scholarly journals Perturbative calculation of the excluded volume effect for nuclear matter in a relativistic mean-field approximation

2002 ◽  
Vol 65 (5) ◽  
Author(s):  
Bao-Xi Sun ◽  
Xiao-Fu Lu ◽  
En-Guang Zhao
Keyword(s):  
Nuclear Matter ◽  
Mean Field ◽  
Field Approximation ◽  
Volume Effect ◽  
Mean Field Approximation ◽  
Excluded Volume ◽  
Perturbative Calculation ◽  
Relativistic Mean Field ◽  
Excluded Volume Effect

scholarly journals IN-MEDIUM PROPERTIES OF KAONS IN A CHIRAL APPROACH

2008 ◽  
Vol 17 (09) ◽  
pp. 1895-1905
Author(s):  
YUE-LEI CUI ◽  
BAO-XI SUN
Keyword(s):  
Nuclear Matter ◽  
Effective Mass ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Nuclear Density ◽  
Relativistic Mean Field ◽  
Self Energy ◽  
Sigma Term ◽  
Scattering Matrix Elements

The first order self-energy corrections of the kaon in the symmetric nuclear matter are calculated from kaon-nucleon scattering matrix elements using a chiral Lagrangian within the framework of relativistic mean field approximation. It shows that the effective mass and the potential of K+ meson are identical with those of K- meson in the nuclear matter, respectively. The effective mass of the kaon in the nuclear matter decreases with the nuclear density increasing, and is not relevant to the kaon-nucleon Sigma term. The kaon-nucleus potential is positive and increases with the nuclear density. Moreover, the influence of the resonance Λ(1405) on the K--nucleus potential due to the re-scattering term is discussed. Our results indicate the K- meson could not be bound in the nuclei even if the contribution of Λ(1405) resonance is considered.

scholarly journals Relativistic Mean-Field Approximation with Density-Dependent Screening Meson Masses in Nuclear Matter

2003 ◽  
Vol 12 (04) ◽  
pp. 543-554 ◽  
Author(s):  
Bao-Xi Sun ◽  
Xiao-Fu Lu ◽  
Peng-Nian Shen ◽  
En-Guang Zhao
Keyword(s):  
Nuclear Matter ◽  
Field Model ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Mean Field Model ◽  
Density Dependent ◽  
Relativistic Mean Field ◽  
Saturation Properties ◽  
The Masses

The Debye screening masses of the σ, ω and neutral ρ mesons and the photon are calculated in the relativistic mean-field approximation. As the density of the nucleon increases, all the screening masses of mesons increase. A different result with Brown–Rho scaling is shown, which implies a reduction in the mass of all the mesons in the nuclear matter, except the pion. Replacing the masses of the mesons with their corresponding screening masses in the Walecka-1 model, five saturation properties of the nuclear matter are fixed reasonably, and then a density-dependent relativistic mean-field model is proposed without introducing the nonlinear self-coupling terms of mesons.

LIGHT CLUSTERS IN NUCLEAR MATTER

2011 ◽  
Vol 20 (04) ◽  
pp. 897-901
Author(s):  
GERD RÖPKE
Keyword(s):  
Nuclear Matter ◽  
Mean Field ◽  
Heavy Ion ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Einstein Condensation ◽  
Relativistic Mean Field ◽  
Self Energy ◽  
Ion Collisions ◽  
Mott Effect

Within a quantum statistical approach, a in-medium Schrödinger equation is derived for a few-nucleon system embedded in nuclear matter. Medium modifications of the cluster quasiparticles are described by self-energy and Pauli blocking effects. Benchmarks such as the nuclear statistical equilibrium, virial expansion and the relativistic mean field approximation are considered. An interesting effect is the formation of a four- or two-nucleon quantum condensate, showing the crossover from Cooper pairing to Bose-Einstein condensation. The resulting thermodynamic properties are of interest for heavy-ion collisions and astrophysical applications. Quantum condensates and the Mott effect are also of relevance for the structure of finite nuclei, specially dilute excited states like the Hoyle state of 12 C .

Quartetting in Fermionic Matter and Alpha-Particle Condensation in Nuclear Systems

2006 ◽  
Vol 21 (31n33) ◽  
pp. 2513-2546 ◽  
Author(s):  
G. Röpke ◽  
P. Schuck
Keyword(s):  
Nuclear Matter ◽  
Cluster Formation ◽  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Density Region ◽  
Nuclear Matter Density ◽  
Nuclear Systems ◽  
The Mean ◽  
Finite Nuclei

Quantum condensates in nuclear matter are treated beyond the mean-field approximation, with the inclusion of cluster formation. The occurrence of a separate binding pole in the four-particle propagator in nuclear matter is investigated with respect to the formation of a condensate of α-like particles (quartetting), which is dependent on temperature and density. Due to Pauli blocking, the formation of an α-like condensate is limited to the low-density region. Consequences for finite nuclei are considered. In particular, excitations of self-conjugate 2n-Z–2n-N nuclei near the n-α-breakup threshold are candidates for quartetting. We review some results and discuss their consequences. Exploratory calculations are performed for the density dependence of the α condensate fraction at zero temperature to address the suppression of the four-particle condensate below nuclear-matter density.

Excluded volume effect for the nuclear matter equation of state

1991 ◽  
Vol 51 (3) ◽  
pp. 485-489 ◽  
Author(s):  
D. H. Rischke ◽  
M. I. Gorenstein ◽  
H. St�cker ◽  
W. Greiner
Keyword(s):  
Equation Of State ◽  
Nuclear Matter ◽  
Volume Effect ◽  
Excluded Volume ◽  
Excluded Volume Effect

scholarly journals Relativistic mean field approximation to the analysis of16O(e,e′p)15Ndata at|Q2|<~0.4 (GeV/c)2

2001 ◽  
Vol 64 (2) ◽  
Author(s):  
J. M. Udías ◽  
J. A. Caballero ◽  
E. Moya de Guerra ◽  
Javier R. Vignote ◽  
A. Escuderos
Keyword(s):  
Mean Field ◽  
Field Approximation ◽  
Mean Field Approximation ◽  
Relativistic Mean Field

scholarly journals ISOSPIN LATTICE GAS MODEL AND NUCLEAR-MATTER PHASE DIAGRAM AND PRESSURE-VOLUME ISOTHERMS

1996 ◽  
Vol 05 (02) ◽  
pp. 303-311 ◽  
Author(s):  
T.T.S. KUO ◽  
S. RAY ◽  
J. SHAMANNA ◽  
R.K. SU
Keyword(s):  
Nuclear Matter ◽  
Lattice Gas ◽  
Nearest Neighbor ◽  
Mean Field ◽  
Field Approximation ◽  
Lattice Gas Model ◽  
Mean Field Approximation ◽  
Kinetic Energy Term ◽  
Phase Liquid ◽  
Matter Phase

We study a cubic lattice gas model for nuclear matter where each lattice site can be either occupied, by one proton or one neutron, or unoccupied. A nearest-neighbor interaction of the form - ∑<ij>Jijτziτzj is assumed. Our model is an isospin-1 Ising model, with τz= (1, 0, –1) representing respectively (proton, vacancy, neutron). A kinetic-energy term has been included in our model. Under the Bragg-Williams mean-field approximation our model exhibits the existence of a dense phase (liquid-like) and a rare phase (gas-like). The nuclear-matter p−v isotherms given by our model are discussed.

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