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1. Hot neutron stars and their equation of state

Author

Jin-Biao Wei, G. F. Burgio, Ad. R. Raduta, and H.-J. Schulze

Subjects
Nuclear Theory (nucl-th), High Energy Astrophysical Phenomena (astro-ph.HE), Nuclear Theory, FOS: Physical sciences, Astrophysics - High Energy Astrophysical Phenomena
Abstract

A set of microscopic, covariant density-functional, and non-relativistic Skyrme-type equations of state is employed to study the structure of purely nucleonic neutron stars at finite temperature. After examining the agreement with presently available astrophysical observational constraints, we find that the magnitude of thermal effects depends on the nucleon effective mass as well as on the stiffness of the cold equation of state. We evidence a fairly small but model-dependent effect of finite temperature on stellar stability that is correlated with the relative thermal pressure inside the star., 10 pages, 8 figures

Published
2021

2. Nuclear skin and the curvature of the symmetry energy

Author

Francesca Gulminelli, Ad. R. Raduta, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen ( LPCC ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ) -Normandie Université ( NU ) -Ecole Nationale Supérieure d'Ingénieurs de Caen ( ENSICAEN ), Normandie Université ( NU ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Equation of state, Nuclear Theory, Isovector, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, FOS: Physical sciences, Observable, Curvature, 01 natural sciences, Symmetry (physics), Nuclear Theory (nucl-th), 0103 physical sciences, Neutron, 010306 general physics, Focus (optics), [ PHYS.NUCL ] Physics [physics]/Nuclear Theory [nucl-th], Energy (signal processing), Mathematical physics
Abstract

The effect of correlations between the slope and the curvature of the symmetry energy on ground state nuclear observables is studied within the extended Thomas-Fermi approximation. We consider different isovector probes of the symmetry energy, with a special focus on the skin of $^{208}{\rm Pb}$. We use a recently proposed meta-modelling technique to generate a large number of equation of state models, where the empirical parameters are independently varied. The results are compared to a set of calculations using 17 different Skyrme interactions. We show that the curvature parameter plays a non-negligible role on the neutron skin, while the effect is reduced in Skyrme functionals because of the correlation with the slope parameter., 10 pages, 6 figures

Published
2018

3. Constraints on the nuclear equation of state from nuclear masses and radii in a Thomas-Fermi meta-modeling approach

Author

Jérôme Margueron, Francesca Gulminelli, Debarati Chatterjee, Ad. R. Raduta, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen ( LPCC ), Université de Caen Normandie ( UNICAEN ), Normandie Université ( NU ) -Normandie Université ( NU ) -Ecole Nationale Supérieure d'Ingénieurs de Caen ( ENSICAEN ), Normandie Université ( NU ) -Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Physique Nucléaire de Lyon ( IPNL ), Université Claude Bernard Lyon 1 ( UCBL ), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS ( IN2P3 ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
energy: symmetry, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Posterior probability, Nuclear Theory, Hartree–Fock method, nuclear model, Parameter space, 01 natural sciences, nuclear matter: equation of state, 0103 physical sciences, Neutron, energy: density, Statistical physics, 010306 general physics, Nuclear Experiment, numerical calculations, neutron star, [ PHYS.NUCL ] Physics [physics]/Nuclear Theory [nucl-th], Physics, nucleon: mass, Hartree-Fock approximation, nucleus: ground state, 010308 nuclear & particles physics, Observable, nucleus: mass, Nuclear matter, Symmetry (physics), correlation, Ground state, nucleus: equation of state
Abstract

International audience; The question of correlations among empirical equation of state (EoS) parameters constrained by nuclear observables is addressed in a Thomas-Fermi meta-modeling approach. A recently proposed meta-modeling for the nuclear EoS in nuclear matter is augmented with a single finite size term to produce a minimal unified EoS functional able to describe the smooth part of the nuclear ground state properties. This meta-model can reproduce the predictions of a large variety of models, and interpolate continuously between them. An analytical approximation to the full Thomas-Fermi integrals is further proposed giving a fully analytical meta-model for nuclear masses. The parameter space is sampled and filtered through the constraint of nuclear mass reproduction with Bayesian statistical tools. We show that this simple analytical meta-modeling has a predictive power on masses, radii, and skins comparable to full Hartree-Fock or extended Thomas-Fermi calculations with realistic energy functionals. The covariance analysis on the posterior distribution shows that no physical correlation is present between the different EoS parameters. Concerning nuclear observables, a strong correlation between the slope of the symmetry energy and the neutron skin is observed, in agreement with previous studies.

Published
2017

4. Stellar electron capture rates on neutron-rich nuclei and their impact on stellar core collapse

Author

Francesca Gulminelli, Ad. R. Raduta, Micaela Oertel, IFIN-HH, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)

Subjects
Physics, Electron density, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Electron capture, Degrees of freedom (physics and chemistry), FOS: Physical sciences, Collapse (topology), 01 natural sciences, Nuclear Theory (nucl-th), Nuclear physics, Gravitation, Stars, Isospin, 0103 physical sciences, Neutron, 010306 general physics
Abstract

During the late stages of gravitational core-collapse of massive stars, extreme isospin asymmetries are reached within the core. Due to the lack of microscopic calculations of electron capture (EC) rates for all relevant nuclei, in general simple analytic parameterizations are employed. We study here several extensions of these parameterizations, allowing for a temperature, electron density and isospin dependence as well as for odd-even effects. The latter extra degrees of freedom considerably improve the agreement with large scale microscopic rate calculations. We find, in particular, that the isospin dependence leads to a significant reduction of the global EC rates during core collapse with respect to fiducial results, where rates optimized on calculations of stable $fp$-shell nuclei are used. Our results indicate that systematic microscopic calculations and experimental measurements in the $N\approx 50$ neutron rich region are desirable for realistic simulations of the core-collapse., 14 pages, 8 figures, accepted for publication in Phys. Rev. C

Published
2017

5. Non-statistical decay and $\alpha$-correlations in the $^{12}$C+$^{12}$C fusion-evaporation reaction at 95 MeV

Author

L Morelli, G Baiocco, M D’Agostino, F Gulminelli, M Bruno, U Abbondanno, S Appannababu, S Barlini, M Bini, G Casini, M Cinausero, M Degerlier, D Fabris, N Gelli, F Gramegna, V L Kravchuk, T Marchi, A Olmi, G Pasquali, S Piantelli, S Valdré, Ad R Raduta, Istituto Nazionale di Fisica Nucleare, Sezione di Bologna (INFN, Sezione di Bologna), Istituto Nazionale di Fisica Nucleare (INFN), Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratori Nazionali di Legnaro (LNL), Istituto Nazionale di Fisica Nucleare, Sezione di Padova (INFN, Sezione di Padova), PRIN 2010-2011, L Morelli, G Baiocco, M D’Agostino, F Gulminelli, M Bruno, U Abbondanno, S Appannababu, S Barlini, M Bini, G Casini, M Cinausero, M Degerlier, D Fabri, N Gelli, F Gramegna, V L Kravchuk, T Marchi, A Olmi, G Pasquali, S Piantelli, S Valdré, and Ad R Raduta

Subjects
Nuclear and High Energy Physics, chemistry.chemical_element, E = 95 Amev, fusion evaporation reactions, 12C(12C, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Oxygen, Coincidence, Observed deviation from statistical behaviour, 0103 physical sciences, Neutron, 25.70.z, 24.60.Dr, 27.30.+t, 24.10.Pa, 010306 general physics, Nuclear Experiment, X), Physics, NUCLEAR REACTIONS, Measured Fusion-evaporation reactions, Fusion, 010308 nuclear & particles physics, 3. Good health, chemistry, Phase space, Excited state, Alpha decay, Atomic physics, Excitation
Abstract

Multiple alpha coincidence and correlations are studied in the reaction $^{12}$C+$^{12}$C at 95 MeV for fusion-evaporation events completely detected in charge. Two specific channels with Carbon and Oxygen residues in coincidence with $\alpha$-particles are addressed, which are associated with anomalously high branching ratios with respect the predictions by Hauser-Feshbach calculations. Triple alpha emission appears kinematically compatible with a sequential emission from a highly excited Mg. The phase space distribution of $\alpha$-$\alpha$ coincidences suggests a correlated emission from a Mg compound, leaving an Oxygen residue excited above the threshold for neutron decay. These observations indicate a preferential $\alpha$ emission of $^{24}$Mg at excitation energies well above the threshold for $6-\alpha$ decay., Comment: 21 pages, 17 figures, second paper of a series of two

Published
2014

6. Neutron star radii and crusts: Uncertainties and unified equations of state

Author

Francesca Gulminelli, J. L. Zdunik, Michał Bejger, Ad. R. Raduta, M. Fortin, Constança Providência, Pawel Haensel, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Equation of state, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Star (game theory), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Radius, Nuclear matter, 01 natural sciences, Baryon, Nuclear physics, Nuclear Theory (nucl-th), Stars, Neutron star, Astrophysics - Solar and Stellar Astrophysics, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, 010303 astronomy & astrophysics, Energy (signal processing), Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

