共查询到20条相似文献,搜索用时 31 毫秒
1.
用相对论脉冲近似(RIA)对不同的中能质子(200MeV, 400MeV和800MeV)与14Be, 16O和12C的弹性散射进行了研究, 讨论了不同的入射能量对3种观测量, 即微分散射截面、分析本领和自旋转动函数的影响. 研究发现在小散射角的区域晕中子对观察量的影响趋势保持一致, 不随入射质子能量的改变而改变. 相似文献
2.
《Nuclear Physics A》1986,455(4):653-663
The impulse approximation to the Dirac theory of nucleon-nucleus scattering is reduced to a non-relativistic formalism. It is shown that relativistic effects can be included on the same footing as the effects of the nuclear medium on the effective interaction. We apply the argument to spin observables in 200 MeV and 500 MeV proton elastic scattering on a 40Ca target. 相似文献
3.
R. ��lvarez-Rodr��guez J. M. Ud��as J. R. Vignote E. Garrido P. Sarriguren E. Moya de Guerra E. Pace A. Kievsky G. Salm�� 《Few-Body Systems》2011,50(1-4):359-362
The relativistic distorted-wave impulse approximation is used to describe the 3He(e, e?? p)2H process. We describe the 3He nucleus within the adiabatic hyperspherical expansion method with realistic nucleon-nucleon interactions. The overlap between the 3He and the deuteron wave functions can be accurately computed from a three-body calculation. The nucleons are described by solutions of the Dirac equation with scalar and vector (S?CV) potentials. The wave function of the outgoing proton is obtained by solving the Dirac equation with a S?CV optical potential fitted to elastic proton scattering data on the residual nucleus. Within this theoretical framework, we compute the cross section of the reaction and other observables like the transverse-longitudinal asymmetry, and compare them with the available experimental data measured at JLab. 相似文献
4.
M. Thies 《Nuclear Physics A》1986,460(4):636-644
Recently, we have proposed a new interpretation of the successful Dirac approach to protonnucleus elastic scattering, based on relativistic kinematics and the Lorentz-Lorenz correction. Here, we show that the Dirac distorted wave impulse approximation for low-lying collective states can be understood along the same lines. This confirms our view that relativistic effects are not the only possible explanation of the polarization data at intermediate energies. 相似文献
5.
V. K. Lukyanov E. V. Zemlyanaya K. V. Lukyanov Ali El Lithi Ibrahim Abdulmagead 《Bulletin of the Russian Academy of Sciences: Physics》2014,78(5):421-426
Cross sections of inelastic scattering of π-mesons from Si, Ni, and Pb nuclei at energy T lab = 291 MeV are calculated using the distorted wave approximation. The microscopic direct and transition optical potentials are determined by specifying the pion-nucleon scattering amplitude and the nuclear density distribution, where we use the in-medium πN amplitude parameters obtained earlier by analyzing the elastic scattering data for the same nuclei. The cross sections are calculated on the basis of the relativistic wave equation. The deformation parameters of the nuclei are obtained by comparing inelastic scattering cross sections with the appropriate experimental data. 相似文献
6.
The cross sections for the 16O(α, 2α) reaction have been calculated in the distorted wave impulse approximation. The influence of the optical potentials in the incident and final channels on the energy sharing distribution and the spectroscopic factors has been investigated. Optical potentials with small imaginary content are shown to fit both elastic scattering and the experimental data well and give a spectroscopic factor of 1.1; the contribution from the nuclear interior broadens the energy sharing distributions, in agreement with observations. 相似文献
7.
We investigate the model dependence of the impulse approximation for proton-nucleus elastic scattering stemming from off-shell and non-local effects. A perturbative treatment allows a direct comparison between off-shell and relativistic effects. Off-shell effects are found to be significantly smaller and unable to account in a natural way for the needed repulsive central potential in the nuclear interior region at proton energies between 300 and 800 MeV. 相似文献
8.
Medium energy proton elastic and inelastic scattering to states of 58Ni and 208Pb, and 4He elastic and inelastic scattering to states of 40Ca, are analyzed using the partial wave approach, by solving the Schrödinger equation with relativistic kinematics and using the distorted wave Born approximation. Our results can be compared with results of several previous analyses of the nucleon inelastic data using the Glauber approximation. Our calculations are absolute, using nuclear collective parameters obtained from a survey of a large number of low-energy analyses of inelastic scattering of electrons, nucleons and nuclei from 40Ca, 58Ni and 208Pb. 相似文献
9.
L.C. Liu 《Nuclear Physics A》1974,223(3):523-540
The experimental results of the reaction 12C(π+, π+ p)11B at about 130 MeV can be explained satisfactorily by using a modified distorted wave impulse approximation. The strong inelasticity in the elastic channel at these energies makes the knock-out reaction essentially peripheral. We show that under these circumstances the knock-out reaction can be used to obtain information about the off-shell pion-nucleon scattering amplitude. Future experiments in this direction are suggested. We have introduced an invariant half-off-shell pion-nucleon scattering amplitude and have re-examined the DWIA method in a relativistic way. 相似文献
11.
12.
