Study of the N = 28 shell closure in the Ar isotopic chain

. The structure of the neutron-rich nucleus 47 Ar has been investigated through the d( 46 Ar, 47 Ar)p transfer reaction. The radioactive beam of 46 Ar at 10 A ·MeV was provided by the SPIRAL facility at GANIL. The protons corresponding to a neutron pick-up on bound or unbound states mechanism in 47 Ar nuclei were detected at backward angles by the position-sensitive Si array-detector MUST. The transfer-like ejectiles were detected in the SPEG spectrometer. Level scheme, spin assignments and spectroscopic factors have been deduced for 47 Ar and compared to shell model predictions. They suggest a slight erosion of the N = 28 shell gap from the weakening of the spin-orbit interaction arising from the f and p orbitals. These spectroscopic information are subsequently used to infer ( n ,γ) reaction rates in the Ar isotopic chain to understand the origin of the 48 Ca/ 46 Ca abnormal isotopic ratio observed in certain inclusions of meteorites.