonant enhancement of neutrinoless double-electron capture in 152Gd.
2010
In the search for the nuclide with the largest probability for neutrinoless double-electron capture, we have determined the ${Q}_{ϵϵ}$ value between the ground states of $^{152}\mathrm{Gd}$ and $^{152}\mathrm{Sm}$ by Penning-trap mass-ratio measurements. The new ${Q}_{ϵϵ}$ value of 55.70(18) keV results in a half-life of ${10}^{26}\text{ }\text{ }\mathrm{yr}$ for a 1 eV neutrino mass. With this smallest half-life among known $0\ensuremath{\nu}ϵϵ$ transitions, $^{152}\mathrm{Gd}$ is a promising candidate for the search for neutrinoless double-electron capture.