Abo Amr Khaled | Sohag University (original) (raw)

Papers by Abo Amr Khaled

International Review of Physics, 2014

We study the properties of symmetric nuclear matter and pure neutron matter at zero temperature w... more We study the properties of symmetric nuclear matter and pure neutron matter at zero temperature within the framework of the Brueckner theory using tabulated values of effective masses and depth of the single-particle energies. These tabulated values are chosen according to the work of Hassaneen et al, 2011. The Brueckner–Hartree–Fock approximation plus a density-dependent contact term as a three-body force are used to achieve the empirical saturation property of symmetric nuclear matter. The three-body force provides a strong enhancement of pressure and incompressibility in good agreement with relativistic approaches. Realistic nucleon-nucleon interactions which reproduce the nucleon-nucleon phase shifts are used in the present calculations. Good agreement is obtained in comparison with the experimental data.

Results of cold and hot asymmetric nuclear matter and pure neutron matter calculations are presen... more Results of cold and hot asymmetric nuclear matter and pure neutron matter calculations are presented. The (BHF) approximation + two body density dependent Skyrme potential which is equivalent to three - body interaction are used. Various modern nucleon-nucleon (NN) potentials are used as follows: CD-Bonn potential, Nijm1 potential, Reid 93 potential and Argonne V18 potential are used in the framework of (BHFA). The bulk properties of asymmetric nuclear matter are computed such as the EOS at (T = 0), pressure at (T = 0, 5 and 10 MeV), single particle potential, entropy at (T = 5 and 10 MeV), free energy at (T = 5 and 10 MeV), nuclear matter incompressibility and the symmetry energy. Also the bulk properties of pure neutron matter are computed such as the EOS at (T = 0), pressure at (T = 0, 3 and 6 MeV), single particle potential, entropy at (T = 3 and 6 MeV), free energy at (T = 3 and 6 MeV). The results are compared with B. Freidman and V. R. PandhariPand [45]. By this method good a...

Journal of Environmental Studies, 2014

Brazilian Journal of Physics, 2018

Motivated by the recent measurements from the VEPP-3 electron storage ring, we investigate the te... more Motivated by the recent measurements from the VEPP-3 electron storage ring, we investigate the tensor target polarization asymmetries T2M (M = 0, 1, 2) in the reaction γd → π0d with a particular interest in the effect of the intermediate ηNN three-body approach. This approach is based on realistic separable representations of the driving two-body interaction in the πN, ηN, and NN subsystems. It is shown that the influence of rescattering effects in the intermediate state on the tensor target spin asymmetries is sizable at extreme backward pion angles. At forward angles, the contribution from the pure impulse approximation is dominated and the spin asymmetries show very little influence of rescattering effects. The sensitivity of results to the elementary pion photoproduction operator and to the NN potential model adopted for the deuteron wave function is investigated, and considerable dependences are found. The predicted spin asymmetries are also compared with available experimental data, and a satisfactory agreement with the recent data from VEPP-3 is obtained at photon energies below 400 MeV. At higher energies, the calculated spin asymmetries slightly underestimate the data.

The European Physical Journal Plus, 2018

Abstract.A self-consistent Green’s Function approach is used to study the influence of short-rang... more Abstract.A self-consistent Green’s Function approach is used to study the influence of short-range correlations beyond the mean-field approach of nuclear matter. The ladder equation, including both particle-particle and hole-hole propagation, is solved in nuclear matter for a realistic interaction derived from the CD-Bonn potential. The hole-hole interaction is used to calculate the spectral functions that describe the distribution of holes below Fermi level. The nucleon spectral functions are calculated from the momentum- and energy-dependent self-energy. For comparison, the calculations are investigated by including nuclear three-body force. These spectral functions directly reflect the effects of the nucleon-nucleon correlations and can be explored by the analysis of nucleon knock-out experiments like $ ({\rm e, e' p})$(e,ep).

