Giant dipole emission in N / Z asymmetric heavy-ion reactions

Summary We have measured the high-energy γ-ray spectra from the fusion reactions 130 MeV 16 O + 98 Mo and 240 MeV 48 Ti + 64 Ni, populating the 114 Sn and 112 Sn compound nuclei at the excitation energy of 110 MeV. The comparison of the spectra shows a ~36% enhancement of the α-ray yield in the Giant Dipole Resonance region ( E γ > 8 MeV) when the 16 O-induced reaction is considered. This enhancement is interpreted as due to entrance channel effects related to the N / Z asymmetry between the target and the projectile.