The viscosity cross-section for elastic electron-xenon collisions including electron spin polarization

The results of the evaluation of the viscosity cross-section for elastic electron-xenon collisions, taking into account the spin-orbit interaction of the continuum electron, in the energy interval from 0.1 eV to 50 eV are presented and discussed. The calculations are performed on the basis of three theoretically derived sets of phase shift data obtained by different authors and on the deduced relativistic expression for the viscosity cross-section in terms of phase shifts discerning the spin-up and spin-down states of the scattered electrons. Comparison with viscosity cross-sections, as evaluated from non-relativistic phase shifts extracted from experiments, strongly favours the relativistic results. The assumption of isotropic scattering is critically examined and the error induced by its use is shown to persist to the same extent as in non-relativistic calculations, at least in the energy region considered. Received: 22 April 1998 / Received in final form: 16 December 1998     

Fragmentation and particle production in interactions of 10.6 GeV/N gold nuclei with hydrogen, light and heavy targets

We have investigated the interactions of 10.6 GeV/n Au in nuclear emulsion. Two methods of separating interactions into those with hydrogen, light (C,N,O) and heavy (Ag,Br) target nuclei were used, giving almost identical results, which strengthened our confidence in the correctness of these methods. We also measured the angular distributions of singly and multiply charged relativistic particles emitted from the interaction vertices and the charges of the multiply charged projectile fragments. The fragmentation of the projectile Au nuclei and of the target nuclei were analyzed. The multiparticle production was studied as a function of the mass of the target nucleus. The multiplicity and the pseudorapidity distributions of relativistic singly charged particles were compared with the predictions of the RQMD Model. Received: 22 April 1998 / Published online: 8 September 1998     

Calculation of the contributions from high-n dielectronic satellites to the resonance line in helium-like iron

A simplified relativistic configuration interaction method is used to study the dielectronic satellite transition processes. In this method, the infinite resonant doubly excited states can be calculated, and furthermore, the whole high-n dielectronic satellite transition processes can be treated conveniently by interpolation (rather than extrapolation) in the frame of Quantum Defect Theory. As an example, we calculate the contributions from high-n dielectronic satellites to the resonance line in helium-like iron, and the results are in good agreement with the experimental measurements. Received: 16 April 1998 / Revised: 8 September 1998 / Accepted: 14 September 1998     

类铍离子激发态1s22P2 3Pe的能量、精细结构和跃迁波长的计算

采用多组态相互作用方法及Rayleigh-Ritz变分法,计算了类铍离子等电子系列(Z=4-10)激发态1s22p2 3Pe的非相对论能量,利用截断变分方法得到能量改进量,进一步考虑相对论效应和质量极化效应,从而获得了高精度的能量计算值.给出了类铍离子等电子系列激发态1s22p2 3Pe的相对论能量修正和质量极化效应随核电荷数Z变化的情况.同时还计算了激发态1s22p23Pe的精细结构能级和劈裂,以及1s22s2p3Po到1s22p2 3Pe态的辐射跃迁波长.计算结果与其他理论和实验符合得很好.     

Energies and widths of triply excited states of lithiumlike oxygen and neon

Seven low-lying triply exited states of lithium-like oxygen and neon are calculated with the multichannel saddle-point and saddle-point complex-rotation methods. The term energies are given for these excited states, along with level shifts and partial Auger widths from dominant decay channels. The mass polarization effect and relativistic corrections are included. The radiative transition rates are also calculated. These results are compared with other theoretical data in the literature. Received: 25 May 1998 / Revised: 28 July 1998 / Accepted: 25 August 1998     

Generalized heavy baryon chiral perturbation theory

Standard SU(2) Heavy Baryon Chiral Perturbation Theory is extended in order to include the case of small or even vanishing quark condensate. The effective lagrangian is given to in its most general form and to in the scalar sector. A method is developed to efficiently construct the relativistic baryonic effective lagrangian for chiral SU(2) to all orders in the chiral expansion. As a first application, mass- and wave-function renormalization as well as the scalar form factor of the nucleon is calculated to . The result is compared to a dispersive analysis of the nucleon scalar form factor adopted to the case of a small quark condensate. In this latter analysis, the shift of the scalar form factor between the Cheng-Dashen point and zero momentum transfer is found to be enhanced over the result assuming strong quark condensation by up to a factor of two, with substantial deviations starting to be visible for . Received: 22 July 1998 / Revised version: 2 September 1998 / Published online: 2 November 1998     

Solution to the Rarita-Schwinger equations

A systematical method is presented for solving the relativistic wave equations for particles of arbitrary spin. Explicit helicity relativistic wave functions for particles with arbitrary spin are derived rigorously. Received: 22 August 2001 / Revised version: 5 July 2002 / Published online: 9 December 2002 RID="a" ID="a" Corresponding author.     

Relativistic diffusion model

Evidence is presented that diffusion drives colliding many-particle systems at relativistic energies from the initial δ–functions in rapidity towards the equilibrium distribution. Analytical solutions of a linear Fokker-Planck equation represent rapidity spectra for participant protons in central heavy-ion collisions at SPS-energies accurately. Thermal equilibrium in the interaction region is not attained, nonequilibrium features persist and can account for the broad rapidity spectra. Received: 24 November 1998 / Revised version: 20 February 1999     

Intercombination transition rates in Al-like ions

N =3, intercombination transitions in Al-like ions of Au have been studied by time-resolved EUV spectroscopy of foil-excited ion beams. Wavelengths and lifetimes are compared to the available relativistic calculations. The theoretical data are found to be useful for guidance, but of clearly insufficient precision, in particular for the transition probabilities. Received: 23 February 1998 / Accepted: 5 March 1998     

