共查询到20条相似文献,搜索用时 656 毫秒
1.
K. -H. Möbius R. Böttger P. Egelhof Z. Moroz E. Steffens G. Tungate I. Koenig D. Pick 《Zeitschrift für Physik A Hadrons and Nuclei》1982,306(4):335-345
The energy dependence of the total reaction cross sectionσ r and its tensor analyzing powerT 20 r was measured for the7Li?51V interaction in the energy rangeE Li=10–20 MeV using two different experimental methods. Reaction residues were observed directly by their characteristicγ-emission, and the elastic scattering of7Li from51V was investigated. Additionally, the elastic scattering of6Li from51V was measured at 9.8, 12 and 14 MeV. The tensor analyzing power data can be interpreted as being caused by the spectroscopic mass deformation of the Li-ions. The energy dependence of σr andT 20 r above the Coulomb barrier can be described in terms of the classical sharp-cutoff model. 相似文献
2.
R. Dymarz J. L. Molina K. V. Shitikova 《Zeitschrift für Physik A Hadrons and Nuclei》1981,299(3):245-249
The interaction potential of heavy ions4He,6Li,12C and16O is constructed in the folding model. The density distribution of nuclear matter for these nuclei is calculated in the framework of the hyperspherical function method. For the calculation of the folding potentials we have employed the Skyrme nucleon-nucleon forces. The influence of several effects on the results of calculations is studied: the role of the three-body forces of the nucleon-nucleon interaction, dependence of the folding potential on the mass numbers of the colliding nuclei and the possibility of observing the monopole resonance in the ion inelastic scattering. Using our folding potential as a real part of the optical potential we have calculated the differential cross section of elastic scattering of6Li from12C at laboratory energy of lithium ionsT L =90.0 MeV. Reasonable agreement with experiment is obtained. 相似文献
3.
R. Frick H. Clement G. Graw P. Schiemenz N. Seichert Sun Tsu-Hsun 《Zeitschrift für Physik A Hadrons and Nuclei》1984,319(2):133-141
The elastic scattering of vector and tensor polarized deuterons near 20 MeV has been analyzed in terms of the phenomenological optical potential including a complex tensor term ofT R -type. In comparison with folding potentials we find a strong reduction of the real part of theT R -potential with increasing mass number, the contribution of coupling to vibrational excitations is discussed. 相似文献
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5.
A formalism is presented where polarization observables of all ranks for deformed spin ? projectiles are calculated in a parameter-free fashion. Complex optical potentials for the available 7 + 58Ni elastic scattering data at Elab = 20.3 MeV are obtained from single folding calculations, taking the 7Li ground state to be an α + t cluster in relative p-state. The expansion of the hamiltonian in spin-space generates tensor terms of ranks 2 (TR) and 3 (T3) apart from the usual central and spin-orbit terms. The TR potential fits the second-rank tensor analysing powers quite well without being able to resolve discrete ambiguities of input optical parameters. The T3 term generates a J · L contribution, making the spin-orbit interaction three-component. The 7Li vector analysing power so obtained is negative, but the magnitude is not fully reproduced. Modification of parameters to account for absorption modes not included in the superposition model indicates the need for properly handling dynamical polarization effects due in particular to the low-lying first excited state of 7Li. 相似文献
6.
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 T2q 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. 相似文献
7.
K. Nisimura H. Shimizu K. Imai T. Ichihara N. Matsuoka K. Hatanaka H. Sakai T. Saito K. Hosono M. Kondo A. Okihana 《Nuclear Physics A》1985,432(2):378-388
The differential cross section and the vector and tensor analyzing powers Ay, Axx, Ayy and Axz were measured for the d-4He elastic scattering at 56 MeV. The measurement of Axz was performed using a deuteron beam polarized in the horizontal plane. An optical-model analysis of the experimental data was carried out. The magnitude of the tensor analyzing powers could not be reproduced without the tensor potential. By including the TR type tensor potential, the optical-model calculations give a reasonable reproduction of the experimental data at θc.m. < 120°. The obtained TR tensor potential was much stronger than that predicted by the folding model. The strength of the real TR potential was roughly in accordance with that obtained from the optical-model analysis of d-4He elastic scattering at 20.2 MeV. 相似文献
8.
