Symmetry Energy of Dilute Warm Nuclear Matter

Cluster formation is a fundamental aspect of the equation of state (EOS) of warm and dense nuclear matter such as can be found in supernovae (SN). Similar matter can be studied in heavy-ion collisions (HIC). We use the experimental data of Qin et al. 2012 to test calculations of cluster formation and the role of in-medium modifications of cluster properties in SN EOSs. For the comparison between theory and experiment we use chemical equilibrium constants as the main observables. This reduces some of the systematic uncertainties and allows deviations from ideal gas behavior to be identified clearly. In the analysis, we carefully account for the differences between matter in SN and HIC. We find that, at the lowest densities, the experiment and all theoretical models are consistent with the ideal gas behavior. At higher densities ideal behavior is clearly ruled out and interaction effects have to be considered. The contributions of continuum correlations are of relevance in the virial expansion and remain a difficult problem to solve at higher densities. We conclude that at the densities and temperatures discussed mean-field interactions of nucleons, inclusion of all relevant light clusters, and a suppression mechanism of clusters at high densities have to be incorporated in the SN EOS.

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“…Refs. [6,7]. From theory, the necessity to account for medium effects on clusters is known since a long time.…”

Section: Introductionmentioning

confidence: 99%

“…To our knowledge, Ref. [6] is the first work with a clear statement on density effects in the EOS of clusterized matter deduced from experiments.…”

Section: Introductionmentioning

confidence: 99%

Constraining supernova equations of state with equilibrium constants from heavy-ion collisions

et al. 2015

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“…The mass fraction of different clusters has been calculated, and it was shown how clusters are suppressed with increasing density due to Pauli blocking. This quantum statistical approach that reproduces NSE and virial expansions in the low-density limit has been applied to supernova explosions [13] as well as to HIC to determine the symmetry energy in the low-density region [14].…”

Section: Introductionmentioning

confidence: 99%

Parametrization of light nuclei quasiparticle energy shifts and composition of warm and dense nuclear matter

Röpke

2011

Nuclear Physics A

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Correlations and the formation of bound states (nuclei) are essential for the properties of nuclear matter in equilibrium as well as in nonequilibrium. In a quantum statistical approach, quasiparticle energies are obtained for the light elements that reflect the influence of the medium. We present analytical fits for the quasiparticle energy shifts of light nuclei that can be used in various applications. This is a prerequisite for the investigation of warm and dense matter that reproduces the nuclear statistical equilibrium and virial expansions in the low-density limit as well as relativistic mean field and Brueckner Hartree-Fock approaches near saturation density.

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“…The topics of current interest are, for example, the improvements on the supernova and warm neutron star equations of state and thermodynamics [7,8] which include the multi-cluster composition of matter [9,10,11,12,13,14,15,16,17,18,19,20,21]. Another aspect of the problem is the effects of light clusters in intermediate energy heavy ion collisions [22,23,24,25,26,27] which were extensively studied using various methods, see for example [28,29,30]. Furthermore, the general many-body problem of bound state formation in nuclear medium is an outstanding problem on its own right [31,32,33,34,35,36,37,38,39,40,41,42].…”

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confidence: 99%

Composition of Nuclear Matter with Light Clusters and Bose–Einstein Condensation of $$\alpha $$ α Particles

et al. 2017

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The Bose-Einstein condensation of α partciles in the multicomponent environment of dilute, warm nuclear matter is studied. We consider the cases of matter composed of light clusters with mass numbers A ≤ 4 and matter that in addition these clusters contains 56 Fe nuclei. We apply the quasiparticle gas model which treats clusters as bound states with infinite life-time and binding energies independent of temperature and density. We show that the α particles can form a condensate at low temperature T ≤ 2 MeV in such matter in the first case. When the 56 Fe nucleus is added to the composition the cluster abundances are strongly modified at low temperatures, with an important implication that the α condensation at these temperatures is suppressed.

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Symmetry Energy of Dilute Warm Nuclear Matter

Cited by 163 publications

References 32 publications

Constraining supernova equations of state with equilibrium constants from heavy-ion collisions

Constraining supernova equations of state with equilibrium constants from heavy-ion collisions

Parametrization of light nuclei quasiparticle energy shifts and composition of warm and dense nuclear matter

Composition of Nuclear Matter with Light Clusters and Bose–Einstein Condensation of $$\alpha $$ α Particles

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