Measurement of the Isoscalar Monopole Response in the Neutron-Rich Nucleus $^{68}$Ni using the active target MAYA

We report the measurement of the isoscalar monopole strength in the unstable nucleus $^{68}$Ni using inelastic alpha scattering at 50AMeV in inverse kinematics. This experiment has been performed at GANIL with LISE spectrometer using a dedicated detector: the active target MAYA. A part of the isoscalar giant monopole resonance (ISGMR) has been measured at 21:1 $\pm$ 1:9MeV and indications for a soft monopole mode are provided for the first time at 12:9 $\pm$ 1:0MeV. Distorted-wave born ap- proximation (DWBA) with random-phase approximation (RPA) transition densities have been used to study angular distribution and indicate that the L = 0 multipolarity dominates the cross-section for the ISGMR, and significantly contributes to the soft mode.