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M. S. Hussein

Publications and source records attributed to M. S. Hussein.

At least 127 records · Page 7Linked to original sources
arXiv2002

Toward a global description of the nucleus-nucleus interaction

Extensive systematization of theoretical and experimental nuclear densities and of optical potential strengths exctracted from heavy-ion elastic scattering data analyses at low and intermediate energies are presented.The energy-dependence of the nuclear potential is accounted for within a model based on the nonlocal nature of the interaction.The systematics indicate that the heavy-ion nuclear potential can be described in a simple global way through a double-folding shape,which basically depends only on the density of nucleons of the partners in the collision.The poissibility of extracting information about the nucleon-nucleon interaction from the heavy-ion potential is investigated.

nucl-th↗
arXiv2002

Effect of symmetry breaking on level curvature distributions

We derive an exact general formalism that expresses the eigenvector and the eigenvalue dynamics as a set of coupled equations of motion in terms of the matrix elements dynamics. Combined with an appropriate model Hamiltonian, these equations are used to investigate the effect of the presence of a discrete symmetry in the level curvature distribution. An explanation of the unexpected behavior of the data regarding frequencies of acoustic vibrations of quartz block is provided.

quant-ph↗
arXiv2001

Anomalous anapole moment of an exotic nucleus

Using the information on the nuclear structure of exotic neutron-rich halo nucleus $^{11}$Be, we evaluate the parity violating anapole moment in its ground state. The resulting value $κ(^{11}$Be)$=0.17$ is fifteen times bigger than the typical value of the anapole moment of a normal nucleus of the same mass, and in fact exceeds by few times anapole moments of any known neutron-odd nuclei (e.g., kappa(^{11}Be) > 2|κ(^{207}Pb)|. It is also few times bigger than the neutral current contribution to the lepton-nucleus interaction.

nucl-th↗
arXiv2001

Attenuation of the intensity within a superdeformed band

The attenuation of the intraband intensity of a superdeformed band, which results from mixing with normally deformed configurations, is calculated using reaction theory. It is found that the sharp increase of the attenuation is mostly due to the tunnelling through a spin dependent barrier and not to the chaotic nature of the normally deformed states.

nucl-th↗
arXiv2001

Causal Classical Theory of Radiation Damping

It is shown how initial conditions can be appropriately defined for the integration of Lorentz-Dirac equations of motion. The integration is performed \QTR{it}{forward} in time. The theory is applied to the case of the motion of an electron in an intense laser pulse, relevant to nonlinear Compton scattering.

physics.gen-ph↗
arXiv2001

Approximations in Fusion and Breakup reactions induced by Radioactive Beams

Some commonly used approximations for complete fusion and breakup transmission coefficients in collisions of weakly bound projectiles at near barrier energies are assessed. We show that they strongly depend on the adopted classical trajectory and can be significantly improved with proper treatment of the incident and emergent currents in the WKB approximation.

nucl-th↗
arXiv2001

Generalized yrast states of a Bose condensate in harmonic trap for a universality class of repulsive interactions

For a system of N bosons in a 2d harmonic trap with frequency omega, interacting via repulsive forces V<<omega, we develop supersymmetric method to find the lowest energy states of rotating Bose condensate as function of two quantum numbers, the total angular momentum and the angular momentum of internal excitations (generalized yrast states). The energies of these condensed vortex states are expressed through the single two-body matrix element of interaction V. A broad universality class of the repulsive interactions for which these results hold is described by a simple integral condition on V. It includes Gaussian, delta-function and log-Coulomb forces.

cond-mat↗
arXiv2000

Theory of Complex Scattering Lengths

We derive a generalized Low equation for the T-matrix appropriate for complex atom-molecule interaction. The properties of this new equation at very low energies are studied and the complex scattering length and effective range are derived.

physics.atom-ph↗
arXiv2000

Transverse Isotropy in Identical Particle Scattering

It is pointed out that the cross section for the scattering of identical charged bosons is isotropic over a broad angular range around 90 degrees when the Sommerfeld parameter has a critical value, which depends exclusively on the spin of the particle. A discussion of systems where this phenomenon can be observed is presented.

quant-ph↗
arXiv1999

Virtual states of light non-Borromean halo nuclei

It is shown that the three-body non-Borromean halo nuclei like ^{12}Be, ^{18}C, ^{20}C have p-wave virtual states with energy of about 1.6 times the corresponding neutron-core binding energy. We use a renormalizable model that guarantees the general validity of our results in the context of short range interactions.

nucl-th↗
arXiv1999

Collective Excitation of a Hybrid Atomic/Molecular Bose Einstein Condensate$^{\ast}$

The collective excitation of hybrid atomic-molecular condensate are studied using variational method. The dipole response of the system is studied in detail. We found that the out-of-phase dipole oscillation frequency increasing slowly with the detuning parameter and is only few times large than the trap frequency making the experimental observation of this mode of vibration feasible.

cond-mat.soft↗
arXiv1999

Saturation of the width of the strength function

The strength function of a single state $|d>$ is studied using the deformed Gaussian orthogonal ensemble. In particular we study the dependence of the spreading width of $|d>$ on the degree of mixing.

nucl-th↗
arXiv1999

SU(2,1) Dynamics of Multiple Giant Dipole Resonance Coulomb Excitation

We construct a three-dimensional analytically soluble model of the nonlinear effects in Coulomb excitation of multiphonon Giant Dipole Resonances (GDR) based on the SU(2,1) algebra. The full 3-dimensional model predicts further enhancement of the Double GDR (DGDR) cross sections at high bombarding energies. Enhancement factors for DGDR measured in thirteen different processes with various projectiles and targets at different bombarding energies are well reproduced with the same value of the nonlinearity parameter with the exception of the anomalous case of $^{136}$Xe which requires a larger value.

nucl-th↗
arXiv1999

Effective Widths and Effective Number of Phonons of Multiphonon Giant Resonances

We discuss the origin of the difference between the harmonic value of the width of the multiphonon giant resonances and the smaller observed value. Analytical expressions are derived for both the effective width and the average cross-section. The contribution of the Brink-Axel mechanism in resolving the discrepancy is pointed out.

nucl-th↗
arXiv1999

Giant Resonances in Coulomb Excitations of Relativistic Ions

We propose a soluble model to incorporate the nonlinear effects in the transition probabilities of the multiphonon Giant Dipole Resonances based on the SU(1,1) algebra. Analytical expressions for the multi-phonon transition probabilities are derived. For reasonably small magnitude of nonlinearity $x\simeq 0.1-0.2$ enhancement factor for the Double Giant Resonance excitation probabilities and the cross sections %in relativistic ion collisions reaches values $1.3-2$ compatible with experimental data.

nucl-th↗
arXiv1999

Long-Range Excitation of Collective Modes in Mesoscopic Metal Clusters

We develop a semiclassical theory for the long range excitation of plasmon resonances in atomic clusters, based on the doorway hypothesis. The effect of the width of the plasmon resonance is fully taken into account. As an application we study plasmon excitation in small Sodium clusters, in collisions with electrons and protons.

cond-mat↗