Journal of Modern Physics, 2014

The equation of state (EOS) of symmetric nuclear and pure neutron matter has been investigated ex... more The equation of state (EOS) of symmetric nuclear and pure neutron matter has been investigated extensively by adopting the non-relativistic Brueckner-Hartree-Fock (BHF). For more comparison, the extended BHF approaches using the self-consistent Green's function approach or by including a three-body force will be done. The EOS will be studied for different approaches at zero temperature. We can calculate the total mass and radius of neutron stars using various equations of state. A comparison with relativistic BHF calculations will be done. Relativistic effects are known to be important at high densities, giving an increased repulsion. This leads to a stiffer EOS compared to the EOS derived with a non-relativistic approach.

Physics Research International, 2013

Symmetric nuclear matter is studied within the Brueckner-Hartree-Fock (BHF) approach and is exten... more Symmetric nuclear matter is studied within the Brueckner-Hartree-Fock (BHF) approach and is extending to the self-consistent Green’s function (SCGF) approach. Both approximations are based on realistic nucleon-nucleon interaction; that is, CD-Bonn potential is chosen. The single-particle energy and the equation of state (EOS) are studied. The Fermi energy at the saturation point fulfills the Hugenholtz-Van Hove theorem. In comparison to the BHF approach, the binding energy is reduced and the EOS is stiffer. Both the SCGF and BHF approaches do not reproduce the correct saturation point. A simple contact interaction should be added to SCGF and BHF approaches to reproduce the empirical saturation point.

The properties of nuclear matter at zero and finite temperatures in the frame of the Brueckner th... more The properties of nuclear matter at zero and finite temperatures in the frame of the Brueckner theory realistic nucleon-nucleon potentials are studied. Comparison with other calculations is made. In addition we present results for the symmetry energy obtained with different potentials, which is of great importance in astrophysical calculation. Properties of asymmetric nuclear matter are derived from various many-body approaches. This includes phenomenological ones like the Skyrme Hartree-Fock and relativistic mean field approaches, which are adjusted to fit properties of nuclei, as well as more microscopic attempts like the BHF approximation, a Self-Consistent Greens Function (SCGF) method and the so-called Vlowk approach, which are based on realistic nucleon-nucleon interactions which reproduce the nucleon-nucleon phase shifts. These microscopic approaches are supplemented by a density-dependent contact interaction to achieve the empirical saturation property of symmetric nuclear m...

Studies on the structure of nuclear systems are performed, ~which are based on realistic nucleon-... more Studies on the structure of nuclear systems are performed, ~which are based on realistic nucleon-nucleon interactions. Such realistic interactions induce two-body correlations in the nuclear many-body wave function. In particular one finds deviations of the single-particle Green's function from the mean field prediction of a Hartree-Fock theory. Such modifications give rise to a modification in the response function of the nuclear system. This response function characterizes the excitation modes of the nuclear system. It is also the most relevant ingredient for the study of the propagator of a meson in the nuclear medium. This meson propagators, on the other hand, ~are very important to study modifications of the nucleon-nucleon force in the nuclear medium and thereby influence the self-consistent evaluation of the single-particle Green's function. The nuclear spectral function at high missing energies and momenta has been determined from a self-consistent calculation of the...

Journal of the Physical Society of Japan

Journal of Modern Physics, 2013

Journal of Nuclear and Particle Physics, 2012

Results of cold and hot symmetric nuclear matter and pure neutron matter calculations are present... more Results of cold and hot symmetric nuclear matter and pure neutron matter calculations are presented. The Brueckner-Hartree-Fock (BHF) approximation + two body density dependent Skyrme potential which is equivalent to three body interaction are used. Various modern nucleon-nucleon (NN) potentials are used in the framework of BHF approximation, e.g.: CD-Bonn potential, Nijm1 potential, Reid 93 potential and Argonne V 18 potential. The bulk properties of asymmetric nuclear matter are computed such as the equation of state (EOS) at (T = 0), pressure at (T = 0, 5 and 10 MeV), single particle potential, free energy at (T = 5 and 10 MeV), nuclear matter incompressibility and the symmetry energy. Also the bulk properties of pure neutron matter are computed such as the EOS at (T = 0), pressure at (T = 0, 3 and 6 MeV), single particle potential, free energy at (T = 3 and 6MeV). Good agreement is obtained in comparison with previous theoretical estimates and experimental data.

