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 〈rn2〉 1 2-〈rp2〉 1 2=0.03(3) fm.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 51-54 |
| Number of pages | 4 |
| Journal | Physics Letters B |
| Volume | 82 |
| Issue number | 1 |
| DOIs | |
| State | Published - Mar 12 1979 |
Funding
It has long been a fond hope in nuclear structure physics to separate the roles of neutrons and protons in nuclear excitations \[1\].R ecent pion scattering experiments make it possible to realize this hope. In an earlier letter \[2\]w e reported that the cross section for the excitation of the 1.98 MeV 2~" state in 180 by inelastic scattering of 230 MeV negative pions was a factor 1.66(13) larger than that by positive pions of the same energy. Because of the dominance of the pion-nucleon (3,3) resonance near this energy, enhancement of n-cross section over n + by a factor 1.25 is expected just because 18 0 contains 10 neutrons and only 8 protons. The much larger observed enhance- Research supported by the U.S. Department of Energy, the Research Corporation and the Robert A. Welch Foundation.
ASJC Scopus subject areas
- Nuclear and High Energy Physics