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Author |
Cederwall, B. et al; Algora, A.; Gadea, A. |
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Title |
Evidence for a spin-aligned neutron-proton paired phase from the level structure of Pd-92 |
Type |
Journal Article |
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Year  |
2011 |
Publication |
Nature |
Abbreviated Journal |
Nature |
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Volume |
469 |
Issue |
7328 |
Pages |
68-71 |
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Keywords |
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Abstract |
Shell structure and magic numbers in atomic nuclei were generally explained by pioneering work(1) that introduced a strong spin-orbit interaction to the nuclear shell model potential. However, knowledge of nuclear forces and the mechanisms governing the structure of nuclei, in particular far from stability, is still incomplete. In nuclei with equal neutron and proton numbers (N = Z), enhanced correlations arise between neutrons and protons (two distinct types of fermions) that occupy orbitals with the same quantum numbers. Such correlations have been predicted to favour an unusual type of nuclear superfluidity, termed isoscalar neutron-proton pairing(2-6), in addition to normal isovector pairing. Despite many experimental efforts, these predictions have not been confirmed. Here we report the experimental observation of excited states in the N = Z = 46 nucleus Pd-92. Gamma rays emitted following the Ni-58(Ar-36,2n)Pd-92 fusion-evaporation reaction were identified using a combination of state-of-the-art high-resolution c-ray, charged-particle and neutron detector systems. Our results reveal evidence for a spin-aligned, isoscalar neutron-proton coupling scheme, different from the previous prediction(2-6). We suggest that this coupling scheme replaces normal superfluidity (characterized by seniority coupling(7,8)) in the ground and low-lying excited states of the heaviest N = Z nuclei. Such strong, isoscalar neutron-proton correlations would have a considerable impact on the nuclear level structure and possibly influence the dynamics of rapid proton capture in stellar nucleosynthesis. |
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Address |
[Cederwall, B.; Moradi, F. Ghazi; Back, T.; Johnson, A.; Blomqvist, J.; Andgren, K.; Lagergren, K.; Liotta, R.; Qi, C.; Hadinia, B.; Khaplanov, A.; Persson, A.; Sandzelius, M.] Royal Inst Technol, Dept Phys, SE-10691 Stockholm, Sweden, Email: cederwall@nuclear.kth.se |
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Nature Publishing Group |
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English |
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ISSN |
0028-0836 |
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Notes |
ISI:000285921600032 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
588 |
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Author |
Dijon, A. et al; Gadea, A. |
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Title |
Lifetime measurements in Co-63 and Co-65 |
Type |
Journal Article |
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Year |
2011 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
83 |
Issue |
6 |
Pages |
064321 - 7pp |
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Keywords |
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Abstract |
Lifetimes of the 9/2(1)(-) and 3/2(1)(-) states in Co-63 and the 9/2(1)(-) state in Co-65 were measured using the recoil distance Doppler shift and the differential decay curve methods. The nuclei were populated by multinucleon transfer reactions in inverse kinematics. gamma rays were measured with the EXOGAM Ge array and the recoiling fragments were fully identified using the large-acceptance VAMOS spectrometer. The E2 transition probabilities from the 3/2(1)(-) and 9/2(1)(-) states to the 7/2(-) ground state could be extracted in Co-63 as well as an upper limit for the 9/2(1)(-) -> 7/2(1)(-) B(E2) value in Co-65. The experimental results were compared to large-scale shell-model calculations in the pf and pfg(9/2) model spaces, allowing us to draw conclusions on the single-particle or collective nature of the various states. |
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Address |
[Dijon, A.; Clement, E.; de France, G.; Van Isacker, P.; Ljungvall, J.; Rejmund, M.; Schmitt, C.] CEA DSM CNRS IN2P3, Grand Accelerateur Natl Ions Lourds GANIL, F-14076 Caen, France, Email: dijon@ganil.fr |
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Publisher |
Amer Physical Soc |
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English |
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ISSN |
0556-2813 |
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Notes |
ISI:000291889200002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
664 |
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Author |
Szilner, S. et al; Gadea, A. |
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Title |
Interplay between single-particle and collective excitations in argon isotopes populated by transfer reactions |
Type |
Journal Article |
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Year |
2011 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
84 |
Issue |
1 |
Pages |
014325 - 7pp |
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Abstract |
