Absolute(γ12,p0)11B cross section and angular distributions in the giant dipole resonance region

The absolute differential cross sections for the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(γ, ${\mathrm{p}}_0$ ${)\mathrm{}}^{11}$B were measured at seven angles in the energy region between 21 and 29 MeV. Using a standard Legendre polynomial expansion, the total integrated-over-angles absolute ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(γ,${\mathrm{p}}_0$) cross section was derived, as well as the angular distribution coefficients $a_i$ (i=1,...,4). Taking into account the statistical and systematic uncertainties, the present data confirm reasonably well the (p,${\gamma }_0$) results of Allas et al., both with regard to the absolute value and to the shape of the cross section, with the exception of the $a_2$ coefficient in the low energy region.