Tauscher L. Backenstoss G. Fransson K. Koch H. Nilsson A. De Raedt J. 《Zeitschrift für Physik A Hadrons and Nuclei》1978,288(2):139-152
The real parts of the optical model potentials for 104 MeV alpha-particle and 156 MeV6Li ion scattering from40, 48Ca are calculated in terms of folding model approaches. The validity of different procedures is tested by comparing the differential cross section predictions with experimental data measured with high angular accuracy. It is found that a refined folding potential accounting for density dependence of an effective nucleon-nucleon interaction is appropriate for alpha particle scattering without any parameter adjustment. However, for6Li ion scattering renormalization of the depth of the real potential is necessary. 相似文献
9.
F. Strieder L. Gialanella U. Greife C. Rolfs S. Schmidt W. H. Schulte H. P. Trautvetter D. Zahnow F. Terrasi L. Campajola A. D’Onofrio V. Roca M. Romano M. Romoli 《Zeitschrift für Physik A Hadrons and Nuclei》1996,355(1):209-218
The absolute cross sectionσ of thed(7Li,p)8Li reaction near theE cm=0.61 MeV resonance has been measured using a7Li ion beam and a windowless gas target system filled with D2 gas. The proton yield of the reaction and theβ-delayedα-activity of the residual nuclides8Li were observed both concurrently with the elastic scattering yield, relatingσ to the Rutherford scattering cross sectionσ R. The resulting values,σ (fromp)=143.6±8.9 mb andσ (from8Li)=151±20 mb, lead to a weighted mean value ofσ=153±6 mb (x 2=2.26) including all available values andσ=146±5 mb (x 2=0.05) removing some values from the data set. The consequences for the expected flux of high-energy solar neutrinos are discussed. 相似文献
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11.
Z. Moroz P. Zupranski R. Böttger P. Egelhof K.-H. Möbius G. Tungate E. Steffens W. Dreves I. Koenig D. Fick 《Nuclear Physics A》1982,381(2):294-316
Elastic and inelastic scattering of aligned 7Li on 58Ni was studied experimentally for several energies between 14 and 22 MeV. Complete sets of second-rank tensor analyzing powers were measured for two energies, 14.2 and 22.0 MeV. The shape-effect model has been used for a qualitative interpretation of the data. The success of this model indicates the spectroscopic deformation of 7Li to be the main source of the observed second-rank tensor analyzing powers. The result enters the formulation of the diffraction as well as the optical model both of which are used to improve the analysis of the data. Besides the parameters which determine the central interaction the spectroscopic deformation was the only adjustable parameter. The deformation was found to be negative, in agreement with the oblate shape of 7Li. However the extracted value of the deformation varies within a factor of two when comparing different experiments and/or analyses with different models. The second-rank tensor analyzing powers for projectile excitation are roughly explained by the assumption that the angular momentum transfer is perpendicular to the momentum transfer. 相似文献
12.
The surface friction model for heavy ion induced fusion is extended to cover collisions of aligned deformed nuclei taking into account dynamic quadrupole and octupole vibrations and rotations of the reaction partners. Calculated fusion cross sections for unpolarized beam and the tensor analyzing powerT 20 for fusion of23Na +23Na are compared with data. The analyzing power is found to be sensitive to variations of the tangential friction strength. 相似文献
13.
《Nuclear Physics A》1998,628(2):203-220
Angular distributions of the differential cross section and the second-rank tensor analysing power T20 have been measured for the one-proton transfer reaction induced by polarized 7Li on 208Pb at 33 MeV leading to several states in 209Bi. The experimental data were analysed simultaneously with data for elastic and inelastic scattering of 7Li by means of CCBA and CRC calculations. The spectroscopic factors for 209Bi states are obtained. 相似文献
14.
The Heidelberg shape-effect model for heavy-ion tensor interactions is reformulated and generalized using the Hooton-Johnson formulation. The generalized semiclassical model (the turning-point model) predicts that the components of the tensor analysing power have certain relations with each other for each type of tensor interaction (TR, TP and TL types). The predicted relations between the are very simple and have a direct connection with the properties of the tensor interaction at the turning point. The model predictions are satisfied in quantum-mechanical calculations for 7Li and 23Na elastic scattering from 58Ni in the Fresnel-diffraction energy region. As a consequence of this model, it becomes possible to single out effects from a TP? or TL-type tensor interaction in polarized heavy-ion scattering. The presence of a TP-type tensor interaction is suggested by measured ratios for 7Li+58Ni scattering. In the turning-point model the three types of tensor operator are not independent, and this is found to be true also in a quantum-mechanical calculation. The model also predicts relations between the components of higher-rank tensor analysing power in the presence of a higher-rank tensor interaction. The rank-3 tensor case is discussed in detail. 相似文献
15.
