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Isospin diffusion from $^{40,48}$Ca$+^{40,48}$Ca experimental data at Fermi energies: Direct comparisons with transport model calculations
Authors:
Q. Fable,
L. Baldesi,
S. Barlini,
Eric Bonnet,
Bernard Borderie,
Remi Bougault,
A. Camaiani,
G. Casini,
A. Chbihi,
Caterina Ciampi,
J. A. Dueñas,
J. D. Frankland,
T. Genard,
Diego D. Gruyer,
Maxime Henri,
Byungsik Hong,
S. Kim,
A. J. Kordyasz,
T. Kozik,
Arnaud Le Fèvre,
Nicolas Le Neindre,
Ivano Lombardo,
Olivier Lopez,
T. Marchi,
Paola Marini
, et al. (8 additional authors not shown)
Abstract:
This article presents an investigation of isospin equilibration in cross-bombarding $^{40,48}$Ca$+^{40,48}$Ca reactions at 35 MeV/nucleon, by comparing experimental data with filtered transport model calculations. Isospin diffusion is studied using the evolution of the isospin transport ratio with centrality. The asymmetry parameter $δ=(N-Z)/A$ of the quasiprojectile (QP) residue is used as isospi…
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This article presents an investigation of isospin equilibration in cross-bombarding $^{40,48}$Ca$+^{40,48}$Ca reactions at 35 MeV/nucleon, by comparing experimental data with filtered transport model calculations. Isospin diffusion is studied using the evolution of the isospin transport ratio with centrality. The asymmetry parameter $δ=(N-Z)/A$ of the quasiprojectile (QP) residue is used as isospin-sensitive observable, while a recent method for impact parameter reconstruction is used for centrality sorting. A benchmark of global observables is proposed to assess the relevance of the antisymmetrized molecular dynamics (AMD) model, coupled to GEMINI++, in the study of dissipative collisions. Our results demonstrate the importance of considering cluster formation to reproduce observables used for isospin transport and centrality studies. Within the AMD model, we prove the applicability of the impact parameter reconstruction method, enabling a direct comparison to the experimental data for the investigation of isospin diffusion. For both, we evidence a tendency to isospin equilibration with an impact parameter decreasing from 9 to 3 fm, while the full equilibration is not reached. A weak sensitivity to the stiffness of the equation of state employed in the model is also observed, with a better reproduction of the experimental trend for the neutron-rich reactions.
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Submitted 6 June, 2024; v1 submitted 4 December, 2023;
originally announced December 2023.
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Examination of cluster production in excited light systems at Fermi energies from new experimental data and comparison with transport model calculations
Authors:
C. Frosin,
S. Piantelli,
G. Casini,
A. Ono,
A. Camaiani,
L. Baldesi,
S. Barlini,
B. Borderie,
R. Bougault,
C. Ciampi,
M. Cicerchia,
A. Chbihi,
D. Dell'Aquila,
J. A. Dueñas,
D. Fabris,
Q. Fable,
J. D. Frankland,
T. Génard,
F. Gramegna,
D. Gruyer,
M. Henri,
B. Hong,
M. J. Kweon,
S. Kim,
A. Kordyasz
, et al. (22 additional authors not shown)
Abstract:
Four different reactions, $^{32}$S+$^{12}$C and $^{20}$Ne+$^{12}$C at 25 and 50 MeV/nucleon, have been measured with the FAZIA detector capable of full isotopic identification of most forward emitted reaction products. Fragment multiplicities, angular distributions and energy spectra have been measured and compared with Monte Carlo simulations, i.e. the antisymmetrized molecular dynamics (AMD) and…
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Four different reactions, $^{32}$S+$^{12}$C and $^{20}$Ne+$^{12}$C at 25 and 50 MeV/nucleon, have been measured with the FAZIA detector capable of full isotopic identification of most forward emitted reaction products. Fragment multiplicities, angular distributions and energy spectra have been measured and compared with Monte Carlo simulations, i.e. the antisymmetrized molecular dynamics (AMD) and the heavy-ion phase space exploration (HIPSE) models. These models are combined with two different afterburner codes (HF$l$ and SIMON) to describe the decay of the excited primary fragments. In the case of AMD, the effect of including the clustering and inter-clustering processes to form bound particles and fragments is discussed. A clear confirmation of the role of cluster aggregation in the reaction dynamics and particle production for these light systems, for which the importance of the clustering process increases with bombarding energy, is obtained.
