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Author |
Guendelman, E.I.; Olmo, G.J.; Rubiera-Garcia, D.; Vasihoun, M. |
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Title |
Nonsingular electrovacuum solutions with dynamically generated cosmological constant |
Type |
Journal Article |
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Year |
2013 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
726 |
Issue |
4-5 |
Pages |
870-875 |
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Keywords |
Modified gravity; Palatini formalism; Nonlinear electrodynamics; Dynamical cosmological constant; Nonsingular solutions; Wormholes |
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Abstract |
We consider static spherically symmetric configurations in a Palatini extension of General Relativity including R-2 and Ricci-squared terms, which is known to replace the central singularity by a wormhole in the electrovacuum case. We modify the matter sector of the theory by adding to the usual Maxwell term a nonlinear electromagnetic extension which is known to implement a confinement mechanism in flat space. One feature of the resulting theory is that the nonlinear electric field leads to a dynamically generated cosmological constant. We show that with this matter source the solutions of the model are asymptotically de Sitter and possess a wormhole topology. We discuss in some detail the conditions that guarantee the absence of singularities and of traversable wormholes. |
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Address  |
[Guendelman, E. I.; Vasihoun, M.] Ben Gurion Univ Negev, Dept Phys, IL-84105 Beer Sheva, Israel, Email: guendel@bgumail.bgu.ac.il; |
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Publisher |
Elsevier Science Bv |
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Language |
English |
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ISSN |
0370-2693 |
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Conference |
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Notes |
WOS:000327907000045 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1680 |
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Author |
n_TOF Collaboration (Guerrero, C. et al); Domingo-Pardo, C.; Tain, J.L. |
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Title |
Study of Photon Strength Function of Actinides: the Case of (235)U, (238)Np and (241)Pu |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of the Korean Physical Society |
Abbreviated Journal |
J. Korean Phys. Soc. |
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Volume |
59 |
Issue |
2 |
Pages |
1510-1513 |
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Keywords |
Photon/Gamma strength functions; Pygmy; Scissor mode; n_TOF; Total absorption calorimeter; TAC; Neutron capture |
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Abstract |
The decay from excited levels in medium and heavy nuclei can be described in a statistical approach by means of Photon Strength Functions and Level Density distributions. The study of electromagnetic cascades following neutron capture based on the use of high efficiency detectors has been shown to be well suited for probing the properties of the Photon Strength Function of heavy (high level density) and/or radioactive (high background) nuclei. In this work we have investigated for the first time the validity of the recommended PSF of actinides, in particular (235)U, (238)Np and (241)Pu. Our study includes the search for resonance structures in the PSF below S(n) and draws conclusions regarding their existence and their characteristics in terms of energy, width and electromagnetic nature. |
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Address |
[Guerrero, C; Alvarez-Velarde, F; Ano-Ott, DC; Martinez, T; Mendoza, E; Villamarin, D] Ctr Invest Energet Medioambientales & Technol CIE, Madrid, Spain, Email: carlos.guerrero@ciemat.es |
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Corporate Author |
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Publisher |
Korean 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 |
0374-4884 |
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Conference |
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Notes |
WOS:000294080700013 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
731 |
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Author |
n_TOF Collaboration (Guerrero, C. et al); Giubrone, G.; Tain, J.L. |
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Title |
Characterization of the New n_TOF Neutron Beam: Fluence, Profile and Resolution |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of the Korean Physical Society |
Abbreviated Journal |
J. Korean Phys. Soc. |
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Volume |
59 |
Issue |
2 |
Pages |
1624-1627 |
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Keywords |
n_TOF; Time-of-flight; Neutron beam; Nuclear data; Cross sections |
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Abstract |
After a halt of four years, the nTOF spallation neutron facility at CERN has resumed operation in November 2008 with a new spallation target characterized by an improved safety and engineering design, resulting in a more robust overall performance and efficient cooling. The first measurement during the 2009 run has aimed at the full characterization of the neutron beam. Several detectors, such as calibrated fission chambers, the nTOF Silicon Monitor, a MicroMegas detector with (10)B and (235)U samples, as well as liquid and solid scintillators have been used in order to characterize the properties of the neutron fluence. The spatial profile of the beam has been studied with a specially designed “X-Y” MicroMegas which provided a 2D image of the beam as a function of neutron energy. Both properties have been compared with simulations performed. with the FLUKA code. The characterization of the resolution function is based on results from simulations which have been verified by the study of narrow capture resonances. of (56)Fe, which were measured as part of a new campaign of (n,gamma) measurements on Fe and Ni isotopes. |
