Temperature and spin dependence of the giant dipole resonance width

Abstract The dependence of the GDR width on temperature and spin was investigated in Sn nuclei, by using the reactions 17 O + 100 Mo and 18 O + 100 Mo to form 117 Sn and 118 Sn, respectively. Widths of Γ = 6.9 ± 0.5 MeV and Γ = 8.2 ± 0.5 MeV were extracted for temperatures of 1.74 and 1.84 MeV, respectively. The large increase of the width over this relatively small temperature range is inconsistent with the thermal shape fluctuation model. However, the spin dependence of the width is well reproduced by the model.