Isomers in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi>Pd</mml:mi><mml:mprescripts /><mml:none /><mml:mn>128</mml:mn></mml:mmultiscripts></mml:math>and<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi>Pd</mml:mi><mml:mprescripts /><mml:none /><mml:mn>126</mml:mn></mml:mmultiscripts></mml:math>: Evidence for a Robust Shell Closure at the Neutron Magic Number 82 in Exotic Palladium Isotopes

Watanabe, H.; Lorusso, G.; Nishimura, S.; Xu, Z. Y.; Sumikama, T.; Söderström, P.-A.; Doornenbal, P.; Browne, F.; Gey, G.; Jung, H. S.; Taprogge, J.; Vajta, Zsolt; Wu, J.; Yagi, A.; Baba, H.; Benzoni, G.; Chae, K. Y.; Crespi, F. C. L.; Fukuda, N.; Gernhäuser, R.; Inabe, N.; Isobe, T.; Jungclaus, A.; Kameda, D.; Kim, G. D.; Kim, Y.-K.; Kojouharov, I.; Kondev, F. G.; Kubo, T.; Kurz, N.; Kwon, Y. K.; Lane, G. J.; Li, Z.; Moon, Chang-Bum; Montaner-Pizá, A.; Moschner, K.; Naqvi, F.; Nııkura, M.; Nıshıbata, H.; Nishimura, D.; Odahara, A.; Orlandi, R.; Patel, Z.; Podolyák, Zs.; Sakuraï, H.; Schaffner, H.; Simpson, G. S.; Steiger, Katja; Suzuki, Hiroshi; Takeda, Hiroyuki; Wendt, A.; Yoshinaga, K.

doi:10.1103/physrevlett.111.152501

Cited by 69 publications

(22 citation statements)

References 26 publications

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“…The half-lives of these waiting-point nuclei determine the time scale of the r process and shape the prominent r-process abundance peak of isotopes with A ≈ 130. The precise theoretical prediction of these halflives is challenging because the structure evolution of N ≈ 82 nuclei is still unknown despite the recent experimental efforts [24][25][26][27][28][29][30]. The data we present in this Letter also serve as important constraints to probe and improve nuclear models in this region.…”

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confidence: 82%

β-Decay Half-Lives of 110 Neutron-Rich Nuclei across theN=82Shell Gap: Implications for the Mechanism and Universality of the AstrophysicalrProcess

Lorusso¹,

Nishimura²,

Xu³

et al. 2015

Phys. Rev. Lett.

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182

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The β-decay half-lives of 110 neutron-rich isotopes of the elements from 37 Rb to 50 Sn were measured at the Radioactive Isotope Beam Factory. The 40 new half-lives follow robust systematics and highlight the persistence of shell effects. The new data have direct implications for r-process calculations and reinforce the notion that the second (A ≈ 130) and the rare-earth-element (A ≈ 160) abundance peaks may result from the freeze-out of an ðn; γÞ ⇄ ðγ; nÞ equilibrium. In such an equilibrium, the new half-lives are important factors determining the abundance of rare-earth elements, and allow for a more reliable discussion of the PRL 114, 192501 (2015) P H Y S I C A L R E V I E W L E T T E R S week ending 15 MAY 2015 0031-9007=15=114(19)=192501 (7) 192501-1 © 2015 American Physical Society r process universality. It is anticipated that universality may not extend to the elements Sn, Sb, I, and Cs, making the detection of these elements in metal-poor stars of the utmost importance to determine the exact conditions of individual r-process events. Introduction.-The origin of the heavy elements from iron to uranium is one of the main open questions in science. The slow neutron-capture (s) process of nucleosynthesis [1,2], occurring primarily in helium-burning zones of stars, produces about half of the heavy element abundance in the universe. The remaining half requires a more violent process known as the rapid neutron-capture (r) process [3][4][5][6]. During the r process, in environments of extreme temperatures and neutron densities, a reaction network of neutron captures and β decays synthesizes very neutron-rich isotopes in a fraction of a second. These isotopes, upon exhaustion of the supply of free neutrons, decay into the stable or semistable isotopes observed in the solar system. However, none of the proposed stellar models, including explosion of supernovae [7][8][9][10][11][12] and merging neutron stars [13][14][15][16], can fully explain abundance observations. The mechanism of the r process is also uncertain. At temperatures of one billion degrees or more, photons can excite unstable nuclei which then emit neutrons, thus, counteracting neutron captures in an ðn; γÞ ⇄ ðγ; nÞ equilibrium that determines the r process. These conditions may be found in the neutrino-driven wind following the collapse of a supernova core and the accreting torus formed around the black hole remnant of merging neutron stars. Alternatively, recent r-process models have shown that the r process is also possible at lower temperatures or higher neutron densities where the contribution from ðγ; nÞ reactions is minor. These conditions are expected in supersonically expanding neutrino-driven outflow in low-mass supernovae progenitors (e.g., 8 − 12 M ⊙ ) or prompt ejecta from neutron star mergers [17]. The final abundance distribution may also be dominated by postprocessing effects such as fission of heavy nuclei (A ≳ 280) possibly produced in merging neutron stars [18].New clues about the r process have come from the discovery of de...

