On the decay of the J = 11/2-, T1/2 = 38.9 h isomer in 133Ba: search for the E5 transition and verification of the EC branch

• Published in: Journal of physics. G, Nuclear and particle physics Vol. 38; no. 1
• Main Authors: GRANHOTM, P, LÖNNROTH, T, SUHONEN, J, BERGMAN, J, KÄLLMAN, K.-M, LILL, J.-O, NORRBY, M, YDREFORS, E, TIKKANEN, P
• Format: Journal Article
• Language: English
• Published: Bristol Institute of Physics 2011; IOP Publishing
• Subjects: Exact sciences and technology; Nuclear physics; Physics; The physics of elementary particles and fields; Shell models; Upper bound; Intensity; Quasiparticle-phonon model; Meson decay; Microscopic model; Isomers; B mesons; Mathematical physics; Nuclear physics; 23.40.-s; 23.20.-g; 21.60.-n; 23.35.+g; 21.60.Cs
• ISSN: 0954-3899; 1361-6471
• DOI: 10.1088/0954-3899/38/1/015101

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 low-lying 11/2 state could be identified in the latter nuclide, supporting the experimental results.