Analysis of pion scattering to stretched states inNi60and other nuclei using Woods-Saxon wave functions

Abstract

Inelastic scattering of 162 MeV~and n. + was used to study the previously known J =8 stretched transitions in Ni. A consistent analysis of data from electron and pion scattering to stretched states using both harmonic oscillator and Woods-Saxon wave functions (unbound as necessary) was performed for Ni and three other nuclei: ' C, "Si, and ' Fe. The experimental pion scattering cross sections were reproduced by distorted-wave impulse approximation calculations using wave functions from (e, e ) with a normalization factor N that generally varied from 1 to 5. The ratio of the total isoscalar to the total isovector strength ranged from 0.2 to 1.2. The use of Woods-Saxon wave functions in the analysis did not significantly improve the fits to the angular distributions.

Pion scattering to6−stretched states inMg24<

“…In- input to the pion distorted-wave code MSUDwpI [14], using the same spin-orbit force and optical potential parameters as previously reported [6], and a charge radius of 3.06 fm for ' Mg from electron scattering [15]. The ground-state density distribution parameters used in these two codes were assumed to have a Woods-Saxon (WS) form p(r) (x-(1+e'" '/') ' with radius c =2.88 fm and di6'useness a =0.52 fm taken from previous pion scattering analysis [11].…”

“…The theoretical Z coefficients are from the sum rules of Ref. [6] for the extreme-single-particle model (ESPM) and from the large basis shell model (LBSM) calculations of Carr [7,8]. The ratio between experiment and theory is defined as Mg, which is in strong disagreement with that from ana1ysis of recent proton scattering measurements [10].…”