Non-Topological Solutions of the Relativistic SU(3) Chern–Simons Higgs Model

In this paper, we obtain non-topological solutions of the self-dual equations arising in the relativistic SU(3) Chern–Simons Higgs model. Received: 11 July 1998 / Accepted: 1 November 1998     

Comment Triton Binding Energy and Minimal Relativity

For relativistic three-body calculations, essentially two different approaches are in use: field theory and relativistic direct interactions. However, while results based upon relativistic field theory show an increase of the triton binding energy by about 0.3 MeV due to relativistic effects, calculations that claim to apply relativistic direct interactions obtain 0.3 MeV repulsion. In this paper, we discuss the origin of such a discrepancy. We show that the use of an invariant two-body amplitude increases the triton binding energy by about 0.3 MeV, consistent with the results from relativistic field theory. Furthermore, we point out that in calculations relying on the direct-interactions approach, indeed expansions are used, which may be a bad approximation and the reason for the discrepancy. Received November 4, 1996; revised January 15, 1998; accepted for publication January 19, 1998     

Pseudo-spin as a relativistic symmetry

The existence of broken pseudo-spin symmetry in the Pb nucleus has been studied in the relativistic mean field approach using realistic Lagrangian parameters. Its relationship to spin orbit splitting and the vanishingly small surface delta character of the mean spin orbit potential are investigated. In the ²⁰⁸Pb nucleus the broken pseudo-spin doublets are found to exist above the neutron (proton) Fermi surfaces. Received: 16 April 1998 / Revised version: 26 June 1998     

Two interacting particles in a disordered chain II: Critical statistics and maximum mixing of the one body states

For two particles in a disordered chain of length L with on-site interaction U, a duality transformation maps the behavior at weak interaction onto the behavior at strong interaction. Around the fixed point of this transformation, the interaction yields a maximum mixing of the one body states. When (the one particle localization length), this mixing results in weak chaos accompanied by multifractal wave functions and critical spectral statistics, as in the one particle problem at the mobility edge or in certain pseudo-integrable billiards. In one dimension, a local interaction can only yield this weak chaos but can never drive the two particle system to full chaos with Wigner-Dyson statistics. Received: 22 May 1998 / Received in final form: 24 August 1998 / Accepted: 4 September 1998     

组态相互作用和Breit相互作用对类氖离子2p-3s碰撞激发特性的影响

基于全相对论扭曲波(RDW)电子碰撞激发计算程序REIE06,系统计算了类氖Fe~(16+)、Xe~(44+)和U~(82+)离子基态1s~22s~22p~(61)S_0到激发态1s~22s~22p~53s精细结构能级的碰撞强度,详细研究了组态相互作用和Breit相互作用对碰撞强度的影响,总结了一些有意义的结论 .在目前计算中,由于细致考虑了组态相互作用和Breit相互作用,其部分结果与已有的理论结果进行比较,对实验值的相对误差较小.     

Reliability of the pseudospin symmetry in atomic nuclei

The reliability of the pseudospin symmetry (PSS) in atomic nuclei is analyzed in the framework of the relativistic Hartree approach. We find that the nuclear surface strongly increases the effect of the pseudospin-orbit potential (PSOP), spoiling the possibility of the exact realization of the PSS even in the limit of a vanishing PSOP. It is also shown that the PSS cannot be explained by the fact that Σ_S ≃ - Σ. New arguments to explain the PSS in finite nuclei are given. The important role the spin-orbit interaction plays in the achievement of the PSS is also discussed. Received: 22 July 2002 / Accepted: 18 February 2003 / Published online: 20 May 2003     

碳原子1s22s22pns 3P态的能量和波函数

提出了构造碳原子1s22s22pns 3P态波函数的新方法,以Rayleigh-Ritz变分法为基础开发了一套计算碳原子1s22s22pns 3P态波函数和能量的Mathemtica程序,具体计算了碳原子1s22s22pns 3P(n=3-6)态的波函数和非相对论能量及其相对论修正值(包括质量修正、单体达尔文修正、双体达尔文修正、自旋-自旋接触相互作用修正),计算结果与实验值非常接近。     

碳原子1s~22s~22pns~3P态的能量和波函数

提出了构造碳原子1s~22s~22pns~3P态波函数的新方法,以Rayleigh-Ritz变分法为基础开发了一套计算碳原子1s~22s2~2pns~3P态波函数和能量的Mathemtica程序,具体计算了碳原子1s~22s~22pns~3P(n=3～6)态的波函数和非相对论能量及其相对论修正值(包括质量修正、单体达尔文修正、双体达尔文修正、自旋-自旋接触相互作用修正),计算结果与实验值非常接近.     

Nucleon form factors in a relativistic quark model

Electromagnetic form factors of protons and neutrons are investigated based on a relativistic quark model with the inclusion of a pion cloud. Pseudo-scalar π-quark interaction is employed to study the coupling between the nucleon and the π. The results show the important role of the pion cloud for the neutron charge form factor. Moreover, our numerical analysis indicates a difference between the relativistic and the nonrelativistic treatments. Received: 10 March 1999 / Revised version: 14 June 1999     

Superheavy nuclei in deformed mean--field calculations

The ground–state properties of superheavy nuclei are investigated within various parametrisations of relativistic and nonrelativistic nuclear mean–field models. The heaviest known even–even nuclei starting with Z = 98 are used as a benchmark to estimate the predictive power of the models and forces. From that starting point, deformed doubly magic nuclei are searched in the region 100 ≤ Z ≤ 130 and 142 ≤ N ≤ 190. Received: 6 April 1998 / Revised version: 16 June 1998