Positron-helium elastic scattering at intermediate energies

Total cross sections for elastic positron-helium collisions have been computed and compared with other theoretical results. Integrated cross sections over small angular regions extending from zero angle, for which a set of experimental estimates is available, are also presented.     

Alpha-nucleus elastic scattering at intermediate energies

Elastic scattering of 288,340,480 and 699 MeV Alpha-particles was measured on ²⁰⁸Pb, ¹¹⁶Sn and ⁵⁸Ni. The data were analysed in terms of a phenomenological optical model. The optical potentials obtained were found to vary consistently with the target nucleus and the incident energy. The radial zone where the potentials are well determined was studied in detail. The data for ²⁰⁸Pb were also analysed with a folding model. The energy dependence of the strong-absorption radius and of the reaction cross section shows that the nuclear surface becomes slightly transparent for incident energies above 150 MeV per nucleon.     

Deuteron-proton elastic scattering at intermediate energies

The deuteron-proton elastic scattering has been studied in the multiple-scattering expansion formalism. Primary attention has been given to such relativistic problems as a deuteron wave function in a moving frame and transformation of spin states due to Wigner rotation. Parametrization of the nucleon—nucleon t matrix has been used to take the off-energy-shell effects into account. The vector, A _y , and tensor, A _yy , analyzing powers of the deuteron have been calculated at two deuteron kinetic energies: 395 and 1200 MeV. The obtained results are compared with the experimental data. The text was submitted by the authors in English.     

Calculation of elastic electron-helium scattering at intermediate energies

The two-potential eikonal approximation is applied to the calculation of the differential cross section for elastic scattering of electrons by ground state helium atoms at energies 50 and 100 rV. The results agree very well with experiments.     

Three-body elastic and inelastic scattering at intermediate energies

The Faddeev equation for three-body scattering at arbitrary energies is formulated in momentum space and directly solved in terms of momentum vectors without employing a partial wave decomposition. For identical bosons this results in a three-dimensional integral equation in five variables, magnitudes of relative momenta and angles. The cross sections for both elastic and breakup processes in the intermediate energy range up to about 1 GeV are calculated based on a Malfliet-Tjon type potential, and the convergence of the multiple scattering series is investigated.     

Differential cross-section of dp elastic scattering at intermediate energies

The deuteron-proton elastic scattering is studied in the multiple-scattering expansion formalism. The contributions of the one-nucleon exchange, single and double scattering are taken into account. The Love and Franey parameterization of the nucleon-nucleon t -matrix is used, that gives an opportunity to include the off-energy-shell effects into calculations. Differential cross-sections are considered at four energies, T _d = 390 , 500, 880, 1200MeV. The obtained results are compared with the experimental data.     

Proton-deuteron radiative capture cross-sections at intermediate energies

Differential cross-sections of the reaction p(d, ³He)γ have been measured at deuteron laboratory energies of 110, 133 and 180 MeV. The data were obtained with a coincidence setup measuring both the outgoing ³He and the photon. The data are compared with modern calculations including all possible meson-exchange currents and two- and three-nucleon forces in the potential. The data clearly show a preference for one of the models, although the shape of the angular distribution cannot be reproduced by any of the presented models.     

Spin effects in elastic pp scattering at high energies

A brief survey is made of those popular and recent models of pp-scattering which incorporate spin at least to some extent. These models are: conventional Regge pole models, models of the eikonal type and geometric (optical) models. Particular attention is paid to the structure of polarization to be expected at higher energies.Presented at the Symposium on Hadron-Hadron Scattering at High Energies, Liblice, Czechoslovakia, June 16–21, 1975.     

Proton-4He elastic scattering at intermediate energies

Differential elastic cross sections and polarizations are calculated in a multiple-scattering formalism for proton-⁴He scattering for energies in the range 0.6–24.0 GeV and for momentum transfers up to 4.0 fm^?1. The calculations include Coulomb and spin effects. Corrections due to target-nucleon overlap and charge exchange are estimated. The results are compared with experimental data.     

Phase shift analysis of heavy-ion elastic scattering measured at intermediate energies

An elastic scattering phase shift analysis based on McIntyre parametrization is presented. It has been applied to¹²C+¹²C system at 360- and 1,016 MeV incident energies as well as to¹⁶O scattering on¹²C,⁴⁰Ca,⁹⁰Zr and²⁰⁸Pb targets at 1,503 MeV. The success of this model allows the interplay between diffraction and refraction to be pinned down: a presence of a nuclear rainbow is clearly evidenced in several cases.     

