/ Experiment-Nucl GANIL-P-2012-08

Unveiling the intruder deformed 0$^+_2$ state in $^{34}$Si

Rotaru, F. (Bucharest, IFIN-HH) ; Negoita, F. (Bucharest, IFIN-HH) ; Mrazek, J. (Rez, Nucl. Phys. Inst.) ; Lukyanov, S. (Dubna, JINR) ; Nowacki, F. (Louis Pasteur U., Strasbourg I) ; Poves, A. (Madrid, IFT) ; Sorlin, O. (GANIL) ; Borcea, C. (Bucharest, IFIN-HH) ; Borcea, R. (Bucharest, IFIN-HH) ; Buta, A. (Bucharest, IFIN-HH) ; Caceres, L. (GANIL) ; Calinescu, S. (Bucharest, IFIN-HH) ; Chevrier, R. (CEA DAM) ; Dombradi, Zs. (Debrecen, Inst. Nucl. Res.) ; Daugas, J.M. (CEA DAM) ; Lebhertz, D. (GANIL) ; Penionzhkevich, Y. (Dubna, JINR) ; Petrone, C. (Bucharest, IFIN-HH) ; Sohler, D. (Debrecen, Inst. Nucl. Res.)

Pages: 5

Abstract: The 0$^+_2$ state in $^{34}$Si has been populated at the {\sc Ganil/Lise3} facility through the $\beta$-decay of a newly discovered 1$^+$ isomer in $^{34}$Al of 26(1) ms half-life. The simultaneous detection of $e^+e^-$ pairs allowed the determination of the excitation energy E(0$^+_2$)=2719(3) keV and the half-life T$_{1/2}$=19.4(7) ns, from which an electric monopole strength of $\rho^2$(E0)=13.0(0.9)$\times10^{-3}$ was deduced. The 2$^+_1$ state is observed to decay both to the 0$^+_1$ ground state and to the newly observed 0$^+_2$ state (via a 607(2) keV transition) with a ratio R(2$^+_1$$\rightarrow0^+_1/2^+_1$$\rightarrow0^+_2$)=1380(717). Gathering all information, a weak mixing with the 0$^+_1$ and a large deformation parameter of $\beta$=0.29(4) are found for the 0$^+_2$ state, in good agreement with shell model calculations using a new {\sc sdpf-u-mix} interaction allowing \textit{np-nh} excitations across the N=20 shell gap.

Web-Page: http://inspirehep.net/record/1120321/files/arXiv:1206.6572.pdf; http://inspirehep.net/record/1120321/files/fig1.png; http://inspirehep.net/record/1120321/files/fig2.png; http://inspirehep.net/record/1120321/files/fig3.png

Note: 5 pages, 3 figures, accepted for publication in Physical Review Letters

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 Record created 2012-07-06, last modified 2014-01-30

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