Analysis of elastic and inelastic hadron scattering on 6,7Li nuclei within diffraction theory

Within Glauber-Sitenko multiple-scattering theory, the differential cross sections for elastic and inelastic proton, positive-pion, and positive-kaon scattering on ^6,7Li nuclei are calculated at incident-hadron energies ranging between 0.143 and 1.0 GeV. The ⁶Li and ⁷Li wave functions are taken in, respectively, the α2N and the αt clustermodel. The resulting cross sections are investigated as functions of the scattered-particle energy, parameters of the model wave functions, and various scattering multiplicities. It is concluded that a partial filling of the diffraction minimum in the cross section is due to the D-wave contribution to the wave function for the ⁶Li target nucleus.     

Vertex function and coupling constant for the virtual decay of7Li

The alpha-triton relative wave function with various nucleon exchange contributions and their asymptotic normalization are considered in the framework of the generator coordinate method (GCM). The asymptotic normalization of relative wave function provide the estimate of the coupling constant. The relative wave function is also used to obtain⁷Li-α-t vertex function in the virtual decay of⁷Li. The extrapolation of vertex function for negative values ofq ² up to the alpha-triton pole provide the vertex constant, which is compared with the experimentally determined estimates 0.67 FM and 0.72 FM. Our calculated value is 0.656 FM which is in close agreement with the above estimates.     

Puzzle of the <Superscript>6</Superscript>Li quadrupole moment: Steps toward solving it

The problem of the origin of the quadrupole deformation in the ⁶Li ground state is investigated with allowance for the three-deuteron component of the ⁶Li wave function. Two long-standing puzzles related to the tensor interaction in the ⁶Li nucleus are known: that of an anomalous smallness of the ⁶Li quadrupole moment (being negative, it is smaller in magnitude than the ⁷Li quadrupole moment by a factor of 5) and that of an anomalous behavior of the tensor analyzing power T_2q in the scattering of polarized ⁶Li nuclei on various targets. It is shown that a large (in magnitude) negative exchange contribution to the ⁶Li quadrupole moment from the three-deuteron configuration cancels almost completely the “direct” positive contribution due to the αd folding potential. As a result, the total quadrupole moment proves to be close to zero and highly sensitive to fine details of the tensor nucleon-nucleon interaction in the ⁴He nucleus and of its wave function.     

Elastic scattering of protons from 9Li in inverse kinematics within diffraction theory

The differential cross section for elastic scattering of protons from the ⁹Li nucleus has been calculated within the framework of the Glauber multiple scattering theory. The calculations were carried out with two versions of cluster wave functions for the nucleus obtained within the α-t-2n and ⁷Li-n-n three-body models with realistic potentials of intercluster interactions. The differential cross section was calculated at E = 700 and 60 MeV/nucleon. A comparison with the experimental data allows the conclusion that the wave function in the ⁷Li-n-n model describes the cross section better than in the α-t-2n model.     

The construction of wave functions in the <Superscript>7</Superscript>Li → d + <Superscript>5</Superscript>He channel by the projection method

Relative motion wave functions in the d + ⁵He channel were constructed by the projection method using the two-body αt model of ⁷Li nucleus. The asymptotic constants in this channel were calculated using various models of ⁵He{αn} wave function.     

A Study of Bound States of Systems of Helium and Lithium Using the Method of Discrete-Variable Representation

The systems of particles He₂, ⁶Li–He, ⁷Li–He, He₃, ⁶Li–He₂, and ⁷Li–He₂, the binding energies of which are small and the bound-state wave functions of which are widely distributed in space, are considered. Because the interaction potential is weak and rather localized compared to the characteristic sizes of wave functions of these systems, the problem of an accurate determination of binding energy and wave functions is complicated. Small changes in input parameters or an inaccuracy of calculations can lead to considerable deviations of calculated results from true values. An essential part of the study is the development and application of the discrete-variable representation method. This method is based on the determination of basis functions and the nodes and weights of a quadrature formula in such way that the values of a function are zero at all these nodes but one. With this representation the time required for calculating the Hamiltonianmatrix elements is reduced several times. The binding energies of several systems consisting of helium and lithium atoms were obtained using the method of discrete-variable representation. Thanks to the application of this approach, the calculation time was significantly reduced without loss in accuracy.     

Mechanisms in d + 6Li three-body reactions at low bombarding energies

The three-body reactions induced by low energy deuterons on ⁶Li have been studied. The contributions from the sequential processes through the excited states of the intermediate ⁴He, ⁵Li, ⁶Li and ⁷Li nuclei dominate the coincidence spectra. The quasi-free d + d → d + d, d + α → d + α, and d + d → p + t reactions have been observed and compared with plane wave impulse approximation (PWIA) calculations.     

Elastic and inelastic scattering of π mesons on 7Li nuclei

Within the diffraction theory of multiple scattering, the differential cross sections for elastic and inelastic pion scattering on a ⁷Li nucleus are calculated for the case where the final nucleus is either in the ground or in the first excited state. The nuclear wave function is set to that in the αt cluster model. The sensitivity of the calculated observables to variations in the type of the wave functions for the alpha-particle and the triton cluster and for their relative motion is investigated. Various multiplicities of scattering and rescattering on the clusters constituting the ⁷Li nucleus are taken into account, and their contributions to the cross section are revealed. The results of the calculations are compared with experimental data at E _π=143, 164, and 194 MeV.     

