Toward the N = 40 sub-shell closure in Co isotopes and the new island of inversion

Neutron-rich Co isotopes from N = 34 to 40 were studied through multinucleon transfer by bombarding a 238U target with a 460 MeV 70Zn beam at the Legnaro National Laboratories. Gamma-recoil coincidences were recorded identifying the ions by using a high-acceptance magnetic spectrometer (PRISMA) and detecting the gamma radiation by using an array of HPGe clover detectors (CLARA). The results are discussed in comparison with the predictions of large-scale shell-model calculations.