DOI: 10.1140/epja/i2002-10105-x
Beta-decay of the
nucleus
I. Piqueras1, 2, M.J.G. Borge1, Ph. Dessagne2, J. Giovinazzo2, A. Huck2, A. Jokinen3, A. Knipper2, C. Longour2, G. Marguier4, M. Ramdhane3, V. Rauch2, O. Tengblad1, 3, G. Walter2, Ch. Miehé2 and the ISOLDE Collaboration3
1 Instituto de Estructura de la Materia, CSIC, Serrano 113bis, E-28006 Madrid, Spain
2 Institut de Recherches Subatomiques, UMR 7500 CNRS-IN2P3 et Université Louis Pasteur, 23 rue du Loess, B.P. 28, F-67037 Strasbourg Cedex 2, France
3 ISOLDE, Division EP, CERN CH-1211 Geneva, Switzerland
4 Institut de Physique Nucléaire, Université Claude Bernard-Lyon I, F-69622 Villeurbanne Cedex, France
borge@pinar2.csic.es
(Received: 7 February 2002 / Revised version: 14 October 2002 / Published online: 6 March 2003)
Abstract
The beta-decay of the
N=Z, even-even nucleus
has been studied
at the ISOLDE PSB facility at CERN.
Measurements of
and
coincidences have enriched the decay scheme of the daughter
nucleus
with 27 new low spin levels.
A more precise half-life of
T1/2=17.1(2) s has been determined.
Strong feeding to the
ground state is established yielding
an unambiguous
= 1
+ assignment for this state.
Candidates for the
g.s. wave function are discussed in the
framework of a self-consistent deformed mean-field calculation with SG2 Skyrme
force and pairing correlations. A search for
beta-delayed particle emission was made and an upper limit
of 10
-6 for this decay branch obtained.
The cumulated experimental level density
of 1
+
states has been fitted with the constant temperature formula.
The comparison indicates that most likely all 1
+ levels up to 1.2 MeV
have been
observed in this investigation.
The corresponding nearest-neighbour
level spacing
does not follow a Poisson distribution.
The Gamow-Teller
strength distribution is compared, in terms of nuclear
deformation, with different calculations
made in the framework
of the quasiparticle random phase approximation.
21.10.Hw - Spin, parity, and isobaric spin.
23.20.Lv - Gamma transitions and level energies.
23.40.Hc - Relation with nuclear matrix elements and nuclear structure.
27.50.+e -

© Società Italiana di Fisica, Springer-Verlag 2003