High resolution study of pionic 0(-) state in O-16

The cross sections and analyzing powers of the O-16(p,p')O-16(0(-),T = 1) scattering were measured at a bombarding energy of 295 MeV and an angular range of 14degrees less than or equal to theta(lab) less than or equal to 30degrees. The isovector 0(-) state at E-x = 12.80 MeV is clearly separated from the neighboring states with an energy resolution of DeltaE similar or equal to 30 keV. The data have been compared with distorted wave impulse approximation (DWIA) calculations. The analyzing powers are sensitve to the effective nucleon-nucleon (NN) interaction used in DWIA calculations, and our data support the medium modification of the NN interaction in nuclei. The DWIA calculation employing a random phase approximation (RPA) response function predicts an enhancement of the cross sections around a momentum transfer of q similar or equal to 1.7 fm(-1), and it gives a reasonable agreement with the data.