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Author  |
Siciliano, M. et al; Gadea, A. |
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Title |
Shape coexistence in neutron-deficient Hg-188 investigated via lifetime measurements |
Type |
Journal Article |
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Year |
2020 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
102 |
Issue |
1 |
Pages |
014318 - 16pp |
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Keywords |
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Abstract |
Background: Shape coexistence in the Z approximate to 82 region has been established in mercury, lead, and polonium isotopes. For even-even mercury isotopes with 100 <= N <= 106 multiple fingerprints of this phenomenon are observed, which seems to be no longer present for N >= 110. According to a number of theoretical calculations, shape coexistence is predicted in the Hg-188 isotope. Purpose: The aim of this work was to measure lifetimes of excited states in Hg-188 to infer their collective properties, such as the deformation. Extending the investigation to higher-spin states, which are expected to be less affected by band-mixing effects, can provide additional information on the coexisting structures. Methods: The Hg-188 nucleus was populated using two different fusion-evaporation reactions with two targets, Gd-158 and Gd-160, and a beam of S-34 provided by the Tandem-ALPI accelerator complex at the Laboratori Nazionali di Legnaro. The channels of interest were selected using the information from the Neutron Wall array, while the gamma rays were detected using the GALILEO gamma-ray spectrometer. Lifetimes of excited states were determined using the recoil-distance Doppler-shift method, employing the dedicated GALILEO plunger device. Results: Lifetimes of the states up to spin 16 (h) over bar were measured and the corresponding reduced transition probabilities were calculated. Assuming two-band mixing and adopting, as done commonly, the rotational model, the mixing strengths and the deformation parameters of the unperturbed structures were obtained from the experimental results. In order to shed light on the nature of the observed configurations in the Hg-188 nucleus, the extracted transition strengths were compared with those resulting from state-of-the-art beyond-mean-field calculations using the symmetry-conserving configuration-mixing approach, limited to axial shapes, and the five-dimensional collective Hamiltonian, including the triaxial degree of freedom. Conclusions: The first lifetime measurement for states with spin >= 6 suggested the presence of an almost spherical structure above the 12(1)(+) isomer and allowed elucidating the structure of the intruder band. The comparison of the extracted B(E2) strengths with the two-band mixing model allowed the determination of the ground-state band deformation. Both beyond-mean-field calculations predict coexistence of a weakly deformed band with a strongly prolate-deformed one, characterized by elongation parameters similar to those obtained experimentally, but the calculated relative position of the bands and their mixing strongly differ. |
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Address |
[Siciliano, M.; Zanon, I; Cicerchia, M.; de Angelis, G.; Galtarossa, F.; Gozzelino, A.; Hadynska-Klek, K.; Jaworski, G.; Napoli, D. R.; Valiente-Dobon, J. J.] INFN, Lab Nazl Legnaro, I-35020 Legnaro, Italy, Email: marco.siciliano@lnl.infn.it |
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Amer Physical Soc |
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English |
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ISSN |
0556-2813 |
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Conference |
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Notes |
WOS:000551404600001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4471 |
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Author |
Sekihara, T.; Yamagata-Sekihara, J.; Jido, D.; Kanada-En'yo, Y. |
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Title |
Branching ratios of mesonic and nonmesonic antikaon absorptions in the nuclear medium |
Type |
Journal Article |
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Year |
2012 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
86 |
Issue |
6 |
Pages |
065205 - 17pp |
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Abstract |
The branching ratios of K- absorption in nuclear matter are theoretically investigated in order to understand the mechanism of K- absorption into nuclei. For this purpose mesonic and nonmesonic absorption potentials are evaluated as functions of nuclear density, the kaon momentum, and energy from one- and two-body K- self-energy, respectively. By using a chiral unitary approach for the s-wave (K) over bar N amplitude we find that both the mesonic and nonmesonic absorption potentials are dominated by the Lambda(1405) contributions. The fraction of the mesonic and nonmesonic absorptions are evaluated to be respectively about 70% and 30% at the saturation density almost independently of the kaon momentum. We also observe different behavior of the branching ratios to pi(+)Sigma(-) and pi(-)Sigma(+) channels in mesonic absorption due to the interference between Lambda(1405) and the I = 1 nonresonant background, which is consistent with experimental results. The nonmesonic absorption ratios [Lambda p]/[Sigma(0)p] and [Lambda n]/[Sigma(0)n] are about unity while [Sigma(+)n]/[Sigma(0)p] and [Sigma(-) p]/[Sigma(0)n] are about 2 due to the Lambda(1405) dominance in absorption. Taking into account the kaon momenta and energies, the absorption potentials become weaker due to the downward shift of the initial K- N two-body energy, but this does not drastirally change the nonmesonic fraction. The Sigma(1385) contribution in the p-wave (K) over bar N amplitude is examined and found to be very small compared to the Lambda(1405) contribution in slow K- absorption. |
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Address |
[Sekihara, Takayasu] Tokyo Inst Technol, Dept Phys, Tokyo 1528551, Japan |