L. S. Azhgirey M. A. Ignatenko N. P. Yudin 《Zeitschrift für Physik A Hadrons and Nuclei》1992,343(1):35-38
The momentum spectra of protons, produced at 0° as a result of fragmentation of relativistic deuterons on nuclei, are analyzed. Possible causes of the existing discrepancy of the data on the 0° proton spectrum from the1
H(d,p)X reaction at 9.1 GeV/c with results of the impulse approximation calculations are considered. It is shown that taking into account the finite angular resolution of the experimental setup and the corresponding renormalization of the experimental data, on the one hand, and also the inclusion of the additional (to stripping) contribution of protons from the scattering of deuteron nucleons by target protons, on the other, make it possible to match these data with the results of calculations within the framework of the relativistic impulse approximation using the deuteron wave function for the Paris potential. 相似文献
13.
Platchkov S Pomatsalyuk R Prout DL Punjabi VA Pussieux T Quemener G Ransome RD Ravel O Roblin Y Roche R Rowntree D Rutledge GA Rutt PM Saha A Saito T Sarty AJ Serdarevic-Offermann A Smith TP Soldi A Sorokin P Souder P Suleiman R Templon JA Terasawa T Todor L Tsubota H 《Physical review letters》2000,84(15):3265-3269
We have measured the cross section for quasielastic 1p-shell proton knockout in the 16O(e,e(')p) reaction at omega = 0.439 GeV and Q2 = 0.8 (GeV/c)(2) for missing momentum P(miss)=355 MeV/c. We have extracted the response functions R(L+TT), R(T), R(LT), and the left-right asymmetry, A(LT), for the 1p(1/2) and the 1p(3/2) states. The data are well described by relativistic distorted wave impulse approximation calculations. At large P(miss), the structure observed in A(LT) indicates the existence of dynamical relativistic effects. 相似文献
14.
《中国物理C(英文版)》2015,(8)
A set of optimal proton optical potential parameters for p+184W reactions are obtained at incident proton energy up to 250 MeV.Based on these parameters,the reaction cross-sections,elastic scattering angular distributions,energy spectra and double differential cross sections of proton-induced reactions on184W are calculated and analyzed by using theoretical models which integrate the optical model,distorted Born wave approximation theory,intranuclear cascade model,exciton model,Hauser-Feshbach theory and evaporation model.The calculated results are compared with existing experimental data and good agreement is achieved. 相似文献
15.
《Physics letters. [Part B]》1988,215(4):602-606
Elastic scattering of protons from nuclei is studied based on the Dirac-Brueckner approach. Effective N-N interactions in the nuclear medium are obtained by solving the relativistic Brueckner-Bethe-Goldstone equation in infinite nuclear matter. Relativistic optical potentials for p-40Ca scattering at 200 MeV are calculated in the improved local density approximation. It is found that medium effects other than Pauli blocking reduce the strengths of scalar and vector potentials very much. Differential cross section and spin observables are calculated and compared with experimental data. 相似文献
16.
Starting from the Walecka model about relativistic nucleon-meson field theory,the effect of interaction range in the relativistic microscopic optical potentials for nucleon-nucleus is included by folding the optical potentials in Local Density Approximity with nucleon-nucleon interaction potentials from the Walecka model.The present potentials are used to analyze the proton elastic scattering from nuclei.The agreement of the present calculation with experiment data is better than that of LDA. 相似文献
17.
R. Wenskus A. Baumann P. Rullhusen D. Schaupp F. Smend M. Schumacher 《Zeitschrift für Physik A Hadrons and Nuclei》1985,320(2):179-184
Cross section profiles d2σ/dΩdω′ for Compton scattering of photons by bound electrons are calculated for all subshells of the atom. Results obtained from the form factor approximation and from a relativistic version of the impulse approximation are compared with experimental data for Cu and Pb at a scattering angle ofθ=145° and a photon energy of 662 keV. The impulse approximation proves to be superior to the form factor approximation and is used to predict cross section profiles for a primary energy of 50 MeV and different scattering angles and charge numbers. It is shown that only for the heaviest atoms and scattering angles belowθ=5° there is a non-negligible contribution of Compton scattering to the elastic peak. 相似文献
18.
B. D. Keister 《Nuclear Physics A》1980,350(3-4):365-376
Since pion-nucleus elastic scattering data can only constrain the asymptotic behavior of the scattered wave, it remains for inelastic scattering and reaction data to test the wave function in the nuclear interior. To this end, distorted-wave impulse approximation calculations have been performed for a variety of low-energy pion reactions using phase-shift-equivalent pion-nucleus potentials: inelastic excitation, photoproduction, and the (π, p) reaction. Sensitivity of the reaction cross sections to variations in the equivalent potentials is examined, with an eye toward understanding what can be learned about pion-nucleus dynamics from a given set of reaction data. 相似文献
19.
The elastic scattering differential cross section is calculated for proton scattering from 6He at 717 MeV, using single-scattering terms of the multiple-scattering expansion of the total transition amplitude. We analyze
the effects of different scattering frameworks, specifically the factorized impulse approximation and the fixed scatterer
(adiabatic) approximation.
The text was submitted by the authors in English. 相似文献
20.
A new computational method for solving the nucleon?Cdeuteron breakup scattering problem has been applied to study the elastic nucleon?Cdeuteron scattering on the basis of the configuration-space Faddeev?CNoyes?CNoble?CMerkuriev equations. The Merkuriev?CGignoux?CLaverne approach has been generalized for arbitrary nucleon?Cnucleon potentials and with an arbitrary number of partial waves. The nucleon?Cdeuteron observables at the incident nucleon energy 3?MeV have been calculated using the charge-independent AV14 nucleon?Cnucleon potential including the Coulomb force for the proton?Cdeuteron scattering. Results have been compared with those of other authors and with experimental proton?Cdeuteron scattering data. 相似文献