Progress of Theoretical Physics, 2010

The one-body potentials for protons and neutrons are obtained from the self-consistent Green-func... more The one-body potentials for protons and neutrons are obtained from the self-consistent Green-function calculations of asymmetric nuclear matter, in particular their dependence on the degree of proton/neutron asymmetry. Results of the binding energy per nucleon as a function of the density and asymmetry parameter are presented for the self-consistent Green function approach using the CD-Bonn potential. For the sake of comparison, the same calculations are performed using the Brueckner-Hartree-Fock approximation. The contribution of the hole-hole terms leads to a repulsive contribution to the energy per nucleon which increases with the nuclear density. The incompressibility for asymmetric nuclear matter has been also investigated in the framework of the self-consistent Green-function approach using the CD-Bonn potential. The behavior of the incompressibility is studied for different values of the nuclear density and the neutron excess parameter. The nuclear symmetry potential at fixed nuclear density is also calculated and its value decreases with increasing the nucleon energy. In particular, the nuclear symmetry potential at saturation density changes from positive to negative values at nucleon kinetic energy of about 200 MeV. For the sake of comparison, the same calculations are performed using the Brueckner-Hartree-Fock approximation. The proton/neutron effective mass splitting in neutron-rich matter has been studied. The predicted isospin splitting of the proton/neutron effective mass splitting in neutron-rich matter is such that m * n ≥ m * p .

Ядерная физика, 2014

ABSTRACT The properties of nuclear matter are studied in the frame of the Brueckner theory. The B... more ABSTRACT The properties of nuclear matter are studied in the frame of the Brueckner theory. The Brueckner– Hartree–Fock approximation plus two-body density-dependent Skyrme potential which is equivalent to three-body interaction are used. Various modern nucleon–nucleon potentials are used in the framework of the Brueckner–Hartree–Fock approximation, e.g.: CD-Bonn potential, Nijm1 potential, and Reid 93 potential. These modern nucleon–nucleon potentials fit the deuteron properties and are phase shifts equivalent. The equation of state at T = 0, pressure at T = 0, 8, and 12 MeV, free energy at T = 8 and 12 MeV, nuclear matter incompressibility, and the symmetry energy calculation are presented. The hot properties of nuclear matter are calculated using T 2-approximation method at low temperatures. Good agreement is obtained in comparison with previous theoretical estimates and experimental data, especially at low densities.

Physical Review Letters, 1994

In this work we calculate the total mass, radius, moment of inertia, and surface gravitational re... more In this work we calculate the total mass, radius, moment of inertia, and surface gravitational redshift for neutron stars using various equations of state (EOS). Modern meson-exchange potential models are used to evaluate the G-matrix for asymmetric nuclear matter. We calculate both a nonrelativistic and a relativistic EOS. Of importance here is the fact that relativistic Brueckner-Hartree-Fock calculations for symmetric nuclear matter fit the empirical data, which are not reproduced by non-relativistic calculations. Relativistic effects are known to be important at high densities, giving an increased repulsion. This leads to a stiffer EOS compared to the EOS derived with a nonrelativistic approach. Both the non-relativistic and the relativistic EOS yield moments of inertia and redshifts in agreement with the accepted values. The relativistic EOS yields, however, too large mass and radius. The implications are discussed.

Physical Review C, 2004

The self-energy of nucleons in asymmetric nuclear matter is evaluated employing different realist... more The self-energy of nucleons in asymmetric nuclear matter is evaluated employing different realistic models for the nucleon-nucleon interaction. Starting from the Brueckner Hartree Fock approximation without the usual angle-average in the two-nucleon propagator the effects of the hole-hole contributions are investigated within the self-consistent Green's function approach. Special attention is paid to the isospin-dependence of correlations, which can be deduced from the spectral functions of nucleons in asymmetric matter. The strong components of the proton-neutron interaction lead in neutron-rich matter to a larger depletion for the occupation probability of proton states below the Fermi momentum.