Search results for "Gamow-Teller"
showing 9 items of 9 documents
Investigation of the Δn = 0 selection rule in Gamow-Teller transitions : The β-decay of 207Hg
2019
Gamow-Teller β decay is forbidden if the number of nodes in the radial wave functions of the initial and final states is different. This Δn = 0 requirement plays a major role in the β decay of heavy neutron-rich nuclei, affecting the nucleosynthesis through the increased half-lives of nuclei on the astrophysical r-process pathway below both Z = 50 (for N > 82) and Z = 82 (for N >126). The level of forbiddenness of the Δn = 1ν1g9/2 → π0g7/2 transition has been investigated from the β− decay of the ground state of 207Hg into the single-proton-hole nucleus 207Tl in an experiment at the ISOLDE Decay Station. From statistical observational limits on possible γ-ray transitions depopulating the π0…
Investigation of the Δn = 0 selection rule in Gamow-Teller transitions: The β-decay of 207Hg
2019
5 pags., 3 figs., 1 tab. -- Open Access funded by Creative Commons Atribution Licence 4.0
β Decay of 127Cd and Excited States in 127In
2019
A dedicated spectroscopic study of the β decay of 127Cd was conducted at the IGISOL facility at the University of Jyväskylä. Following high-resolution mass separation in a Penning trap, β−γ−γcoincidences were used to considerably extend the decay scheme of 127In. The β-decaying 3/2+ and 11/2− states in 127Cd have been identified with the 127Cd ground state and the 283-keV isomer. Their respective half-lives have been measured to 0.45(128)s and 0.36(4) s. The experimentally observed βfeeding to excited states of 127In and the decay scheme of 127In are discussed in conjunction with large-scale shell-model calculations. peerReviewed
Value of the Axial-Vector Coupling Strength in β and ββ Decays : A Review
2017
In this review the quenching of the weak axial-vector coupling constant, $g_{\rm A}$, is discussed in nuclear $\beta$ and double-$\beta$ decays. On one hand, the nuclear-medium and nuclear many-body effects are separated, and on the other hand the quenching is discussed from the points of view of different many-body methods and different $\beta$-decay and double-$\beta$-decay processes. Both the historical background and the present status are reviewed and contrasted against each other. The theoretical considerations are tied to performed and planned measurements, and possible new measurements are urged, whenever relevant and doable. Relation of the quenching problem to the measurements of …
Double β Decay and the Axial Strength
2019
Quenching of the weak axial strength gA is discussed and relations of this quenching to the nuclear matrix elements of double beta decays are highlighted. An analysis of Gamow-Teller transitions in the mass range A = 62 − 142 is presented and its results are compared with those of many previous works. The enhancement of the axial charge is discussed for first-forbidden pseudoscalar β transitions. Higher-forbidden β transitions are introduced and their role in determining the effective value of gA is examined, in particular from the point of view of the β-decay half-lives and the shapes of electron spectra of forbidden non-unique β transitions. peerReviewed
Two-neutrino ββ decays and low-lying Gamow-Teller β− strength functions in the mass range A=70–176
2017
We apply the proton-neutron deformed quasiparticle random-phase approximation (pn-dQRPA) to describe the low-lying (E 6 MeV) 1+ Gamow-Teller (GT) strength functions in odd-odd deformed nuclei which participate as intermediate nuclei in two-neutrino double-β-decay (2νββ) transitions within the mass range A = 70–176. In deriving equations of motion we use a single-particle basis with projected angular momentum, provided by the diagonalization of a spherical mean field furnished with a quadrupole-quadrupole interaction. The schematic residual Hamiltonian contains pairing and proton-neutron interaction terms in particle-hole (ph) and particle-particle (pp) channels, with constant strengths. By …
Impact of shell evolution on Gamow-Teller β decay from a high-spin long-lived isomer in 127Ag
2021
6 pags., 4 figs., 2 tabs.
Value of the Axial-Vector Coupling Strength in β and ββ Decays : A Review
2017
Studying Gamow-Teller transitions and the assignment of isomeric and ground states at $N=50$
2022
Direct mass measurements of neutron-deficient nuclides around the N=50 shell closure below $^{100}$Sn were performed at the FRS Ion Catcher (FRS-IC) at GSI, Germany. The nuclei were produced by projectile fragmentation of $^{124}$Xe, separated in the fragment separator FRS and delivered to the FRS-IC. The masses of 14 ground states and two isomers were measured with relative mass uncertainties down to 1×10−7 using the multiple-reflection time-of-flight mass spectrometer of the FRS-IC, including the first direct mass measurements of $^{98}$Cd and $^{97}$Rh. A new QEC=5437±67 keV was obtained for $^{98}$Cd, resulting in a summed Gamow-Teller (GT) strength for the five observed transitions (0+…