New gamma transitions have been identified in argon isotopes in (40)Ar + (208)Pb multiple transfer reactions by exploiting, in a fragment-gamma measurement, the new generation of magnetic spectrometers based on trajectory reconstruction coupled to large gamma arrays. The coupling of single-particle degrees of freedom to nuclear vibration quanta was discussed. The interpretation of the newly observed states within a particle-phonon coupling picture was used to consistently follow, via their excitation energies, the evolution of collectivity in odd Ar isotopes. The proposed level schemes are supported by the results of sd-pf shell-model calculations, which have been also employed to evaluate the strength functions of the populated states. |
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Address |
[Szilner, S; Jelavic-Malenica, D; Soic, N] Rudjer Boskovic Inst, HR-10002 Zagreb, Croatia |
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Amer Physical Soc |
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English |
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Series Volume |
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Series Issue |
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ISSN |
0556-2813 |
ISBN |
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Conference |
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Notes |
WOS:000293129600004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
711 |
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Author |
Morales, A.I. et al; Agramunt, J.; Algora, A.; Gadea, A.; Molina, F.; Rubio, B. |
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Title |
Synthesis of N=127 isotones through (p,n) charge-exchange reactions induced by relativistic (208)Pb projectiles |
Type |
Journal Article |
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Year |
2011 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
84 |
Issue |
1 |
Pages |
011601 - 5pp |
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Keywords |
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Abstract |
The production cross sections of four N = 127 isotones ((207)Hg, (206)Au, (205)Pt, and (204)Ir) have been measured using (p,n) charge-exchange reactions, induced in collisions of a (208)Pb primary beam at 1 A GeV with a Be target. These data allow one to investigate the use of a reaction mechanism to extend the limits of the chart of nuclides toward the important r-process nuclei in the region of the third peak of elemental abundance distribution. |
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Address |
[Morales, AI; Benlliure, J; Alvarez-Pol, H; Casarejos, E; Dragosavac, D; Perez-Loureiro, D; Verma, S] Univ Santiago de Compostela, Santiago De Compostela 15782, Spain, Email: anaisabel.morales@usc.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 |
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:000292925800001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
697 |
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Author |
Corradi, L.; Szilner, S.; Pollarolo, G.; Colo, G.; Mason, P.; Farnea, E.; Fioretto, E.; Gadea, A.; Haas, F.; Jelavic-Malenica, D.; Marginean, N.; Michelagnoli, C.; Montagnoli, G.; Montanari, D.; Scarlassara, F.; Soic, N.; Stefanini, A.M.; Ur, C.A.; Valiente-Dobon, J.J. |
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Title |
Single and pair neutron transfers at sub-barrier energies |
Type |
Journal Article |
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Year |
2011 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
84 |
Issue |
3 |
Pages |
034603 - 10pp |
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Keywords |
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Abstract |
Multinucleon transfer cross sections in the (96)Zr+(40)Ca system have been measured, in inverse kinematics, at bombarding energies ranging from the Coulomb barrier to similar to 25% below. Targetlike recoils have been identified in A, Z and velocity with the large solid angle magnetic spectrometer PRISMA. The experimental data for one- and two-neutron transfer channels have been compared with semiclassical microscopic calculations. For the two-neutron transfer channels the relevance of the transitions to the ground state and to the 0(+) excited states of (42)Ca are discussed by employing, for the reaction mechanism, the successive approximation. It is found that the transition to the 0(+) state at similar to 6 MeV, whose wave function is dominated by the two neutrons in the 2p(3/2) shell, is much larger than the ground state one. The comparison with the inclusive data reveals that transitions to states with high multipolarity and non-natural parity are important. This suggests that more complex two-particle correlations have to be incorporated in the treatment of the transfer process. |
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Address |
[Corradi, L; Szilner, S; Fioretto, E; Michelagnoli, C; Stefanini, AM; Valiente-Dobon, JJ] Ist Nazl Fis Nucl, Lab Nazl Legnaro, I-35020 Legnaro, Italy |
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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 |
0556-2813 |
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:000294566900007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
751 |
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| Permanent link to this record |
