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Unveiling the intruder deformed 0$^+_2$ state in $^(34)$Si
Rotaru F., Negoita F., Grévy S., Mrazek J., Lukyanov S. et al
Physical Review Letters 109 (2012) 092503 - http://hal.in2p3.fr/in2p3-00712670
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Physique/Physique Nucléaire Expérimentale
Unveiling the intruder deformed 0$^+_2$ state in $^{34}$Si
F. Rotaru, F. Negoita, S. Grévy1, J. Mrazek, S. Lukyanov, F. Nowacki2, A. Poves, O. Sorlin1, C. Borcea, R. Borcea, A. Buta, L. Caceres1, S. Calinescu, R. Chevrier3, Zs. Dombradi, J.M. Daugas3, D. Lebhertz1, Y. Penionzhkevich, C. Petrone, D. Sohler, M. Stanoiu, J.C. Thomas1
1 :  GANIL - Grand Accélérateur National d'Ions Lourds
http://www.ganil-spiral2.eu
CNRS : UPR3266 – IN2P3 – CEA : DSM/GANIL
Bvd Henri Becquerel - BP 55027 - 14076 CAEN CEDEX 5
France
2 :  IPHC - Institut Pluridisciplinaire Hubert Curien
CNRS : UMR7178 – Université de Strasbourg
France
3 :  DAM/DIF - DAM Île-de-France
http://www-dam.cea.fr/
CEA : DAM/DIF
CEA Bruyères-le-Châtel 91297 Arpajon cedex
France
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)$\times$10$^{-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$$\rightarrow$0$^+_1$/2$^+_1$$\rightarrow$0$^+_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.

Articles dans des revues avec comité de lecture
2012
Physical Review Letters (Phys. Rev. Lett.)
Publisher American Physical Society
ISSN 0031-9007 (eISSN : 1079-7114)
109
092503

GANIL P 2012-08, GANIL 2012-099 A
23.35.+g,23.40.-s,23.20.Lv,27.30.+t
5 pages, 3 figures, Expérience GANIL/LISE3
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34Si_grevy.tex(28.3 KB)
fig1.eps(103.1 KB)
fig2.eps(9.9 KB)
fig3.eps(7 KB)
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34Si_grevy.pdf(551.5 KB)
PS
34Si_grevy.ps(652.6 KB)