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Author |
Krupczak, R.; da Silva, T.N.; Domingues, T.S.; Luzum, M.; Denicol, G.S.; Gardim, F.G.; Giannini, A.V.; Ferreira, M.N.; Hippert, M.; Noronha, J.; Chinellato, D.D.; Takahashi, J. |
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Title |
Causality violations in simulations of large and small heavy-ion collisions |
Type |
Journal Article |
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Year |
2024 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
109 |
Issue |
3 |
Pages |
034908 - 12pp |
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Keywords |
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Abstract  |
Heavy-ion collisions, such as Pb-Pb or p-Pb, produce extreme conditions in temperature and density that make the hadronic matter transition to a new state, called quark-gluon plasma (QGP). Simulations of heavy-ion collisions provide a way to improve our understanding of the QGP's properties. These simulations are composed of a hybrid description that results in final observables in agreement with accelerators like LHC and RHIC. However, recent works pointed out that these hydrodynamic simulations can display acausal behavior during the evolution in certain regions, indicating a deviation from a faithful representation of the underlying QCD dynamics. To pursue a better understanding of this problem and its consequences, this work simulated two different collision systems, Pb-Pb and p-Pb at root sNN = 5.02 TeV. In this context, our results show that causality violation, even though always present, typically occurs on a small part of the system, quantified by the total energy fraction residing in the acausal region. In addition, the acausal behavior can be reduced with changes in the prehydrodynamic factors and the definition of the bulk-viscous relaxation time. Since these aspects are fairly arbitrary in current simulation models, without solid guidance from the underlying theory, it is reasonable to use the disturbing presence of acausal behavior in current simulations to guide improvements towards more realistic modeling. While this work does not solve the acausality problem, it sheds more light on this issue and also proposes a way to solve this problem in simulations of heavy-ion collisions. |
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Address |
[Krupczak, Renata; da Silva, Tiago Nunes] Univ Fed Santa Catarina, Ctr Ciencias Fis & Matemat, Dept Fis, Campus Univ Reitor Joao David Ferreira Lima, BR-88040900 Florianopolis, Brazil, Email: rkrupczak@physik.uni-bielefeld.de; |
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Amer Physical Soc |
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English |
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ISSN |
2469-9985 |
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Notes |
WOS:001198699800003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
6113 |
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Author |
Cheng, Y.; Csernai, L.P.; Magas, V.K.; Schlei, B.R.; Strottman, D. |
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Title |
Matching stages of heavy-ion collision models |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
81 |
Issue |
6 |
Pages |
064910 - 8pp |
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Keywords |
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Abstract |
Heavy-ion reactions and other collective dynamical processes are frequently described by different theoretical approaches for the different stages of the process, like initial equilibration stage, intermediate locally equilibrated fluid dynamical stage, and final freeze-out stage. For the last stage, the best known is the Cooper-Frye description used to generate the phase space distribution of emitted, noninteracting particles from a fluid dynamical expansion or explosion, assuming a final ideal gas distribution, or (less frequently) an out-of-equilibrium distribution. In this work we do not want to replace the Cooper-Frye description, but rather clarify the ways of using it and how to choose the parameters of the distribution and, eventually, how to choose the form of the phase space distribution used in the Cooper-Frye formula. Moreover, the Cooper-Frye formula is used in connection with the freeze-out problem, while the discussion of transition between different stages of the collision is applicable to other transitions also. More recently, hadronization and molecular dynamics models have been matched to the end of a fluid dynamical stage to describe hadronization and freeze-out. The stages of the model description can be matched to each other on space-time hypersurfaces (just like through the frequently used freeze-out hypersurface). This work presents a generalized description of how to match the stages of the description of a reaction to each other, extending the methodology used at freeze-out, in simple covariant form which is easily applicable in its simplest version for most applications. |
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Address |
[Cheng, Yun; Csernai, L. P.] Univ Bergen, Inst Phys & Technol, N-5007 Bergen, Norway, Email: yun.cheng@uib.no |
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Amer Physical Soc |
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English |
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ISSN |
0556-2813 |
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Notes |
ISI:000279267600002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
417 |
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Author |
AGATA Collaboration (Soderstrom, P.A. et al); Gadea, A. |
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Title |
High-spin structure in K-40 |
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 |
5 |
Pages |
054320 - 9pp |
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Abstract |
