George Kahrimanis

Comparison of the double giant-dipole states observed in (. pi. sup minus ,. pi. sup + ) and (. pi. sup + ,. pi. sup minus ) reactions on sup 40 Ca and sup 27 Al

The double isovector giant-dipolar state has been observed in the ({pi}{sup {minus}},{pi}{sup +}) {Delta}{ital T}{sub {ital z}}=+2 and ({pi}{sup +},{pi}{sup {minus}}) {Delta}{ital T}{sub {ital z}}={minus}2 double-charge-exchange reactions on {sup 40}Ca and {sup 27}Al. The resonances observed in the ({pi}{sup {minus}},{pi}{sup +}) reaction are closely related via Coulomb energy and isospin symmetry to the resonances measured in the inverse ({pi}{sup +},{pi}{sup {minus}}) reaction on the same nuclei. The new observations provide strong support for the identification of the double giant-dipole state in nuclei. The differences between the self-conjugate and non-self-conjugate cases are outlined.

Pion-nucleus elastic scattering on {sup 12}C, {sup 40}Ca, {sup 90}Zr, and {sup 208}Pb at 400 and 500 MeV

Pion-nucleus elastic scattering at energies above the Delta(1232) resonance is studied using both pi+ and pi- beams on 12C, 40Ca, 90Zr, and 208Pb. The present data provide an opportunity to study the interaction of pions with nuclei at energies where second-order corrections to impulse approximation calculations should be small. The results are compared with other data sets at similar energies, and with four different first-order impulse approximation calculations. Significant disagreement exists between the calculations and the data from this experiment.

Pion - nucleus elastic scattering on C-12, Ca-40, Zr-90, and Pb-208 at 400-MeV and 500-MeV

Pion-nucleus elastic scattering at energies above the Delta(1232) resonance is studied using both pi+ and pi- beams on 12C, 40Ca, 90Zr, and 208Pb. The present data provide an opportunity to study the interaction of pions with nuclei at energies where second-order corrections to impulse approximation calculations should be small. The results are compared with other data sets at similar energies, and with four different first-order impulse approximation calculations. Significant disagreement exists between the calculations and the data from this experiment.

Pion double charge exchange on sup 42,44,48 Ca for 300 le T sub. pi. le 550 MeV

Measurements of cross sections for pion-induced double-charge-exchange reactions to the double-isobaric-analog state for {sup 42,44,48}Ca at incident pion energies of 300--550 MeV at {theta}{sub lab}=5{degree} are reported, together with upper limits for cross sections for transitions to the residual ground states for {sup 44,48}Ca. The data are fitted with a two-amplitude model which gives expressions for cross sections for both transitions. The fit overpredicts the ground-state cross sections, indicating a failure of the model in this energy range.

Pion double charge exchange on Ca 4 2 , 4 4 , 4 8 for 300≤ T π ≤550 MeV

Measurements of cross sections for pion-induced double-charge-exchange reactions to the double-isobaric-analog state for {sup 42,44,48}Ca at incident pion energies of 300--550 MeV at {theta}{sub lab}=5{degree} are reported, together with upper limits for cross sections for transitions to the residual ground states for {sup 44,48}Ca. The data are fitted with a two-amplitude model which gives expressions for cross sections for both transitions. The fit overpredicts the ground-state cross sections, indicating a failure of the model in this energy range.

Pion double charge exchange onCa42,44,48for 300≤Tπ≤550 MeV

Measurements of cross sections for pion-induced double-charge-exchange reactions to the double-isobaric-analog state for {sup 42,44,48}Ca at incident pion energies of 300--550 MeV at {theta}{sub lab}=5{degree} are reported, together with upper limits for cross sections for transitions to the residual ground states for {sup 44,48}Ca. The data are fitted with a two-amplitude model which gives expressions for cross sections for both transitions. The fit overpredicts the ground-state cross sections, indicating a failure of the model in this energy range.