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Author  |
Afonso, V.I.; Olmo, G.J.; Rubiera-Garcia, D. |
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Title |
Scalar geons in Born-Infeld gravity |
Type |
Journal Article |
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Year |
2017 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
08 |
Issue |
8 |
Pages |
031 - 35pp |
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Keywords |
modified gravity; Wormholes |
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Abstract |
The existence of static, spherically symmetric, self-gravitating scalar field solutions in the context of Born-Infeld gravity is explored. Upon a combination of analytical approximations and numerical methods, the equations for a free scalar field (without a potential term) are solved, verifying that the solutions recover the predictions of General Relativity far from the center but finding important new effects in the central regions. We find two classes of objects depending on the ratio between the Schwarzschild radius and a length scale associated to the Born-Infeld theory: massive solutions have a wormhole structure, with their throat at r = 2 M, while for the lighter configurations the topology is Euclidean. The total energy density of these solutions exhibits a solitonic profile with a maximum peaked away from the center, and located at the throat whenever a wormhole exists. The geodesic structure and curvature invariants are analyzed for the various configurations considered. |
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Address |
[Afonso, V. I.] Univ Fed Campina Grande, Unidade Acad Fis, BR-58109970 Campina Grande, PB, Brazil, Email: viafonso@df.ufcg.edu.br; |
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Publisher |
Iop Publishing Ltd |
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English |
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ISSN |
1475-7516 |
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Conference |
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Notes |
WOS:000408311900031 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3285 |
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Author |
AGATA Collaboration (Clement, E. et al); Domingo-Pardo, C.; Gadea, A.; Perez-Vidal, R.M.; Civera, J.V. |
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Title |
Conceptual design of the AGATA 1 pi array at GANIL |
Type |
Journal Article |
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Year |
2017 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
855 |
Issue |
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Pages |
1-12 |
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Keywords |
AGATA spectrometer; GANIL facility; gamma-ray tracking; Pulse shape analysis; VAMOS plus plus spectrometer; NEDA detector; DIAMANT detector; PARIS LaBr3 detector; FATIMA LaBr3 detector; Plunger device |
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Abstract |
The Advanced GAmma Tracking Array (AGATA) has been installed at the GANIL facility, Caen-France. This setup exploits the stable and radioactive heavy-ions beams delivered by the cyclotron accelerator complex of GANIL. Additionally, it benefits from a large palette of ancillary detectors and spectrometers to address in-beam gamma-ray spectroscopy of exotic nuclei. The set-up has been designed to couple AGATA with a magnetic spectrometer, charged-particle and neutron detectors, scintillators for the detection of high-energy gamma rays and other devices such as a plunger to measure nuclear lifetimes. In this paper, the design and the mechanical characteristics of the set-up are described. Based on simulations, expected performances of the AGATA l pi array are presented. |
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Address |
[Clement, E.; Michelagnoli, C.; de France, G.; Li, H. J.; Lemasson, A.; Dejeon, C. Barthe; Beuzard, M.; Bougault, P.; Cacitti, J.; Foucher, J. -L.; Fremont, G.; Gangnant, P.; Goupil, J.; Houarner, C.; Jean, M.; Lefevre, A.; Legeard, L.; Legruel, F.; Maugeais, C.; Menager, L.; Menard, N.; Munoz, H.; Ozille, M.; Raine, B.; Ropert, J. A.; Saillant, F.; Spitaels, C.; Tripon, M.; Vallerand, Ph.; Voltolini, G.; Lopez-Martens, A.] CEA, DRF, CNRS, IN2P3,GANIL, F-14076 Caen 05, France |
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Publisher |
Elsevier Science Bv |
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English |
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Series Volume |
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Edition |
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ISSN |
0168-9002 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000399846900001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3091 |
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Author |
AGATA Collaboration (John, P.R. et al); Gadea, A. |
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Title |
In-beam gamma-ray spectroscopy of the neutron-rich platinum isotope Pt-200 toward the N=126 shell gap |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
95 |
Issue |
6 |
Pages |
064321 - 8pp |
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Keywords |
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Abstract |
The neutron-rich nucleus Pt-200 is investigated via in-beam gamma-ray spectroscopy to study the shape evolution in the neutron-rich platinum isotopes towards the N = 126 shell closure. The two-neutron transfer reaction Pt-198(Se-82, Se-80)Pt-200 is used to populate excited states of Pt-200. The Advanced Gamma Ray Tracking Array (AGATA) demonstrator coupled with the PRISMA spectrometer detects gamma rays coincident with the Se-80 recoils, the binary partner of Pt-200. The binary partner method is applied to extract the gamma-ray transitions and build the level scheme of Pt-200. The level at 1884 keV reported by Yates et al. [S. W. Yates, E. M. Baum, E. A. Henry, L. G. Mann, N. Roy, A. Aprahamian, R. A. Meyer, and R. Estep, Phys. Rev. C 37, 1889 (1988)] was confirmed to be at 1882.1 keV and assigned as the (6(1)(+)) state. An additional gamma ray was found and it presumably deexcites the (8(1)(+)) state. The results are compared with state-of-the-art beyond mean-field calculations, performed for the even-even Pt190-204 isotopes, revealing that Pt-200 marks the transition from the gamma-unstable behavior of lighter Pt nuclei towards a more spherical one when approaching the N = 126 shell closure. |
