Coulomb excitation of $^{44}$Ca and $^{46}$Ar

S. Calinescu (1) , L. Caceres (2) , S. Grévy (3) , O. Sorlin (2) , Z. Dombradi (4) , M. Stanoiu (1) , R. Astabatyan (5) , C. Borcea (1) , R. Borcea (1) , M. Bowry (6) , W. Catford (6) , E. Clément (2) , S. Franchoo (7) , R. Garcia (8) , R. Gillibert , I. H. Guerin (3) , I. Kuti (4) , S. Lukyanov (5) , A. Lepailleur (2) , V. Maslov (5) , P. Morfouace (7) , J. Mrazek (9) , F. Negoita (1) , M. Niikura (7) , L. Perrot (7) , Z. Podolyak (6) , C. Petrone (1) , Y. Penionzhkevich (5) , T. Roger (2) , F. Rotaru (1) , D. Sohler (4) , I. Stefan (7) , J.C. Thomas (2) , Z. Vajta (4) , E. Wilson (6)

1 NIPNE - Horia Hulubei National Institute of Physics and Nuclear Engineering
2 GANIL - Grand Accélérateur National d'Ions Lourds
3 CENBG - Centre d'Etudes Nucléaires de Bordeaux Gradignan
4 ATOMKI - Institute for Nuclear Research [Budapest]
5 FLNR - Flerov Laboratory of Nuclear Reactions [Dubna]
6 Department of Physics, University of Surrey
7 IPNO - Institut de Physique Nucléaire d'Orsay
8 K.U. LEUVEN - Instituut voor Kern- en Stralingsfysica
9 Nuclear Physics Institute [Prague]

The reduced transition probabilities B(E2;0+g.s.→2+1) of the Ar46 and Ca44 nuclei were studied using the Coulomb excitation technique at intermediate energy at the LISE/GANIL facility. The in-flight γ rays, emitted after the Coulomb excitation of their first 2+ states, were detected in an array of 64BaF2 crystals. The present B(E2↑) value for Ca44, 475(36) e2fm4, agrees well with the value of 495(35) e2fm4 obtained by averaging results of previous experiments. Consistent B(E2;0+g.s.→2+1) values of 225(29) e2fm4 and 234(19) e2fm4 have been obtained for Ar46 from an absolute and a relative measurement, normalized to the Ca44 value. Both results agree with the ones obtained with the same experimental technique at the NSCL facility but are a factor of 2 smaller than the shell model predictions. The drop in B(E2;0+g.s.→2+1) in the Ar chain at N=28, confirmed in this experiment, shows that Ar46 is sensitive to the N=28 shell closure.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

S. Calinescu, L. Caceres, S. Grévy, O. Sorlin, Z. Dombradi, et al.. Coulomb excitation of $^{44}$Ca and $^{46}$Ar. Physical Review C, 2016, 93, pp.044333. ⟨10.1103/PhysRevC.93.044333⟩. ⟨in2p3-01306981⟩