[en] There has been considerable interest in using charge-exchange reactions in the medium energy regime to study nuclear structure. This has been delayed by difficulties in understanding the experimental results even when the structure appears to be understood. As a result, even the limited data available in the past have prompted considerable efforts at going beyond a first order treatment. Initially, some of the features of (p,n) and (π⁺,π⁰) reactions are contrasted. Then the published (π⁺,π⁰) treatments will be briefly sketched. Finally, some calculations for mass-7 and mass-14 will be discussed, indicating the way in which pion or nucleon charge exchange may be a particularly fruitful tool. 24 references

[en] The developmnt of the time production chamber and charge coupled devices and their applications are discussed

[en] A brief discussion is given of how the spectrometer works and its capabilities. The physical programs carried out in the first data runs are outlined as well as ideas for future work. Plots are presented for the on-line spectrum for zirconium 90 with the clearly visible analog state, which occurs at an excitation of 5 MeV in ⁹⁰Nb and for the neutral pion kinetic energy spectrum obtained in December, 1978

[en] The differential cross sections of the (p,n) reaction on ⁶Li, ¹²C, and ¹⁴N to the ground state of the final nuclei at E/sub p/ = 144 and 0 < theta/sub LAB/ < 20⁰ were measured. The quantum numbers of these transitions, like those in Gamow-Teler beta decay, have ΔJ = 1, ΔT = 1, and ΔP = 0, which is consistent with the one-pion exchange mechanism. Differential cross sections were calculated with the absorption modified one-pion exchange model. The nucleus was treated as an elementary particle, as first suggested by Kim and Primakoff. Using the partially conserved axial vector current hypothesis (PCAC) the magnitude and momentum dependence of the initial nucleus-pion-final nucleus coupling constant, g/sub NπN'/, was obtained from beta decay and inelastic electron scattering, respectively. The calculations, which had no free parameters, were found to agree with the data for ⁶Li and ¹²C, but not for ¹⁴N. 14 references

[en] A review is given of the different experimental techniques applied to cross section measurements for π^-p → π⁰n near and above the P₃₃ resonances and of some preliminary results of an experiment presently in progress to measure charge-exchange polarization

[en] Calculations describing pion elastic and charge-exchange scattering from three and four nucleon nuclei are described and a comparison with recent data are given. The calculations are based on a theoretical momentum space optical potential constructed from realistic nuclear form factors and πN t-matrices which incorporate the finite range of the two-body interactions. This first principle, parameter free theory provides (at least) qualitative agreement with both the elastic and charge exchange data. 25 references

[en] Analytic expressions are derived for angular distributions for pion single and double charge exchange to analog states. The theory is valid only in the region of the (3-3) resonance and explicates the relation to elastic scattering and nuclear structure. The angular distributions are manifestly sensitive to the difference between the neutron and proton densities in the nuclear surface, especially in the case of double charge exchange. The angular dependence of the cross sections is characterized by a nuclear radius R which corresponds to the 10% to 20% density point. 6 references

[en] Ratios are reported for the excitation of the 1⁺ T = 0(1), 12.7 (15.1) MeV states in ¹²C and the 6^- T = 0(1), 11.58 (14.36) MeV states in ²⁸Si using π⁺ inelastic scattering measured at the EPICS facility at LAMPF. The observed ratios of T = 0 to T = 1, 1.4 +- 0.8 for ¹²C and 1.5 +- 0.2 for ²⁸Si are inconsistent with the prediction of Gupta and Walker of 4.0 for states of different isospin but otherwise identical structure. 11 references

[en] Calculations of pion single charge exchange on ⁷Li, ¹⁰B, and ¹³C are described and results are presented. 10 references

[en] Recent experimental developments on electric giant multipole resonances are discussed with emphasis on isovector excitation. The very complete investigation of isoscalar resonances supports model predictions and, by consistency, lends credence to an increasing body of data on isovector excitations obtained from inelastic electron scattering. Recent developments in the isovector Lane potential, isospin splitting, and isospin mixing are also presented. 36 references