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1.
Effects of the three-nucleon forces on the triton binding energy are investigated using different models for which the xN scattering amplitudes for the off-mass-shell pions are extrapolated from the on-mass-shell data. In the independent model potential, the threenucleon forces are constructed using the chiral symmetry through partial conservation of the axial current vectors and current algebra. On the other hand, the three-nucleon forces in the dependent model potential are derived from an effective Lagrangian which is constrained by chiral and gauge symmetry. The effect of the long range 2π and the repulsive ap-exchange three-nucleon forces on the triton binding energy are investigated. The bound state triton binding energies are then calculated by solving the Faddeev equations with a Hamiltonian including the three-nucleon forces, using different nucleon-nucleon interactions. The pionic form factors are considered with different sets of the form factor cutoff,parameter Λ. The 2π-exchange forces with S- and P-wave amplitudes are found to overbind the triton binding energy by about 0.4~Y 1.6 MeV. However, xp-exchange forces are found to reduce the 2π exchange forces by about 18% of its contribution, to the triton binding energy. 相似文献
2.
By calculating the contribution of the ππ three-body force to the three-nucleon binding energy in terms of the πN amplitude using perturbation theory, we are able to determine the importance of the energy dependence and the contribution
of the different partial waves of the πN amplitude to the three-nucleon force. A separable representation of the non-pole πN amplitude allows us to write the three-nucleon force in terms of the amplitude for NN → NN*, propagation of the NNN* system, and the amplitude for NN* → NN , with N* being the πN quasi-particle amplitude in a given state. The division of the πN amplitude into a pole and non-pole part gives a procedure for the determination of the πNN form factor within the model. The total contribution of the three-body force to the binding energy of the triton for the
separable approximation to the Paris nucleon-nucleon potential (PEST) is found to be very small mainly as a result of the
energy dependence of the πN amplitude, the cancellation between the S- and P-wave πN amplitudes, and the soft πNN form factor.
Received April 12, 1994; revised November 11, 1994; accepted for publication December 1, 1994 相似文献
3.
Minimal-relativity factors, when multiplied to a static local mesonexchange nucleon-nucleon potential, lead to a nonlocal
potential. It is shown that the nonlocality can be represented by an analytically given nonlocality function, which has a
width inversely proportional to the nucleon mass and which tends towards δ(r − r), the usual locality condition, in the limit of the nucleon mass going to infinity. Consequences of this particular type
of non-locality for two-nucleon observables and for the three-nucleon binding energy are investigated along with a Malfliet-Tjjon-type
potential. After readjusting the potential parameters of the nonlocal potential such that its two-nucleon properties are well
matched to the ones of the static local potential the effect of the nonlocality on the three-nucleon binding energy essentially
vanishes.
Received October 9, 1995; revised December 30, 1995; accepted for publication March 12, 1996 相似文献
4.
在不同能量下, 利用核束缚能对虚光子四动量的平方项进行修正, 分别计算了Sn核碰撞中核束缚能对反应截面中湮灭项和康普顿散射项及K因子的影响。 结果表明, 核束缚能在小x区域对反应截面中湮灭项和康普顿散射项及K因子的影响明显, 并且能量越低这种影响越显著, 随着x2增大影响逐渐消失。 We made a revision of square of virtual photon four momentum by means of using nuclear bin ding energy formula in different energy, and we also made an accurate calculation for the effect of nuclear binding energy on K factor and Compton term and annihilate term in the Drell Yan process of the Sn Sn collision. The outcome indicates that the effect of nuclear binding energy on the annihilate term and the Compton term is marked in little x region and the effect will become more obvious with decrease of the energy and come to disappear with increase of the x. 相似文献
5.
G. Soff I. Bednyakov T. Beier F. Erler I. A. Goidenko U. D. Jentschura L. N. Labzowsky A. V. Nefiodov G. Plunien R. Schützhold S. Zschocke 《Hyperfine Interactions》2001,132(1-4):75-103
Atomic binding energies are calculated at utmost precision. A report on the current status of Lamb-shift predictions for hydrogenlike
ions, including all quantum electrodynamical corrections to first and second order in the fine structure constant α is presented.
All relevant nuclear effects are taken into account. High-precision calculations for the Lamb shift in hydrogen are presented.
The hyperfine structure splitting and the g factor of a bound electron in the strong electromagnetic field of a heavy nucleus is considered. Special emphasis is also
put on parity violation effects in atomic systems. For all systems possible investigations beyond precision tests of quantum
electrodynamics are considered.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
6.
Lei YANG Chengjian LIN Huiming JIA Dongxi WANG Feng YANG Fupeng ZHONG Shanhao ZHONG Nanru MA Peiwei WEN 《原子核物理评论》2020,37(3):595-599
应用扰动法提取和研究了紧束缚体系16O+208Pb和弱束缚体系9Be+208Pb 灵敏区域。首次区分了对应于形状散射和共振散射对应的灵敏区域。同时,发现紧束缚体系和弱束缚体系的灵敏区域都存在着强烈的能量相依性:在垒上区域,灵敏区域在强吸收半径附近变化;而在垒下能区,灵敏区域与纯库仑场中的最趋近距离有相似的变化趋势。 相似文献
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J. Golak K. Topolnicki R. Skibiński W. Glöckle H. Kamada A. Nogga 《Few-Body Systems》2013,54(12):2427-2446
Recently a formalism for a direct treatment of the Faddeev equation for the three-nucleon bound state in three dimensions has been proposed. It relies on an operator representation of the Faddeev component in the momentum space and leads to a finite set of coupled equations for scalar functions which depend only on three variables. In this paper we provide further elements of this formalism and show the first numerical results for chiral NNLO nuclear forces. 相似文献
10.
