Fast-timing study of the l-forbidden 1/2(+) -> 3/2(+) M1 transition in Sn-129

Lica, R; Mach, H; Fraile, LM; Gargano, A; Borge, MJG; Marginean, N; Sotty, CO; Vedia, V; Andreyev, AN; Benzoni, G; Bomans, P; Borcea, R; Coraggio, L; Costache, C; Flavigny, F; Fynbo, H; Gaffney, Liam; Greenlees, PT; Harkness-Brennan, LJ; Huyse, Mark; Ibanez, P; Judson, DS; Konki, J; Korgul, A; Kroell, T; Kurcewicz, J; Lalkovski, S; Lazarus, I; Lund, MV; Madurga, M; Marginean, R; Marroquin, I; Mihai, C; Mihai, RE; Morales, AI; Nacher, E; Negret, A; Page, RD; Pakarinen, J; Pascu, S; Paziy, V; Perea, A; Perez-Liva, M; Picado, E; Pucknell, V; Rapisarda, E; Rahkila, P; Rotaru, F; Swartz, JA; Tengblad, O; Van Duppen, Piet; Wadsworth, R; Walters, WB; Warr, N

doi:10.1103/PhysRevC.93.044303

Fast-timing study of the l-forbidden 1/2(+) -> 3/2(+) M1 transition in Sn-129

Author:

Lica, R

Mach, H ; Fraile, LM ; Gargano, A ; Borge, MJG ; Marginean, N ; Sotty, CO ; Vedia, V ; Andreyev, AN ; Benzoni, G ; Bomans, P ; Borcea, R ; Coraggio, L ; Costache, C ; Flavigny, F ; Fynbo, H ; Gaffney, Liam ; Greenlees, PT ; Harkness-Brennan, LJ ; Huyse, Mark ; Ibanez, P ; Judson, DS ; Konki, J ; Korgul, A ; Kroell, T ; Kurcewicz, J ; Lalkovski, S ; Lazarus, I ; Lund, MV ; Madurga, M ; Marginean, R ; Marroquin, I ; Mihai, C ; Mihai, RE ; Morales, AI ; Nacher, E ; Negret, A ; Page, RD ; Pakarinen, J ; Pascu, S ; Paziy, V ; Perea, A ; Perez-Liva, M ; Picado, E ; Pucknell, V ; Rapisarda, E ; Rahkila, P ; Rotaru, F ; Swartz, JA ; Tengblad, O ; Van Duppen, Piet ; Wadsworth, R ; Walters, WB ; Warr, N

Keywords:

Science & Technology, Physical Sciences, Physics, Nuclear, Physics, PICOSECOND LIFETIME MEASUREMENTS, NEUTRON-RICH NUCLEI, 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, 5106 Nuclear and plasma physics

Abstract:

© 2016 authors. Published by the American Physical Society. The levels in Sn129 populated from the β- decay of In129 isomers were investigated at the ISOLDE facility of CERN using the newly commissioned ISOLDE Decay Station (IDS). The lowest 1/2+ state and the 3/2+ ground state in Sn129 are expected to have configurations dominated by the neutron s1/2 (l=0) and d3/2 (l=2) single-particle states, respectively. Consequently, these states should be connected by a somewhat slow l-forbidden M1 transition. Using fast-timing spectroscopy we have measured the half-life of the 1/2+ 315.3-keV state, T1/2= 19(10) ps, which corresponds to a moderately fast M1 transition. Shell-model calculations using the CD-Bonn effective interaction, with standard effective charges and g factors, predict a 4-ns half-life for this level. We can reconcile the shell-model calculations to the measured T1/2 value by the renormalization of the M1 effective operator for neutron holes.