High-spin states of K-40 have been populated in the fusion-evaporation reaction C-12(Si-30,np)K-40 and studied by means of gamma-ray spectroscopy techniques using one triple-cluster detector of the Advanced Gamma Tracking Array at the Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali di Legnaro. Several states with excitation energy up to 8 MeV and spin up to 10(-) have been discovered. These states are discussed in terms of J = 3 and T = 0 neutron-proton hole pairs. Shell-model calculations in a large model space have shown good agreement with the experimental data for most of the energy levels. The evolution of the structure of this nucleus is here studied as a function of excitation energy and angular momentum. |
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Address |
[Soderstrom, P. -A.; Nyberg, J.] Uppsala Univ, Dept Phys & Astron, SE-75120 Uppsala, Sweden |
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Amer Physical Soc |
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English |
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ISSN |
0556-2813 |
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Notes |
WOS:000311537600003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1241 |
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Author |
Blank, B. et al; Agramunt, J.; Algora, A.; Guadilla, V.; Montaner-Piza, A.; Morales, A.I.; Orrigo, S.E.A.; Rubio, B. |
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Title |
New neutron-deficient isotopes from Kr-78 fragmentation |
Type |
Journal Article |
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Year |
2016 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
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Volume |
93 |
Issue |
6 |
Pages |
061301 - 5pp |
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Abstract |
In an experiment with the RIKEN projectile fragment separator called BigRIPS at the RIKEN Nishina Center, the fragmentation of a Kr-78 beam allowed the observation of new neutron-deficient isotopes at the proton drip line. Clean identification spectra could be produced and Se-63, Kr-67, and Kr-68 were identified for the first time. In addition, Ge-59 was also observed. Three of these isotopes, Ge-59, Se-63, and Kr-67, are potential candidates for ground-state two-proton radioactivity. In addition, the isotopes Ge-58, Se-62, and Kr-66 were also sought but without success. The present experiment also allowed the determination of production cross sections for some of the most exotic isotopes. These measurements confirm the trend already observed that the empirical parametrization of fragmentation cross sections, EPAX, significantly overestimates experimental cross sections in this mass region. |
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Address |
[Blank, B.; Goigoux, T.; Ascher, P.; Gerbaux, M.; Giovinazzo, J.; Grevy, S.; Nieto, T. Kurtukian; Magron, C.] Univ Bordeaux, Ctr Etud Nucl Bordeaux Gradignan, UMR CNRS 5797, IN2P3, 19 Chemin Solarium,CS 10120, F-33175 Gradignan, France |
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Amer Physical Soc |
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English |
Summary Language |
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Series Editor |
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Abbreviated Series Title |
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ISSN |
2469-9985 |
ISBN |
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Conference |
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Notes |
WOS:000376997700001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ pastor @ |
Serial |
2701 |
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Author |
Guadilla, V. et al; Tain, J.L.; Algora, A.; Agramunt, J.; Jordan, D.; Monserrate, M.; Montaner-Piza, A.; Orrigo, S.E.A.; Rubio, B.; Valencia, E. |
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Title |
Determination of beta-decay ground state feeding of nuclei of importance for reactor applications |
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 |
6 |
Pages |
064304 - 12pp |
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Keywords |
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Abstract |
In beta-decay studies the determination of the decay probability to the ground state (g.s.) of the daughter nucleus often suffers from large systematic errors. The difficulty of the measurement is related to the absence of associated delayed gamma-ray emission. In this work we revisit the 4 pi gamma – beta method proposed by Greenwood and collaborators in the 1990s, which has the potential to overcome some of the experimental difficulties. Our interest is driven by the need to determine accurately the beta-intensity distributions of fission products that contribute significantly to the reactor decay heat and to the antineutrinos emitted by reactors. A number of such decays have large g.s. branches. The method is relevant for nuclear structure studies as well. Pertinent formulas are revised and extended to the special case of beta-delayed neutron emitters, and the robustness of the method is demonstrated with synthetic data. We apply it to a number of measured decays that serve as test cases and discuss the features of the method. Finally, we obtain g.s. feeding intensities with reduced uncertainty for four relevant decays that will allow future improvements in antineutrino spectrum and decay heat calculations using the summation method. |
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Address |
[Guadilla, V; Tain, J. L.; Algora, A.; Agramunt, J.; Jordan, D.; Monserrate, M.; Montaner-Piza, A.; Orrigo, S. E. A.; Rubio, B.; Valencia, E.] Univ Valencia, Inst Fis Corpuscular, CSIC, E-46071 Valencia, Spain |
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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:000595153500001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4626 |
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| Permanent link to this record |