Isospin effects on particle emission of fissioning isobaric sources
202Fr, 202Po, 202Tl and isotopic sources
189,202,212Po, and its dependence on the excitation energy are studied via Smoluchowski equations. It is shown that with increasing the
isospin of fissioning systems, charged-particle emission is not
sensitive to the strength of nuclear dissipation. In addition, we
have found that increasing the excitation energy not only
increases the influence of nuclear dissipation on particle
emission but also greatly enhances the sensitivity of the emission
of pre-scission neutrons or charged particles to the isospin of
the system. Therefore, in order to extract dissipation strength
more accurately by taking light particle multiplicities it is
important to choose both a highly excited compound nucleus and a
proper kind of particles for systems with different isospins. 相似文献
11.
It is shown how a bare three-nucleon force is incorporated into the formalism of the effective interaction approach for hyperspherical harmonics. As a practical example we calculate the ground-state properties of 3H and 3He using the Argonne V18 nucleon-nucleon potential and the Urbana IX three-nucleon force. A very good convergence of binding energies and matter radii is obtained. We also find a very good agreement of our results compared to other high-precision calculations. 相似文献
12.
The effects of the interaction between electron and bulk longitudinal optical (LO) phonon and surface optical (SO) phonon on the impurity binding energy of the ground state in a polar crystal slab within an external electric field are derived by using the method of a variational wavefunction. The binding energy of the bound polaron is obtained as a function of the impurity position, the slab thickness and the electric field strength. It is found that the polaronic correction to the impurity binding energy by the SO phonon may be enhanced and that by the LO phonon may be reduced with increasing electric field strength. And the effect of the electron-phonon interaction is quite important in increasing the values of binding energy. 相似文献
13.
An ansatz of a single particle picture, known for example from the shell model, has been used to construct a model wave function which is as close as possible to an exact three-body wave function. The exact wave function is obtained by solving the Faddeev equation with the Malfliet–Tjon potential. In order to judge the quality of the model wave function, we compare correlation functions of the model wave function and the exact solution. The correlation functions differ significantly at small distances but are close to each other for larger values of their arguments. 相似文献
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重离子碰撞中原子核阻止的同位旋效应 总被引:1,自引:0,他引:1
利用含有3种对称势形式的同位旋相关的量子分子动力学,研究了中能重离子碰撞中原子核阻止的同位旋效应和随入射道条件的系统演化过程.计算结果表明,原子核阻止灵敏地依赖束流能量、碰撞参数、碰撞系统的质量和核子–核子碰撞截面的同位旋相关性,而3种对称势和碰撞系统的中质比对它的影响不很明显,但在大约费米能量以下能区,原子核阻止同时依赖于介质中核子–核子碰撞截面和对称势.故认为在费米能量以上能区直至150MeV/u,原子核阻止是提取介质中核子–核子碰撞截面的一个新的物理观测量. 相似文献
16.
David M. Saylor Adam Morawiec Brent L. Adams Gregory S. Rohrer 《Interface Science》2000,8(2-3):131-140
Geometric and crystallographic data obtained from a well annealed magnesia polycrystal have been used to specify the five macroscopic degrees of freedom for 4665 grain boundaries. The results indicate, that for this sample, the five parameter grain boundary character space is fully occupied. A finite series of symmetrized spherical harmonics has been used to approximate the misorientation dependence of the relative grain boundary energy. Best fit coefficients for this series were determined by assuming that the interfacial tensions at each triple junction are balanced. The grain boundary energy function shows Read-Shockley behavior at small misorientations and a broad minimum near the 3 misorientation. Furthermore, misorientations about the ‹100› axis create boundaries with relative energies that are less than those created by misorientations about the ‹110› or ‹111› axes. 相似文献
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An experimental electron swarm method with a special electron capture detector arrangement (ECD) is described which allows one to modify the energy of low energetic electrons from thermal to 2.8 eV by means of radio-frequency voltage. Using theoretically calculated values of electron energy distribution functions in nitrogen and argon the attachment coefficients and the formation rates of negative ions for chlorobenzene, benzyl chloride, chloroform, methylene chloride, nitrobenzene, propyl iodide, trichloroethylene and carbon disulfide were determined in dependence on the mean electron energy. Mean electron attachment cross sections could be estimated. 相似文献
19.
A phenomenological estimate is derived such that the binding energies of dimesons are expressed as combinations of masses
of different mesons and baryons. The estimate is almost model-independent, the only major assumptions being that the wave
functions of the two light quarks in Λ
c
, Λ
b
and in the and dimesons are very similar, and that for heavy quarks the QQ interaction is half as strong as the interaction. We get (I = 0, J = 1) bound by about 100 MeV and unbound.
Received July 4, 2000; revised November 28, 2000; accepted for publication February 5, 2001 相似文献