Quasi-elastic electron scattering (e,e′p) and (e,e′d) from 6Li in a coincidence experiment

Coincidence cross sections for the reactions ⁶Li(e, e′p) and ⁶Li(e, e′d) have been measured in the region of quasi-elastic scattering. Using incident electrons of 2.5 and 2.7 GeV, the four-momentum transfers to the proton were 6.6 fm^?2, 10.0 fm^?2 and 11.6 fm^?2. The proton coincidence data agree with shell-model distributions assuming a Woods-Saxon potential and including short-range nucleon-nucleon correlations. The best fit to the deuteron coincidence data is obtained with a cluster wave function for the p-nucleons and a harmonic oscillator wave function for the s-nucleons taking into account the deuteron yield from the s-shell. The ratio of the deuteron cross section from ⁶Li divided by the elastic e-d scattering cross section depends only slightly on the four-momentum transfer and has a value of ≈ 2.     

The optical potential for 6Li-6Li elastic scattering at 156 MeV

Elastic scattering of ⁶Li from ⁶Li has been studied for a beam energy of 156 MeV. The experimental differential cross sections have been analysed on the basis of the optical model using various phenomenological forms. The spin-orbit interaction proves to be less significant. A semimicroscopic double-folding cluster model which generates the real part of the optical potential by an antisymmetrized dα cluster wave function of ⁶Li and αα, dd and dα interactions is well able to describe the experimental data.     

Inelastic scattering of electrons andE2 transition in6Li

A simple nucleon-nucleon correlation function has been included in the independent-particle shell-model (IPSM) wave functions of⁶Li. The reduced transition probability and the nuclear form factor of⁶Li as obtained from the inelastic scattering of electrons have been calculated using the correlated as well as the uncorrelated wave functions of the ground and the first excited states. The correlated transition probability and the form factor are considerably improved over the uncorrelated ones. The correlated form factor is more consistent with the experimental data than the uncorrelated one.     

Comparative analysis of the characteristics of the elastic scattering of protons by lithium isotopes 6, 7, 8, 9Li, performed using Glauber’s multiple diffraction scattering theory

Differential cross sections and vector analyzing powers are calculated for the elastic scattering of protons by lithium isotopes ⁶Li, ⁷Li, ⁸Li, and ⁹Li at energies of 60 and 200 MeV. The calculations are performed using Glauber??s multiple diffraction scattering theory in the two-particle (for ⁷Li) and three-particle (for ^6,8,9Li) models with realistic intercluster interaction potentials. An analysis of the relationship between the differential elastic scattering cross section and various wave functions, calculated using different interaction potentials, is presented for the ^{8, 9}Li isotopes.     

Multibody final states of the 6Li + 6Li reaction AT 97 MeV

Absolute coincidence cross sections were measured for the reactions ⁶Li + ⁶Li → 3α, ⁶Li(⁶Li, 2α), and ⁶Li (⁶Li, 2d), where the latter two represent $\text{N-}\text{body}\text{(N ≧ 4)}$ final states. Broad peaks from the ⁶Li (⁶Li, 2α) reaction are well described by a double spectator pole (DSP) model utilizing a Hulthén wave function, whereas near 40 MeV the DSP peaks are much narrower than predicted. A broad peak in the 3α final-state spectrum, attributed to a single-spectator pole (SSP) process, is well described with the same wave function. The SSP is the principal mechanism for the 3α reaction, in contrast to data near 40 MeV which show that sequential decay from ⁸Be levels is dominant.     

12C(7Li,t)16O和20Ne(d,6Li)16O反应的研究

本文把用于处理重离子引起的单粒子转移反应的Goldfarb-Buttle方法推广到多粒子转移反应。计算了¹²C(⁷Li,t)¹⁶O和²⁰Ne(d,⁶Li)¹⁶O反应,用了¹⁶O的全相干波函数,考虑了某些反冲因素,并将结果与实验作了比较。     

Effect of the structure of neutron-rich <Superscript>8</Superscript>Li and <Superscript>9</Superscript>Li isotopes on the characteristics of proton elastic scattering

The differential cross sections of proton elastic scattering from ⁸Li and ⁹Li nuclei in inverse kinematics have been calculated. The cross sections were determined within the Glauber diffraction theory with the wave functions of nuclei in the three-particle α-t-n, α-t-2n, and ⁷Li-n-n models. Comparison with the existing experimental data for E = 700 and 60 MeV/nucleon made it possible to draw a conclusion about the quality of the wave functions and the adequacy of the potentials used for their calculations.     

Quasi-free electron scattering on light nuclei

The separation energy spectra and the momentum distributions obtained from the (e, e′p) reaction on ⁶Li, ⁷Li, ⁹Be, and ¹²C are presented. A simple DWIA analysis using the Elton-Swift wave functions gives good agreement with the ¹²C data, but does not explain the data for ⁶Li and ⁷Li.     

Spectroscopic factors in the <Superscript>7</Superscript>Li → d + <Superscript>5</Superscript>He{α} fragmentation channel

The spectroscopic S _d factors of the separation of deuterons in the d + ⁵He channel were calculated using the two-body αt model of ⁷Li nucleus and various ⁵He{αn} wave function models.