Search results for "23.20.-g"
showing 2 items of 2 documents
X(5) critical-point symmetries in 138Gd
2011
International audience; The lifetimes of low-lying transitions in 138Gd have been measured using the recoil-distance Doppler-shift technique. The resultant reduced transition probabilities have been compared to X(5) critical-point calculations to assess the potential 'phase-transitional' behaviour of 138Gd. The X(5) symmetry describes the first order 'phase transition' between sphericity, U(5) and an axially deformed nuclear shape, SU(3). Although a high degree of correspondence is observed between the experimental and theoretical excitation energies, the large uncertainties of the experimental B(E2) values cannot preclude contributions from either vibrational or rotational modes of excitat…
On the decay of theJπ= 11/2−,T1/2= 38.9 h isomer in133Ba: search for the E5 transition and verification of the EC branch
2010
International audience; This paper presents a search for the competing 11/2 − → 1/2 + E5 branch to the main 11/2 − → 3/2 + M4 transition from the T 1/2 = 39 h, J π = 11/2 − isomeric state in 133 Ba. An upper limit of 1.8 * 10 −5 could be established for the E5/M4 intensity ratio. In addition a long-standing controversy in the EC-decay of the same isomer was resolved: only one EC branch to the 11/2 + state in 133 Cs was observed. The shell-model structures of the involved states in 133 Ba and 133 Cs were studied with the microscopic quasiparticle-phonon model (MQPM). Good agreement with the decay rates B(λ) was obtained. In particular, the B(M4) value is well reproduced and further only one …