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confidence: 82%

β-Decay Half-Lives of 110 Neutron-Rich Nuclei across theN=82Shell Gap: Implications for the Mechanism and Universality of the AstrophysicalrProcess

Lorusso¹,

Nishimura²,

Xu³

et al. 2015

Phys. Rev. Lett.

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182

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“…This comparison revealed two deficiencies of the interaction which subsequently have been corrected: the pairing in the proton-proton (ππ) channel is too strong, and the multipole part in the neutron-neutron (νν) and πν channels is too weak. Using the modified set of interactions, the experimental-level schemes and transition rates of 126-130 Sn [25], 130 In [12], 127;128 Cd [26,27], 130 Cd [9], and 126;128 Pd [10] are all nicely reproduced.…”

Section: Prl 112 132501 (2014) P H Y S I C a L R E V I E W L E T T Ementioning

confidence: 99%

“…Below 132 Sn, however, experimental information is scarce: along the N ¼ 82 chain of isotones, masses are known only for 131 In and 130 Cd [6] while β-decay half-lives are measured down to 129 Ag [7]. Energies of excited states are available for 131 In, 130 Cd, and 128 Pd [8][9][10]. While there is consensus about the magic nature of 132 Sn, even further from stability, below 132 Sn, a weakening of magicity, and in particular a reduction of the N ¼ 82 gap, was predicted long ago [11].…”

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confidence: 99%

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1p3/2Proton-Hole State inSn132

Taprogge¹,

Jungclaus²,

Grawe³

et al. 2014

Phys. Rev. Lett.

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A low-lying state in 131 In 82 , the one-proton hole nucleus with respect to double magic 132 Sn, was observed by its γ decay to the I π ¼ 1=2 − β-emitting isomer. We identify the new state at an excitation energy of E x ¼ 1353 keV, which was populated both in the β decay of 131 Cd 83 and after β-delayed neutron emission from 132 Cd 84 , as the previously unknown πp 3=2 single-hole state with respect to the 132 Sn core. Exploiting this crucial new experimental information, shell-model calculations were performed to study the structure of experimentally inaccessible N ¼ 82 isotones below 132 Sn. The results evidence a surprising absence of proton subshell closures along the chain of N ¼ 82 isotones. The consequences of this finding for the evolution of the N ¼ 82 shell gap along the r-process path are discussed.

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“…+ excited states in the nuclides around Sn (Z = 50) as a function of neutron number [4]. Data are primarily from [5], [6] for 126,128 Pd, [7] for 136,138 Sn, [8] for 138 Te, and the present work for 140 Te. For discussion, the isobars, 134 Sn and 134 Te with A = 134 are pointed out with an asterisk (*).…”

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confidence: 99%

Nuclear structure and β -decay schemes for Te nuclides beyond N=82

Moon¹,

Moon²,

Söderström³

et al. 2017

Phys. Rev. C

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We study for the first time the internal structure of Te produced by the -decay branch, the -delayed one-neutron and two-neutron emission branches were also established. By identifying the first 2 + and 4 + excited states of 140 Te, we found that Te isotopes persist their vibrator character with E(4 + )/E(2 + ) = 2. We discuss the distinctive features manifest in this region, such as valence neutron symmetry and asymmetry, revealed in pairs of isotopes with the same neutron holes and particles with respect to N = 82.

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Isomers inPd128andPd126: Evidence for a Robust Shell Closure at the Neutron Magic Number 82 in Exotic Palladium Isotopes

Cited by 69 publications

References 26 publications

β-Decay Half-Lives of 110 Neutron-Rich Nuclei across theN=82Shell Gap: Implications for the Mechanism and Universality of the AstrophysicalrProcess

β-Decay Half-Lives of 110 Neutron-Rich Nuclei across theN=82Shell Gap: Implications for the Mechanism and Universality of the AstrophysicalrProcess

1p3/2Proton-Hole State inSn132

Nuclear structure and β -decay schemes for Te nuclides beyond N=82

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