The uncertainties in neutron star (NS) radii and crust properties due to our limited knowledge of the equation of state (EOS) are quantitatively analysed. We first demonstrate the importance of a unified microscopic description for the different baryonic densities of the star. If the pressure functional is obtained matching a crust and a core EOS based on models with different properties at nuclear matter saturation, the uncertainties can be as large as $\sim 30\%$ for the crust thickness and $4\%$ for the radius. Necessary conditions for causal and thermodynamically consistent matchings between the core and the crust are formulated and their consequences examined. A large set of unified EOS for purely nucleonic matter is obtained based on 24 Skyrme interactions and 9 relativistic mean-field nuclear parametrizations. In addition, for relativistic models 17 EOS including a transition to hyperonic matter at high density are presented. All these EOS have in common the property of describing a $2\;M_\odot$ star and of being causal within stable NS. A span of $\sim 3$ km and $\sim 4$ km is obtained for the radius of, respectively, $1.0\;M_\odot$ and $2.0\;M_\odot$ star. Applying a set of nine further constraints from experiment and ab-initio calculations the uncertainty is reduced to $\sim 1$ km and $2$ km, respectively. These residual uncertainties reflect lack of constraints at large densities and insufficient information on the density dependence of the EOS near the nuclear matter saturation point. The most important parameter to be constrained is shown to be the symmetry energy slope $L$ which exhibits a linear correlation with the stellar radius, particularly for masses $\sim 1.0\;M_\odot$. Potential constraints on $L$, the NS radius and the EOS from observations of thermal states of NS are also discussed. [Abriged], Comment: Submitted to Phys. Rev. C. Supplemental material not included

Published
2016

7. Thermal properties of light nuclei from12C +12C fusion–evaporation reactions

Author

L Morelli, G Baiocco, M D’Agostino, F Gulminelli, M Bruno, U Abbondanno, S Appannababu, S Barlini, M Bini, G Casini, M Cinausero, M Degerlier, D Fabris, N Gelli, F Gramegna, V L Kravchuk, T Marchi, A Olmi, G Pasquali, S Piantelli, S Valdré, Ad R Raduta, L Morelli, G Baiocco, M D’Agostino, F Gulminelli, M Bruno, U Abbondanno, S Appannababu, S Barlini, M Bini, G Casini, M Cinausero, M Degerlier, D Fabri, N Gelli, F Gramegna, V L Kravchuk, T Marchi, A Olmi, G Pasquali, S Piantelli, S Valdré, Ad R Raduta, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, NUCLEAR REACTIONS, Nuclear and High Energy Physics, Fusion, 010308 nuclear & particles physics, Evaporation, FOS: Physical sciences, Charge (physics), deviation from statistical behaviour, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Coincidence, 3. Good health, Excited state, 0103 physical sciences, Thermal, Dissipative system, Nuclear Experiment (nucl-ex), Atomic physics, fusion evaporation reaction, 010306 general physics, Nuclear Experiment, Excitation
Abstract

The $^{12}$C+$^{12}$C reaction at 95 MeV has been studied through the complete charge identification of its products by means of the GARFIELD+RCo experimental set-up at INFN Laboratori Nazionali di Legnaro (LNL). In this paper, the first of a series of two, a comparison to a dedicated Hauser-Feshbach calculation allows to select a set of dissipative events which corresponds, to a large extent, to the statistical evaporation of highly excited $^{24}$Mg. Information on the isotopic distribution of the evaporation residues in coincidence with their complete evaporation chain is also extracted. The set of data puts strong constraints on the behaviour of the level density of light nuclei above the threshold for particle emission. In particular, a fast increase of the level density parameter with excitation energy is supported by the data. Residual deviations from a statistical behaviour are seen in two specific channels, and tentatively associated with a contamination from direct reactions and/or $\alpha$-clustering effects. These channels are studied in further details in the second paper of the series., Comment: 24 pages, 15 figures, first paper of a series of two

Published
2014

8. Strong correlations of neutron star radii with the slopes of nuclear matter incompressibility and symmetry energy at saturation

Author

Helena Pais, B. K. Agrawal, M. Fortin, N. Alam, Constança Providência, Anto Sulaksono, and Ad. R. Raduta

Subjects
Nuclear Theory, Star (game theory), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Nuclear physics, Nuclear Theory (nucl-th), 0103 physical sciences, Saturation (graph theory), Nuclear Experiment, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, High Energy Astrophysical Phenomena (astro-ph.HE), 010308 nuclear & particles physics, Equation of state (cosmology), Radius, Nuclear matter, Symmetry (physics), Neutron star, Astrophysics - Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Atomic physics, Astrophysics - High Energy Astrophysical Phenomena, Energy (signal processing)
Abstract

We examine the correlations of neutron star radii with the nuclear matter incompressibility, symmetry energy, and their slopes, which are the key parameters of the equation of state (EoS) of asymmetric nuclear matter. The neutron star radii and the EoS parameters are evaluated using a representative set of 24 Skyrme-type effective forces and 18 relativistic mean field models, and two microscopic calculations, all describing 2$M_\odot$ neutron stars. Unified EoSs for the inner-crust-core region have been built for all the phenomenological models, both relativistic and non-relativistic. Our investigation shows the existence of a strong correlation of the neutron star radii with the linear combination of the slopes of the nuclear matter incompressibility and the symmetry energy coefficients at the saturation density. Such correlations are found to be almost independent of the neutron star mass in the range $0.6\text{-}1.8M_{\odot}$. This correlation can be linked to the empirical relation existing between the star radius and the pressure at a nucleonic density between one and two times saturation density, and the dependence of the pressure on the nuclear matter incompressibility, its slope and the symmetry energy slope. The slopes of the nuclear matter incompressibility and the symmetry energy coefficients as estimated from the finite nuclei data yield the radius of a $1.4M_{\odot}$ neutron star in the range $11.09\text{-}12.86$ km., Comment: 7 pages, 5 figures, accepted in Phys. Rev. C (Rapid Comm.)

Published
2016
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9. Heat capacity of the neutron star inner crust within an extended nuclear statistical equilibrium model

Author

Ad. R. Raduta, François Aymard, S. Burrello, Maria Colonna, Francesca Gulminelli, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear and High Energy Physics, education.field_of_study, number(s): 2660Kp, 7420Fg, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Population, Degrees of freedom (physics and chemistry), Heat capacity, Computational physics, Superfluidity, Neutron star, 2660Gj, 6410+h, Pairing, Quasiparticle, Neutron, Atomic physics, education
Abstract

International audience; Background: Superfluidity in the crust is a key ingredient for the cooling properties of proto-neutron stars. Present theoretical calculations employ the quasiparticle mean-field Hartree-Fock-Bogoliubov theory with temperature-dependent occupation numbers for the quasiparticle states.Purpose: Finite temperature stellar matter is characterized by a whole distribution of different nuclear species. We want to assess the importance of this distribution on the calculation of heat capacity in the inner crust.Method: Following a recent work, the Wigner-Seitz cell is mapped into a model with cluster degrees of freedom. The finite temperature distribution is then given by a statistical collection of Wigner-Seitz cells. We additionally introduce pairing correlations in the local density BCS approximation both in the homogeneous unbound neutron component, and in the interface region between clusters and neutrons.Results: The heat capacity is calculated in the different baryonic density conditions corresponding to the inner crust, and in a temperature range varying from 100 KeV to 2 MeV. We show that accounting for the cluster distribution has a small effect at intermediate densities, but it considerably affects the heat capacity both close to the outer crust and close to the core. We additionally show that it is very important to consider the temperature evolution of the proton fraction for a quantitatively reliable estimation of the heat capacity.Conclusions: We present the first modelization of stellar matter containing at the same time a statistical distribution of clusters at finite temperature, and pairing correlations in the unbound neutron component. The effect of the nuclear distribution on the superfluid properties can be easily added in future calculations of the neutron star cooling curves. A strong influence of resonance population on the heat capacity at high temperature is observed, which deserves to be further studied within more microscopic calculations.

Published
2015

10. Unified treatment of subsaturation stellar matter at zero and finite temperature

Author

Ad. R. Raduta, Francesca Gulminelli, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, Explosive material, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], FOS: Physical sciences, Type II supernova, Nuclear Theory (nucl-th), Formalism (philosophy of mathematics), Neutron star, Theoretical physics, Statistical equilibrium, symbols.namesake, 13. Climate action, Nucleosynthesis, Excluded volume, symbols, Statistical physics, van der Waals force
Abstract

The standard variational derivation of stellar matter structure in the Wigner-Seitz approximation is generalized to the finite temperature situation where a wide distribution of different nuclear species can coexist in the same density and proton fraction condition, possibly out of $\beta$-equilibrium. The same theoretical formalism is shown to describe on one side the single-nucleus approximation (SNA), currently used in most core collapse supernova simulations, and on the other side the nuclear statistical equilibrium (NSE) approach, routinely employed in r- and p-process explosive nucleosynthesis problems. In particular we show that in-medium effects have to be accounted for in NSE to have a theoretical consistency between the zero and finite temperature modeling. The bulk part of these in-medium effects is analytically calculated and shown to be different from a van der Waals excluded volume term. This unified formalism allows controlling quantitatively the deviations from the SNA in the different thermodynamic conditions, as well as having a NSE model which is reliable at any arbitrarily low value of the temperature, with potential applications for neutron star cooling and accretion problems. We present different illustrative results with several mass models and effective interactions, showing the importance of accounting for the nuclear species distribution even at temperatures lower than 1 MeV., Comment: 26 pages, 17 figures; submitted to Phys. Rev. C

Published
2015

11. Microscopic evaluation of the hypernuclear chart withΛhyperons

Author

Jérôme Margueron, Ad. R. Raduta, Elias Khan, and Francesca Gulminelli

Subjects
Physics, Baryon, Nuclear and High Energy Physics, Particle physics, Chart, Nuclear Theory, Binding energy, Hyperon, Neutron, Bond energy, Nuclear Experiment, Lambda, Energy functional
Abstract

We calculate the comprehensive hypernuclear chart for even-even hypernuclei with magic numbers of $\Lambda$'s (for Z $\leq$ 120 and $\Lambda \leq$70) and estimate the number of bound systems, considering the present uncertainties in the $\Lambda-$nucleon and $\Lambda-\Lambda$ interactions. We consider a density functional approach adjusted to microscopic Bruckner-Hartree-Fock calculations, where the $\Lambda\Lambda$ term is corrected in a phenomenological way, to reproduce present experimental constraints. Different models which strongly deviate at large densities, but giving the same bond energy, are generated in order to take into account the uncertainties related to the high density equation of state. The number of bound even-even-even hypernuclei is estimated to 491680 $\pm$ 34400. This relatively low uncertainty is due to the fact that the well constrained low density and highly unconstrained high density behavior of the energy functional turn out to be largely decoupled. Results in hypernuclei appear to be almost independent of the choice for the high-density part of the $\Lambda\Lambda$ interaction. The location of the hyperdriplines is also evaluated. Significant deviations from Iron-Nickel elements can be found for hypernuclei with the largest binding energy per baryon. Proton, neutron and hyperon magicity evolution and triple magic hypernuclei are studied. Possible bubbles and haloes effect in hypernuclei are also discussed. The present results provide a first microscopic evaluation of the hypernuclear landscape.