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Publisher |
Amer Physical Soc |
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English |
Summary Language |
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Original Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0556-2813 |
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Conference |
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Notes |
WOS:000312293900002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1270 |
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Author |
Sarriguren, P.; Algora, A.; Pereira, J. |
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Title |
Gamow-Teller response in deformed even and odd neutron-rich Zr and Mo isotopes |
Type |
Journal Article |
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Year |
2014 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
89 |
Issue |
3 |
Pages |
034311 - 13pp |
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Keywords |
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Abstract |
beta-decay properties of neutron-rich Zr and Mo isotopes are investigated within a microscopic theoretical approach based on the proton-neutron quasiparticle random-phase approximation. The underlying mean field is described self-consistently from deformed Skyrme Hartree-Fock calculations with pairing correlations. Residual separable particle-hole and particle-particle forces are also included in the formalism. The structural evolution in these isotopic chains including both even and odd isotopes is analyzed in terms of the equilibrium deformed shapes. Gamow-Teller strength distributions, beta-decay half-lives, and beta-delayed neutron-emission probabilities are studied, stressing their relevance to describe the path of the nucleosynthesis rapid neutron capture process. |
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Address |
[Sarriguren, P.] CSIC, Inst Estruct Mat, IEM, E-28006 Madrid, Spain, Email: p.sarriguren@csic.es |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0556-2813 |
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Area |
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Conference |
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Notes |
WOS:000334123900005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1762 |
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Author |
Sarriguren, P.; Algora, A.; Kiss, G. |
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Title |
beta-decay properties of neutron-rich Ca, Ti, and Cr isotopes |
Type |
Journal Article |
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Year |
2018 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
98 |
Issue |
2 |
Pages |
024311 - 10pp |
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Keywords |
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Abstract |
beta-decay properties of neutron-rich Ca, Ti, and Cr isotopes are studied within a deformed proton-neutron quasiparticle random-phase approximation. The underlying mean field is described self-consistently from deformed Skyrme Hartree-Fock calculations with pairing correlations. Residual spin-isospin interactions in the particle-hole and particle-particle channels are also included in the formalism. The energy distributions of the Gamow-Teller strength, the beta-decay feedings, the beta-decay half-lives, and the beta-delayed neutron emission probabilities are discussed and compared with other theoretical results, as well as with the available experimental information. The evolution of these nuclear beta-decay properties is investigated in isotopic chains in a search for structural changes. A reliable estimate of the beta-decay properties in this mass region is valuable information for evaluating decay rates in astrophysical scenarios. |
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Address |
[Sarriguren, P.] IEM CSIC, Inst Estruct Mat, Serrano 123, E-28006 Madrid, Spain, Email: p.sarriguren@csic.es |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9985 |
ISBN |
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Conference |
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Notes |
WOS:000442078500001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3698 |
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Author |
Samart, D.; Liang, W.H.; Oset, E. |
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Title |
Triangle mechanisms in the build up and decay of the N*(1875) |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
96 |
Issue |
3 |
Pages |
035202 - 14pp |
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Keywords |
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Abstract |
We studied the N*(1875)(3/ 2-) resonance with a multichannel unitary scheme, considering the Delta pi and Sigma * K, with their interaction extracted from chiral Lagrangians, and then added two more channels, the N*(1535) p and N sigma, which proceed via triangle diagrams involving the Sigma * K and Delta pi respectively in the intermediate states. The triangle diagram in the N*(1535) p case develops a singularity at the same energy as the resonance mass. We determined the couplings of the resonance to the different channels and the partial decay widths. We found a very large decay width to Sigma * K, and also observed that, due to interference with other terms, the N sigma channel has an important role in the pi pi mass distributions at low invariant masses, leading to an apparently large N sigma decay width. We discuss justifying the convenience of an experimental reanalysis of this resonance, in light of the findings of the paper, using multichannel unitary schemes. |
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Address |
[Samart, Daris] Rajamangala Univ Technol Isan, Fac Sci & Liberal arts, Dept Appl Phys, Nakhon Ratchasima 30000, Thailand, Email: daris.sa@rmuti.ac.th; |
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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2469-9985 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000409256500008 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3283 |
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