H. Zankel

Simple Coulomb correction for phase-shifts and application to the p-p system

The Coulomb contributions to the phase-shifts of two-particle systems are described within non-relativistic scattering theory to order e2 exactly. A simple on-shell approximation is then derived and applied to p-p scattering. Both the exact and the approximate version are tested for the particular case of a separable strong interaction model. It is found that this on-shell formula is-in contrast to the WKB approach-reliable also for low partial waves, except for energies Elab below 20 MeV in the 1S0, where a low-energy off-shell approximation is effective.

The influence of the proton charge form factor on the Coulomb effect

Abstract A model independent formula given entirely in terms of the measured phase shifts is used to describe the Coulomb—nuclear interference via the residual phase shift. For the case of proton-proton scattering the influence of the charge form factor and relativistic kinematics are taken into account.

Nucleon-deuteron low energy parameters

Abstract Momentum space Faddeev equations are solved for nucleon-deutron scattering and effective range parameters are calculated. A reverse trend is found in the two spin states by 4 a nd 4 a pd and 2 a pd 2 a nd which is in agreement with a configuration space calculation, but in conflict with all existing experiments. The Coulomb contributions to the effective range are small in quartet but sizeable in doublet scattering.

Prediction of n-4He phase shifts from p-4He data between 20 and 55 MeV

Abstract Effective two-body Coulomb corrections are applied to R -matrix n - 4 He phase shifts below 20 MeV lab energy leading to charge symmetric phase shifts that are qualitatively consistent with R -matrix p - 4 He phases. The inverse procedure is pursued for energies above 20 MeV yielding charge symmetric n- 4 He phases from two different sets of p- 4 He phase shift solutions. The Coulomb corrections to both sets of proton data are roughly the same, whereas the predicted n- 4 He values differ as much as the input proton data do. For energies between 20 and 30 MeV the predictions are compared with the best available neutron data. In some partial waves the measured phase shifts and the predictions are about compatible. The Coulomb corrections above 30 MeV can be utilized for analysing upcoming n- 4 He data on the basis of better known p- 4 He data.

Coulomb corrections in NN coupled states

Abstract Within nonrelativistic scattering theory we derive an on-shell approximation for the Coulomb corrections to elastic p-p scattering in coupled states. The effect of the Coulomb-nuclear interference to the mixing parameters is calculated using both point-like charge and finite charge distribution of the protons. Comparison with available model calculations demonstrates fair agreement, specifically up to E lab = 100 MeV.

Coulomb corrections in non-relativistic π+-p scattering

Separable potentials are used to calculate non-relativistic first-order Coulomb corrections to pi +-p phase-shifts. The off-shell sensitivity of the Coulomb corrections is studied and found to be small in S and P waves if the finite extent of the charged particles is taken into account. A simple on-shell approximation provides good agreement with the model residual phase-shifts in the S31 and P31 partial wave, but fails in the resonant P33.

On Coulomb effects in N-particle scattering processes

Abstract An approximate treatment of Coulomb effects in N-particle scattering is proposed which is the generalisation of the channel distortion approximation developed earlier for nuclear three-body systems.

Influence of Coulomb polarization on pd low energy parameters

Abstract Modified momentum space Faddeev equations are solved for pd scattering using variable tensor force in the 3 S 1 - 3 D 1 NN state. Utilizing an angular momentum truncation pd phase shifts between E p = 0.2 and 2.0 MeV are calculated and low energy parameters are extracted. Contributions of polarization were subtracted to allow for an application of the Coulomb modified effective range functions. The calculated scattering lengths and the pd Phillips line are compatible with results from a configuration space method.

Polarized deuteron elastic scattering from a polarized proton target

Abstract Measurements are reported of the spin correlation parameter C y , y for the elastic scattering of 10.0 MeV vector polarized deuterons from a polarized proton target at five CM angles (76°, 85°, 98°, 115°, 132°). The experimental results are compared with different predictions. A Faddeev type calculation on the basis of local potentials also including approximate Coulomb distortion is favoured by our experimental results.