[en] Abstract only

[en] In this talk I highlight some of the new results from single-pion charge-exchange reactions. Main attention is given to the work on the isovector monopole excitation in nuclei, including a discussion of the selectivity of the (π^-, π⁰) reaction for this particular excitation and the results and plans for the future. Next, new results for giant dipole resonances are discussed, with emphasis on isospin splitting. Last, we revisit the isobaric-analog states and see what they teach about the pion-nucleus interaction

[en] The measurement of low-energy π^- elastic scattering from neighboring nuclei can serve to determine the difference in neutron radii for these isotopes. This is demonstrated for the nuclei ¹²¹³C and ¹⁶¹⁸O. The method can be tested by measuring low energy π⁺ elastic scattering from a pair of isotones such as ¹¹B and ¹²C. By combining the results with electron scattering data it is possible to obtain accurate values for differences between neutron and proton radii in one nucleus in terms of the difference of neutron and proton radii in the nearby N = Z nucleus. 5 figures, 1 table

[en] Experimentally measured angular distributions are presented for the reactions ¹³C(π⁺,π⁰)¹³N (IAS) and ⁷Li(π⁺,π⁰)⁷Be (g.s. + 0.429 MeV) at T/sub π/ = 150 MeV. The data were obtained with the π⁰ spectrometer. The experimental cross sections are larger than calculations, by factors of 2 to 3. Also presented are the excitation function for ¹³C(π⁺,π⁰)¹³N (IAS) at theta = 5⁰ for T/sub π⁺/ = 70 MeV to 180 MeV. The data do not agree with calculations. All our present differential cross sections seem to be consistent with previously measured angle-integrated cross sections. 11 references

No abstract available

[en] The low momentum K⁺ is the weakest of the available strongly interacting particles. It has a mean free path in nuclear matter of about 6 F which makes it a good probe for studying properties of the nuclear interior. It allows one to build a good microscopic optical potential which can be used to calculate elastic scattering and K⁺-nucleus total cross sections. In the latter case the calculated ratio R_T = [σ_tot(K⁺ - A)/A]/[σ_tot(K⁺ - d)/2] can be expected to be more reliable because some in K⁺ N phase shifts will cancel. This ratio can also be measured more reliably than the total cross sections themselves because of cancellation of some systematic errors. We measured the total cross sections of K⁺ on D, ⁶Li, ¹²C, ²⁸Si and ⁴⁰Ca from 480 to 714 MeV/c. The emphasis was placed on extracting values of R_T with a precision of better than 2 percent. The results will be compared with calculations which rely on conventional nuclear medium effects. We will show that unconventional medium effects, such as nucleon swelling or density dependent exchanged meson masses will have to be involved in order to explain the data. (orig.)

No abstract available

No abstract available

[en] The experiment consisted of measurements in coincidence with π⁰ (using the π⁰ spectrometer) and the proton (using a special proton arm built for this experiment). The experimenters finished taking data by the last cycle of 1984. The reaction ¹⁶O(π⁺,π⁰p) was measured at T/sub π/=165 and 245 MeV for the π⁰ angles between 30 and 130⁰. At each angle the protons were detected by using an array of plastic scintillator telescopes, which covered the quasi-free angular-correlation region. Although the data are still being analyzed, preliminary results for the first run indicate that the quasi-free process (a knock-out of a p-shell nucleon) can be identified. When analysis is complete, we hope that it will either confirm the model suggested or shed new light on the process

[en] This is a report on the single and double charge exchange reactions on nuclei. The emphasis is on recent experimental results and calculations. The report is limited to pion energies below 300 MeV. The experimental results are compared with calculations of varying complexity. The current level of understanding of the various aspects of the charge exchange process is presented. (Auth.)