Published
2015

12. Modification of magicity towards the dripline and its impact on electron-capture rates for stellar core-collapse

Author

Francesca Gulminelli, Ad. R. Raduta, Micaela Oertel, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Nuclear Theory, 010308 nuclear & particles physics, Electron capture, Nuclear structure, FOS: Physical sciences, Electron, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear Theory (nucl-th), Nuclear physics, Stellar core, Supernova, 0103 physical sciences, Emissivity, Neutron, Neutrino, 010306 general physics
Abstract

The importance of microphysical inputs from laboratory nuclear experiments and theoretical nuclear structure calculations in the understanding of the core collapse dynamics, and the subsequent supernova explosion, is largely recognized in the recent literature. In this work, we analyze the impact of the masses of very neutron rich nuclei on the matter composition during collapse, and the corresponding electron capture rate. To this aim, we introduce an empirical modification of the popular Duflo-Zuker mass model to account for possible shell quenching far from stability, and study the effect of the quenching on the average electron capture rate. We show that the preeminence of the $N=50$ and $N=82$ closed shells in the collapse dynamics is considerably decreased if the shell gaps are reduced in the region of $^{78}$Ni and beyond. As a consequence, local modifications of the overall electron capture rate up to 30\% can be expected, with integrated values strongly dependent on the stiffness of magicity quenching and progenitor mass and potential important consequences on the entropy generation, the neutrino emissivity, and the mass of the core at bounce. Our work underlines the importance of new experimental measurements in this region of the nuclear chart, the most crucial information being the nuclear mass and the Gamow-Teller strength. Reliable microscopic calculations of the associated elementary rate, in a wide range of temperatures and electron densities, optimized on these new empirical information, will be additionally needed to get quantitative predictions of the collapse dynamics., 12 pages, 10 figures

Published
2015

13. Kinetic energy spectra for fragments and break-up density in multifragmentation

Author

Ad. R. Raduta, M.F. Rivet, Bernard Borderie, E. Bonnet, Silvia Piantelli, N. Le Neindre, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Nuclear Institute for Physics and Nuclear Engineering (NIPNE), Nuclear Institute for Physics and Nuclear Engineering, and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Multifragmentation, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Break-Up, 010308 nuclear & particles physics, fragment kinetic energy, FOS: Physical sciences, microcanonical model, Kinetic energy, 01 natural sciences, Spectral line, Nuclear Theory (nucl-th), Fragmentation (mass spectrometry), 25.70.Pq, 24.10.Pa, 0103 physical sciences, Low density, Atomic physics, Nuclear Experiment, 010306 general physics, Nuclear theory, Excitation, Nuclear density
Abstract

We investigate the possibility, in nuclear fragmentation, to extract information on nuclear density at break-up from fragment kinetic energy spectra using a simultaneous scenario for fragment emission. The conclusions we derive are different from the recently published results of Viola et al. [Phys. Rev. Lett. 93, (2004), 132701] assuming a sequential fragment emission and claiming that the experimentally observed decrease of peak centroids for kinetic energy spectra of fragments with increasing bombarding energy is due to a monotonic decrease of the break-up density., Comment: 6 pages, 3 figures

Published
2005

14. Strangeness driven phase transitions in compressed baryonic matter and their relevance for neutron stars and core collapsing supernovae

Author

Ad. R. Raduta, M. Oertel, Francesca Gulminelli, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Coupling constant, Phase transition, Particle physics, Octet, High Energy Physics::Phenomenology, Nuclear Theory, 020206 networking & telecommunications, 02 engineering and technology, Astrophysics::Cosmology and Extragalactic Astrophysics, Strangeness, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Baryon, Supernova, Neutron star, Mean field theory, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Nuclear Experiment
Abstract

International audience; We discuss the thermodynamics of compressed baryonic matter with strangeness within non-relativistic mean-field models with effective interactions. The phase diagram of the full baryonic octet under strangeness equilibrium is built and discussed in connection with its relevance for core-collapse supernovae and neutron stars. A simplified framework corresponding to (n, p, Λ)(+e)-mixtures is employed in order to test the sensitivity of the existence of a phase transition on the (poorely constrained) interaction coupling constants and the compatibility between important hyperonic abundances and 2M ⊙ neutron stars.

Published
2014

15. Hyperons in neutron star matter within relativistic mean-field models

Author

Ad. R. Raduta, F. Gulminelli, Constança Providência, Micaela Oertel, Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear and High Energy Physics, Spinodal, 26.60.-c 21.65.Mn, 64.10.+h, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], X-ray binary, FOS: Physical sciences, Astrophysics, 01 natural sciences, 7. Clean energy, Instability, Nuclear Theory (nucl-th), Nuclear physics, 0103 physical sciences, 010306 general physics, Nuclear Experiment, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, 010308 nuclear & particles physics, High Energy Physics::Phenomenology, Hyperon, Neutron star, Stars, Mean field theory, High mass, High Energy Physics::Experiment, Astrophysics::Earth and Planetary Astrophysics
Abstract

Since the discovery of neutron stars with masses around 2 solar masses the composition of matter in the central part of these massive stars has been intensively discussed. Within this paper we will (re)investigate the question of the appearance of hyperons. To that end we will perform an extensive parameter study within relativistic mean field models. We will show that it is possible to obtain high mass neutron stars (i) with a substantial amount of hyperons, (ii) radii of 12-13 km for the canonical mass of 1.4 solar masses, and (iii) a spinodal instability at the onset of hyperons. The results depend strongly on the interaction in the hyperon-hyperon channels, on which only very little information is available from terrestrial experiments up to now., 15 pages, 10 figures

Published
2014

16. Equations of state and phase transitions in stellar matter

Author

M. Oertel, Francesca Gulminelli, François Aymard, Ad. R. Raduta, Jérôme Margueron, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Particle physics, Phase transition, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Isovector, Nuclear Theory, 020206 networking & telecommunications, 02 engineering and technology, Strangeness, Neutron star, Theoretical physics, Gravitational collapse, 0202 electrical engineering, electronic engineering, information engineering, 020201 artificial intelligence & image processing, Nuclear Experiment, Random phase approximation, Stellar evolution, Phase diagram
Abstract

International audience; Realistic description of core-collapsing supernovae evolution and structure of proto-neutron stars chiefly depends on microphysics input in terms of equations of state, chemical composition and weak interaction rates. At sub-saturation densities the main uncertainty comes from the symmetry energy. Within a nuclear statistical equilibrium (NSE) model with consistent treatment of clusterized and unbound components we investigate the meaning of symmetry energy in the case of dis-homogeneous systems, as the one thought to constitute the neutron star crust, and its sensitivity to the isovector properties of the effective interaction. At supra-saturation densities the situation is much more difficult because of the poor knowledge of nucleon-hyperon and hyperon-hyperon interactions and thermodynamic behavior in terms of phase transitions. Within a simple (npΛ) model we show that compressed baryonic matter with strangeness manifests a complex phase diagram with first and second order phase transitions. The fact that both are explored under strangeness chemical equilibrium and survive Coulomb suggests that they might have sizable consequences on star evolution. An example in this sense is the drastic reduction of the neutrino-mean free path in the vicinity of the critical point obtained within RPA which would lead to a less rapid star cooling.

Published
2014

19. Description of deformed atomic clusters within a projected spherical basis

Author

A. A. Raduta, Ad. R. Raduta, and Al. H. Raduta

Subjects
Physics, Formalism (philosophy of mathematics), Classical mechanics, Metallic clusters, Spherical basis
Abstract

A projected spherical basis is defined with the scope of treating deformed metallic clusters. It depends on a parameter that simulates the system deformation. When the deformation goes to zero the spherical-shell model states are obtained. The basis is tested, with positive results, in several applications for Na clusters. The present formalism predictions are compared with those obtained within other models. Such a basis is suitable for a realistic and a unified fashion description of spherical and deformed metallic clusters.

Published
1999

20. Interplay between various degrees of freedom in determining the aspect of the caloric curve

Author

Al. H. Raduta and Ad. R. Raduta

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Phase transition, Nuclear Theory, Degrees of freedom (physics and chemistry), Thermodynamics, Caloric theory, Plateau (mathematics), Nuclear matter, Physics::Atomic and Molecular Clusters, Nuclear Experiment, Fermi gas, Isotopes of helium
Abstract

A sharp microcanonical model is used to investigate the primary decay nuclear caloric curve. A wide plateau of the caloric curve corresponding to a temperature of around 5 MeV, sign of liquid-gas phase transition, is evidenced for three sample nuclei. The results are resembling the experimental data of Pochodzalla et al. [Phys. Rev. Lett. 75 (1995) 1040]. Calculated HeLi temperatures manifest a similar behavior. Correlations between different parts of the caloric curves and the energy amounts deposited in the available degrees are discussed. The extent to which the existent degrees of freedom are contributing to the shape of the caloric curve is commented.

