Spin-orbit deformation in the inelastic scattering of polarized protons from12C and16O

Analyzing powers and cross sections for elastic and inelastic scattering of 20, 30 and 40MeV polarized protons from¹²C and¹⁶O have been analyzed in the coupled-channels collective model using the full Thomas deformed spin-orbit term. It is clear from this analysis that the spin-orbit deformation is energy dependent.     

Elastic and inelastic scattering of 185 MeV protons from 12C

The polarization of 185 MeV protons in elastic scattering and in the excitation of the 2⁺ state at 4.44 MeV and the 0⁺ state at 7.65 MeV in ¹²C has been measured in the angular region 2°–60°. Optical model calculations are performed for the elastic scattering. Angular distributions for the inelastic scattering from the 2⁺ state at 4.44 MeV and the 3^? state at 9.64 MeV are calculated in the distorted-wave impulse approximation (DWIA) as well as in the distorted-wave Born approximation (DWBA).     

A resonant interpretation of gross structure in 12C + 12C and16O + 16O inelastic scattering

A barrier-top-resonance model calculation is found adequate to describe the gross structure behavior thus far observed in ${}^{12}\text{C}\text{+}{}^{12}\text{C and}{}^{16}\text{O}\text{+}{}^{16}\text{O}$ inelastic scattering excitation functions.     

Dirac coupled-channels analysis of inelastic scattering of 800 MeV polarized protons from 16O, 24Mg and 26Mg

Coupled-channels calculations using the Dirac phenomenology have been performed to analyse cross sections and analyzing power data for inelastic scattering of 800 MeV protons from low-lying states in ¹⁶O, ²⁴Mg and ²⁶Mg. Large negative reals scalar potentials, large positive real vector potentials and large negative imaginary vector potentials were obtained. Considerable improvements were obtained using the Dirac equation compared to the classical Schrödinger calculations. These best fits have been found compatible with an imaginary scalar potential equal to zero (U_sⁱ=0) and therefore with less parameters (nine) than usually required in the classical calculations (twelve).     

Elastic and inelastic scattering of nucleons from 16O

Measurements of differential elastic and inelastic cross sections for neutron scattering from ¹⁶O at incident energies 18 to 26 MeV are presented. In addition to cross sections for neutron scattering differential cross sections for proton scattering up to 66 MeV are described in terms of phenomenological optical model potentials. At 24.5 MeV incident energy inelastic scattering up to 11.5 MeV excitation was measured. The elastic and inelastic compound nucleus contributions were examined. Direct inelastic scattering from the normal parity states was calculated using the DWBA and coupled-channel formalisms. The inelastic scattering cross section from non-normal parity state 2⁻ was calculated using the coupled-channel formalism via multi-step processes. Cross sections due to inelastic scattering from some of the states, which are thought to be members of an excited state rotational band were calculated using both vibrational and rotational approaches and were compared.     

Study of 16O, 20Ne, 22Ne, 28Si and 32S by inelastic scattering of polarized protons

Analyzing powers and cross sections have been measured for elastic and inelastic scattering of 24.5 MeV protons from ²⁰Ne and ²²Ne, and for ¹⁶O, ²⁸Si and ³²S at 30.3 MeV. The experimental results were analyzed in terms of the coupled-channels formalism using the rotational model and (for ³²S and ¹⁶O) the vibrational model. The results for ²⁰Ne, ²²Ne and ²⁸Si show a systematic trend of the hexadecapole deformation. Prolate shapes for ²⁰Ne and ²²Ne and an oblate shape for ²⁸Si are confirmed. The results for ³²S are almost equally well-reproduced by the vibrational or rotational model, and there is a slight preference for the prolate shape for this nucleus. The best fits for the analyzing power for all the nuclei were obtained by using the full Thomas form for the spin-orbit potential     

Evidence for a real tensor potential in the inelastic scattering of 800 mev polarized protons from20ne using the dirac phenomenology

Coupled-channel calculations using the Dirac phenomenology have been performed to analyze cross-sections and analyzing powers data for inelastic scattering of 800 MeV, polarized protons from low-lying states in²⁰Ne. Good agreement with the data has been obtained by using a real tensor potential V _t ^r =27.02 MeV, in addition to real scalar potential and complex vector potential. Deformation parameters obtained at this energy of 800 MeV are very close to those obtained at an energy much lower (24.5 MeV). Once more, considerable improvements obtained by using Dirac equation, compared to Schrödinger calculations, are confirmed. The calculations are also consistent with V _s ⁱ =0.     

Spin alignment in12C+12C inelastic scattering

The spin alignment P_zz of¹²C(2 ₁ ⁺ ) produced in¹²C+¹²C inelastic scattering at bombarding energies in the region of known resonances between E_cm=18.5 and 32.8 MeV has been determined with a γ-ray detector positioned in the direction of the scattering normal. The values obtained in the centers of three resonances as well as those obtained off-resonance are spread over a range between ?.05 and +.80 with no clear indication in favour of simple pictures of molecular resonances.     

