Measurement of the GMR in the Unstable 56^{56}Ni Nucleus using the Active Target Maya

International audienceThe measurement of the Isoscalar Giant Monopole Resonance(GMR) in unstable nuclei remains a major experimental challenge due to low radioactive beam intensities and unfavourable conditions in reverse kinematics. At GANIL, we have tested a new experimental method based on the unique capabilities of the active target Maya to probe the GMR by the inelastic scattering reaction 56Ni(d,d') at 50 AMeV. The preliminary excitation energy spectrum of 56Ni presents a bump between 12 and 25 MeV where isoscalar resonances are expecte

First Measurement of the Giant Monopole and Quadrupole Resonances in a Short-Lived Nucleus: 56Ni

The isoscalar giant monopole resonance (GMR) and giant quadrupole resonance (GQR) have been measured in the Ni56 unstable nucleus by inducing the Ni56(d,d′) reaction at 50A  MeV in the Maya active target at the GANIL facility. The GMR and GQR centroids are measured at 19.3±0.5  MeV and 16.2±0.5  MeV, respectively. The corresponding angular distributions are extracted from 3° to 7°. A multipole decomposition analysis using distorted wave Born approximation with random phase approximation transition densities shows that both the GMR and the GQR exhaust a large fraction of the energy-weighted sum rule. The demonstration of this new method opens a broad range of giant resonance studies at intermediate-energy radioactive beam facilities