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1.
《Nuclear Physics A》1987,464(4):603-612
The Lorentz-Lorenz correction for linearly velocity-dependent potentials saturates at the second-order term. This sheds some new light onto the role of tensor potentials in the relativistic Dirac approach to proton nucleus scattering. 相似文献
2.
The analysing power of 12C for the elastic scattering of vector-polarized deuterons at 9, 10, 11 and 12.0 MeV is measured. A simultaneous optical-model analysis of the cross section and analysing power shows clearly that there is no reasonable optical potential of the usual form in this energy region. 相似文献
3.
G.N. Epstein 《Nuclear Physics A》1976,271(2):429-446
Using dispersion techniques we show that the parity-violating γ-ray circular polarisation in thermal neutron-proton photocapture may be significantly enhanced by softening the two-nucleon strong force at short distances in a way consistent with current two-nucleon scattering data. 相似文献
4.
Results from the proton transfer reactions, 143Nd(3He, d) and 143Nd(α, t), and γ-ray studies have been used to characterize the levels in 144Pm. The spins, cross section ratios and γ-ray branching ratios for the states below 600 keV can be interpreted consistently in terms of the mixed and shell-model configurations. The γ-ray intensity ratios measured in the 141Pr(α, nγ) and 144Nd(p, nγ) reactions exhibit a strong and smooth dependence on level spin. Theoretical calculations employing a residual surface delta interaction are in reasonable agreement with the twelve observed low-lying negative parity states. The eight positive parity states between 841 and 1451 keV are presumed to arise from the configuration. 相似文献
5.
The magnetic moment of the first excited 96 keV, state of 19O has been determined by an integral perturbed angular correlation measurement in a transverse external magnetic field. The value obtained for the g-factor, ?0.48(6), is discussed in terms of shell-model configurations. The wave function of the level is shown to consist mainly of the configuration. 相似文献
6.
Binary coincident fragments from the 56Fe+238U reaction at 538 MeV have been studied. Fragment energies were measured and fragment masses determined by a kinematic method. Three types of event are defined by suitable adjacent limits in the mass versus energy event space. The angular distributions of cross section, energy and mass have determined for each event region and particular attention paid to that part containing possible fissions following complete fusion. The total reaction cross section consists of about 50 % of binary fragmentation channels. The remaining channels correspond to a ternary process of heavy recoil fission. 相似文献
7.
The applicability of the generator coordinate method as an approximation to the complete shell model diagonalization is tested in the sd shell on 24Ne. We use the quadrupole moment and the pairing energy as generator coordinates and choose as generating function a constrained Hartree-Bogoliubov solution projected on the subspace of good angular momentum and good proton and neutron number. The spectra obtained by the generator coordinate method and the complete diagonalization show good overall agreement. Also we draw some conclusions about the nature of some low-lying states in 24Ne, interpreted in terms of vibrations. 相似文献
8.
J. Rekstad P. Bøe A. Henriquez R. Øyan M. Guttormsen T. Engeland G. Løvhøiden 《Nuclear Physics A》1981,371(3):364-380
The level structure of 153Gd has been studied by means of the 150Sm(α, n)153Gd reaction. The experiment included measurements of γ-γ coincidences, γ-angular distributions, γ-ray yield at 17 MeV and 19 MeV beam energy, and γ-ray multiplicities. Favoured and unfavoured members of the positive-parity i13,2, band were identified. States belonging to the h9,2 and f7,2 band structures have been located.Surprisingly low multiplicity numbers were deduced for 153Gd γ-rays. This may indicate that the (α, n) reaction is not a pure compound reaction. The level structure of 153Gd has been compared to the known structure of other odd-mass N = 89 nuclei, and a close similarity is found.The positive-parity band structure has been compared to calculations with the pairing-plus-recoil model. Good agreement is obtained without any ad hoc Coriolis attenuation. 相似文献
9.
10.
J. Ulbricht W. Arnold H. Berg E. Huttel H.H. Krause G. Clausnitzer 《Nuclear Physics A》1977,287(2):220-236
The polarized proton capture in 7Li was used to study the reaction mechanism and to obtain spectroscopic information on the 8Be nucleus. Gamma-ray angular distributions of the analyzing power were measured as a function of proton energy from Ep = 380–960 keV with three Ge(Li) detectors simultaneously. The excitation functions of the cross section and the analyzing power are strongly energy dependent. The data were analyzed unambiguously and represented by three R-matrix elements, two M1 and one E1. The energy dependence of the two M1 matrix elements agrees with the well-known two 1+ resonances at Ex = 17.642 and 18.157 MeV. The energy dependence of the E1 matrix element shows a smooth background presumably caused by a direct-capture mechanism, and furthermore, a resonant contribution, which is a significant suggestion of a new 1? state in the 8Be system at Ex = 17.70 MeV with a width of Γp = 180 keV. 相似文献
11.
The γ-decay of 26 resonances in the reaction 60Ni(p, γ)61Cu in the range Ep = 3690–3790 keV has been investigated. The isobaric analogue state (IAS) corresponding to the parent state at in 61Mi has been resolved into several fine structure components. The absolute strength for the transition to the antianalogue state is found to be Γγ = 0.24 ± 0.07 W.u. The measured M1 strength distribution for the decay of the . IAS is compared to theoretical predictions. 相似文献
12.