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Submitted 30 March, 2023;
originally announced March 2023.
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First results from the INDRA-FAZIA apparatus on isospin diffusion in $^{58,64}$Ni+$^{58,64}$Ni systems at Fermi energies
Authors:
C. Ciampi,
S. Piantelli,
G. Casini,
G. Pasquali,
J. Quicray,
L. Baldesi,
S. Barlini,
B. Borderie,
R. Bougault,
A. Camaiani,
A. Chbihi,
D. Dell'Aquila,
M. Cicerchia,
J. A. Dueñas,
Q. Fable,
D. Fabris,
J. D. Frankland,
C. Frosin,
T. Génard,
F. Gramegna,
D. Gruyer,
K. I. Hahn,
M. Henri,
B. Hong,
S. Kim
, et al. (21 additional authors not shown)
Abstract:
An investigation of the isospin equilibration process in the reactions $^{58,64}$Ni+$^{58,64}$Ni at two bombarding energies in the Fermi regime ($32\,$MeV/nucleon and $52\,$MeV/nucleon) is presented. Data have been acquired during the first experimental campaign of the coupled INDRA-FAZIA apparatus in GANIL. Selecting from peripheral to semi-central collisions, both the neutron content of the quas…
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An investigation of the isospin equilibration process in the reactions $^{58,64}$Ni+$^{58,64}$Ni at two bombarding energies in the Fermi regime ($32\,$MeV/nucleon and $52\,$MeV/nucleon) is presented. Data have been acquired during the first experimental campaign of the coupled INDRA-FAZIA apparatus in GANIL. Selecting from peripheral to semi-central collisions, both the neutron content of the quasiprojectile residue and that of the light ejectiles coming from the quasiprojectile evaporation have been used as probes of the dynamical process of isospin diffusion between projectile and target for the asymmetric systems. The isospin transport ratio technique has been employed. The relaxation of the initial isospin imbalance with increasing centrality has been clearly evidenced. The isospin equilibration appears stronger for the reactions at $32\,$MeV/nucleon, as expected due to the longer projectile-target interaction time than at $52\,$MeV/nucleon. Coherent indications of isospin equilibration come from the quasiprojectile residue characteristics and from particles ascribed to the quasiprojectile decay.
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Submitted 20 May, 2022;
originally announced May 2022.
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Comparison of AMD calculations with experimental data for peripheral collisions of 93Nb+93Nb,116Sn at 38 MeV/nucleon
Authors:
S. Piantelli,
A. Olmi,
P. R. Maurenzig,
A. Ono,
M. Bini,
G. Casini,
G. Pasquali,
A. Mangiarotti,
G. Poggi,
A. A. Stefanini,
S. Barlini,
A. Camaiani,
C. Ciampi,
C. Frosin,
P. Ottanelli,
S. Valdre'
Abstract:
Experimental data concerning binary events in peripheral collisions for the systems 93Nb+93Nb and 93Nb+116Sn at 38 MeV/nucleon, collected with the Fiasco setup, are compared with calculations performed with the dynamic code AMD, coupled with the statistical code Gemini used as an afterburner. The comparison focuses on the properties of the quasiprojectile (QP) and on the total multiplicities of th…
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Experimental data concerning binary events in peripheral collisions for the systems 93Nb+93Nb and 93Nb+116Sn at 38 MeV/nucleon, collected with the Fiasco setup, are compared with calculations performed with the dynamic code AMD, coupled with the statistical code Gemini used as an afterburner. The comparison focuses on the properties of the quasiprojectile (QP) and on the total multiplicities of the emitted light charged particles. A good reproduction of the average mass ratio, charge Z and c.m. angle of the QP is obtained in the examined impact parameter range (b~7-12 fm). Concerning the light charged particles, a general agreement is found for the total emitted charge, while some discrepancy remains for the multiplicities of the various species, especially for the protons which are always overestimated by the calculations.
