scholarly journals A Novel Algorithm to the Transient State of Nuclear Matter with Isospin Asymmetry, Thermal Excitation, and Compression

2000 ◽  
Vol 138 ◽  
pp. 32-33
Author(s):  
Feng-Shou Zhang ◽  
Lie-Wen Chen ◽  
Zhao-Yu Ming ◽  
Zhi-Yuan Zhu
Keyword(s):  
Nuclear Matter ◽  
Transient State ◽  
Thermal Excitation ◽  
Isospin Asymmetry ◽  
Novel Algorithm

scholarly journals Isospin Physics in Heavy-Ion Collisions at Intermediate Energies

1998 ◽  
Vol 07 (02) ◽  
pp. 147-229 ◽  
Author(s):  
Bao-An Li ◽  
Che Ming Ko ◽  
Wolfgang Bauer
Keyword(s):  
Equation Of State ◽  
Nuclear Matter ◽  
Cross Sections ◽  
Heavy Ion Collisions ◽  
Transport Model ◽  
Transient State ◽  
Heavy Ion ◽  
Nucleon Nucleon ◽  
Asymmetric Nuclear Matter ◽  
Ion Collisions

In nuclear collisions induced by stable or radioactive neutron-rich nuclei a transient state of nuclear matter with an appreciable isospin asymmetry as well as thermal and compressional excitation can be created. This offers the possibility to study the properties of nuclear matter in the region between symmetric nuclear matter and pure neutron matter. In this review, we discuss recent theoretical studies of the equation of state of isospin-asymmetric nuclear matter and its relations to the properties of neutron stars and radioactive nuclei. Chemical and mechanical instabilities as well as the liquid-gas phase transition in asymmetric nuclear matter are investigated. The in-medium nucleon-nucleon cross sections at different isospin states are reviewed as they affect significantly the dynamics of heavy ion collisions induced by radioactive beams. We then discuss an isospin-dependent transport model, which includes different mean-field potentials and cross sections for the proton and neutron, and its application to these reactions. Furthermore, we review the comparisons between theoretical predictions and available experimental data. In particular, we discuss the study of nuclear stopping in terms of isospin equilibration, the dependence of nuclear collective flow and balance energy on the isospin-dependent nuclear equation of state and cross sections, the isospin dependence of total nuclear reaction cross sections, and the role of isospin in preequilibrium nucleon emissions and subthreshold pion production.

Equation of state of asymmetric nuclear matter: a VMC study

Open Physics ◽  
2010 ◽  
Vol 8 (4) ◽  
Author(s):  
Kaan Manisa ◽  
Ülfet Atav ◽  
Sibel Sarıaydın
Keyword(s):  
Nuclear Matter ◽  
Many Body ◽  
Isospin Asymmetry ◽  
Asymmetric Nuclear Matter ◽  
Methods And Techniques ◽  
Microscopic Interactions ◽  
Many Body Interactions ◽  
Asymmetry Parameters ◽  
Kinetic And Potential Energies ◽  
Good Agreement

AbstractA Variational Monte Carlo (VMC) method is employed to investigate the properties of symmetric and asymmetric nuclear matter. The realistic Urbana V 14 twonucleon interaction potential of Lagaris and Pandharipande was used to describe the microscopic interactions. Also, many body interactions are included as a density dependent term in the potential. Total kinetic and potential energies per particle are calculated for asymmetric nuclear matter by VMC method at various densities and isospin asymmetry parameters. The results are compared with data found in literature, and it was observed that the results obtained in this study reasonably agree with the results found in the literature. Also, the symmetry energy and incompressibility factor of the nuclear matter were obtained. The results obtained are in good agreement with those obtained by various authors with different methods and techniques.

ISOSPIN DEPENDENCE OF THE SATURATION PROPERTIES OF ASYMMETRIC NUCLEAR MATTER IN NONRELATIVISTIC MEAN FIELD MODEL

2012 ◽  
Vol 21 (09) ◽  
pp. 1250079 ◽  
Author(s):  
S. CHAKRABORTY ◽  
B. SAHOO ◽  
S. SAHOO
Keyword(s):  
Nuclear Matter ◽  
Fourth Order ◽  
Symmetry Energy ◽  
Mean Field ◽  
Saturation Density ◽  
Order Effects ◽  
Mean Field Model ◽  
Isospin Asymmetry ◽  
Asymmetric Nuclear Matter ◽  
Isospin Dependence

A phenomenological momentum dependent interaction (MDI) is considered to describe the equation of state (EOS) for isospin asymmetric nuclear matter (ANM), where the density dependence of the nuclear symmetry is the basic input. In this interaction, the symmetry energy shows soft dependence of density. Within the nonrelativistic mean field approach we calculate the nuclear matter fourth-order symmetry energy E sym, 4 (ρ). Our result shows that the value of E sym, 4 (ρ) at normal nuclear matter density ρ0( = 0.161 fm -3) is less than 1 MeV conforming the empirical parabolic approximation to the EOS of ANM at ρ0. Then the higher-order effects of the isospin asymmetry on the saturation density ρ sat (β), binding energy per nucleon K sat (β) and isobaric incompressibility K sat (β) of ANM is being studied, where [Formula: see text] is the isospin asymmetry. We have found that the fourth-order isospin asymmetry β cannot be neglected, while calculating these quantities. Hence the second-order K sat , 2 parameter basically characterizes the isospin dependence of the incompressibility of ANM at saturation density.

