Spectroscopy of Ar by the () two-neutron transfer reaction

Nowak, K.*; Wimmer, K.*; Hellgartner, S.*; Mcher, D.*; Bildstein, V.*; Diriken, J.*; Elseviers, J.*; Gaffney, L. P.*; Gernhuser, R.*; Iwanicki, J.*; Johansen, J. G.*; Huyse, M.*; Konki, J.*; Krll, T.*; Krcken, R.*; Lutter, R.*; Orlandi, R.  ; Pakarinen, J.*; Raabe, R.*; Reiter, P.*; Roger, T.*; Schrieder, G.*; Seidlitz, M.*; Sorlin, O.*; Van Duppen, P.*; Warr, N.*; De Witte, H.*; Zieliska, M.*

The Ar()Ar two-neutron transfer reaction at 2.16 MeV/u was studied at CERN using a Ar radioactive beam and a tritium loaded radioactive target. Angular distributions for three final states were measured and based on the shape of the differential cross section an excited state at 3695 keV was identified as the first excited 0 state. The differential cross-sections for the 0-ground state, and first excited 2 and 0 states are compared to DWBA calculations including two-step reactions through the intermediate nucleus Ar. By comparison large scale shell model calculations using state-of-the-art effective interactions, with and without the tensor components of the interactions, it was observed that the cross-shell proton-neutron tensor interaction has measurable effects on the observables at low excitation energy in Ar.