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Address |
[Guerrero, C; Becares, V; Cano-Ott, D; Fernandez-Ordonez, M; Gonzalez-Romero, E; Martin-Fuertes, F; Martinez, T; Mendoza, E; Pina, G; Quinones, J; Vlachoudis, V] Ctr Invest Energet Medioambientales & Tecnol, Madrid 28040, Spain, Email: carlos.guerrero@ciemat.es |
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Corporate Author |
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Thesis |
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Publisher |
Korean 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 |
0374-4884 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000294080700041 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
735 |
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Author |
Guerrero, M.; Mora-Perez, G.; Olmo, G.J.; Orazi, E.; Rubiera-Garcia, D. |
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Title |
Charged BTZ-type solutions in Eddington-inspired Born-Infeld gravity |
Type |
Journal Article |
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Year |
2021 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
11 |
Issue |
11 |
Pages |
025 - 23pp |
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Keywords |
modified gravity; Exact solutions; black holes and black hole thermodynamics in GR and beyond; Wormholes |
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Abstract |
We construct an axially symmetric solution of Eddington-inspired Born-Infeld gravity coupled to an electromagnetic field in 2 + 1 dimensions including a (negative) cosmological constant term. This is achieved by using a recently developed mapping procedure that allows to generate solutions in certain families of metric-affine gravity theories starting from a known seed solution of General Relativity, which in the present case corresponds to the electrically charged Banados-Teitelboim-Zanelli (BTZ) solution. We discuss the main features of the new configurations, including the modifications to the ergospheres and horizons, the emergence of wormhole structures, and the consequences for the regularity (or not) of these space-times via geodesic completeness. |
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Address |
[Guerrero, Merce; Rubiera-Garcia, Diego] Univ Complutense Madrid, Dept Fis Teor, Plaza Ciencias S-N, E-28040 Madrid, Spain, Email: merguerr@ucm.es; |
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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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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 |
1475-7516 |
ISBN |
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Conference |
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Notes |
WOS:000727716400006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5050 |
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Author |
ATLAS Collaboration (Adragna, P. et al); Castelo, J.; Castillo Gimenez, V.; Cuenca, C.; Ferrer, A.; Fullana, E.; Gonzalez, V.; Higon-Rodriguez, E.; Poveda, J.; Ruiz, A.; Salvachua, B.; Sanchis, E.; Solans, C.; Torres, J.; Valero, A.; Valls Ferrer, J.A. |
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Title |
Measurement of pion and proton response and longitudinal shower profiles up to 20 nuclear interaction lengths with the ATLAS Tile calorimeter |
Type |
Journal Article |
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Year |
2010 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
615 |
Issue |
2 |
Pages |
158-181 |
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Keywords |
Calorimeter; Test-beam; ATLAS; Monte Carlo simulation; GEANT4; Hadronic shower development; Pion-proton response; Longitudinal shower profile for hadrons |
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Abstract |
The response of pions and protons in the energy range of 20-180 GeV, produced at CERN's SPS H8 test-beam line in the ATLAS iron-scintillator Tile hadron calorimeter, has been measured. The test-beam configuration allowed the measurement of the longitudinal shower development for pions and protons up to 20 nuclear interaction lengths. It was found that pions penetrate deeper in the calorimeter than protons. However, protons induce showers that are wider laterally to the direction of the impinging particle. Including the measured total energy response, the pion-to-proton energy ratio and the resolution, all observations are consistent with a higher electromagnetic energy fraction in pion-induced showers. The data are compared with GEANT4 simulations using several hadronic physics lists. The measured longitudinal shower profiles are described by an analytical shower parametrization within an accuracy of 5-10%. The amount of energy leaking out behind the calorimeter is determined and parametrized as a function of the beam energy and the calorimeter depth. This allows for a leakage correction of test-beam results in the standard projective geometry. |
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Address |
[Hakobyan, H.; Simonyan, M.] Yerevan Phys Inst, Yerevan 375036, Armenia, Email: Margar.Simonyan@cern.ch |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
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 |
0168-9002 |
ISBN |
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Conference |
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Notes |
ISI:000276299900002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
252 |
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