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Submitted 6 February, 2019;
originally announced February 2019.
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Probing the statistical decay and alpha-clustering effects in 12c+12c and 14n+10b reactions
Authors:
Luca Morelli,
G. Baiocco,
M. D Agostino,
M. Bruno,
F. Gulminelli,
M. Cinausero,
M. Degerlier,
D. Fabris,
F. Gramegna,
T. Marchi,
S. Barlini,
M. Bini,
G. Casini,
N. Gelli,
A. Lopez,
G. Pasquali,
S. Piantelli,
S. Valdre'
Abstract:
An experimental campaign has been undertaken at INFN Laboratori Nazionali di Legnaro, Italy, in order to progress in our understanding of the statistical properties of light nuclei at excitation energies above particle emission threshold, by measuring exclusive data from fusion-evaporation reactions. A first reaction 12C+12C at 7.9 AMeV beam energy has been measured, using the GARFIELD+Ring Counte…
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An experimental campaign has been undertaken at INFN Laboratori Nazionali di Legnaro, Italy, in order to progress in our understanding of the statistical properties of light nuclei at excitation energies above particle emission threshold, by measuring exclusive data from fusion-evaporation reactions. A first reaction 12C+12C at 7.9 AMeV beam energy has been measured, using the GARFIELD+Ring Counter experimental setup. Fusion-evaporation events have been exclusively selected. The comparison to a dedicated Hauser-Feshbach calculation allows us to give constraints on the nuclear level density at high excitation energy for light systems ranging from C up to Mg. Out-of-equilibrium emission has been evidenced and attributed both to entrance channel effects favoured by the cluster nature of reaction partners and, in more dissipative events, to the persistence of cluster correlations well above the 24Mg threshold for 6 alphas decay. The 24Mg compound nucleus has been studied with a new measurement 14N + 10B at 5.7 AMeV. The comparison between the two datasets would allow us to further constrain the level density of light nuclei. Deviations from a statistical behaviour can be analyzed to get information on nuclear clustering.
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Submitted 2 September, 2013;
originally announced September 2013.
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α-clustering effects in dissipative 12C+12C reactions at 95 MeV
Authors:
G. Baiocco,
L. Morelli,
F. Gulminelli,
M. D'Agostino,
M. Bruno,
U. Abbondanno,
S. Barlini,
M. Bini,
S. Carboni,
G. Casini,
M. Cinausero,
M. Degerlier F. Gramegna,
V. L. Kravchuk,
T. Marchi,
A. Olmi,
G. Pasquali,
S. Piantelli,
Ad. R. Raduta
Abstract:
Dissipative 12C+12C reactions at 95 MeV are fully detected in charge with the GARFIELD and RCo apparatuses at LNL. A comparison to a dedicated Hauser-Feshbach calculation allows to select events which correspond, to a large extent, to the statistical evaporation of highly excited 24Mg, as well as to extract information on the isotopic distribution of the evaporation residues in coincidence with th…
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Dissipative 12C+12C reactions at 95 MeV are fully detected in charge with the GARFIELD and RCo apparatuses at LNL. A comparison to a dedicated Hauser-Feshbach calculation allows to select events which correspond, to a large extent, to the statistical evaporation of highly excited 24Mg, as well as to extract information on the isotopic distribution of the evaporation residues in coincidence with their complete evaporation chain. Residual deviations from a statistical behaviour are observed in αyields and attributed to the persistence of cluster correlations well above the 24Mg threshold for 6 α's decay.
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Submitted 25 January, 2013;
originally announced January 2013.