Published
1999

21. Microcanonical investigation of the primary decay nuclear caloric curve

Author

Ad. R. Raduta and Al. H. Raduta

Subjects
Physics, Nuclear and High Energy Physics, Phase transition, Range (particle radiation), Condensed matter physics, Nuclear Theory, Degrees of freedom (physics and chemistry), Plateau (mathematics), Fragmentation (mass spectrometry), Atomic physics, Nuclear Experiment, Nucleon, Excitation, Sign (mathematics)
Abstract

Primary decay caloric curves are calculated via a sharp microcanonical multifragmentation model for three representative sample nuclei. In all cases, a plateau corresponding to temperatures of around 5 MeV is manifested for the excitation energy range 2.5 to around 8.5 MeV/nucleon, a fact resembling the experimental evidence and sign of liquid-gas phase transition. Correlations of different parts of the temperature curves with the energy deposited in the availables degrees of freedom and with the relative probabilities of different fragmentation modes are discussed. He-Li isotopic temperatures calculated for the same sample nuclei manifest a similar behavior. Calculated microcanonical and He-Li temperatures are compared with experimental He-Li temperatures.

Published
1999

22. Statistical view on nuclear multifragmentation: Primary decays

Author

Al. H. Raduta and Ad. R. Raduta

Subjects
Physics, Nuclear and High Energy Physics, Mass distribution, Fission, media_common.quotation_subject, Monte Carlo method, Charge density, Statistical model, Breakup, Universe, Nuclear physics, Fragmentation (mass spectrometry), Nuclear Experiment, media_common
Abstract

An overall view on the universe of primary decays appearing in the process of nuclear multifragmentation via a microcanonical Monte Carlo Metropolis type simulation is given. General characteristics like mass and charge distributions, relative probabilities of evaporation, fission, fragmentation and vaporization, average number of fragments and distributions of a number of intermediate mass fragments offer valuable information about the intimacy of the process. The capability of the model to describe unitary very different breakup regimes is pointed out. Predictions for charge distributions, isotopic yields, and fission mass distributions are compared with experimental data. {copyright} {ital 1997} {ital The American Physical Society}

Published
1997

23. Simulation of statistical ensembles suitable for the description of nuclear multifragmentation

Author

Al. H. Raduta and Ad. R. Raduta

Subjects
Nuclear physics, Physics, Statistical ensemble, Nuclear and High Energy Physics, Mass distribution, Nuclear Theory, Detailed balance, Statistical model, Observable, Charge (physics), Configuration space, Nuclear Experiment, Nucleon
Abstract

A general statistical ensemble is defined. The statistical weights for each configuration and consequently the mean value of any global observable can be expressed analytically. Since the resulting formulas are not numerically tractable, a statistical method of simulation is proposed. The method, a generalization of Koonin and Randrup's procedure, provides an exploration of configuration space according to the detailed balance principle. This method is then applied to investigate the nuclear multifragmentation phenomenon. Charge and mass distributions calculated for reactions ${}^{40}$Ar+${}^{45}$Sc at 35--115 MeV/nucleon and ${}^{93}$Nb+${}^{9}$Be at 11.4 and 30.3 MeV/nucleon are compared with the respective experimental data.

Published
1997

24. Densities and energies of nuclei in dilute matter at zero temperature

Author

Francesca Gulminelli, Ad. R. Raduta, Panagiota Papakonstantinou, Jérôme Margueron, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), and IFIN-HH

Subjects
Surface (mathematics), Physics, Nuclear and High Energy Physics, SIMPLE (dark matter experiment), [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, Nuclear Theory, 01 natural sciences, Volume (thermodynamics), 0103 physical sciences, Cluster (physics), Circular symmetry, Zero temperature, Atomic physics, 010306 general physics, Nucleon, Saturation (chemistry)
Abstract

20 pages, incl. 12 figures; We explore the ground-state properties of nuclear clusters embedded in a gas of nucleons with the help of Skyrme-Hartree-Fock microscopic calculations. Two alternative representations of clusters are introduced, namely coordinate-space and energy-space clusters. We parameterize their density profiles in spherical symmetry in terms of basic properties of the energy density functionals used and propose an analytical, Woods-Saxon density profile whose parameters depend, not only on the composition of the cluster, but also of the nucleon gas. We study the clusters' energies with the help of the local-density approximation, validated through our microscopic results. We find that the volume energies of coordinate-space clusters are determined by the saturation properties of matter, while the surface energies are strongly affected by the presence of the gas. We conclude that both the density profiles and the cluster energies are strongly affected by the gas and discuss implications for the nuclear EoS and related perspectives. Our study provides a simple, but microscopically motivated modeling of the energetics of clusterized matter at subsaturation densities, for direct use in consequential applications of astrophysical interest.

Published
2013

25. Constrained caloric curves and phase transition for hot nuclei

Author

N. Le Neindre, G. Ademard, A. Chbihi, Piotr Pawłowski, P. Lautesse, E. Galichet, D. Guinet, R. Roy, Paola Marini, Eric Bonnet, M. Pârlog, E. Rosato, O. Lopez, R. Bougault, J.D. Frankland, Diego Gruyer, Ad. R. Raduta, M.F. Rivet, Mariano Vigilante, S. Piantelli, B. Borderie, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Istituto Nazionale di Fisica Nucleare, Sezione di Firenze (INFN, Sezione di Firenze), Istituto Nazionale di Fisica Nucleare (INFN), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Conservatoire National des Arts et Métiers [CNAM] (CNAM), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Sciences et Société, Historicité, Éducation et Pratiques (EA S2HEP), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Institute of Nuclear Physics PAN (IFJ-PAN), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Istituto Nazionale di Fisica Nucleare, Sezione di Napoli (INFN, Sezione di Napoli), Laboratoire de Physique Nucléaire, Université Laval [Québec] (ULaval), INDRA Collaboration, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), B., Borderie, S., Piantelli, M. F., Rivet, Raduta, A. d. R., G., Ademard, E., Bonnet, R., Bougault, A., Chbihi, J. D., Frankland, E., Galichet, D., Gruyer, D., Guinet, Lautesse, P. h., N., Le Neindre, O., Lopez, P., Marini, M., Pârlog, P., Pawlowski, Rosato, Elio, R., Roy, and Vigilante, Mariano

Subjects
Nuclear and High Energy Physics, Phase transition, nucl-th, Nuclear Theory, Proton, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], FOS: Physical sciences, Monotonic function, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], nucl-ex, 7. Clean energy, 01 natural sciences, Nuclear Theory (nucl-th), Caloric curves, 0103 physical sciences, Thermal, Quasi-fusion reactions Nuclear multifragmentation Caloric curves First order phase transition, Quasi-fusion reactions, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Range (particle radiation), nuclear multifragmentation, 010308 nuclear & particles physics, Caloric theory, first order phase transition, Atomic physics, Event (particle physics), Excitation
Abstract

Simulations based on experimental data obtained from multifragmenting quasi-fused nuclei produced in central $^{129}$Xe + $^{nat}$Sn collisions have been used to deduce event by event freeze-out properties in the thermal excitation energy range 4-12 AMeV [Nucl. Phys. A809 (2008) 111]. From these properties and the temperatures deduced from proton transverse momentum fluctuations, constrained caloric curves have been built. At constant average volumes caloric curves exhibit a monotonic behaviour whereas for constrained pressures a backbending is observed. Such results support the existence of a first order phase transition for hot nuclei., 14 pages, 5 figures, accepted in Physics Letters B

Published
2013

26. α-clustering effects in dissipative12C+12C reactions at 95 MeV

Author

Giovanni Casini, V. L. Kravchuk, Tommaso Marchi, Giorgio Baiocco, F. Gramegna, Luca Morelli, M. D'Agostino, M. Cinausero, Ad. R. Raduta, M. Bruno, Sandro Barlini, Maurizio Bini, Francesca Gulminelli, Alessandro Olmi, S. Carboni, U. Abbondanno, Gabriele Pasquali, Silvia Piantelli, and M. Degerlier

Subjects
Physics, Nuclear and High Energy Physics, 010308 nuclear & particles physics, Evaporation, Charge (physics), 01 natural sciences, Coincidence, Distribution (mathematics), Excited state, 0103 physical sciences, Dissipative system, Cluster (physics), Atomic physics, 010306 general physics, Cluster analysis
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 their complete evaporation chain. Residual deviations from a statistical behaviour are observed in \alpha yields and attributed to the persistence of cluster correlations well above the 24Mg threshold for 6 \alpha's decay.

