Beta-delayed proton and gamma decay of 58Zn and comparison

Beta-delayed proton and gamma decay of 58Zn and
comparison with 58Ni(3He,t)58Cu reaction*
A. Jokinen
CERN/AB-division, CH-1211 GENEVA 23, Switzerland
Department of Physics, FIN-40014 UNIVERSITY OF JYVÄSKYLÄ, Finland
Helsinki Institute of Physics, FIN-00014 UNIVERSITY OF HELSINKI, Finland
Assuming the isospin is a good quantum number one expects symmetry between
transitions from T=1, Tz=±1 nuclei to the common excited states in the Tz=0 nucleus
between them. Such a symmetry test can be performed by comparing the strengths of
Gamow-Teller (GT) transitions obtained from (p,n)-type charge-exchange reactions
with those obtained from the beta decay. Mass A=58 provides an ideal case, since
Ni(3He,t)58Cu charge exchange reaction performed in Osaka [1] provides a high
resolution data, which can be compared to the beta decay of 58Zn.
The beta decay of 58Zn was observed for the first time at ISOLDE [2] and the decay
was revisited in 2002 with an improved experimental set-up by applying laser
ionisation and high-resolution mass separation to reduce the unwanted isobaric
contaminants. These studies involved a high efficiency beta-gamma spectroscopy as
well as dedicated search for proton decay from higher lying excited states in 58Cu. The
latter part of the experiment applied Si-ball array to be discussed in another
contribution to this conference [3]. In this contribution, we will describe the physics
case and review the first results.
Y. Fujita et al., Eur. Phys. J. A 13 (2002) 411
A. Jokinen et al., Eur. Phys. J. A 3 (1998) 271
L. Fraile, this conference.
This work has been supported by the Academy of Finland