Sudden approximation for elastic scattering of composite projectiles at intermediate energies

Elastic scattering of deuterons by nuclei at intermediate energies is investigated by the sudden approximation. Scattering amplitudes of the deuteron are described in terms of those of the constituent nucleons. They consist of the amplitude of nucleon-nucleus single collision and that of double collision. The neglect of the latter explains similarity relations between the deuteron observables and the proton ones, which are found in experimental data. Cross sections and vector analyzing powers calculated with the single-collision terms successfully reproduce the measured ones for ¹⁶O, ⁴⁰Ca and ⁵⁸Ni targets in the energy region, E_d = 200 ˜ 700 MeV. Scattering of ⁶Li by ⁵⁸Ni is investigated in a similar way assuming the d + cluster model for ⁶Li.     

Inelasticity corrections in the elastic proton-deuteron back-angle scattering at intermediate energies

The elastic proton-deuteron scattering cross sections at back angles have been calculated in the light of Kerman-Kisslinger model, using a generalised baryon transfer mechanism on the assumption that theN ^*'s exist (with a probability～1 %) in the deuteron and that the backward peak is caused by their exchange. The effect of numerous competing open inelastic channels at intermediate energies on the elastic cross section is computed in a particularly simple model of Sopkovich. The resultant damping of the back scattering amplitude is expressed directly in terms of the forward angle elastic scattering data. The results are compared with the experimental cross sections in the energy range of 1.5–2.5 GeV.     

Measurement of positron-rare gas total cross-sections at intermediate energies

Total scattering cross-sections for positrons in the rare gases in the energy range of 2–960 eV have been measured using a time-of-flight system for which the uncertainty arising from forward scattering is substantially lower than in the 1974 experiment of Canter et al. A comparison of these cross-sections with current theoretical estimates is made.     

Developing a generalized diffraction model for elastic pd scattering at intermediate energies

A generalization of the Glauber-Sitenko diffraction model that includes the spin dependence of NN amplitudes, the D-wave of the deuteron, and the charge exchange effects is constructed for elastic pd scattering at intermediate energies. The developed model was used to analyze differential cross sections and some spin observables (analyzing powers) at the incident proton energies T _p = 1 GeV, 440 and 250 MeV. It was shown that predictions of the generalized diffraction model agree both with the experimental data and with the exact Faddeev calculations at low transfer momenta.     

Complete set of deuteron analyzing powers for dp elastic scattering at intermediate energies

With the aim of clarifying roles of the 3NFs in nuclei experimental programs with polarized deuterons beams at intermediate energies are in progress at RIKEN RI Beam Factory. As the first step, we have measured a complete set of deuteron analyzing powers (iT ₁₁, T ₂₀, T ₂₁, T ₂₂) in deuteron-proton elastic scattering at 250 and 294 MeV/nucleon. The obtained data are compared with the Faddeev calculations based on the modern nucleon-nucleon forces together with the Tucson-Melbourne’99, and UrbanaIX three nucleon forces.     

Hadron-nucleon elastic scattering at high energies

A review of experiments on high energy hadron-nucleon elastic scattering is given. Emphasis is placed on the most recent experiments at FNAL and CERN/ISR. Results (mostly preliminary) are discussed and compared with earlier experiments.Presented at the Symposium on Hadron-Hadron Scattering at High Energies, Liblice, Czechoslovakia, June 16–21, 1975.I like to thank the Czechoslovakian Academy of Sciences and the Organizing Committee of the Symposium, especially Dr. J.Fischer, for their invitation and hospitality. I am indebted to D. D.Jovanovitch of the Michigan-Argonne-Fermilab-Indiana collaboration for sending me their data prior to publication.     

A search at high energies for antineutrino-electron elastic scattering

We have searched for candidates for the weak neutral leptonic current reaction $\text{ν}{}_{\mathrm{\mu }}\text{+}\text{e}{}^{\mathrm{?}}\text{→}\text{ν}{}_{\mathrm{\mu }}\text{+}\text{e}{}^{\mathrm{?}}$ in the Fermilab 15 ft bubble chamber filled with a heavy neon-hydrogen mix. Based on zero observed events of this type we find the 90% confidence level upper limit for the rate for this reaction relative to the total antineutrino charged current rate to be 3.9 × 10^?4 and, in the Weinberg-Salam model, sin²θ_W ? 0.37.     

Total cross-sections for the scattering of positrons by helium,neon, and argon at intermediate energies

A slow positron beam time of flight system in which scattering is localised to a region of the flight path close to the slow positron source is described. Total cross-sections measured in helium, neon, and argon at intermediate energies are presented. The results for helium and neon are in agreement with the recent results of Brenton et al. While significant disagreement still exists in the argon data. The helium and neon data are in agreement with the sum rule predictions of Bransden et al.