Published
2013

27. Strangeness-driven phase transition in (proto)- neutron star matter

Author

Francesca Gulminelli, M. Oertel, Ad. R. Raduta, and Jérôme Margueron

Subjects
Physics, Nuclear and High Energy Physics, Phase transition, Particle physics, Nuclear Theory, 010308 nuclear & particles physics, FOS: Physical sciences, Strangeness, 01 natural sciences, Electric charge, Nuclear physics, Baryon, Nuclear Theory (nucl-th), Critical point (thermodynamics), 0103 physical sciences, Neutrino, 010306 general physics, Nuclear Experiment, Lepton, Phase diagram
Abstract

The phase diagram of a system constituted of neutrons, protons, $\Lambda$-hyperons and electrons is evaluated in the mean-field approximation in the complete three-dimensional space given by the baryon, lepton and strange charge. It is shown that the phase diagram at sub-saturation densities is strongly affected by the electromagnetic interaction, while it is almost independent of the electric charge at supra-saturation density. As a consequence, stellar matter under the condition of strangeness equilibrium is expected to experience a first as well as a second-order strangeness-driven phase transition at high density, while the liquid-gas phase transition is expected to be quenched. An RPA calculation indicates that the presence of this critical point might have sizable implications for the neutrino propagation in core-collapse supernovae., Comment: 7 pages, 5 figures; accepted for publication in Phys. Rev. C

Published
2013
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28. Clusterized nuclear matter in the (proto-)neutron star crust and the symmetry energy

Author

François Aymard, Ad. R. Raduta, Francesca Gulminelli, Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear and High Energy Physics, Equation of state, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Nuclear Theory (nucl-th), 0103 physical sciences, Nuclear fusion, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Solar and Stellar Astrophysics (astro-ph.SR), Physics, Isovector, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 010308 nuclear & particles physics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Nuclear matter, Symmetry (physics), Baryon, Neutron star, Astrophysics - Solar and Stellar Astrophysics, Isospin
Abstract

Though generally agreed that the symmetry energy plays a dramatic role in determining the structure of neutron stars and the evolution of core-collapsing supernovae, little is known in what concerns its value away from normal nuclear matter density and, even more important, the correct definition of this quantity in the case of unhomogeneous matter. Indeed, nuclear matter traditionally addressed by mean-field models is uniform while clusters are known to exist in the dilute baryonic matter which constitutes the main component of compact objects outer shells. In the present work we investigate the meaning of symmetry energy in the case of clusterized systems and the sensitivity of the proto-neutron star composition and equation of state to the effective interaction. To this aim an improved Nuclear Statistical Equilibrium (NSE) model is developed, where the same effective interaction is consistently used to determine the clusters and unbound particles energy functionals in the self-consistent mean-field approximation. In the same framework, in-medium modifications to the cluster energies due to the presence of the nuclear gas are evaluated. We show that the excluded volume effect does not exhaust the in-medium effects and an extra isospin and density dependent energy shift has to be considered to consistently determine the composition of subsaturation stellar matter. The symmetry energy of diluted matter is seen to depend on the isovector properties of the effective interaction, but its behavior with density and its quantitative value are strongly modified by clusterization., Comment: A contribution to the upcoming EPJA Special Volume on Nuclear Symmetry Energy

Published
2013
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29. Impact of pairing on thermodynamical properties of stellar matter

Author

Maria Colonna, Francesca Gulminelli, François Aymard, S. Burrello, Ad. R. Raduta, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, QC1-999, Crust, Fermion, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Heat capacity, Physics::Geophysics, Superfluidity, Stars, Neutron star, Pairing, 0103 physical sciences, Statistical physics, 010306 general physics, Nucleon
Abstract

International audience; Superfluidity in the crust is a key ingredient for the cooling properties of proto-neutron stars. Investigations on crust superfluidity carried out so far typically assumed that the cluster component was given by a single representative nucleus and did not consider the fact that at finite temperature a wide distribution of nuclei is expected to be populated at a given crust pressure condition. We want to assess the importance of this distribution on the calculation of the heat capacity in the inner crust, in the framework of an extended NSE model. We additionally show that it is very important to consider the temperature evolution of the proton fraction, imposed by the β-equilibrium condition, for a quantitatively reliable estimation of the heat capacity.

Published
2016

30. Constrained caloric curves for hot nuclei

Author

Silvia Piantelli, Bernard Borderie, M.F. Rivet, and Ad. R. Raduta

Subjects
Physics, Phase transition, Range (particle radiation), QC1-999, Nuclear Theory, Caloric theory, Thermal, Statistical physics, Atomic physics, Constant (mathematics), Nuclear Experiment, Event (particle physics), Excitation
Abstract

Simulations based on experimental data obtained from multifragmenting quasi-fused nuclei produced in central 129 Xe + nat Sn collisions have been used to deduce event by event freeze-out properties on the thermal excitation energy range 4-12 AMeV. From such properties, information on constrained caloric curves has been derived. At constant average volumes caloric curves exhibit a monotonous behaviour whereas for constrained pressures backbending is observed. Such results support the existence of a first order phase transition for hot nuclei.

Published
2012

31. Direct evidence of α-particle condensation for the Hoyle state

Author

Ad. R. Raduta, N. Le Neindre, B. Borderie, M. F. Rivet, P. Napolitani, E. Geraci, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and ISOSPIN

Subjects
Nuclear reaction, Physics, 010308 nuclear & particles physics, Direct evidence, QC1-999, Molecular configuration, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Kinetic energy, 01 natural sciences, Charged particle, Fragmentation (mass spectrometry), Excited state, 0103 physical sciences, Atomic physics, 010306 general physics, Nucleon, Nuclear Experiment
Abstract

International audience; The fragmentation of quasi-projectiles from the nuclear reaction 40Ca+12C at 25 MeV/nucleon was used to produce excited states candidates to α-particle condensation. Complete kinematic characterization of individual decay events, made possible by the CHIMERA high-granularity 4π charged particle multi-detector, reveals that 7.5±4.0 % of the Hoyle state particle decays correspond to direct decays in three equal-energy α-particles. Moreover, events with increased kinetic energy dispersion in the 12C center of mass, which amount to 9.5±4.0 %, point toward the occurrence of a second competing molecular configuration, of a linear α-chain.

Published
2012

32. The behaviour of constrained caloric curves as ultimate signature of a phase transition for hot nuclei

Author

Bernard Borderie, A. Chbihi, E. Galichet, O. Lopez, N. Le Neindre, E. Rosato, Mariano Vigilante, G. Spadaccini, D. Guinet, E. Vient, Ad. R. Raduta, M. Parlog, R. Bougault, R. Roy, M. F. Rivet, Silvia Piantelli, Eric Bonnet, P. Lautesse, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Istituto Nazionale di Fisica Nucleare, Sezione di Firenze (INFN, Sezione di Firenze), Istituto Nazionale di Fisica Nucleare (INFN), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Istituto Nazionale di Fisica Nucleare, Sezione di Napoli (INFN, Sezione di Napoli), Laboratoire de Physique Nucléaire, Université Laval [Québec] (ULaval), B.A.Li and J.B.Natowitz, B., Borderie, S. Piantelli M. F., Rivet, A., Raduta, E., Bonnet, R., Bougault, A., Chbihi, E., Galichet, D., Guinet, P., Lautesse, N., Le Neindre, O., Lopez, M., Parlog, Rosato, Elio, R., Roy, Spadaccini, Giulio, E., Vient, Vigilante, Mariano, Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
History, Phase transition, Nuclear Theory, Proton, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, Education, Nuclear Theory (nucl-th), 0103 physical sciences, Thermal, Nuclear Experiment (nucl-ex), 010306 general physics, Nuclear Experiment, Physics, Range (particle radiation), 010308 nuclear & particles physics, Caloric theory, Computer Science Applications, Atomic physics, 21.65.-f Nuclear matter 25.70.Pq Multifragment emission and correlations 24.60.Ky Fluctuation phenomena, Constant (mathematics), Event (particle physics), Excitation
Abstract

Simulations based on experimental data obtained from multifragmenting quasifused nuclei produced in central 129Xe + natSn collisions have been used to deduce event by event freeze-out properties on the thermal excitation energy range 4-12 AMeV. From these properties and temperatures deduced from proton transverse momentum fluctuations constrained caloric curves have been built. At constant average volumes caloric curves exhibit a monotonous behaviour whereas for constrained pressures a backbending is observed. Such results support the existence of a first order phase transition for hot nuclei., Comment: 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas : United States (2012)

Published
2012

33. Phase transition towards strange matter

Author

Francesca Gulminelli, Ad. R. Raduta, M. Oertel, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)

Subjects
Physics, Thermal equilibrium, Quantum phase transition, [PHYS]Physics [physics], Nuclear and High Energy Physics, Phase transition, Condensed matter physics, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, FOS: Physical sciences, Strangeness, 01 natural sciences, Nuclear Theory (nucl-th), Baryon, Neutron star, Strange matter, 0103 physical sciences, 010306 general physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Nuclear Experiment, Phase diagram
Abstract

The phase diagram of a system constituted of neutrons and $\Lambda$-hyperons in thermal equilibrium is evaluated in the mean-field approximation. It is shown that this simple system exhibits a complex phase diagram with first and second order phase transitions. Due to the generic presence of attractive and repulsive couplings, the existence of phase transitions involving strangeness appears independent of the specific interaction model. In addition we will show under which conditions a phase transition towards strange matter at high density exists, which is expected to persist even within a complete treatment including all the different strange and non- strange baryon states. The impact of this transition on the composition of matter in the inner core of neutron stars is discussed., Comment: 10 pages, 8 figures

Published
2012

34. Phase diagram of neutron-rich nuclear matter and its impact on astrophysics

Author

Micaela Oertel, Panagiota Papakonstantinou, Jérôme Margueron, Francesca Gulminelli, Ad. R. Raduta, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
History, Phase transition, Equation of state, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Particle physics and field theory, Astrophysics::High Energy Astrophysical Phenomena, Degrees of freedom (physics and chemistry), Nuclear physics, FOS: Physical sciences, 01 natural sciences, Education, Nuclear Theory (nucl-th), Astrophysics and astroparticles, Phase (matter), 0103 physical sciences, Neutron, 010303 astronomy & astrophysics, Physics, 010308 nuclear & particles physics, Nuclear matter, Computer Science Applications, Supernova, Neutron star, 21.65.-f Nuclear matter, 97.60.Jd Neutron stars, 95.30.Cq Elementary particle processes, 97.60.Bw Supernovae, 24.10.Pa Thermal and statistical models, 26.50.+x Nuclear physics aspects of novae, supernovae, and other explosive environments
Abstract