RELATIVISTIC URCA PROCESSES IN NEUTRON STARS WITH AN ANTIKAON CONDESATE

2011 ◽  
Vol 20 (supp02) ◽  
pp. 146-151 ◽  
Author(s):  
MOISÉS RAZEIRA ◽  
ALEXANDRE MESQUITA ◽  
CÉSAR A. Z. VASCONCELLOS ◽  
ROSANA O. GOMES ◽  
AURORA PÉREZ MARTÍNEZ ◽  
...  
Keyword(s):  
Neutron Star ◽  
Neutron Stars ◽  
Nuclear Matter ◽  
Degrees Of Freedom ◽  
Critical Density ◽  
Heat Radiation ◽  
Critical Threshold ◽  
Neutron Star Matter ◽  
Isospin Asymmetry ◽  
Urca Process

A recently developed effective relativistic theory for nuclear matter is applied to the description of the cooling process of baryon degenerate neutron star matter through neutrino emission considering direct URCA processes. In our approach nucleons and antikaon condensates interact with σ, ω, ρ, δ and ς meson fields. Our results indicate a substantial decrease of the critical threshold density for the URCA process. This is because the presence of these interacting degrees of freedom increase the proportion of protons, producing simultaneously the reduction of the isospin asymmetry in nuclear matter. Our results also indicate that neutron stars with larger masses than MNE ~ 0.9M⊙, which represents the stellar critical threshold (the mass of the neutron star whose baryon central density reached the critical density) would be cooled efficiently and be outside the possibility of observation by heat radiation in a few years.

scholarly journals Probing the nuclear matter isospin asymmetry by nucleon-induced reactions at Fermi energies

2007 ◽  
Vol 76 (2) ◽  
Author(s):  
F. Sébille ◽  
V. de la Mota ◽  
I. C. Sagrado Garcia ◽  
J. F. Lecolley ◽  
V. Blideanu
Keyword(s):  
Nuclear Matter ◽  
Isospin Asymmetry

scholarly journals INCOMPRESSIBILITY OF ASYMMETRIC NUCLEAR MATTER

2010 ◽  
Vol 19 (08n09) ◽  
pp. 1675-1685
Author(s):  
LIE-WEN CHEN ◽  
BAO-JUN CAI ◽  
CHUN SHEN ◽  
CHE MING KO ◽  
JUN XU ◽  
...  
Keyword(s):  
Nuclear Matter ◽  
Symmetry Energy ◽  
Saturation Density ◽  
Third Order ◽  
Isospin Asymmetry ◽  
Asymmetric Nuclear Matter ◽  
Hartree Fock ◽  
Normal Nuclear Density ◽  
Curvature Parameter ◽  
Isospin Dependence

Using an isospin- and momentum-dependent modified Gogny (MDI) interaction, the Skyrme-Hartree-Fock (SHF) approach, and a phenomenological modified Skyrme-like (MSL) model, we have studied the incompressibility K sat (δ) of isospin asymmetric nuclear matter at its saturation density. Our results show that in the expansion of K sat (δ) in powers of isospin asymmetry δ, i.e., K sat (δ) = K0 + K sat ,2δ2 + K sat ,4δ4 + O(δ6), the magnitude of the 4th-order K sat ,4 parameter is generally small. The 2nd-order K sat ,2 parameter thus essentially characterizes the isospin dependence of the incompressibility of asymmetric nuclear matter at saturation density. Furthermore, the K sat ,2 can be expressed as [Formula: see text] in terms of the slope parameter L and the curvature parameter K sym of the symmetry energy and the third-order derivative parameter J0 of the energy of symmetric nuclear matter at saturation density, and we find the higher order J0 contribution to K sat ,2 generally cannot be neglected. Also, we have found a linear correlation between K sym and L as well as between J0/K0 and K0. Using these correlations together with the empirical constraints on K0 and L, the nuclear symmetry energy E sym (ρ0) at normal nuclear density, and the nucleon effective mass, we have obtained an estimated value of K sat ,2 = -370 ± 120 MeV for the 2nd-order parameter in the isospin asymmetry expansion of the incompressibility of asymmetric nuclear matter at its saturation density.

Analyzing reactions of single mechanoenzyme molecules by light microscopy

1992 ◽  
Vol 50 (1) ◽  
pp. 426-427
Author(s):  
Jeff Gelles
Keyword(s):  
Image Processing ◽  
Reaction Mechanisms ◽  
Transient State ◽  
Nanometer Scale ◽  
Reaction Intermediates ◽  
Enzyme Molecule ◽  
Directed Movement ◽  
Enzyme Molecules ◽  
Individual Enzyme ◽  
Single Reaction

Mechanoenzymes are enzymes which use a chemical reaction to power directed movement along biological polymer. Such enzymes include the cytoskeletal motors (e.g., myosins, dyneins, and kinesins) as well as nucleic acid polymerases and helicases. A single catalytic turnover of a mechanoenzyme moves the enzyme molecule along the polymer a distance on the order of 10−9 m We have developed light microscope and digital image processing methods to detect and measure nanometer-scale motions driven by single mechanoenzyme molecules. These techniques enable one to monitor the occurrence of single reaction steps and to measure the lifetimes of reaction intermediates in individual enzyme molecules. This information can be used to elucidate reaction mechanisms and determine microscopic rate constants. Such an approach circumvents difficulties encountered in the use of traditional transient-state kinetics techniques to examine mechanoenzyme reaction mechanisms.

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