Relations between measured and calculated spin observables in inelastic scattering of polarized protons for excitation of the 1+, T = 0 state in 12C

We analyze the most important spin observables representing the difference functions (P-A _y ) and (P-A _y )σ, along with the spin-transfer coefficients D _NN , D _SS , and D _LL in the inelastic scattering of polarized protons. We examine the excitation of the state 1⁺, T = 0 (12.71 MeV) in the ¹²C nucleus at the energies of projectile protons E _p = 200 MeV and E _p ～ 400 MeV. These spin observables are treated in the context of the exchange features of the effective interaction.     

Elastic and the 2+ inelastic scattering of high energy protons on12C and the alpha-particle model

The alpha-particle model has been applied to calculate the elastic and the 2⁺ inelastic angular distribution of 1 GeV protons on¹²C within the framework of Glauber multiple scattering theory. The results are compared with the recent experimental data and with some previous calculations. The model gives a fairly good account of the inelastic data and its predictions for the elastic scattering are essentially the same as those of the shell model.     

Application of the incoming wave boundary condition to16O+16O and12C+12C elastic scattering

The elastic scattering of¹²C+¹²C and¹⁶O+¹⁶O has been studied in the framework of an incoming wave boundary condition model. Different logarithmic derivatives for the incoming waves have been tested and their effects investigated with the help of Fourier analyses. It is shown that a logarithmic derivative obtained from a JWKB approximation leads to strong absorption of the low partial waves while a logarithmic derivative constant for all partial waves causes reflections. These reflections are necessary to describe the high energy elastic scattering of¹²C+¹²C. The fits thus obtained with shallow real potentials are comparable to those obtained with deep folding potentials. It is shown that not the lowest partial waves, but those within a window just below the grazing angular momentum are most important for the higher energy¹²C+¹²C angular distributions.     

Elastic and inelastic scattering of polarized protons from even n=82 nuclei near isobaric analog resonances

Excitation curves for the elastic and the inelastic scattering of polarized protons on the target nuclei ¹³⁸Ba, ¹⁴⁰Ce, ¹⁴²Nd and ¹⁴⁴Sm have been measured in the energy region of prominent isobaric analog resonances. A detailed analysis of the data is presented. Definite J^π assignments are given for a number of parent analog states. Spectroscopic factors and amplitudes for configurations with the core in the ground state or in the 2₁⁺ excited state are derived from the elastic and inelastic proton decay amplitudes. They show consistency with sum rules including orthogonality conditions. Different methods for the-calculation of single particle decay widths have been applied. The qualitative agreement with present unified model calculations is remarkable; an overestimattion of the weak coupling structure, however, becomes apparent.     

Quasi-free scattering of polarized protons

Cross section and analyzing power, energy-sharing spectra have been measured for the ¹⁶O($\text{p}$, 2p) reaction at an incident energy of 200 MeV for twenty-four different pairs of angles of the detected final-state protons. This general survey is intended to test the validity of the distorted wave impulse approximation (DWIA), particularly with respect to the predicted j-dependent analyzing power caused by the distorting optical potentials and nuclear spin-orbit coupling. Although the data in general confirm this j-dependence, agreement in detail between DWIA calculations and the analyzing power data becomes worse as the momentum of the recoiling nucleus increases. Predictably, the cross-section calculations show more sensitivity to the optical-model parameters than do the analyzing powers. Within the present limits imposed by scanty elastic scattering data, there seems to remain a choice between predicted ($\text{p}$, 2p) cross sections which either are unreasonably large or which have the incorrect energy-sharing shapes. More comprehensive elastic scattering and total reaction cross section data are clearly needed.     

Exchange interaction and elastic 16O + 12C scattering

The effect of core exchange on the potential of interaction between the ¹⁶O and ¹²C nuclei is considered. The amplitudes corresponding to nonlocal exchange interactions are calculated in the Born approximation. It is shown that the inclusion of exchange processes leads to the growth of the elasticscattering amplitude in in the region of large scattering angles. The dependence of amplitudes on the parity of relative motion is analyzed.     

Excitation of isobaric analogue resonances by inelastic scattering of polarized protons from 126Te

An experimental study of inelastic scattering of polarized protons from ¹²⁶Te, leaving this nucleus in its first excited state, is presented. The scattering proceeds through isobaric analogue resonances in ¹²⁷I.A method has been developed and applied to extract partial width amplitudes from measured cross sections and analyzing powers. From these amplitudes coefficients of fractional parentage are deduced, characterizing the relation between five negative parity parent states in ¹²⁷Te and the first excited state of ¹²⁶Te.     

Elastic and inelastic scattering of 18O by 16O and 18O

Angular distributions have been measured for the elastic and inelastic scattering of ¹⁸O by ¹⁶O and ¹⁸O at laboratory bombarding energies of 42 and 52 MeV. The inelastic scattering data are analyzed in terms of collective excitations using a coupled channel approach. Deformation parameters are obtained for the strongly excited states. The relationship between the strength of inelastic scattering and the amount of structure in the elastic scattering distributions is discussed.     

Asymmetry in polarized e-d inelastic scattering

The parity violating asymmetry is calculated for polarized electron-deuteron inelastic scattering in the closure approximation for the outgoing nucleons. The results are applicable in the intermediate-energy region of the incident electron where asymmetries are found to be in the range accessible to the present experiments.