Dense matter as it can be found in core-collapse supernovae and neutron stars is expected to exhibit different phase transitions which impact the matter composition and equation of state, with important consequences on the dynamics of core-collapse supernova explosion and on the structure of neutron stars. In this paper we will address the specific phenomenology of two of such transitions, namely the crust-core solid-liquid transition at sub-saturation density, and the possible strange transition at super-saturation density in the presence of hyperonic degrees of freedom. Concerning the neutron star crust-core phase transition at zero and finite temperature, it will be shown that, as a consequence of the presence of long-range Coulomb interactions, the equivalence of statistical ensembles is violated and a clusterized phase is expected which is not accessible in the grand-canonical ensemble. A specific quasi-particle model will be introduced to illustrate this anomalous thermodynamics and some quantitative results relevant for the supernova dynamics will be shown. The opening of hyperonic degrees of freedom at higher densities corresponding to the neutron stars core modifies the equation of state. The general characteristics and order of phase transitions in this regime will be analyzed in the framework of a self-consistent mean-field approach., Comment: Invited Talk given at the 11th International Conference on Nucleus-Nucleus Collisions (NN2012), San Antonio, Texas, USA, May 27-June 1, 2012. To appear in the NN2012 Proceedings in Journal of Physics: Conference Series (JPCS)

Published
2012
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35. Search for $\alpha$-particle condensation in nuclei from the Hoyle state deexcitation

Author

M. B. Chatterjee, M. F. Rivet, E. Geraci, A. Pagano, B. Borderie, F. Rizzo, P. Napolitani, O. Lopez, I. Lombardo, D. Guinet, P. Russotto, F. Porto, G. Cardella, P. Lautesse, E. La Guidara, G. Lanzano, S. Pirrone, Ad. R. Raduta, G. Lanzalone, F. Amorini, G. Politi, J.P. Wieleczko, R. Alba, N. Le Neindre, E. De Filippo, C. Maiolino, Institut de Physique Nucléaire d'Orsay (IPNO), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique Nucléaire de Lyon (IPNL), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Grand Accélérateur National d'Ions Lourds (GANIL), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear reaction, Physics, History, 010308 nuclear & particles physics, Molecular configuration, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Kinetic energy, 01 natural sciences, 7. Clean energy, Projectile and target fragmentation, Binding energies and masses, Alpha decay, Charged particle, Computer Science Applications, Education, Nuclear physics, Fragmentation (mass spectrometry), Excited state, 0103 physical sciences, Nuclear Experiment, 010306 general physics, Nucleon, α particles, ComputingMilieux_MISCELLANEOUS
Abstract

Heavy ion reactions induced by few tens MeV/nucleon beams constitute an ideal framework for producing and studying nuclear excited states close to the decay threshold. The fragmentation of quasi-projectiles from the nuclear reaction 40Ca+12C at 25 MeV/nucleon performed at LNS-Catania was employed in order to populate the Hoyle state of 12C and investigate the theoretically predicted molecular structures. Complete kinematic characterization of individual decay events, made possible by the CHIMERA high-granularity 4π charged particle multi-detector, reveals that 7.5±4.0% of the particle decays of the Hoyle state correspond to direct decays in three equal-energy α-particles and thus fulfill the decay criteria of an α-particle condensate. Moreover, events with increased kinetic energy dispersion in the 12C center of mass, which amount to 9.5±4.0%, point toward the occurrence of a second competing molecular configuration, a linear α-chain type. Both α-particle condensate and linear chain structures have been theoretically predicted but, to our knowledge, not experimentally confirmed so far.

Published
2012

36. Experimental evidence for alpha-particle condensation from the Hoyle state deexcitation

Author

N. Le Neindre, M. F. Rivet, Ad. R. Raduta, P. Napolitani, B. Borderie, E. Geraci, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Nuclear reaction, History, Direct evidence, High granularity, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Experimental evidence, Education, Cluster Models, Nuclear physics, Projectile and Target Fragmentation, Particle decay, Fragmentation (mass spectrometry), 0103 physical sciences, Kinematic characterization, 010306 general physics, Nuclear Experiment, Multi-particle correlation, Physics, 010308 nuclear & particles physics, Alpha particle, Computer Science Applications, Excited state, De-excitations, Granularity, Nuclear reactions, Atomic physics
Abstract

International audience; Fragmentation of quasi-projectiles from the nuclear reaction 40Ca+12C was used to produce excited states candidates to alpha-particle condensation. The methodology relies on high granularity 4π detection coupled to multi-particle correlations. Complete kinematic characterization reveals that 7.5±4.0% of the Hoyle state particle decays correspond to direct decay into three equal-energy alpha-particles. This is the first direct evidence for alpha-particle condensation in nuclei.

Published
2011

37. Statistical (?) decay of light hot nuclei

Author

Francesca Gulminelli, Giorgio Baiocco, M. Bruno, Luca Morelli, Ad. R. Raduta, M. D'Agostino, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Light nucleus, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, QC1-999, Monte Carlo method, Astrophysics, 01 natural sciences, Nuclear physics, Particle emission, 0103 physical sciences, 010306 general physics, Nuclear Experiment, Beam energy, Excitation
Abstract

International audience; The reaction 12C+12C at 95 MeV beam energy has been measured using the GARFIELD+RCo apparatuses at Laboratori Nazionali di Legnaro LNL - INFN, Italy, in the framework of an experimental campaign proposed by the NUCL-EX collaboration. The aim is to progress in the understanding of statistical properties of light nuclei at excitation energies above particle emission thresholds, by measuring exclusive fusion-evaporation data. A theoretical study of the system, performed with a newly developed Monte Carlo Hauser-Feshbach code, is shown, together with preliminary results of the data analysis.

Published
2011

38. Ensemble in-equivalence in supernova matter within a simple model

Author

Francesca Gulminelli, Ad. R. Raduta, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
64.60.-i, 64.10.+h, 26.50.+x, 26.60.-c, Canonical ensemble, Statistical ensemble, Physics, Nuclear and High Energy Physics, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Nuclear Theory, 010308 nuclear & particles physics, FOS: Physical sciences, Observable, Nuclear matter, 01 natural sciences, Nuclear Theory (nucl-th), Grand canonical ensemble, Microcanonical ensemble, Astrophysics - Solar and Stellar Astrophysics, 0103 physical sciences, Open statistical ensemble, Statistical physics, 010306 general physics, Phenomenology (particle physics), Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

A simple, exactly solvable statistical model is presented for the description of baryonic matter in the thermodynamic conditions associated to the evolution of core-collapsing supernova. It is shown that the model presents a first-order phase transition in the grand-canonical ensemble which is not observed in the canonical ensemble. Similarly to other model systems studied in condensed matter physics, this ensemble inequivalence is accompanied by negative susceptibility and discontinuities in the intensive observables conjugated to the order parameter. This peculiar behavior originates from the fact that baryonic matter is subject to attractive short-range strong forces as well as repulsive long-range electromagnetic interactions, partially screened by a background of electrons. As such, it is expected in any theoretical treatment of nuclear matter in the stellar environment. Consequences for the phenomenology of supernova dynamics are drawn.

Published
2011
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39. Reaction mechanisms and staggering in S+Ni collisions

Author

Giovanni Casini, M. DʼAgostino, E. Geraci, Luca Morelli, A. Ordine, V. L. Kravchuk, A. Moroni, Francesca Gulminelli, Ad. R. Raduta, F. Cannata, M. Bruno, L. Bardelli, Tommaso Marchi, F. Gramegna, Sandro Barlini, Giorgio Baiocco, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), M. DʼAgostino, M. Bruno, F. Gulminelli, L. Morelli, G. Baiocco, L. Bardelli, S. Barlini, F. Cannata, G. Casini, E. Geraci, F. Gramegna, V.L. Kravchuk, T. Marchi, A. Moroni, A. Ordine, and Ad.R. Raduta

Subjects
Nuclear reaction, Nuclear and High Energy Physics, Reaction mechanism, measured fragment yield and charge distribution, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], HEAVY ION REACTIONS, 01 natural sciences, odd-even effects, Fragment size, 0103 physical sciences, measured fragment yield and charge distribution, deduced reaction mechanism features, odd–even effects, Comparison with GEMINI evaporation model, NUCLEAR REACTIONS, 58,64Ni(32S, X), E=463 MeV, Neutron, 010306 general physics, Nuclear Experiment, X), Physics, NUCLEAR REACTIONS, GARFIELD detector array and ring counter, 010308 nuclear & particles physics, odd–even effects, technology, industry, and agriculture, 64Ni(32S, staggering, deduced reaction mechanism features, Pairing, Atomic physics, E=463 MeV, Excitation
Abstract

The reactions 32S + 58Ni and 32S + 64Ni are studied at 14.5 A MeV. After a selection of the collision mechanism, we show that important even-odd effects are present in the isotopic fragment distributions when the excitation energy is small. Close to the multifragmentation threshold this staggering appears hidden by the rapid variation of the production yields with the fragment size. Once this effect is accounted for, the staggering appears to be a universal feature of fragment production, slightly enhanced when the emission source is neutron poor. A closer look at the behavior of the production yields as a function of the neutron excess N−Z, reveals that odd-even effects cannot be explained by pairing effects in the nuclear masses alone, but depend in a more complex way on the de-excitation chain.