H. Klewe-Nebenius D. Habs K. Wisshak H. Faust G. Nowicki S. Göring H. Rebel G. Schatz M. Schwall 《Nuclear Physics A》1975,240(1):137-170
The level scheme of 137Pr was investigated by means of the γ-rays following the β-decay of 137Nd as well as by prompt γ-rays accompanying (α, xn) reactions. We measured γ-ray single spectra, γγ coincidences (both in-beam and off-beam), angular distributions of prompt γ-rays and conversion electrons. About 100 γ-rays were assigned to the 38 min decay of 137Nd most of which fit into a scheme of 26 deduced levels. From in-beam experiments we tentatively assigned an ? level which is the basis of a strong cascade of stretched E2 transitions with a probable level sequence of ? ?? ?? ??. The interpretation of this cascade in the framework of a strong coupling model indicates a prolate deformation of 137Pr. Another indication for such a deformation was obtained from the very low energy (75 keV) of the first + level which could not be interpreted in an intermediate coupling model, but is suggested by a Nilsson scheme. 相似文献
13.
G. T. A. Squier A. R. Johnston E. W. SpiersS. A. Harbison N. M. Stewart 《Nuclear Physics A》1971,160(3):602-608
Cross sections have been measured for the transitions to the ground state and first excited state of 8Be and to the two 2+ levels at 16.63 MeV and 16.93 MeV excitation in the reaction 10B(p, 3He) at Ep = 49.5 MeV. The angular distributions of the cross section were compared with DWBA predictions. 相似文献
14.
A. Zemel C. Broude E. Dafni A. Gelberg M.B. Goldberg J. Gerber G.J. Kumbartzki K.-H. Speidel 《Nuclear Physics A》1982,383(1):165-188
Employing the static hyperfine fields at cerium nuclei in magnetized Fe and Gd hosts, the g-factor of the 134Ce(10+) state at backbending (Ex = 3719.3 keV) has been determined as g = ? 0.30 (25). The coexistence of this neutron-dominated state with the ( isomer (Ex = 3208.5 keV, g = ?0.19(1)) is unexpected. A comprehensive spectroscopic study following the 122Sn(16O, 4n) reaction, including γ-angular distributions, prompt and delayed γ coincidence and recoil-distance measurements has yielded new information on quasi-collective bands of both parities. The properties of the low-lying positive-parity states are well described by the interacting boson model. 相似文献
15.
Masumi Ohshima Eisuke Minehara Mitsuhiko Ishii Takashi Inamura Akira Hashizume 《Nuclear Physics A》1985,436(3):518-537
The ground-state rotational band in 167Er has been investigated through multiple Coulomb excitation with a 160 MeV 35Cl beam. Excited states up to were established by measuring γγ coincidences and γ-ray angular distributions. Gamma-gamma angular correlations were also measured. Nuclear lifetimes of levels up to spin have been determined from Doppler-broadened γ-ray lineshapes, and B(M1) and B(E2) values of intra-band transitions deduced. Considerable signature dependence was observed for level energies and M1 transition probabilities. A Coriolis band-mixing calculation was carried our for comparison with the experimental results. The measured M1 transition probabilities are compared to calculations based on a particle-rotor model, a cranking model, and a microscopic model with quantum-number projection. 相似文献
16.
The formation of superheavy electronic quasimolecules leads to measurable deviations from the Rutherford cross section in heavy ion collisions. For the system 23892U-23592U with Ec.m. = 800 MeV we find an average correction of 1.5% for the scattering cross section in forward directions. Additional background contributions like electronic shielding of the nucleus, vacuum polarization, nuclear Coulomb excitation and static deformations of the nuclei are taken into account. 相似文献
17.
Raymond A. Sorensen 《Nuclear Physics A》1977,281(3):475-485
In nuclear models approximate wave functions are often used which do no have sharp angular momentum as required of the exact wave functions. It seem obvious that model wave functions of this type should be improved by projection onto states of good angular momentum. It is not the purpose of this paper to discuss the technical difficulties of projection (which can be formidable for many particle systems), but rather to present in an elementary way certain fundamental ambiguities in the use of projection. An application to high spin states near the yrast line is suggested. 相似文献
18.
19.
T. Sugitate T. Nomura M. Ishihara Y. Gono H. Utsunomiya K. Ieki S. Kohmoto 《Nuclear Physics A》1982,388(2):402-420
Spin polarization of protons emitted at 20° and 40° in the 93Nb + 14N reaction at 95 MeV has been measured by the double scattering method using a polarimeter particularly designed for protons having a continuous energy distribution.The result shows that the polarization is small for low-energy protons, but increases smoothly with the increase of proton energy, reaching around + 20 % at about 20 MeV in the center-of-mass system. Energy and angular distributions of protons measured in the same reaction indicate coexistence of equilibrium and preequilibrium components in the proton emission of interest, the fraction of the preequilibrium component increasing with the increasing proton energy. If we assume that protons emitted in equilibrium are completely unpolarized, and that the value of polarization (P) for the preequilibrium component is independent of proton energy, the present result is consistent with for the emission at 20° and for the emission at 40°.The result is discussed in terms of the hot-spot model for precompound decay. 相似文献
20.
The 94Mo(n, n′γ) reaction has been studied in the neutron energy range 1.5–4.0 MeV. Neutron inelastic scattering cross sections for levels up to an excitation energy of 2.6 MeV have been measured from 1.5 to 3.0 MeV. The results have been analyzed with the optical-statistical and coupled-channels theories. The 1.74 MeV level has been observed and has been assigned to be 0+. The branching ratios for the γ-rays deexciting the levels below the 3.5 MeV excitation have also been obtained. 相似文献