Manifestation of one- and two-body currents in longitudinal and transverse response functions of the 12C nucleus at q = 300 MeV/c

The experimental values of longitudinal and transverse response functions of the 12C nucleus have been obtained at the 3-momentum transfer q = 300 MeV/c. The data are compared with the calculations made with due regard to the dynamics of all the nucleons constituting the 12C nucleus, and also, to the contributions of both the one-body currents only, and their combination with two-body currents.Comment: 4 pages, 2 figure

Saturation of Coulomb sum rules in the 6^Li case

The Coulomb sums S_L(q) of the 6^Li nucleus have been obtained from electron scattering measurements at 3-momentum transfers q = 1.125 - 1.625 fm^{-1}. It is found that at q > 1.35 fm^{-1} the Coulomb sum of the nucleus becomes saturated: S_L(q) = 1.Comment: 6 pages, 4 figures, 1 tabl

The Coulomb sum of 7Li

The experimental values of longitudinal response function of the 7Li nucleus have been obtained and these results have been used as the basis to find the Coulomb sum values at momentum transfers ranging from 0.55 to 1.625 fm-1. The obtained experimental Coulomb sum values have been used to determine the total Coulomb energy of the 7Li nucleus. The result of the comparison of the Coulomb energy for the 7Li nucleus with the Coulomb energies for the 6Li and 4He nuclei a) is consistent with the paradox (revealed in the elastic electron scattering experiment) that the 7Li rms charge radius is smaller than the one of the 6Li nucleus; b) leads to the conclusion that, within the framework of the two-cluster model of the 7Li nucleus (α + t), the size of the α-cluster should be larger than the one of the 4He nucleus

MANIFESTATION OF NUCLEAR CLUSTERIZATION IN COULOMB SUMS

The new experimental Coulomb sums values of 6Li and 7Li nuclei have been obtained at momentum transfers range q = 0.750¸ 1.000 fm-1 and q = 0.750¸ 1.125 fm-1, respectively, extending significantly the earlier reported momentum transfers range of Coulomb sums for these nuclei. The dependence of the 6Li and 7Li Coulomb sums on the momentum transferred is shown to differ substantially from same dependences for all the other investigated nuclei. It is suggested that the observed feature of the 6Li and 7Li Coulomb sums is related to a strong clusterization of these nuclei. The parameter qp corresponding to the value of the momentum transferred, at which the Coulomb sum ceases to grow and remains constant for larger momentum transfers, is introduced. The values of the parameter qp for the lithium isotopes nuclei were obtained (qp(7Li) = 1.20 ± 0.10fm-1 and qp(7Li) = 1.35 ± 0.10 fm-1), which are much lower than qp of 4He, 12C, 40Ca, 48Ca and 56Fe nuclei (qp » 2 fm-1). The graph represented the qp values of the nuclei as a function of the isolation parameter x, which characterizing the degree of nuclear clusterization, is constructed. The obtained graph shows the explicit proportionality of the qp dependence from the parameter x and predicts the qp value for the Coulomb sum of the 9Be nucleus not yet measured

Application of the equivalent radiator method for radiative corrections to the spectra of elastic electron scattering by nuclei

For calculating the radiative tails in the spectra of inelastic electron scattering by nuclei, the approximation, namely, the equivalent radiator method (ERM), is used. However, the applicability of this method for evaluating the radiative tail from the elastic scattering peak has been little investigated, and therefore, it has become the subject of the present study for the case of light nuclei. As a result, spectral regions were found, where a significant discrepancy between the ERM calculation and the exact-formula calculation was observed. A link was established between this phenomenon and the diffraction minimum of the squared form-factor of the nuclear ground state. Varieties of calculations were carried out for different kinematics of electron scattering by nuclei. The analysis of the calculation results has shown the conditions, at which the equivalent radiator method can be applied for adequately evaluating the radiative tail of the elastic scattering peak

Relation between (e, e′) sum rules in

The sums over (e, e′) spectra of 6Li and 7Li nuclei which correspond to the longitudinal sum rule are studied. It is suggested that due to the cluster structure of the lithium isotopes these sums may approximately be expressed in terms of such a sum pertaining to the $\alpha$-particle. Calculation of these sums is performed in the framework of cluster models with antisymmetrization done with respect to all the nucleons. At momentum transfers higher than 0.8 fm-1 the relations expressing the A = 6 or 7 sum in terms of the A = 4 sum prove to be valid with rather high accuracy. In the region of momentum transfers around 1 fm-1 the longitudinal correlation functions of 6Li and 7Li nuclei are found to be close to that of the $\alpha$-particle. Basing on this, the difference between the q values at which the high-q limit of the inelastic sum rule is reached in the 6, 7Li cases and the 4He case is explained. The experimental longitudinal sums in the range between 0.450 and 1.625 fm-1 are employed to perform comparison with the theoretical sum rule calculated in the framework of cluster models. Out of the experimental sums, those in the range between 0.750 and 1.000 fm-1 in the 6Li case and between 0.750 and 1.125 fm-1 in the 7Li case are obtained in the present work. In the 6 Li case a complete agreement between experiment and the calculated sum rule is found while in the 7Li case an agreement only at a qualitative level is observed