Contribution of J-Dependent Potential in Differential Cross-Sections of Two-Nucleon Transfer Reactions

Heavy-ion reactions with two-nucleon transfer are studied within the framework of the distorted wave Born approximation (DWBA) calculations. The bound-states of the transferred particle with the core nucleus forming the projectile or target and residual nuclei are represented by a Yukawa potential. The calculated differential cross-sections are in good agreement with the experimental data. The study exhibits the important contributions of the J-dependent potential in reproducing thelarge-angle oscillatory structures of two-nucleon transfer reactions.     

The Skyrme model with pion masses

We study the SU(2) × SU(2) Skyrme model with an explicit chiral breaking term. The new quantities that we evaluate are the pion-nucleon sigma term and the isovector charge radii, whose values come out in reasonable agreement with experiment. The other static properties of nucleons differ by a few percent from the corresponding values in the chiral limit.     

Potential energy surface and formation of superheavy nuclei with the Skyrme energy-density functional

With the Skyrme energy-density functional theory, the nucleus–nucleus potential is calculated and the potential energy surface is obtained with different effective forces for accurately estimating the formation cross sections of superheavy nuclei in massive fusion reactions. The width and height of the potential pocket are influenced by the Skyrme effective forces SkM, SkM^*, SkP, SIII, Ska, and SLy4, which correspond to the different equations of state for the isospin symmetry nuclear matter. It is found that the nucleus–nucleus potential is associated with the collision orientation and Skyrme forces. A more repulsive nuclear potential is pronounced with increasing the incompressible modulus of nuclear matter, which hinders the formation of superheavy nuclei. The available data in the fusion-evaporation reaction of ⁴⁸Ca+²³⁸U are nicely reproduced with the SkM^* parameter by implementing the potential into the dinuclear system model.     

Skyrme solitons with vector mesons

We investigate the Skyrme type soliton with vector mesons (ρ, A₁ and ω), first in the massive Yang-Mills approach and then using the hidden local symmetry Lagrangian. It is demonstrated that the two schemes give identical results for the soliton properties. A comparison is made with alternative approaches in which the A₁ degrees of freedom is eliminated.     

The phonon-coupling model for Skyrme forces

A short review on the self-consistent RPA based on the energy-density functional of the Skyrme type is given. We also present an extension of the RPA where the coupling of phonons to the single-particle states is considered. Within this approach we present numerical results which are compared with data. The self-consistent approach is compared with the Landau–Migdal theory. Here we derive from the self-consistent ph interaction, the Landau–Migdal parameters as well as their density dependence. In the Appendix a new derivation of the reduced matrix elements of the ph interaction is presented.     

The Skyrme Model on Riemannian manifolds

The Skyrme Model on Riemannian manifolds is analysed. Under certain assumptions it is shown that the identity map is essentially the only absolute minimizer proving a conjecture stated by Manton and Ruback. In some other circumstances, it is shown that the identity map is a stable local minimum.     

The Skyrme model on a four-dimensional lattice

The SU(2) Skyrme model is formulated on a four-dimensional lattice with the nearest and next-to-nearest neighbor interactions in the action. To establish a continuum limit, the phase structure is studied and the order of phase transition is determined by various methods. Coexistence of two phases and hysteresis effect are observed at the critical point, indicating a first-order phase transition in the parameter space.     

The Skyrme model on a four-dimensional lattice

The SU(2) Skyrme model is formulated on a four-dimensional lattice with the nearest and next-to-nearest neighbor interactions in the action. To establish a continuum limit, the phase structure is studied and the order of phase transition is determined by various methods. Coexistence of two phases and hysteresis effect are observed at the critical point, indicating a first-order phase transition in the parameter space.     

The Interaction Energy of Well-Separated Skyrme Solitons

We prove that the asymptotic field of a Skyrme soliton of any degree has a non-trivial multipole expansion. It follows that every Skyrme soliton has a well-defined leading multipole moment. We derive an expression for the linear interaction energy of well-separated Skyrme solitons in terms of their leading multipole moments. This expression can always be made negative by suitable rotations of one of the Skyrme solitons in space and iso-space. We show that the linear interaction energy dominates for large separation if the orders of the Skyrme solitons multipole moments differ by at most two. In that case there are therefore always attractive forces between the Skyrme solitons.     

Neutron stars in a Skyrme model with hyperons

Available Skyrme parametrizations with hyperons are examined from the point of view of their suitability for applications to neutron stars. It is shown that the hyperons can attenuate or even remove the problem of ferromagnetic instability common to (nearly) all Skyrme parametrizations of the nucleon-nucleon interaction. At high density the results are very sensitive to the choice of the interaction. The selected parameter sets are then used to obtain the resulting properties of both cold neutron stars and hot protoneutron stars. The general features known from other models are recovered.     

Description of proton-neutron mixed-symmetry states with Skyrme interaction

Starting from an effective Skyrme interaction we study the effects of the phonon-phonon coupling on the M1 transitions between quadrupole states. The finite rank separable approach for the quasiparticle random phase approximation is used. Choosing as an example the nucleus ⁹⁴Mo, we demonstrate an ability of the method to describe the properties of the low-lying states.     

Semiclassical calculation of fission barriers with Skyrme forces

We present semiclassically calculated fission barriers for ²⁴⁰Pu starting from effective nuclear interactions of the Skyrme type. We show that at least one of the existing Skyrme parametrisations leads to a reasonably low fission barrier.     

Description of low-lying state structures with Skyrme interaction

We use the quasiparticle random phase approximation to study properties of the low-lying 2⁺ states in the even-even nuclei around ¹³²Sn. Starting from a Skyrme interaction in the particle-hole channel and a density-dependent zero-range interaction in the particle-particle channel, the calculation within the finite-rank separable approximation for the residual interaction is performed.     

Relativistic RPA for finite nuclei with Skyrme type interaction

A relativistic RPA is derived starting from a model Lagrangean with four-fermion coupling. The exchange terms are taken exactly into account by exploiting Fierz relations. The model is applied to negative parity states of¹⁶O. Exchange terms turn out to give large contributions.     

CYCIAE型回旋加速器负离子剥离引出的光学行为研究

为了CYCIAE型回旋加速器的剥离靶轴线及旋转角的概念设计,必须对负离子剥离后的光学特性进行研究,基于根据CYCIAE型回旋加速器剥离引出特点编制的程序CYCRS,计算了CYCIAE30加速器不同能量束流引出剥离点的位置,并与实际位置进行比较,证明计算所用的理论及方法是正确的,同时,考察了剥离后的束流空间运动的光学特性.在此基础上,确定了CYCIAE70回旋加速器能量为35—70MeV的束流引出剥离点位置.     

Sound of Speed in Nuclear Matter with Skyrme Forces

An analytical expression for sound of speed in asymmetric nuclear matter is acquired, based on the thermal Fermi-gas model and Skyrme-type nucleon-nucleon interactions. A low temperature high density approximation is adopted to the Fermi-Dirac integrals. The dependence of sound of apeed on the temperature and density bf nuclear matter under consideration ie investigated. For all the cases concerned, the so-called superluminosity is observed, the position of which is found to depend on the force parameters used and the asymmetric parameter of the nuclear matter. A possible way to avoid this causal-constraint violation is suggested.