The 1-(1.9 MeV ?-)2+ transition in the decay of148Pm

Abstract

The non-unique first-forbidden 1-(1.9 MeV/?-)2 § transition in the decay of 148pm is studied. The nuclear matrix elements are evaluated using for the ground state of the odd-odd 148pm a phenomenological wave function derived in a previous work in the framework of the two-quasiparticle model and assuming that the first excited 2 § state in 148Sm can be described as the first quadrupole phonon state. This model provides nuclear matrix elements which are capable of describing experimental data like the spectrum shape factor, the longitudinal polarization of the electrons and a particular set of fl-7 directional correlation coefficients, but it fails to interpret the large log ft value of this transition. In addition, the validity of the i-approximation is discussed.

Nuclear electromagnetic moments of the ground states of148Pm and210Bi calculated with phenomenological wave functions derived from analyses of?-decay experiments

“…The occupation factors Vj for 148pm were taken from the solutions of the gap equations obtained with the parameters quoted in Ref. [3]. For both nuclides the magnetic dipole moments were calculated using three different approaches for the single-particle contributions #(j) as given by (7).…”

“…More recently, the wave function singled out in Ref. [1] has been used to calculate fi-observables corresponding to the decay from the groundstate of 14SPm to the first excited state 2 + in the even-even l~SSm nucleus [3]. tn this latter work [3] the success was only partial.…”

“…[1] has been used to calculate fi-observables corresponding to the decay from the groundstate of 14SPm to the first excited state 2 + in the even-even l~SSm nucleus [3]. tn this latter work [3] the success was only partial. Although the predictions for energy dependent observables like the spectrum shape factor, the longitudinal polarization of the electrons and some data on the fi-7 angular 1 Fellow of the Consejo Nacional de Investigaciones Cientificas y T~cnicas (CONICET) of Argentina 2 Fellow of the Alexander yon Humboldt Foundation.…”

Theoretical estimates of the 1/2? (693 keV) 3/2x002B;x002B;x002B;first-forbidden beta decay transition in111Ag

“…Therefore the contributions D' of [3] are given, in the present case, by the same expressions (15), after the replacement of the neutron states by proton states. Similar expressions have been reported previously for even mass superfluid systems [8,11,19]. At this point we are in condition to compute the values of the beta decay observables as they result both from the configuration mixing (10), and from the renormalization mechanism (12)-(15).…”