Published
2011

40. Evidence for $\alpha$-particle condensation in nuclei from the Hoyle state deexcitation

Author

E. Geraci, S. Pirrone, P. Lautesse, G. Lanzalone, M. F. Rivet, R. Alba, E. De Filippo, F. Amorini, E. La Guidara, M. B. Chatterjee, G. Lanzano, I. Lombardo, A. Pagano, B. Borderie, P. Russotto, P. Napolitani, O. Lopez, F. Porto, F. Rizzo, D. Guinet, G. Cardella, N. Le Neindre, C. Maiolino, Ad. R. Raduta, J.P. Wieleczko, G. Politi, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, Nuclear and High Energy Physics, Correlation functions, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 7. Clean energy, 01 natural sciences, Nuclear physics, Fragmentation (mass spectrometry), Cluster model, 0103 physical sciences, Heavy ion reactions, Nuclear structure, Nuclear Experiment, 010306 general physics, α-particle condensation, Physics, 010308 nuclear & particles physics, Charged particle, 3. Good health, Excited state, Atomic physics, Nucleon, α particles
Abstract

The fragmentation of quasi-projectiles from the nuclear reaction $^{40}$Ca+$^{12}$C at 25 MeV/nucleon was used to produce excited states candidates to $\alpha$-particle condensation. Complete kinematic characterization of individual decay events, made possible by a high-granularity 4$\pi$ charged particle multi-detector, reveals that 7.5$\pm$4.0% of the particle decays of the Hoyle state correspond to direct decays in three equal-energy $\alpha$-particles., Comment: Phys. Lett. B, in press

Published
2011

41. New scaling in nuclear fragmentation

Author

R. Roy, B. Zwieglinski, R. Bougault, Ad. R. Raduta, J.P. Wieleczko, Paola Marini, M. Pârlog, P. Lautesse, A. Chbihi, B. Borderie, G. Spadaccini, M.F. Rivet, J. Lukasik, F. Gagnon-Moisan, Eric Bonnet, N. Le Neindre, Mariano Vigilante, Elio Rosato, J.D. Frankland, E. Galichet, D. Guinet, E., Bonnet, B., Borderie, N., Le Neindre, Raduta, A. d. R., M. F., Rivet, R., Bougault, A., Chbihi, J. D., Frankland, E., Galichet, F., Gagnon Moisan, D., Guinet, P., Lautesse, J., Łukasik, P., Marini, M., Pârlog, Rosato, Elio, R., Roy, Spadaccini, Giulio, Vigilante, Mariano, J. P., Wieleczko, B., Zwieglinski, Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), National Institute for Physics and Nuclear Engineering (NIPNE), National Institute for Physics and Nuclear Engineering, Conservatoire National des Arts et Métiers [CNAM] (CNAM), Laboratoire de Physique Nucléaire, Université Laval [Québec] (ULaval), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institute of Nuclear Physics (IFJ-PAN), Institute of Nuclear Physics, Dipartimento di Scienze Fisiche e Sezione INFN, Istituto Nazionale di Fisica Nucleare (INFN)-Università degli studi di Napoli Federico II, The Andrzej Soltan Institute for Nuclear Studies, The Andrzej Soltan Institute of Nuclear Studies, INDRA, ALADIN, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Istituto Nazionale di Fisica Nucleare (INFN)-University of Naples Federico II = Università degli studi di Napoli Federico II

Subjects
Nuclear reaction, Hadron, Nuclear Theory, FOS: Physical sciences, General Physics and Astronomy, Elementary particle, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, fragmentation, 0103 physical sciences, central and peripheral collisions, Nuclear Experiment (nucl-ex), Multiplicity (chemistry), 010306 general physics, Nuclear Experiment, PACS, Physics, 010308 nuclear & particles physics, scaling, finite system, Fermion, Baryon, Atomic physics, Nucleon, Excitation, fragment charge partition
Abstract

Fragment partitions of fragmenting hot nuclei produced in central and semiperipheral collisions have been compared in the excitation energy region 4-10 MeV per nucleon where radial collective expansion takes place. It is shown that, for a given total excitation energy per nucleon, the amount of radial collective energy fixes the mean fragment multiplicity. It is also shown that, at a given total excitation energy per nucleon, the different properties of fragment partitions are completely determined by the reduced fragment multiplicity (fragment multiplicity normalized to the source size). Freeze-out volumes seem to play a role in the scalings observed., Comment: 4 pages, submitted to PRL

Published
2010

42. Statistical description of complex nuclear phases in supernovae and proto-neutron stars

Author

Francesca Gulminelli, Ad. R. Raduta, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), and Guesnon, Sandrine

Subjects
[PHYS.NUCL] Physics [physics]/Nuclear Theory [nucl-th], Physics, Nuclear and High Energy Physics, Particle physics, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, FOS: Physical sciences, Elementary particle, Fermion, Nuclear matter, 01 natural sciences, Nuclear Theory (nucl-th), Nuclear physics, Neutron star, Astrophysics - Solar and Stellar Astrophysics, 0103 physical sciences, Neutrino, 010306 general physics, Nucleon, Nuclear Experiment, Mass fraction, Solar and Stellar Astrophysics (astro-ph.SR), Nuclear density
Abstract

We develop a phenomenological statistical model for dilute star matter at finite temperature, in which free nucleons are treated within a mean-field approximation and nuclei are considered to form a loosely interacting cluster gas. Its domain of applicability, that is baryonic densities ranging from about $��>10^8$ g $\cdot$ cm$^{-3}$ to normal nuclear density, temperatures between 1 and 20 MeV and proton fractions between 0.5 and 0, make it suitable for the description of baryonic matter produced in supernovae explosions and proto-neutron stars. The first finding is that, contrary to the common belief, the crust-core transition is not first order, and for all subsaturation densities matter can be viewed as a continuous fluid mixture between free nucleons and massive nuclei. As a consequence, the equations of state and the associated observables do not present any discontinuity over the whole thermodynamic range. We further investigate the nuclear matter composition over a wide range of densities and temperatures. At high density and temperature our model accounts for a much larger mass fraction bound in medium nuclei with respect to traditional approaches as Lattimer-Swesty, with sizeable consequences on the thermodynamic quantities. The equations of state agree well with the presently used EOS only at low temperatures and in the homogeneous matter phase, while important differences are present in the crust-core transition region. The correlation among the composition of baryonic matter and neutrino opacity is finally discussed, and we show that the two problems can be effectively decoupled., 40 pages, 25 figures

Published
2010

43. The prominent role of the heaviest fragment in multifragmentation and phase transition for hot nuclei

Author

B. Tamain, Elio Rosato, Bernard Borderie, R. Roy, M. Parlog, M.F. Rivet, R. Dayras, Ad. R. Raduta, D. Mercier, R. Bougault, J.P. Wieleczko, E. Galichet, A. Chbihi, D. Guinet, J.D. Frankland, Eric Bonnet, F. Gagnon-Moisan, J. Lukasik, N. Le Neindre, Francesca Gulminelli, Silvia Piantelli, Mariano Vigilante, P. Lautesse, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Conservatoire National des Arts et Métiers [CNAM] (CNAM), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de Physique Nucléaire, Université Laval [Québec] (ULaval), Dipartimento di Scienze Fisiche e Sezione INFN, Istituto Nazionale di Fisica Nucleare (INFN)-Università degli studi di Napoli Federico II, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institute of Nuclear Physics (IFJ-PAN), Institute of Nuclear Physics, INDRA and ALADIN, B., Borderie, E., Bonnet, N., Le Neindre, S., Piantelli, Raduta, A. d. A., M. F., Rivet, E., Galichet, F., Gulminelli, D., Mercier, B., Tamain, R., Bougault, M., Parlog, J. D., Frankland, A., Chbihi, J. P., Wieleczko, D., Guinet, P., Lautesse, F., Gagnon Moisan, R., Roy, Vigilante, Mariano, Rosato, Elio, R., Dayra, J., Lukasik, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), and Istituto Nazionale di Fisica Nucleare (INFN)-University of Naples Federico II = Università degli studi di Napoli Federico II

Subjects
Physics, Nuclear and High Energy Physics, Phase transition, Fisica nucleare, 010308 nuclear & particles physics, Mean value, Nuclear Theory, General Physics and Astronomy, Charge density, FOS: Physical sciences, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, Nuclear physics, Fragment (logic), 0103 physical sciences, reazioni nucleari, Nuclear Experiment (nucl-ex), multiframmentazione, 010306 general physics, Nuclear Experiment
Abstract

The role played by the heaviest fragment in partitions of multifragmenting hot nuclei is emphasized. Its size/charge distribution (mean value, fluctuations and shape) gives information on properties of fragmenting nuclei and on the associated phase transition., Comment: 11 pages, Proceedings of IWND09, August 23-25, Shanghai (China)

Published
2009

44. Break-up fragment topology in statistical multifragmentation models

Author

Ad. R. Raduta, Institut de Physique Nucléaire d'Orsay (IPNO), and Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11)

Subjects
Physics, [STAT.AP]Statistics [stat]/Applications [stat.AP], Nuclear and High Energy Physics, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Break-Up, 010308 nuclear & particles physics, FOS: Physical sciences, Statistical model, Kinematics, Kinetic energy, 01 natural sciences, Coulomb repulsion, Nuclear Theory (nucl-th), Fragmentation (mass spectrometry), 0103 physical sciences, Atomic physics, Nuclear Experiment, 010306 general physics, Nuclear theory, Excitation
Abstract

Break-up fragmentation patterns together with kinetic and configurational energy fluctuations are investigated in the framework of a microcanonical model with fragment degrees of freedom over a broad excitation energy range. As far as fragment partitioning is approximately preserved, energy fluctuations are found to be rather insensitive to both the way in which the freeze-out volume is constrained and the trajectory followed by the system in the excitation energy - freeze-out volume space. Due to hard-core repulsion, the freeze-out volume is found to be populated un-uniformly, its highly depleted core giving the source a bubble-like structure. The most probable localization of the largest fragments in the freeze-out volume may be inferred experimentally from their kinematic properties, largely dictated by Coulomb repulsion.

