DWBA approach to inelastic scattering at medium energies

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.     

Two-step process in proton inelastic scattering

Proton inelastic scattering exciting single-neutron states is calculated in the framework of the three-body model. The transition amplitude is approximately given by a sum of the one-step Born term and the pickup-stripping terms including the continuum p-n system propagation as well as the deuteron propagation in the intermediate state. The continuum contribution is not negligible at low energy and becomes as important as the terms at higher energies.     

Two-step processes in inelastic proton scattering

A discussion is given of effects ofp-d-p′ type two-step processes on inelastic scattering from¹⁶O and⁴⁰Ca with incident proton energies between E_p=25 and 46 MeV. It is found that the two-step processes increase the magnitude of the cross-section by about 20 % without altering the shape significantly.     

Relativistic calculations of inelastic collisions between electrons and atoms

The Feynman S-matrix formalism is used to consider the inelastic collisions of electrons with a hydrogen atom. The two leading Feynman diagrams are calculated, and the 1s-2s transition is treated in detail. Results are given for scattering amplitudes at energies of 1.0–8.0 (atomic units) and for various scattering angles, as well as the differential cross sections for direct scattering in the energy region 1.36–118.5 keV. On the basis of comparison with nonrelativistic calculations, we conclude that relativistic effects are appreciable and increase with energy. Total cross sections are calculated in both nonrelativistic and relativistic approximations. The difference between them increases with energy and is 15–20% for energies of 20–50 keV.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 7–12, August, 1977.     

Limitation of angular momentum transfer in adiabatic calculations of rotational excitation by inelastic scattering

A new method is proposed for quantummechanical calculations of rotational excitation of nuclei by inelastic scattering. It is based on a combination of coupled-channels method (few-states approximation) and adiabatic method. Results are presented for α scattering from ¹⁷⁶Yb.     

Amplitude correlations for inelastic proton scattering from44Ca

The magnitudes and relative signs of inelastic proton channel amplitudes were determined for three decay channels for 53 5/2+ resonances in 45Sc. Although the reduced widths in each channel agree well with the Porter-Thomas distribution, large correlations are observed between widths and between amplitudes. The expected equality between the width correlation and the square of the amplitude correlation does not hold.     

Amplitude correlations for inelastic proton scattering from48Ti

The magnitudes and relative signs of inelastic proton channel amplitudes were determined for three decay channels for 45 5/2⁺ resonances in⁴⁹V. The reduced widths in each channel follow a Porter-Thomas distribution, but extremely large amplitude correlations are observed — for one pair of channel amplitudes the relative sign is positive for 43 of 45 resonances. These results provide the first direct test of the Krieger-Porter reduced width amplitude distribution.     

Relativistic effects on the tensor polarization in electron-deuteron scattering

The tensor analysing power P_e in electron deuteron scattering is calculated including relativistic corrections to the deuteron form factor as determined by Friar and Gross. These effects are found to be quite comparable to the differences between various potentials, and should therefore not be ignored.     

Exact-finite-range DWBA calculations of massive transfer reactions treated as breakup-fusion reactions

Distorted-wave-Born-approximation calculations, with the exact-finite-range method, were performed, and good fits were obtained to data of the α singles cross sections in the ¹⁸¹Ta(¹⁴N,α) reaction, taken as an example. It is shown that the breakup-fusion is not a simple peripheral process, but takes place in a region which is about 2 fm deeper than is the usual peripheral region.     

Analyses of inelastic proton scattering from 20Ne

Differential cross sections and analyzing powers for inelastic proton scattering to the 2⁺₁, 4⁺₁ and 6⁺₁ states of ²⁰Ne are analyzed using an antisymmetrized distorted wave approximation in direct reaction theory. The spectroscopy of these states was obtained by angular momentum projection from an axially symmetric minimal-energy Hartree-Fock intrinsic state.     

Coulomb effects in polarization transfer in elastic antiproton and proton electron scattering at low energies

The influence of Coulomb distortion on the polarization transfer in elastic proton and antiproton electron scattering at low energies is calculated in a distorted-wave Born approximation. For antiproton electron scattering Coulomb effects reduce substantially the polarization transfer cross-section compared to the plane-wave Born approximation, whereas for proton electron scattering they lead to a dramatic increase for kinetic proton lab energies below about 20keV.     

Channel spin mixing ratios in high resolution proton inelastic scattering

A simple method of determining both the magnitudes and phase for channel spin mixing is described. An example is presented and a variety of applications discussed.     

The spectroscopy of 13C by inelastic proton scattering

At 135 MeV incident energy, differential proton scattering cross sections have been measured for many states of ¹³C, up to 23 MeV in excitation. These data are supplemented by analysing power data for states up to 10 MeV in excitation, measured at 119 MeV incident energy. Distorted wave analysis using a density-dependent form of the nucleon-nucleon interaction has provided a thorough assessment of the model predictions of the nuclear structure of many of these excited states.     

Theoretical investigation of giant resonances by inelastic proton scattering

A fully microscopic, antisymmetrized DWBA analysis of (p, p') spectra in the giant resonance region of ¹⁶O, ⁴⁰Ca and ²⁰⁸Pb is presented. The nuclear structure information is derived from RPA wave functions calculated in large configuration spaces. The theoretical spectra are in general in agreement with the experimental results. A new interpretation follows from our. investigation for the spectrum of the giant dipole region in the heavy nuclei: This resonance structure is mainly due to the breathing mode, whereas the electric dipole contribution is much smaller.