Composition and thermodynamics of nuclear matter with light clusters

Journal Article · Fri Jan 15 00:00:00 EST 2010 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.81.015803· OSTI ID:21388863

Typel, S ^[1]; Roepke, G ^[2]; Klaehn, T ^[3]; Blaschke, D ^[4]; Wolter, H H ^[5]

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1. Excellence Cluster Universe, Technische Universitaet Muenchen, Boltzmannstrasse 2, D-85748 Garching (Germany)
2. Institut fuer Physik, Universitaet Rostock, Universitaetsplatz 3, D-18051 Rostock (Germany)
3. Theory Group, Physics Division, Building 203, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)
4. Instytut Fizyki Teoretycznej, Uniwersytet Wroclawski, Max Born Place 9, 50-204 Wroclaw (Poland)
5. Fakultaet fuer Physik, Universitaet Muenchen, Am Coulombwall 1, D-85748 Garching (Germany)

We investigate nuclear matter at a finite temperature and density, including the formation of light clusters up to the alpha particle (1<=A<=4). The novel feature of this work is to include the formation of clusters as well as their dissolution due to medium effects in a systematic way using two many-body theories: a microscopic quantum statistical (QS) approach and a generalized relativistic mean-field (RMF) model. Nucleons and clusters are modified by medium effects. While the nucleon quasiparticle properties are determined within the RMF model from the scalar and vector self-energies, the cluster binding energies are reduced because of Pauli blocking shifts calculated in the QS approach. Both approaches reproduce the limiting cases of nuclear statistical equilibrium (NSE) at low densities and cluster-free nuclear matter at high densities. The treatment of the cluster dissociation is based on the Mott effect due to Pauli blocking, implemented in slightly different ways in the QS and the generalized RMF approaches. This leads to somewhat different results in the intermediate density range of about 10{sup -3} to 10{sup -1} fm{sup -3}, which gives an estimate of the present accuracy of the theoretical predictions. We compare the numerical results of these models for cluster abundances and thermodynamics in the region of medium excitation energies with temperatures T<=20 MeV and baryon number densities from zero to a few times saturation density. The effects of cluster formation on the liquid-gas phase transition and on the density dependence of the symmetry energy are studied. It is demonstrated that the parabolic approximation for the asymmetry dependence of the nuclear equation of state breaks down at low temperatures and at subsaturation densities because of cluster formation. Comparison is made with other theoretical approaches, in particular, those that are commonly used in astrophysical calculations. The results are relevant for heavy-ion collisions and astrophysical applications.

• OSTI ID: 21388863
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 81, Issue 1; Other Information: DOI: 10.1103/PhysRevC.81.015803; (c) 2010 The American Physical Society; ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA PARTICLES
APPROXIMATIONS
ASTROPHYSICS
ASYMMETRY
BARYON NUMBER
BINDING ENERGY
CHANNELING
COMPARATIVE EVALUATIONS
DENSITY
DISSOCIATION
DISSOLUTION
EQUATIONS OF STATE
EQUILIBRIUM
EXCITATION
FORECASTING
HEAVY ION REACTIONS
LIQUIDS
MEAN-FIELD THEORY
MEV RANGE 10-100
NEUTRON SPECTROSCOPY
NUCLEAR MATTER
NUCLEONS
PHASE TRANSFORMATIONS
RELATIVISTIC RANGE
SELF-ENERGY
SPIN ECHO
SYMMETRY
THERMODYNAMICS
BARYONS
CALCULATION METHODS
CHARGED PARTICLES
ELEMENTARY PARTICLES
ENERGY
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EQUATIONS
EVALUATION
FERMIONS
FLUIDS
HADRONS
IONIZING RADIATIONS
MATTER
MEV RANGE
NUCLEAR REACTIONS
PHYSICAL PROPERTIES
PHYSICS
RADIATIONS
SPECTROSCOPY