Prolate-Spherical Shape Coexistence at N=28 in $^{44}$S

C. Force (1) , S. Grévy (1) , L. Gaudefroy (2) , O. Sorlin (1) , L. Caceres (1) , F. Rotaru (3) , J. Mrazek (4) , N.L. Achouri (5) , J.C. Angélique (5) , F. Azaiez (6) , B. Bastin (5) , R. Borcea (3) , A. Buta (3) , J.M. Daugas (2) , Z. Dlouhy (4) , Zs. Dombradi (7) , Francois de Oliveira Santos (1) , F. Negoita (3) , Y. Penionzhkevich (8) , M.G. Saint-Laurent (1) , D. Sohler (7) , M. Stanoiu (3) , I. Stefan (6) , C. Stodel (1) , F. Nowacki (9)

1 GANIL - Grand Accélérateur National d'Ions Lourds
2 DAM/DIF - DAM Île-de-France
3 NIPNE - Horia Hulubei National Institute of Physics and Nuclear Engineering
4 Nuclear Physics Institute, ASCR Rez
5 LPCC - Laboratoire de physique corpusculaire de Caen
6 IPNO - Institut de Physique Nucléaire d'Orsay
7 ATOMKI - Institute for Nuclear Research [Budapest]
8 FLNR - Flerov Laboratory of Nuclear Reactions [Dubna]
9 IPHC - Institut Pluridisciplinaire Hubert Curien

The structure of $^{44}$S has been studied using delayed $\gamma$ and electron spectroscopy at \textsc{ganil}. The decay rates of the 0$^+_2$ isomeric state to the 2$^+_1$ and 0$^+_1$ states have been measured for the first time, leading to a reduced transition probability B(E2~:~2$^{+}_1$$\rightarrow$0$^{+}_2)$= 8.4(26)~e$^2$fm$^4$ and a monopole strength $\rho^2$(E0~:~0$^{+}_2$$\rightarrow$0$^{+}_1)$ =~8.7(7)$\times$10$^{-3}$. Comparisons to shell model calculations point towards prolate-spherical shape coexistence and a phenomenological two level mixing model is used to extract a weak mixing between the two configurations.

Domaines: Physique Nucléaire Expérimentale [nucl-ex]

C. Force, S. Grévy, L. Gaudefroy, O. Sorlin, L. Caceres, et al.. Prolate-Spherical Shape Coexistence at N=28 in $^{44}$S. Physical Review Letters, 2010, 105, pp.102501. ⟨10.1103/PhysRevLett.105.102501⟩. ⟨in2p3-00506598⟩