Figure 1

Top panel: comparison of quasifree (circle) and free (open square) coplanar $pp\gamma$ cross sections for a number of angle combinations as a function of proton angles. The systematic errors of both experiments have been added to the statistical uncertainties to make the comparison more sensible. Bottom two panels: cross sections for coplanar geometry as a function of neutron (proton) angle for a number of fixed proton (neutron) and photon angles. The proton and neutron are emitted on opposite sides of the beam. Only statistical uncertainties are shown. The systematic uncertainties in the cross sections of about 20%, which are dominated by the uncertainty in the neutron detection efficiency, are not shown. The quasifree data ($pp\gamma$ and $pn\gamma$) have been multiplied by a factor of $0.4$ (see text for details). The two SPM are $st$-SPM (dashed curves), and the $tu$-SPM (dash-dotted curves). The solid curves correspond to the results of the microscopic calculation.Reuse & Permissions

Figure 2

Cross sections for the coplanar geometry for three different combinations of proton and neutron scattering angles as a function of the photon polar angle. The meaning of the curves is the same as in Fig. 2.Reuse & Permissions