J. A. Carr

Consistent folding model description of nucleon elastic, inelastic, and charge-exchange scattering from 6,7Li at 25–50 MeV

Abstract The results of a consistent theoretical microscopic single scattering model study of nucleon elastic, inelastic, and charge-exchange scattering from 6,7 Li at E p(n) = 25–50 MeV are reported. A realistic effective nucleon-nucleon interaction, adopted from the work of Mahaux and collaborators and Bertsch and coworkers, has been employed in the model calculations. The density distributions needed to describe the structure of the mass 6 and 7 systems in the calculations are the same as those used in recent proton-nucleus scattering studies of these targets at E p = 200 MeV. The present, parameter-free model calculations provide an excellent description of the available low-energy nucleon-nucleus scattering data on 6,7 Li.

Spin-current effects in inelastic scattering from nuclei

Abstract The role of non-normal parity transfer amplitudes in the excitation of the third 0+ state in 16O by 135 MeV protons is discussed. The dominant effect is from the spin-orbit interaction which provides non-normal parity transfer via both the direct and knockout exchange terms in the transition amplitude. A less important effect comes from the central and tensor interactions which provide non-normal transfer only via the knockout exchange terms. In lowest approximation, the non-normal transfer to the target can be associated with the longitudinal spin-current transition density. Electron and pion scattering cross sections are also sensitive to the same transition density. These points have been confused in a recent article.

Spectroscopic considerations and the exchange non-locality in nucleon-nucleus scattering

Abstract A mixed density expansion of the off-diagonal density matrix is introduced to study the spectroscopic content of the non-local knockout exchange amplitude for nucleon-nucleus scattering. This expansion provides a clear basis for discussing specific consequences of non-local amplitudes in hadronic reaction processes. Additionally, it provides a means to develop approximations to simplify the treatment of these amplitudes.

Pion scattering to 6- stretched states in Mg24 and Mg26

Inelastic {pi}{sup {plus minus}} cross-section measurements at pion incident energies of 150 and 180 MeV were made on 6{sup {minus}} states in {sup 24,26}Mg. In particular, we have determined the ({ital f}{sub 7/2}{ital d5/2}{sup {minus}1}){sub 6}{sup {minus}} isoscalar {ital Z}{sub 0}=0.21{plus minus}0.02 strength for the strongest {ital T}=0, {ital J} {sup {pi}}=6{sup {minus}} state located at 12.11{plus minus}0.05 MeV in {sup 24}Mg, and the isoscalar {ital Z}{sub 0}=0.17{plus minus}0.04 and isovector {ital Z}{sub 1}=0.21{plus minus}0.02 strength for the strongest {ital T}=1, {ital J} {sup {pi}}=6{sup {minus}} state located at 9.18 MeV in {sup 26}Mg. The distorted-wave impulse-approximation pion cross-section calculations required a multiplicative normalization factor of 1.2{plus minus}0.1 in order to reproduce the pure isovector strength deduced from electron scattering for the well-known {ital T}=1, {sup {pi}}=6{sup {minus}} state at 15.15 MeV in {sup 24}Mg and the {ital T}=2, {ital J} {sup {pi}}=6{sup {minus}} state at 18.05 MeV in {sup 26}Mg.

Pion scattering to 6 sup minus stretched states in sup 24 Mg and sup 26 Mg

Inelastic {pi}{sup {plus minus}} cross-section measurements at pion incident energies of 150 and 180 MeV were made on 6{sup {minus}} states in {sup 24,26}Mg. In particular, we have determined the ({ital f}{sub 7/2}{ital d5/2}{sup {minus}1}){sub 6}{sup {minus}} isoscalar {ital Z}{sub 0}=0.21{plus minus}0.02 strength for the strongest {ital T}=0, {ital J} {sup {pi}}=6{sup {minus}} state located at 12.11{plus minus}0.05 MeV in {sup 24}Mg, and the isoscalar {ital Z}{sub 0}=0.17{plus minus}0.04 and isovector {ital Z}{sub 1}=0.21{plus minus}0.02 strength for the strongest {ital T}=1, {ital J} {sup {pi}}=6{sup {minus}} state located at 9.18 MeV in {sup 26}Mg. The distorted-wave impulse-approximation pion cross-section calculations required a multiplicative normalization factor of 1.2{plus minus}0.1 in order to reproduce the pure isovector strength deduced from electron scattering for the well-known {ital T}=1, {sup {pi}}=6{sup {minus}} state at 15.15 MeV in {sup 24}Mg and the {ital T}=2, {ital J} {sup {pi}}=6{sup {minus}} state at 18.05 MeV in {sup 26}Mg.

Pion scattering to6−stretched states inMg24andMg26

Inelastic {pi}{sup {plus minus}} cross-section measurements at pion incident energies of 150 and 180 MeV were made on 6{sup {minus}} states in {sup 24,26}Mg. In particular, we have determined the ({ital f}{sub 7/2}{ital d5/2}{sup {minus}1}){sub 6}{sup {minus}} isoscalar {ital Z}{sub 0}=0.21{plus minus}0.02 strength for the strongest {ital T}=0, {ital J} {sup {pi}}=6{sup {minus}} state located at 12.11{plus minus}0.05 MeV in {sup 24}Mg, and the isoscalar {ital Z}{sub 0}=0.17{plus minus}0.04 and isovector {ital Z}{sub 1}=0.21{plus minus}0.02 strength for the strongest {ital T}=1, {ital J} {sup {pi}}=6{sup {minus}} state located at 9.18 MeV in {sup 26}Mg. The distorted-wave impulse-approximation pion cross-section calculations required a multiplicative normalization factor of 1.2{plus minus}0.1 in order to reproduce the pure isovector strength deduced from electron scattering for the well-known {ital T}=1, {sup {pi}}=6{sup {minus}} state at 15.15 MeV in {sup 24}Mg and the {ital T}=2, {ital J} {sup {pi}}=6{sup {minus}} state at 18.05 MeV in {sup 26}Mg.