Published
2009

45. Thermodynamics of clusterized matter

Author

Francesca Gulminelli, Ad. R. Raduta, Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear and High Energy Physics, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Nuclear Theory, 010308 nuclear & particles physics, Finite system, FOS: Physical sciences, Thermodynamics, Statistical model, Electron, 01 natural sciences, Surface energy, Nuclear Theory (nucl-th), Neutron star, Homogeneous, Critical point (thermodynamics), Quantum mechanics, 0103 physical sciences, 25.70.Mn, 64.70.F, 26.60.-c, 64.60.an, Statistical physics, 010306 general physics, Phase diagram
Abstract

Thermodynamics of clusterized matter is studied in the framework of statistical models with non-interacting cluster degrees of freedom. At variance with the analytical Fisher model, exact Metropolis simulation results indicate that the transition from homogeneous to clusterized matter lies along the $\rho=\rho_0$ axis at all temperatures and the limiting point of the phase diagram is not a critical point even if the surface energy vanishes at this point. Sensitivity of the inferred phase diagram to the employed statistical framework in the case of finite systems is discussed by considering the grand-canonical and constant-pressure canonical ensembles. A Wigner-Seitz formalism in which the fragment charge is neutralized by an uniform electron distribution allows to build the phase diagram of neutron star matter., Comment: 18 pages, 9 figures

Published
2009

46. Multifragmentation and phase transition for hot nuclei: recent progress

Author

R. Dayras, Bernard Borderie, B. Tamain, E. Bonnet, A. Chbihi, D. Guinet, J.D. Frankland, R. Bougault, Mariano Vigilante, E. Galichet, Francesca Gulminelli, Ad. R. Raduta, Elio Rosato, J. Lukasik, P. Lautesse, D. Mercier, S. Piantelli, F. Gagnon-Moisan, M. Pârlog, N. Le Neindre, J.P. Wieleczko, M.F. Rivet, René Roy, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), ALADIN, INDRA, B., Borderie, E., Bonnet, F., Gulminelli, N., Le Neindre, D., Mercier, S., Piantelli, Raduta, A. d. A., M. F., Rivet, B., Tamain, R., Bougault, A., Chbihi, R., Dayra, J. D., Frankland, E., Galichet, F., Gagnon Moisan, D., Guinet, P., Lautesse, J., Lukasik, M., Parlog, Rosato, Elio, R., Roy, Vigilante, Mariano, J. P., Wieleczko, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nuclear reaction, Physics, Nuclear and High Energy Physics, Phase transition, 010308 nuclear & particles physics, Nuclear Theory, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, 7. Clean energy, fisica nucleare multiframmentazione nucleare transizione di fase della materia nucleare, Nuclear physics, Latent heat, 0103 physical sciences, 010306 general physics, Nuclear Experiment, Simulation based
Abstract

International audience; Recent important progress on the knowledge of multifragmentation and phase transition for hot nuclei, thanks to the high detection quality of the INDRA array, is reported. It concerns i) the radial collective energies involved in hot fragmenting nuclei/sources produced in central and semi-peripheral collisions and their influence on the observed fragment partitions, ii) a better knowledge of freeze-out properties obtained by means of a simulation based on all the available experimental information and iii) the quantitative study of the bimodal behaviour of the heaviest fragment distribution for fragmenting hot heavy quasi-projectiles which allows the extraction, for the first time, of an estimate of the latent heat of the phase transition.

Published
2009

47. Freeze-out properties of multifragmentation events

Author

A. Chbihi, N. Le Neindre, J.D. Frankland, P. Lautesse, Bernard Tamain, Elio Rosato, O. Lopez, J. Moisan, E. Vient, Ad. R. Raduta, E. Galichet, S. Piantelli, F. Gagnon-Moisan, René Roy, R. Bougault, B. Borderie, R. Dayras, E. Bonnet, M. Pârlog, Mariano Vigilante, G. Lehaut, D. Mercier, D. Guinet, M. F. Rivet, J.P. Wieleczko, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Istituto Nazionale di Fisica Nucleare, Sezione di Firenze (INFN, Sezione di Firenze), Istituto Nazionale di Fisica Nucleare (INFN), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Grand Accélérateur National d'Ions Lourds (GANIL), Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Conservatoire National des Arts et Métiers [CNAM] (CNAM), Laboratoire de Physique Nucléaire, Université Laval [Québec] (ULaval), Institut de Physique Nucléaire de Lyon (IPNL), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Istituto Nazionale di Fisica Nucleare, Sezione di Napoli (INFN, Sezione di Napoli), INDRA, Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), S., Piantelli, B., Borderie, E., Bonnet, N., Le Neindre, Raduta, A. d. R., M. F., Rivet, R., Bougault, A., Chbihi, R., Dayra, J. D., Frankland, E., Galichet, F., Gagnon Moisan, D., Guinet, P., Lautesse, G., Lehaut, O., Lopez, D., Mercier, J., Moisan, M., Parlog, Rosato, Elio, R., Roy, B., Tamain, E., Vient, Vigilante, Mariano, and J. P., Wielezcko

Subjects
Nuclear reaction, Nuclear and High Energy Physics, Hadron, Elementary particle, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 01 natural sciences, central collisions, Nuclear physics, freeze-out properties estimated from fragment velocity distributions and charged particle energy spectra, E = 32, 0103 physical sciences, 25.70.-z, 25.70.Pq, 010306 general physics, X), Physics, 010308 nuclear & particles physics, comparison with a microcanonical statistical model, Fermion, Charged particle, Baryon, 50 MeV/nucleon, NUCLEAR REACTIONS natSn(129Xe, Atomic physics, Nucleon, Excitation
Abstract

Expérience GANIL; International audience; Freeze-out properties of multifragmentation events produced in central 129Xe+natSn collisions at different beam energies (32, 39, 45 and 50 AMeV) were estimated by means of a simulation based on the experimental data collected by the 4π INDRA multidetector. A rapid increase (between 32 and 45 AMeV) of the fraction of particles emitted at freeze-out is deduced. The existence of a limitation of excitation energy for fragments around 3.0-3.5 AMeV is confirmed. A comparison with the results of a microcanonical statistical model is also performed to verify the overall physical coherence of the present approach.

Published
2008

48. Multifragmentation and the symmetry term of the nuclear equation of state

Author

Francesca Gulminelli, Ad. R. Raduta, Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)

Subjects
Physics, Nuclear and High Energy Physics, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, FOS: Physical sciences, Nuclear equation of state, Observable, Residual, Nuclear matter, 01 natural sciences, Symmetry (physics), Term (time), Nuclear Theory (nucl-th), Nuclear physics, Excited state, 0103 physical sciences, 010306 general physics, Relevant information, 25.70.Pq, 21.30.Fe, 21.65.+f, 24.10.Pa
Abstract

We investigate the possibility to extract the symmetry energy from multifragmentation data. The applicability of the grandcanonical formula earlier proposed by Ono {\it et al.} [Phys. Rev. C {\bf 68}, 051601(R)] in the case of finite excited nuclei is tested within a microcanonical framework. Relatively good results are obtained except for large residual nuclei, especially when large sources are highly excited. Effects of secondary particle emission and the extent in which relevant information may be inferred from experimental observables are finally discussed., 13 pages, 4 figures

Published
2007

49. Break-up stage restoration in multifragmentation reactions

Author

N. Le Neindre, Ad. R. Raduta, Bernard Borderie, Eric Bonnet, M. F. Rivet, Silvia Piantelli, Institut de Physique Nucléaire d'Orsay (IPNO), Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Sud - Paris 11 (UP11), and Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Nuclear and High Energy Physics, Break-Up, Isotope, Nuclear Theory, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], 010308 nuclear & particles physics, FOS: Physical sciences, Decoupling (cosmology), Kinetic energy, 01 natural sciences, Spectral line, Nuclear physics, Nuclear Theory (nucl-th), 0103 physical sciences, Thermal, 010306 general physics, Nucleon, Nuclear Experiment, Excitation
Abstract

In the case of Xe+Sn at 32 MeV/nucleon multifragmentation reaction break-up fragments are built-up from the experimentally detected ones using evaluations of light particle evaporation multiplicities which thus settle fragment internal excitation. Freeze-out characteristics are extracted from experimental kinetic energy spectra under the assumption of full decoupling between fragment formation and energy dissipated in different degrees of freedom. Thermal kinetic energy is determined uniquely while for freeze-out volume - collective energy a multiple solution is obtained. Coherence between the solutions of the break-up restoration algorithm and the predictions of a multifragmentation model with identical definition of primary fragments is regarded as a way to select the true value. The broad kinetic energy spectrum of $^3$He is consistent with break-up genesis of this isotope., 17 pages, 5 figures

Published
2007

50. Comparisons of Statistical Multifragmentation and Evaporation Models for Heavy Ion Collisions

Author

Sergio R. Souza, A. Le Fèvre, R. Wada, W. A. Friedman, M. B. Tsang, W. Trautmann, Ad. R. Raduta, R. J. Charity, Dominique Durand, Al. H. Raduta, Francesca Gulminelli, R. Bougault, Laboratoire de physique corpusculaire de Caen (LPCC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Helmholtz zentrum für Schwerionenforschung GmbH (GSI), Horia Hulubei National Institute of Physics and Nuclear Engineering (NIPNE), IFIN-HH, Laboratori Nazionali del Sud (LNS), and Istituto Nazionale di Fisica Nucleare (INFN)

Subjects
Physics, Nuclear and High Energy Physics, 25.70.Mn - 25.70.Gh - 25.70.Pq, Hadron, Evaporation, FOS: Physical sciences, Observable, Statistical model, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], Nuclear physics, Nuclear fusion, Heavy ion, Statistical physics, Nuclear Experiment (nucl-ex), Nuclear Experiment
Abstract

The results from ten statistical multifragmentation models have been compared with each other using selected experimental observables. Even though details in any single observable may differ, the general trends among models are similar. Thus these models and similar ones are very good in providing important physics insights especially for general properties of the primary fragments and the multifragmentation process. Mean values and ratios of observables are also less sensitive to individual differences in the models. In addition to multifragmentation models, we have compared results from five commonly used evaporation codes. The fluctuations in isotope yield ratios are found to be a good indicator to evaluate the sequential decay implementation in the code. The systems and the observables studied here can be used as benchmarks for the development of statistical multifragmentation models and evaporation codes., To appear on Euorpean Physics Journal A as part of the Topical Volume "Dynamics and Thermodynamics with Nuclear Degrees of Freedom

Published
2006

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