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Address |
[John, P. R.; Mengoni, D.; Lunardi, S.; Gottardo, A.; Lenzi, S.; Menegazzo, R.; Michelagnoli, C.; Montagnoli, G.; Montanari, D.; Recchia, F.; Scarlassara, F.] Univ Padua, Dipartimento Fis & Astron, I-35131 Padua, Italy, Email: philipp.john@ikp.tu-darmstadt.de |
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Corporate Author |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Language |
English |
Summary Language |
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Series Volume |
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Edition |
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ISSN |
2469-9985 |
ISBN |
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Conference |
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Notes |
WOS:000404021900005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3178 |
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Author |
AGATA Collaboration (Klintefjord, M. et al); Gadea, A.; Perez-Vidal, R.M. |
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Title |
Measurement of lifetimes in Fe-62,Fe-64, Co-61,Co-63, and Mn-59 |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
95 |
Issue |
2 |
Pages |
024312 - 11pp |
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Keywords |
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Abstract |
Lifetimes of the 4(1)(+) states in Fe-62,Fe-64 and the 11/2(1)(-) states in Co-61,Co-63 and Mn-59 were measured at the Grand Accelerateur National d'Ions Lourds (GANIL) facility by using the Advanced Gamma Tracking Array (AGATA) and the large-acceptance variable mode spectrometer (VAMOS++). The states were populated through multinucleon transfer reactions with a U-238 beam impinging on a Ni-64 target, and lifetimes in the picosecond range were measured by using the recoil distance Doppler shift method. The data show an increase of collectivity in the iron isotopes approaching N = 40. The reduction of the subshell gap between the nu 2p(1/2) and nu 1g(9/2) orbitals leads to an increased population of the quasi-SU(3) pair (nu 1g(9/2), nu 2d(5/2)), which causes an increase in quadrupole collectivity. This is not observed for the cobalt isotopes withN < 40 for which the neutron subshell gap is larger due to the repulsive monopole component of the tensor nucleon-nucleon interaction. The extracted experimental B(E2) values are compared with large-scale shell-model calculations and with beyond-mean-field calculations with the Gogny D1S interaction. A good agreement between calculations and experimental values is found, and the results demonstrate in particular the spectroscopic quality of the Lenzi, Nowacki, Poves, and Sieja (LNPS) shell-model interaction. |
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Address |
[Klintefjord, M.; Gorgen, A.; Garrote, F. L. Bello; Hadynska-Klek, K.; Sahin, E.] Univ Oslo, Dept Phys, N-0316 Oslo, Norway, Email: malin.klintefjord@fys.uio.no |
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Corporate Author |
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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 |
2469-9985 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000393743300002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2958 |
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Author |
AGATA Collaboration (Ralet, D. et al); Gadea, A.; Perez-Vidal, R.M. |
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Title |
Toward lifetime and g factor measurements of short-lived states in the vicinity of Pb-208 |
Type |
Journal Article |
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Year |
2017 |
Publication |
Physica Scripta |
Abbreviated Journal |
Phys. Scr. |
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Volume |
92 |
Issue |
5 |
Pages |
054004 - 4pp |
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Keywords |
multi-nucleon transfer reaction; lifetime measurement; AGATA; VAMOS plus |
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Abstract |
The multi-nucleon transfer reaction mechanism was used to produce and study nuclei in the vicinity of 208Pb. This mass region is a test case for the nuclear shell model. The mass identification of the fragments was performed with the large acceptance magnetic spectrometer VAMOS++ coupled to the AGATA gamma-tracking array. This experiment aimed to determine both lifetimes and gyromagnetic ratios of excited states with the Cologne plunger device. The analysis indicates promising results with the possibility to determine several new lifetimes in this region. |
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Address |
[Ralet, D.; Georgiev, G.; Konstantinopoulos, T.; Korichi, A.; Ljungvall, J.] Univ Paris Saclay, Univ Paris Sud, CNRS IN2P3, CSNSM, F-91405 Orsay, France, Email: damian.ralet@csnsm.in2p3.fr |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
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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Abbreviated Series Title |
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Series Issue |
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Edition |
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ISSN |
0031-8949 |
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Conference |
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Notes |
WOS:000399888300001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3092 |
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