J. Styczen M. Piiparinen Y. Nagai P. Kleinheinz D. Bazzacco J. Eberth J. Blomqvist 《Zeitschrift für Physik A Hadrons and Nuclei》1983,312(3):149-154
Firm spin-parity assignments for the high-spin states up to 3.5 MeV in the one-proton nucleus147Tb were obtained from144Sm(6Li, 3n) in-beamγ-ray and conversion electron measurements. The energies of these two-particle one-hole excitations were calculated from the shell model with empirical nucleon-nucleon interaction energies. The calculated energy splittings agree well with experiment, whereas the theoretical excitation energies disagree by ?1 MeV if recently measured ground state masses are used. 相似文献
16.
Elastic and inelastic scattering of 7Li by 58Ni at Elab = 14.2 and 20.3 MeV is investigated theoretically, special emphasis being laid on polarization phenomena. A parameter-independent study shows second-rank tensor interactions to be the main origin of tensor analyzing powers for both elastic and inelastic scattering. Coupled-channel (CC) calculations using cluster-folding interactions which include the tensor terms are found to be successful in reproducing the data for cross sections and vector and tensor analyzing powers, when projectile excitation effects are sufficiently taken into account. Scattering of 6Li by 58Ni at Elab = 20.0 MeV is also investigated by the CC calculation, where successes similar to the 7Li case are obtained in understanding experimental data. 相似文献
17.
《Nuclear Physics A》1988,486(2):261-270
Differential cross section and all four analyzing powers iT11, T20, T31 and T22 have been measured for deuteron elastic scattering from 208Pb at incident energies from 10 to 23 MeV. The energy dependence of the tensor analyzing powers was investigated. A considerable deviation of the data from optical-model calculations including a Tr-type tensor potential is found near the Coulomb barrier. 相似文献
18.
The energy dependence of neutron-deuteron elastic scattering observables has been calculated from 5 to 45 MeV via rigorous three-nucleon calculations using the Bonn B nucleon-nucleon interaction. The goal of these calculations was to identify energy and angular regions that may be investigated experimentally to study the question of charge-symmetry breaking in the3
P
J
nucleon-nucleon forces and/or Coulomb interactions. It was found that the measurement of the neutron-deuteron elastic analyzing power at 16 and 22.7 MeV and its comparison to proton-deuteron data obtained at the same incident energy is the most promising case for studying the issue of charge-symmetry breaking in the3
P
J
nucleon-nucleon forces and/or Coulomb interactions. 相似文献
19.
《Nuclear Physics A》1987,462(1):173-204
Scattering of 7Li by 120Sn targets at Elab = 44 MeV is investigated in the coupled-channel frame by taking account of the projectile virtual excitations to the lowest three excited states. Calculations are performed by the cluster-folding (CF) interactions and the double-folding (DF) one. Both interactions reproduce very well the experimental data on the cross section, the vector analyzing power, the second-rank tensor ones and the third-rank tensor one in elastic and projectile inelastic scattering, although some differences are found between the CF results and the DF ones. In the calculation, the virtual excitations of the projectile are important for most of the analyzing powers and the spin-orbit interaction is indispensable for the vector analyzing power. These features are in contrast to those in 7Li-58Ni scattering at 20 MeV and are interpreted as over-Coulomb-barrier effects. The scattering amplitudes and the analyzing powers are investigated by the invariant amplitude method, which provides a key connecting the spin-dependent interactions to the analyzing powers. The method proposes an important relationship between the tensor analyzing powers, which is useful in analyses of both theoretical and experimental results. Finally, it is found that in the elastic scattering the second-rank tensor analyzing powers are proportional to the strength of the second-rank tensor interaction and the vector and third-rank tensor analyzing powers to the square or cube of the strength of this interaction, while in the inelastic scattering the cross section is proportional to the square of the strength of the tensor interaction, other quantities being weakly dependent on the strength. 相似文献
20.
The effective pairing interaction in the 1 S 0 channel as calculated microscopically within the Brueckner method for a planar slab of nuclear matter by using the separable version of the Paris nucleon-nucleon potential is investigated. The effective interaction is determined for the model space including all negative-energy single-particle states. An analysis is performed for two values of the chemical potential, μ=?8 and ?4 MeV. It is shown that, to a high precision, the effective interaction can be approximated by the off-shell T matrix for free nucleon-nucleon interaction, the T matrix in question being taken at a negative value of the total energy of two nucleons E=2μ. 相似文献