Yoshio Sumi

Experimantal Study of Inclusive Reaction 12C(γ, π-) at 44.2°

It is found that, even at a considerably large jab angle 44.2°, momentum spectra of pions in the reaction 12 C(γ, π - ) show a clear singly-peaked structure throughout a photon energy range between 300 and 850 MeV. The peak momentum is always about 40 MeV/c less than that determined by free nucleon kinematics. The width increses almost inearly with photon energy. Differential cross section does not exhibit a marked variation with energy. These data are quite well explained by an impulse-approximation calculation.

Recoil Proton Polarization and Differential Cross Section in Eta-Meson Photoproduction at 890 MeV

The differential cross section and recoil proton polarization for the process γ+ p →η°+ p were measured by detecting photons from η-decay and recoil protons. The differential cross sections are 0.75±0.03 and 1.04±0.07 µb/sr at the CM angles θ η * =82.3° and 108.3°, respectively, at the incident photon energy k =890 MeV, † and 0.20±0.05 µb/sr at θ η * =83.1° and k =1050 MeV. Thus the differential cross sections at k =890 MeV seem to show a backward peaking. The value of recoil proton polarization is -0.15±0.30 at θ η * =82.3°, whereas it is 0.27±0.25 at θ η * =108.3°, both at k =890 MeV, thus suggesting a sign change around θ η * =90°. In addition to the S 11 (1535), a comparably large contribution of the D 13 (1520) is needed to explain the experimental results.

N overbar N and N overbar D Interactions -- A compilation

Author(s): Enstrom, James E.; Ferbel, Thomas; Slattery, Paul F.; Werner, Barry L.; Guiragossian, Zaven G.T.; Sumi, Yoshio; Yoshida, Toshihiro

Radiative pion capture in 16O

Abstract The absolute values of the radiative capture rate in 16 O are predicted to be of order of 10 17 sec −1 by the shell model calculation. The observed peak of the gamma ray spectra is interpreted as the giant resonance similar to that of the photo absorption.