Kenneth G. Boyer

Neutron-proton radius differences and isovector deformations from π+ and π− inelastic scattering from 18O

Abstract π+ and π− elastic and inelastic scattering from 18O have been measured at T(π)=164 MeV. Consistent with the results at 230 MeV, it is found that the ratio σ(π − ) σ(π + ) for the 21+ state is 1.86(16), while for the 31− state it is 0.89(6). These results are interpreted as indicating differences in neutron and proton deformations characterizing the 21+ transition and partial neutron blocking for the 31− transition. Optical model analysis of elastic scattering leads to the conclusion that 〈r n 2 〉 1 2 −〈r p 2 〉 1 2 =0.03(3) fm .

Observation of enhanced excitation of 12C by inelastic pion scattering on the (3,3) pion-nucleon resonance

Abstract Pion inelastic scattering on 12 C to states at an excitation energy of approximately 19 MeV shows a strong enhancement at an incident pion energy near the pion-nucleon (3,3) resonance. This resonance may therefore provide a mechanism for the selective enhancement of inelastic transitions.